freebsd-nq/module/zfs/dnode.c

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2008-11-20 20:01:55 +00:00
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2017 by Delphix. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
2008-11-20 20:01:55 +00:00
*/
#include <sys/zfs_context.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_dataset.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/dmu_zfetch.h>
#include <sys/range_tree.h>
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 02:07:39 +00:00
#include <sys/trace_dnode.h>
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
#include <sys/zfs_project.h>
2008-11-20 20:01:55 +00:00
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_stats_t dnode_stats = {
{ "dnode_hold_dbuf_hold", KSTAT_DATA_UINT64 },
{ "dnode_hold_dbuf_read", KSTAT_DATA_UINT64 },
{ "dnode_hold_alloc_hits", KSTAT_DATA_UINT64 },
{ "dnode_hold_alloc_misses", KSTAT_DATA_UINT64 },
{ "dnode_hold_alloc_interior", KSTAT_DATA_UINT64 },
{ "dnode_hold_alloc_lock_retry", KSTAT_DATA_UINT64 },
{ "dnode_hold_alloc_lock_misses", KSTAT_DATA_UINT64 },
{ "dnode_hold_alloc_type_none", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_hits", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_misses", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_lock_misses", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_lock_retry", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_overflow", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_refcount", KSTAT_DATA_UINT64 },
{ "dnode_hold_free_txg", KSTAT_DATA_UINT64 },
{ "dnode_free_interior_lock_retry", KSTAT_DATA_UINT64 },
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
{ "dnode_allocate", KSTAT_DATA_UINT64 },
{ "dnode_reallocate", KSTAT_DATA_UINT64 },
{ "dnode_buf_evict", KSTAT_DATA_UINT64 },
{ "dnode_alloc_next_chunk", KSTAT_DATA_UINT64 },
{ "dnode_alloc_race", KSTAT_DATA_UINT64 },
{ "dnode_alloc_next_block", KSTAT_DATA_UINT64 },
{ "dnode_move_invalid", KSTAT_DATA_UINT64 },
{ "dnode_move_recheck1", KSTAT_DATA_UINT64 },
{ "dnode_move_recheck2", KSTAT_DATA_UINT64 },
{ "dnode_move_special", KSTAT_DATA_UINT64 },
{ "dnode_move_handle", KSTAT_DATA_UINT64 },
{ "dnode_move_rwlock", KSTAT_DATA_UINT64 },
{ "dnode_move_active", KSTAT_DATA_UINT64 },
};
static kstat_t *dnode_ksp;
2008-11-20 20:01:55 +00:00
static kmem_cache_t *dnode_cache;
ASSERTV(static dnode_phys_t dnode_phys_zero);
2008-11-20 20:01:55 +00:00
int zfs_default_bs = SPA_MINBLOCKSHIFT;
int zfs_default_ibs = DN_MAX_INDBLKSHIFT;
#ifdef _KERNEL
static kmem_cbrc_t dnode_move(void *, void *, size_t, void *);
#endif /* _KERNEL */
static int
dbuf_compare(const void *x1, const void *x2)
{
const dmu_buf_impl_t *d1 = x1;
const dmu_buf_impl_t *d2 = x2;
Performance optimization of AVL tree comparator functions perf: 2.75x faster ddt_entry_compare() First 256bits of ddt_key_t is a block checksum, which are expected to be close to random data. Hence, on average, comparison only needs to look at first few bytes of the keys. To reduce number of conditional jump instructions, the result is computed as: sign(memcmp(k1, k2)). Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} , which is computed efficiently. Synthetic performance evaluation of original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R) CPU E5-2660 v3: old 6.85789 s new 2.49089 s perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare() Compute the result directly instead of using conditionals perf: zfs_range_compare() Speedup between 1.1x - 2.5x, depending on compiler version and optimization level. perf: spa_error_entry_compare() `bcmp()` is not suitable for comparator use. Use `memcmp()` instead. perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare() perf: 2.8x faster zil_bp_compare() perf: 2.8x faster mze_compare() perf: faster dbuf_compare() perf: faster compares in spa_misc perf: 2.8x faster layout_hash_compare() perf: 2.8x faster space_reftree_compare() perf: libzfs: faster avl tree comparators perf: guid_compare() perf: dsl_deadlist_compare() perf: perm_set_compare() perf: 2x faster range_tree_seg_compare() perf: faster unique_compare() perf: faster vdev_cache _compare() perf: faster vdev_uberblock_compare() perf: faster fuid _compare() perf: faster zfs_znode_hold_compare() Signed-off-by: Gvozden Neskovic <neskovic@gmail.com> Signed-off-by: Richard Elling <richard.elling@gmail.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #5033
2016-08-27 18:12:53 +00:00
int cmp = AVL_CMP(d1->db_level, d2->db_level);
if (likely(cmp))
return (cmp);
Performance optimization of AVL tree comparator functions perf: 2.75x faster ddt_entry_compare() First 256bits of ddt_key_t is a block checksum, which are expected to be close to random data. Hence, on average, comparison only needs to look at first few bytes of the keys. To reduce number of conditional jump instructions, the result is computed as: sign(memcmp(k1, k2)). Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} , which is computed efficiently. Synthetic performance evaluation of original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R) CPU E5-2660 v3: old 6.85789 s new 2.49089 s perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare() Compute the result directly instead of using conditionals perf: zfs_range_compare() Speedup between 1.1x - 2.5x, depending on compiler version and optimization level. perf: spa_error_entry_compare() `bcmp()` is not suitable for comparator use. Use `memcmp()` instead. perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare() perf: 2.8x faster zil_bp_compare() perf: 2.8x faster mze_compare() perf: faster dbuf_compare() perf: faster compares in spa_misc perf: 2.8x faster layout_hash_compare() perf: 2.8x faster space_reftree_compare() perf: libzfs: faster avl tree comparators perf: guid_compare() perf: dsl_deadlist_compare() perf: perm_set_compare() perf: 2x faster range_tree_seg_compare() perf: faster unique_compare() perf: faster vdev_cache _compare() perf: faster vdev_uberblock_compare() perf: faster fuid _compare() perf: faster zfs_znode_hold_compare() Signed-off-by: Gvozden Neskovic <neskovic@gmail.com> Signed-off-by: Richard Elling <richard.elling@gmail.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #5033
2016-08-27 18:12:53 +00:00
cmp = AVL_CMP(d1->db_blkid, d2->db_blkid);
if (likely(cmp))
return (cmp);
if (d1->db_state == DB_SEARCH) {
ASSERT3S(d2->db_state, !=, DB_SEARCH);
return (-1);
} else if (d2->db_state == DB_SEARCH) {
ASSERT3S(d1->db_state, !=, DB_SEARCH);
return (1);
}
Performance optimization of AVL tree comparator functions perf: 2.75x faster ddt_entry_compare() First 256bits of ddt_key_t is a block checksum, which are expected to be close to random data. Hence, on average, comparison only needs to look at first few bytes of the keys. To reduce number of conditional jump instructions, the result is computed as: sign(memcmp(k1, k2)). Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} , which is computed efficiently. Synthetic performance evaluation of original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R) CPU E5-2660 v3: old 6.85789 s new 2.49089 s perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare() Compute the result directly instead of using conditionals perf: zfs_range_compare() Speedup between 1.1x - 2.5x, depending on compiler version and optimization level. perf: spa_error_entry_compare() `bcmp()` is not suitable for comparator use. Use `memcmp()` instead. perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare() perf: 2.8x faster zil_bp_compare() perf: 2.8x faster mze_compare() perf: faster dbuf_compare() perf: faster compares in spa_misc perf: 2.8x faster layout_hash_compare() perf: 2.8x faster space_reftree_compare() perf: libzfs: faster avl tree comparators perf: guid_compare() perf: dsl_deadlist_compare() perf: perm_set_compare() perf: 2x faster range_tree_seg_compare() perf: faster unique_compare() perf: faster vdev_cache _compare() perf: faster vdev_uberblock_compare() perf: faster fuid _compare() perf: faster zfs_znode_hold_compare() Signed-off-by: Gvozden Neskovic <neskovic@gmail.com> Signed-off-by: Richard Elling <richard.elling@gmail.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #5033
2016-08-27 18:12:53 +00:00
return (AVL_PCMP(d1, d2));
}
2008-11-20 20:01:55 +00:00
/* ARGSUSED */
static int
dnode_cons(void *arg, void *unused, int kmflag)
{
dnode_t *dn = arg;
int i;
2008-11-20 20:01:55 +00:00
Identify locks flagged by lockdep When running a kernel with CONFIG_LOCKDEP=y, lockdep reports possible recursive locking in some cases and possible circular locking dependency in others, within the SPL and ZFS modules. This patch uses a mutex type defined in SPL, MUTEX_NOLOCKDEP, to mark such mutexes when they are initialized. This mutex type causes attempts to take or release those locks to be wrapped in lockdep_off() and lockdep_on() calls to silence the dependency checker and allow the use of lock_stats to examine contention. For RW locks, it uses an analogous lock type, RW_NOLOCKDEP. The goal is that these locks are ultimately changed back to type MUTEX_DEFAULT or RW_DEFAULT, after the locks are annotated to reflect their relationship (e.g. z_name_lock below) or any real problem with the lock dependencies are fixed. Some of the affected locks are: tc_open_lock: ============= This is an array of locks, all with same name, which txg_quiesce must take all of in order to move txg to next state. All default to the same lockdep class, and so to lockdep appears recursive. zp->z_name_lock: ================ In zfs_rmdir, dzp = znode for the directory (input to zfs_dirent_lock) zp = znode for the entry being removed (output of zfs_dirent_lock) zfs_rmdir()->zfs_dirent_lock() takes z_name_lock in dzp zfs_rmdir() takes z_name_lock in zp Since both dzp and zp are type znode_t, the locks have the same default class, and lockdep considers it a possible recursive lock attempt. l->l_rwlock: ============ zap_expand_leaf() sometimes creates two new zap leaf structures, via these call paths: zap_deref_leaf()->zap_get_leaf_byblk()->zap_leaf_open() zap_expand_leaf()->zap_create_leaf()->zap_expand_leaf()->zap_create_leaf() Because both zap_leaf_open() and zap_create_leaf() initialize l->l_rwlock in their (separate) leaf structures, the lockdep class is the same, and the linux kernel believes these might both be the same lock, and emits a possible recursive lock warning. Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3895
2015-10-15 20:08:27 +00:00
rw_init(&dn->dn_struct_rwlock, NULL, RW_NOLOCKDEP, NULL);
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mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL);
2009-01-15 21:59:39 +00:00
cv_init(&dn->dn_notxholds, NULL, CV_DEFAULT, NULL);
/*
* Every dbuf has a reference, and dropping a tracked reference is
* O(number of references), so don't track dn_holds.
*/
refcount_create_untracked(&dn->dn_holds);
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refcount_create(&dn->dn_tx_holds);
list_link_init(&dn->dn_link);
bzero(&dn->dn_next_nblkptr[0], sizeof (dn->dn_next_nblkptr));
bzero(&dn->dn_next_nlevels[0], sizeof (dn->dn_next_nlevels));
bzero(&dn->dn_next_indblkshift[0], sizeof (dn->dn_next_indblkshift));
bzero(&dn->dn_next_bonustype[0], sizeof (dn->dn_next_bonustype));
bzero(&dn->dn_rm_spillblk[0], sizeof (dn->dn_rm_spillblk));
bzero(&dn->dn_next_bonuslen[0], sizeof (dn->dn_next_bonuslen));
bzero(&dn->dn_next_blksz[0], sizeof (dn->dn_next_blksz));
Encryption Stability and On-Disk Format Fixes The on-disk format for encrypted datasets protects not only the encrypted and authenticated blocks themselves, but also the order and interpretation of these blocks. In order to make this work while maintaining the ability to do raw sends, the indirect bps maintain a secure checksum of all the MACs in the block below it along with a few other fields that determine how the data is interpreted. Unfortunately, the current on-disk format erroneously includes some fields which are not portable and thus cannot support raw sends. It is not possible to easily work around this issue due to a separate and much smaller bug which causes indirect blocks for encrypted dnodes to not be compressed, which conflicts with the previous bug. In addition, the current code generates incompatible on-disk formats on big endian and little endian systems due to an issue with how block pointers are authenticated. Finally, raw send streams do not currently include dn_maxblkid when sending both the metadnode and normal dnodes which are needed in order to ensure that we are correctly maintaining the portable objset MAC. This patch zero's out the offending fields when computing the bp MAC and ensures that these MACs are always calculated in little endian order (regardless of the host system's byte order). This patch also registers an errata for the old on-disk format, which we detect by adding a "version" field to newly created DSL Crypto Keys. We allow datasets without a version (version 0) to only be mounted for read so that they can easily be migrated. We also now include dn_maxblkid in raw send streams to ensure the MAC can be maintained correctly. This patch also contains minor bug fixes and cleanups. Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #6845 Closes #6864 Closes #7052
2017-11-08 19:12:59 +00:00
bzero(&dn->dn_next_maxblkid[0], sizeof (dn->dn_next_maxblkid));
2008-11-20 20:01:55 +00:00
for (i = 0; i < TXG_SIZE; i++) {
list_link_init(&dn->dn_dirty_link[i]);
dn->dn_free_ranges[i] = NULL;
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list_create(&dn->dn_dirty_records[i],
sizeof (dbuf_dirty_record_t),
offsetof(dbuf_dirty_record_t, dr_dirty_node));
}
dn->dn_allocated_txg = 0;
dn->dn_free_txg = 0;
dn->dn_assigned_txg = 0;
dn->dn_dirtyctx = 0;
dn->dn_dirtyctx_firstset = NULL;
dn->dn_bonus = NULL;
dn->dn_have_spill = B_FALSE;
dn->dn_zio = NULL;
dn->dn_oldused = 0;
dn->dn_oldflags = 0;
dn->dn_olduid = 0;
dn->dn_oldgid = 0;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
dn->dn_oldprojid = ZFS_DEFAULT_PROJID;
dn->dn_newuid = 0;
dn->dn_newgid = 0;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
dn->dn_newprojid = ZFS_DEFAULT_PROJID;
dn->dn_id_flags = 0;
dn->dn_dbufs_count = 0;
avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
2008-11-20 20:01:55 +00:00
offsetof(dmu_buf_impl_t, db_link));
dn->dn_moved = 0;
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return (0);
}
/* ARGSUSED */
static void
dnode_dest(void *arg, void *unused)
{
int i;
dnode_t *dn = arg;
rw_destroy(&dn->dn_struct_rwlock);
mutex_destroy(&dn->dn_mtx);
mutex_destroy(&dn->dn_dbufs_mtx);
2009-01-15 21:59:39 +00:00
cv_destroy(&dn->dn_notxholds);
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refcount_destroy(&dn->dn_holds);
refcount_destroy(&dn->dn_tx_holds);
ASSERT(!list_link_active(&dn->dn_link));
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for (i = 0; i < TXG_SIZE; i++) {
ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
ASSERT3P(dn->dn_free_ranges[i], ==, NULL);
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list_destroy(&dn->dn_dirty_records[i]);
ASSERT0(dn->dn_next_nblkptr[i]);
ASSERT0(dn->dn_next_nlevels[i]);
ASSERT0(dn->dn_next_indblkshift[i]);
ASSERT0(dn->dn_next_bonustype[i]);
ASSERT0(dn->dn_rm_spillblk[i]);
ASSERT0(dn->dn_next_bonuslen[i]);
ASSERT0(dn->dn_next_blksz[i]);
Encryption Stability and On-Disk Format Fixes The on-disk format for encrypted datasets protects not only the encrypted and authenticated blocks themselves, but also the order and interpretation of these blocks. In order to make this work while maintaining the ability to do raw sends, the indirect bps maintain a secure checksum of all the MACs in the block below it along with a few other fields that determine how the data is interpreted. Unfortunately, the current on-disk format erroneously includes some fields which are not portable and thus cannot support raw sends. It is not possible to easily work around this issue due to a separate and much smaller bug which causes indirect blocks for encrypted dnodes to not be compressed, which conflicts with the previous bug. In addition, the current code generates incompatible on-disk formats on big endian and little endian systems due to an issue with how block pointers are authenticated. Finally, raw send streams do not currently include dn_maxblkid when sending both the metadnode and normal dnodes which are needed in order to ensure that we are correctly maintaining the portable objset MAC. This patch zero's out the offending fields when computing the bp MAC and ensures that these MACs are always calculated in little endian order (regardless of the host system's byte order). This patch also registers an errata for the old on-disk format, which we detect by adding a "version" field to newly created DSL Crypto Keys. We allow datasets without a version (version 0) to only be mounted for read so that they can easily be migrated. We also now include dn_maxblkid in raw send streams to ensure the MAC can be maintained correctly. This patch also contains minor bug fixes and cleanups. Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #6845 Closes #6864 Closes #7052
2017-11-08 19:12:59 +00:00
ASSERT0(dn->dn_next_maxblkid[i]);
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}
ASSERT0(dn->dn_allocated_txg);
ASSERT0(dn->dn_free_txg);
ASSERT0(dn->dn_assigned_txg);
ASSERT0(dn->dn_dirtyctx);
ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL);
ASSERT3P(dn->dn_bonus, ==, NULL);
ASSERT(!dn->dn_have_spill);
ASSERT3P(dn->dn_zio, ==, NULL);
ASSERT0(dn->dn_oldused);
ASSERT0(dn->dn_oldflags);
ASSERT0(dn->dn_olduid);
ASSERT0(dn->dn_oldgid);
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
ASSERT0(dn->dn_oldprojid);
ASSERT0(dn->dn_newuid);
ASSERT0(dn->dn_newgid);
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
ASSERT0(dn->dn_newprojid);
ASSERT0(dn->dn_id_flags);
ASSERT0(dn->dn_dbufs_count);
avl_destroy(&dn->dn_dbufs);
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}
void
dnode_init(void)
{
ASSERT(dnode_cache == NULL);
Improve meta data performance Profiling the system during meta data intensive workloads such as creating/removing millions of files, revealed that the system was cpu bound. A large fraction of that cpu time was being spent waiting on the virtual address space spin lock. It turns out this was caused by certain heavily used kmem_caches being backed by virtual memory. By default a kmem_cache will dynamically determine the type of memory used based on the object size. For large objects virtual memory is usually preferable and for small object physical memory is a better choice. See the spl_slab_alloc() function for a longer discussion on this. However, there is a certain amount of gray area when defining a 'large' object. For the following caches it turns out they were just over the line: * dnode_cache * zio_cache * zio_link_cache * zio_buf_512_cache * zfs_data_buf_512_cache Now because we know there will be a lot of churn in these caches, and because we know the slabs will still be reasonably sized. We can safely request with the KMC_KMEM flag that the caches be backed with physical memory addresses. This entirely avoids the need to serialize on the virtual address space lock. As a bonus this also reduces our vmalloc usage which will be good for 32-bit kernels which have a very small virtual address space. It will also probably be good for interactive performance since unrelated processes could also block of this same global lock. Finally, we may see less cpu time being burned in the arc_reclaim and txg_sync_threads. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #258
2011-11-01 23:56:48 +00:00
dnode_cache = kmem_cache_create("dnode_t", sizeof (dnode_t),
0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0);
kmem_cache_set_move(dnode_cache, dnode_move);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_ksp = kstat_create("zfs", 0, "dnodestats", "misc",
KSTAT_TYPE_NAMED, sizeof (dnode_stats) / sizeof (kstat_named_t),
KSTAT_FLAG_VIRTUAL);
if (dnode_ksp != NULL) {
dnode_ksp->ks_data = &dnode_stats;
kstat_install(dnode_ksp);
}
2008-11-20 20:01:55 +00:00
}
void
dnode_fini(void)
{
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
if (dnode_ksp != NULL) {
kstat_delete(dnode_ksp);
dnode_ksp = NULL;
}
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kmem_cache_destroy(dnode_cache);
dnode_cache = NULL;
2008-11-20 20:01:55 +00:00
}
#ifdef ZFS_DEBUG
void
dnode_verify(dnode_t *dn)
{
int drop_struct_lock = FALSE;
ASSERT(dn->dn_phys);
ASSERT(dn->dn_objset);
ASSERT(dn->dn_handle->dnh_dnode == dn);
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ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
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if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY))
return;
if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
rw_enter(&dn->dn_struct_rwlock, RW_READER);
drop_struct_lock = TRUE;
}
if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) {
int i;
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots);
2008-11-20 20:01:55 +00:00
ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT);
if (dn->dn_datablkshift) {
ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT);
ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT);
ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz);
}
ASSERT3U(dn->dn_nlevels, <=, 30);
ASSERT(DMU_OT_IS_VALID(dn->dn_type));
2008-11-20 20:01:55 +00:00
ASSERT3U(dn->dn_nblkptr, >=, 1);
ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT3U(dn->dn_bonuslen, <=, max_bonuslen);
2008-11-20 20:01:55 +00:00
ASSERT3U(dn->dn_datablksz, ==,
dn->dn_datablkszsec << SPA_MINBLOCKSHIFT);
ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0);
ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) +
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dn->dn_bonuslen, <=, max_bonuslen);
2008-11-20 20:01:55 +00:00
for (i = 0; i < TXG_SIZE; i++) {
ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels);
}
}
if (dn->dn_phys->dn_type != DMU_OT_NONE)
ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels);
2009-07-02 22:44:48 +00:00
ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL);
2008-11-20 20:01:55 +00:00
if (dn->dn_dbuf != NULL) {
ASSERT3P(dn->dn_phys, ==,
(dnode_phys_t *)dn->dn_dbuf->db.db_data +
(dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT)));
}
if (drop_struct_lock)
rw_exit(&dn->dn_struct_rwlock);
}
#endif
void
dnode_byteswap(dnode_phys_t *dnp)
{
uint64_t *buf64 = (void*)&dnp->dn_blkptr;
int i;
if (dnp->dn_type == DMU_OT_NONE) {
bzero(dnp, sizeof (dnode_phys_t));
return;
}
dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec);
dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dnp->dn_extra_slots = BSWAP_8(dnp->dn_extra_slots);
2008-11-20 20:01:55 +00:00
dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid);
dnp->dn_used = BSWAP_64(dnp->dn_used);
/*
* dn_nblkptr is only one byte, so it's OK to read it in either
* byte order. We can't read dn_bouslen.
*/
ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT);
ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR);
for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++)
buf64[i] = BSWAP_64(buf64[i]);
/*
* OK to check dn_bonuslen for zero, because it won't matter if
* we have the wrong byte order. This is necessary because the
* dnode dnode is smaller than a regular dnode.
*/
if (dnp->dn_bonuslen != 0) {
/*
* Note that the bonus length calculated here may be
* longer than the actual bonus buffer. This is because
* we always put the bonus buffer after the last block
* pointer (instead of packing it against the end of the
* dnode buffer).
*/
int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
int slots = dnp->dn_extra_slots + 1;
size_t len = DN_SLOTS_TO_BONUSLEN(slots) - off;
dmu_object_byteswap_t byteswap;
ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype));
byteswap = DMU_OT_BYTESWAP(dnp->dn_bonustype);
dmu_ot_byteswap[byteswap].ob_func(dnp->dn_bonus + off, len);
2008-11-20 20:01:55 +00:00
}
/* Swap SPILL block if we have one */
if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
byteswap_uint64_array(DN_SPILL_BLKPTR(dnp), sizeof (blkptr_t));
2008-11-20 20:01:55 +00:00
}
void
dnode_buf_byteswap(void *vbuf, size_t size)
{
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
int i = 0;
2008-11-20 20:01:55 +00:00
ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT));
ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
while (i < size) {
dnode_phys_t *dnp = (void *)(((char *)vbuf) + i);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dnode_byteswap(dnp);
i += DNODE_MIN_SIZE;
if (dnp->dn_type != DMU_OT_NONE)
i += dnp->dn_extra_slots * DNODE_MIN_SIZE;
2008-11-20 20:01:55 +00:00
}
}
void
dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx)
{
ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
dnode_setdirty(dn, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT3U(newsize, <=, DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) -
2008-11-20 20:01:55 +00:00
(dn->dn_nblkptr-1) * sizeof (blkptr_t));
dn->dn_bonuslen = newsize;
if (newsize == 0)
dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN;
else
dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
rw_exit(&dn->dn_struct_rwlock);
}
void
dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx)
{
ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
dnode_setdirty(dn, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
dn->dn_bonustype = newtype;
dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype;
rw_exit(&dn->dn_struct_rwlock);
}
void
dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx)
{
ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
dnode_setdirty(dn, tx);
dn->dn_rm_spillblk[tx->tx_txg&TXG_MASK] = DN_KILL_SPILLBLK;
dn->dn_have_spill = B_FALSE;
}
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static void
dnode_setdblksz(dnode_t *dn, int size)
{
ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE));
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ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
ASSERT3U(size, >=, SPA_MINBLOCKSIZE);
ASSERT3U(size >> SPA_MINBLOCKSHIFT, <,
1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8));
dn->dn_datablksz = size;
dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT;
dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0;
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}
static dnode_t *
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db,
uint64_t object, dnode_handle_t *dnh)
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{
dnode_t *dn;
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dn = kmem_cache_alloc(dnode_cache, KM_SLEEP);
ASSERT(!POINTER_IS_VALID(dn->dn_objset));
dn->dn_moved = 0;
/*
* Defer setting dn_objset until the dnode is ready to be a candidate
* for the dnode_move() callback.
*/
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dn->dn_object = object;
dn->dn_dbuf = db;
dn->dn_handle = dnh;
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dn->dn_phys = dnp;
if (dnp->dn_datablkszsec) {
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dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
} else {
dn->dn_datablksz = 0;
dn->dn_datablkszsec = 0;
dn->dn_datablkshift = 0;
}
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dn->dn_indblkshift = dnp->dn_indblkshift;
dn->dn_nlevels = dnp->dn_nlevels;
dn->dn_type = dnp->dn_type;
dn->dn_nblkptr = dnp->dn_nblkptr;
dn->dn_checksum = dnp->dn_checksum;
dn->dn_compress = dnp->dn_compress;
dn->dn_bonustype = dnp->dn_bonustype;
dn->dn_bonuslen = dnp->dn_bonuslen;
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dn->dn_num_slots = dnp->dn_extra_slots + 1;
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dn->dn_maxblkid = dnp->dn_maxblkid;
dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0);
dn->dn_id_flags = 0;
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dmu_zfetch_init(&dn->dn_zfetch, dn);
ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
ASSERT(zrl_is_locked(&dnh->dnh_zrlock));
ASSERT(!DN_SLOT_IS_PTR(dnh->dnh_dnode));
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mutex_enter(&os->os_lock);
/*
* Exclude special dnodes from os_dnodes so an empty os_dnodes
* signifies that the special dnodes have no references from
* their children (the entries in os_dnodes). This allows
* dnode_destroy() to easily determine if the last child has
* been removed and then complete eviction of the objset.
*/
if (!DMU_OBJECT_IS_SPECIAL(object))
list_insert_head(&os->os_dnodes, dn);
membar_producer();
/*
* Everything else must be valid before assigning dn_objset
* makes the dnode eligible for dnode_move().
*/
dn->dn_objset = os;
dnh->dnh_dnode = dn;
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mutex_exit(&os->os_lock);
Limit the amount of dnode metadata in the ARC Metadata-intensive workloads can cause the ARC to become permanently filled with dnode_t objects as they're pinned by the VFS layer. Subsequent data-intensive workloads may only benefit from about 25% of the potential ARC (arc_c_max - arc_meta_limit). In order to help track metadata usage more precisely, the other_size metadata arcstat has replaced with dbuf_size, dnode_size and bonus_size. The new zfs_arc_dnode_limit tunable, which defaults to 10% of zfs_arc_meta_limit, defines the minimum number of bytes which is desirable to be consumed by dnodes. Attempts to evict non-metadata will trigger async prune tasks if the space used by dnodes exceeds this limit. The new zfs_arc_dnode_reduce_percent tunable specifies the amount by which the excess dnode space is attempted to be pruned as a percentage of the amount by which zfs_arc_dnode_limit is being exceeded. By default, it tries to unpin 10% of the dnodes. The problem of dnode metadata pinning was observed with the following testing procedure (in this example, zfs_arc_max is set to 4GiB): - Create a large number of small files until arc_meta_used exceeds arc_meta_limit (3GiB with default tuning) and arc_prune starts increasing. - Create a 3GiB file with dd. Observe arc_mata_used. It will still be around 3GiB. - Repeatedly read the 3GiB file and observe arc_meta_limit as before. It will continue to stay around 3GiB. With this modification, space for the 3GiB file is gradually made available as subsequent demands on the ARC are made. The previous behavior can be restored by setting zfs_arc_dnode_limit to the same value as the zfs_arc_meta_limit. Signed-off-by: Tim Chase <tim@chase2k.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #4345 Issue #4512 Issue #4773 Closes #4858
2016-07-13 12:42:40 +00:00
arc_space_consume(sizeof (dnode_t), ARC_SPACE_DNODE);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
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return (dn);
}
/*
* Caller must be holding the dnode handle, which is released upon return.
*/
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static void
dnode_destroy(dnode_t *dn)
{
objset_t *os = dn->dn_objset;
boolean_t complete_os_eviction = B_FALSE;
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ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0);
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mutex_enter(&os->os_lock);
POINTER_INVALIDATE(&dn->dn_objset);
if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
list_remove(&os->os_dnodes, dn);
complete_os_eviction =
list_is_empty(&os->os_dnodes) &&
list_link_active(&os->os_evicting_node);
}
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mutex_exit(&os->os_lock);
/* the dnode can no longer move, so we can release the handle */
if (!zrl_is_locked(&dn->dn_handle->dnh_zrlock))
zrl_remove(&dn->dn_handle->dnh_zrlock);
dn->dn_allocated_txg = 0;
dn->dn_free_txg = 0;
dn->dn_assigned_txg = 0;
dn->dn_dirtyctx = 0;
if (dn->dn_dirtyctx_firstset != NULL) {
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kmem_free(dn->dn_dirtyctx_firstset, 1);
dn->dn_dirtyctx_firstset = NULL;
}
if (dn->dn_bonus != NULL) {
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mutex_enter(&dn->dn_bonus->db_mtx);
OpenZFS 6950 - ARC should cache compressed data Authored by: George Wilson <george.wilson@delphix.com> Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: Paul Dagnelie <pcd@delphix.com> Reviewed by: Tom Caputi <tcaputi@datto.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Ported by: David Quigley <david.quigley@intel.com> This review covers the reading and writing of compressed arc headers, sharing data between the arc_hdr_t and the arc_buf_t, and the implementation of a new dbuf cache to keep frequently access data uncompressed. I've added a new member to l1 arc hdr called b_pdata. The b_pdata always hangs off the arc_buf_hdr_t (if an L1 hdr is in use) and points to the physical block for that DVA. The physical block may or may not be compressed. If compressed arc is enabled and the block on-disk is compressed, then the b_pdata will match the block on-disk and remain compressed in memory. If the block on disk is not compressed, then neither will the b_pdata. Lastly, if compressed arc is disabled, then b_pdata will always be an uncompressed version of the on-disk block. Typically the arc will cache only the arc_buf_hdr_t and will aggressively evict any arc_buf_t's that are no longer referenced. This means that the arc will primarily have compressed blocks as the arc_buf_t's are considered overhead and are always uncompressed. When a consumer reads a block we first look to see if the arc_buf_hdr_t is cached. If the hdr is cached then we allocate a new arc_buf_t and decompress the b_pdata contents into the arc_buf_t's b_data. If the hdr already has a arc_buf_t, then we will allocate an additional arc_buf_t and bcopy the uncompressed contents from the first arc_buf_t to the new one. Writing to the compressed arc requires that we first discard the b_pdata since the physical block is about to be rewritten. The new data contents will be passed in via an arc_buf_t (uncompressed) and during the I/O pipeline stages we will copy the physical block contents to a newly allocated b_pdata. When an l2arc is inuse it will also take advantage of the b_pdata. Now the l2arc will always write the contents of b_pdata to the l2arc. This means that when compressed arc is enabled that the l2arc blocks are identical to those stored in the main data pool. This provides a significant advantage since we can leverage the bp's checksum when reading from the l2arc to determine if the contents are valid. If the compressed arc is disabled, then we must first transform the read block to look like the physical block in the main data pool before comparing the checksum and determining it's valid. OpenZFS-issue: https://www.illumos.org/issues/6950 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7fc10f0 Issue #5078
2016-06-02 04:04:53 +00:00
dbuf_destroy(dn->dn_bonus);
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dn->dn_bonus = NULL;
}
dn->dn_zio = NULL;
dn->dn_have_spill = B_FALSE;
dn->dn_oldused = 0;
dn->dn_oldflags = 0;
dn->dn_olduid = 0;
dn->dn_oldgid = 0;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
dn->dn_oldprojid = ZFS_DEFAULT_PROJID;
dn->dn_newuid = 0;
dn->dn_newgid = 0;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
dn->dn_newprojid = ZFS_DEFAULT_PROJID;
dn->dn_id_flags = 0;
dmu_zfetch_fini(&dn->dn_zfetch);
2008-11-20 20:01:55 +00:00
kmem_cache_free(dnode_cache, dn);
Limit the amount of dnode metadata in the ARC Metadata-intensive workloads can cause the ARC to become permanently filled with dnode_t objects as they're pinned by the VFS layer. Subsequent data-intensive workloads may only benefit from about 25% of the potential ARC (arc_c_max - arc_meta_limit). In order to help track metadata usage more precisely, the other_size metadata arcstat has replaced with dbuf_size, dnode_size and bonus_size. The new zfs_arc_dnode_limit tunable, which defaults to 10% of zfs_arc_meta_limit, defines the minimum number of bytes which is desirable to be consumed by dnodes. Attempts to evict non-metadata will trigger async prune tasks if the space used by dnodes exceeds this limit. The new zfs_arc_dnode_reduce_percent tunable specifies the amount by which the excess dnode space is attempted to be pruned as a percentage of the amount by which zfs_arc_dnode_limit is being exceeded. By default, it tries to unpin 10% of the dnodes. The problem of dnode metadata pinning was observed with the following testing procedure (in this example, zfs_arc_max is set to 4GiB): - Create a large number of small files until arc_meta_used exceeds arc_meta_limit (3GiB with default tuning) and arc_prune starts increasing. - Create a 3GiB file with dd. Observe arc_mata_used. It will still be around 3GiB. - Repeatedly read the 3GiB file and observe arc_meta_limit as before. It will continue to stay around 3GiB. With this modification, space for the 3GiB file is gradually made available as subsequent demands on the ARC are made. The previous behavior can be restored by setting zfs_arc_dnode_limit to the same value as the zfs_arc_meta_limit. Signed-off-by: Tim Chase <tim@chase2k.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #4345 Issue #4512 Issue #4773 Closes #4858
2016-07-13 12:42:40 +00:00
arc_space_return(sizeof (dnode_t), ARC_SPACE_DNODE);
if (complete_os_eviction)
dmu_objset_evict_done(os);
2008-11-20 20:01:55 +00:00
}
void
dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx)
2008-11-20 20:01:55 +00:00
{
int i;
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT3U(dn_slots, >, 0);
ASSERT3U(dn_slots << DNODE_SHIFT, <=,
spa_maxdnodesize(dmu_objset_spa(dn->dn_objset)));
Illumos 5027 - zfs large block support 5027 zfs large block support Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com> Reviewed by: Richard Elling <richard.elling@richardelling.com> Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@omniti.com> References: https://www.illumos.org/issues/5027 https://github.com/illumos/illumos-gate/commit/b515258 Porting Notes: * Included in this patch is a tiny ISP2() cleanup in zio_init() from Illumos 5255. * Unlike the upstream Illumos commit this patch does not impose an arbitrary 128K block size limit on volumes. Volumes, like filesystems, are limited by the zfs_max_recordsize=1M module option. * By default the maximum record size is limited to 1M by the module option zfs_max_recordsize. This value may be safely increased up to 16M which is the largest block size supported by the on-disk format. At the moment, 1M blocks clearly offer a significant performance improvement but the benefits of going beyond this for the majority of workloads are less clear. * The illumos version of this patch increased DMU_MAX_ACCESS to 32M. This was determined not to be large enough when using 16M blocks because the zfs_make_xattrdir() function will fail (EFBIG) when assigning a TX. This was immediately observed under Linux because all newly created files must have a security xattr created and that was failing. Therefore, we've set DMU_MAX_ACCESS to 64M. * On 32-bit platforms a hard limit of 1M is set for blocks due to the limited virtual address space. We should be able to relax this one the ABD patches are merged. Ported-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #354
2014-11-03 20:15:08 +00:00
ASSERT3U(blocksize, <=,
spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
2008-11-20 20:01:55 +00:00
if (blocksize == 0)
blocksize = 1 << zfs_default_bs;
else
blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE);
if (ibs == 0)
ibs = zfs_default_ibs;
ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d dn_slots=%d\n",
dn->dn_objset, dn->dn_object, tx->tx_txg, blocksize, ibs, dn_slots);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_allocate);
2008-11-20 20:01:55 +00:00
ASSERT(dn->dn_type == DMU_OT_NONE);
ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0);
ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE);
ASSERT(ot != DMU_OT_NONE);
ASSERT(DMU_OT_IS_VALID(ot));
2008-11-20 20:01:55 +00:00
ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
(bonustype == DMU_OT_SA && bonuslen == 0) ||
2008-11-20 20:01:55 +00:00
(bonustype != DMU_OT_NONE && bonuslen != 0));
ASSERT(DMU_OT_IS_VALID(bonustype));
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT3U(bonuslen, <=, DN_SLOTS_TO_BONUSLEN(dn_slots));
2008-11-20 20:01:55 +00:00
ASSERT(dn->dn_type == DMU_OT_NONE);
ASSERT0(dn->dn_maxblkid);
ASSERT0(dn->dn_allocated_txg);
ASSERT0(dn->dn_assigned_txg);
2008-11-20 20:01:55 +00:00
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
ASSERT3U(refcount_count(&dn->dn_holds), <=, 1);
ASSERT(avl_is_empty(&dn->dn_dbufs));
2008-11-20 20:01:55 +00:00
for (i = 0; i < TXG_SIZE; i++) {
ASSERT0(dn->dn_next_nblkptr[i]);
ASSERT0(dn->dn_next_nlevels[i]);
ASSERT0(dn->dn_next_indblkshift[i]);
ASSERT0(dn->dn_next_bonuslen[i]);
ASSERT0(dn->dn_next_bonustype[i]);
ASSERT0(dn->dn_rm_spillblk[i]);
ASSERT0(dn->dn_next_blksz[i]);
Encryption Stability and On-Disk Format Fixes The on-disk format for encrypted datasets protects not only the encrypted and authenticated blocks themselves, but also the order and interpretation of these blocks. In order to make this work while maintaining the ability to do raw sends, the indirect bps maintain a secure checksum of all the MACs in the block below it along with a few other fields that determine how the data is interpreted. Unfortunately, the current on-disk format erroneously includes some fields which are not portable and thus cannot support raw sends. It is not possible to easily work around this issue due to a separate and much smaller bug which causes indirect blocks for encrypted dnodes to not be compressed, which conflicts with the previous bug. In addition, the current code generates incompatible on-disk formats on big endian and little endian systems due to an issue with how block pointers are authenticated. Finally, raw send streams do not currently include dn_maxblkid when sending both the metadnode and normal dnodes which are needed in order to ensure that we are correctly maintaining the portable objset MAC. This patch zero's out the offending fields when computing the bp MAC and ensures that these MACs are always calculated in little endian order (regardless of the host system's byte order). This patch also registers an errata for the old on-disk format, which we detect by adding a "version" field to newly created DSL Crypto Keys. We allow datasets without a version (version 0) to only be mounted for read so that they can easily be migrated. We also now include dn_maxblkid in raw send streams to ensure the MAC can be maintained correctly. This patch also contains minor bug fixes and cleanups. Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #6845 Closes #6864 Closes #7052
2017-11-08 19:12:59 +00:00
ASSERT0(dn->dn_next_maxblkid[i]);
2008-11-20 20:01:55 +00:00
ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL);
ASSERT3P(dn->dn_free_ranges[i], ==, NULL);
2008-11-20 20:01:55 +00:00
}
dn->dn_type = ot;
dnode_setdblksz(dn, blocksize);
dn->dn_indblkshift = ibs;
dn->dn_nlevels = 1;
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dn->dn_num_slots = dn_slots;
if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
dn->dn_nblkptr = 1;
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
else {
dn->dn_nblkptr = MIN(DN_MAX_NBLKPTR,
1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >>
SPA_BLKPTRSHIFT));
}
2008-11-20 20:01:55 +00:00
dn->dn_bonustype = bonustype;
dn->dn_bonuslen = bonuslen;
dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
dn->dn_compress = ZIO_COMPRESS_INHERIT;
dn->dn_dirtyctx = 0;
dn->dn_free_txg = 0;
if (dn->dn_dirtyctx_firstset) {
kmem_free(dn->dn_dirtyctx_firstset, 1);
dn->dn_dirtyctx_firstset = NULL;
}
dn->dn_allocated_txg = tx->tx_txg;
dn->dn_id_flags = 0;
2008-11-20 20:01:55 +00:00
dnode_setdirty(dn, tx);
dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs;
dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype;
2008-11-20 20:01:55 +00:00
dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz;
}
void
dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx)
2008-11-20 20:01:55 +00:00
{
2009-07-02 22:44:48 +00:00
int nblkptr;
2008-11-20 20:01:55 +00:00
ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
Illumos 5027 - zfs large block support 5027 zfs large block support Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com> Reviewed by: Richard Elling <richard.elling@richardelling.com> Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@omniti.com> References: https://www.illumos.org/issues/5027 https://github.com/illumos/illumos-gate/commit/b515258 Porting Notes: * Included in this patch is a tiny ISP2() cleanup in zio_init() from Illumos 5255. * Unlike the upstream Illumos commit this patch does not impose an arbitrary 128K block size limit on volumes. Volumes, like filesystems, are limited by the zfs_max_recordsize=1M module option. * By default the maximum record size is limited to 1M by the module option zfs_max_recordsize. This value may be safely increased up to 16M which is the largest block size supported by the on-disk format. At the moment, 1M blocks clearly offer a significant performance improvement but the benefits of going beyond this for the majority of workloads are less clear. * The illumos version of this patch increased DMU_MAX_ACCESS to 32M. This was determined not to be large enough when using 16M blocks because the zfs_make_xattrdir() function will fail (EFBIG) when assigning a TX. This was immediately observed under Linux because all newly created files must have a security xattr created and that was failing. Therefore, we've set DMU_MAX_ACCESS to 64M. * On 32-bit platforms a hard limit of 1M is set for blocks due to the limited virtual address space. We should be able to relax this one the ABD patches are merged. Ported-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #354
2014-11-03 20:15:08 +00:00
ASSERT3U(blocksize, <=,
spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
ASSERT0(blocksize % SPA_MINBLOCKSIZE);
2008-11-20 20:01:55 +00:00
ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx));
ASSERT(tx->tx_txg != 0);
ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
(bonustype != DMU_OT_NONE && bonuslen != 0) ||
(bonustype == DMU_OT_SA && bonuslen == 0));
ASSERT(DMU_OT_IS_VALID(bonustype));
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT3U(bonuslen, <=,
DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))));
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dn_slots = dn_slots > 0 ? dn_slots : DNODE_MIN_SLOTS;
dnode_free_interior_slots(dn);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_reallocate);
2008-11-20 20:01:55 +00:00
/* clean up any unreferenced dbufs */
dnode_evict_dbufs(dn);
2009-02-18 20:51:31 +00:00
dn->dn_id_flags = 0;
2008-11-20 20:01:55 +00:00
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
dnode_setdirty(dn, tx);
2009-07-02 22:44:48 +00:00
if (dn->dn_datablksz != blocksize) {
/* change blocksize */
ASSERT(dn->dn_maxblkid == 0 &&
(BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) ||
dnode_block_freed(dn, 0)));
dnode_setdblksz(dn, blocksize);
dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
}
if (dn->dn_bonuslen != bonuslen)
dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
nblkptr = 1;
else
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
nblkptr = MIN(DN_MAX_NBLKPTR,
1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >>
SPA_BLKPTRSHIFT));
if (dn->dn_bonustype != bonustype)
dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype;
2009-02-18 20:51:31 +00:00
if (dn->dn_nblkptr != nblkptr)
dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr;
if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
dbuf_rm_spill(dn, tx);
dnode_rm_spill(dn, tx);
}
2008-11-20 20:01:55 +00:00
rw_exit(&dn->dn_struct_rwlock);
/* change type */
dn->dn_type = ot;
/* change bonus size and type */
mutex_enter(&dn->dn_mtx);
dn->dn_bonustype = bonustype;
dn->dn_bonuslen = bonuslen;
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dn->dn_num_slots = dn_slots;
2009-02-18 20:51:31 +00:00
dn->dn_nblkptr = nblkptr;
2008-11-20 20:01:55 +00:00
dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
dn->dn_compress = ZIO_COMPRESS_INHERIT;
ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
2009-02-18 20:51:31 +00:00
/* fix up the bonus db_size */
if (dn->dn_bonus) {
2008-11-20 20:01:55 +00:00
dn->dn_bonus->db.db_size =
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) -
(dn->dn_nblkptr-1) * sizeof (blkptr_t);
2008-11-20 20:01:55 +00:00
ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size);
}
dn->dn_allocated_txg = tx->tx_txg;
mutex_exit(&dn->dn_mtx);
}
#ifdef _KERNEL
static void
dnode_move_impl(dnode_t *odn, dnode_t *ndn)
{
int i;
ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock));
ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx));
ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx));
ASSERT(!RW_LOCK_HELD(&odn->dn_zfetch.zf_rwlock));
/* Copy fields. */
ndn->dn_objset = odn->dn_objset;
ndn->dn_object = odn->dn_object;
ndn->dn_dbuf = odn->dn_dbuf;
ndn->dn_handle = odn->dn_handle;
ndn->dn_phys = odn->dn_phys;
ndn->dn_type = odn->dn_type;
ndn->dn_bonuslen = odn->dn_bonuslen;
ndn->dn_bonustype = odn->dn_bonustype;
ndn->dn_nblkptr = odn->dn_nblkptr;
ndn->dn_checksum = odn->dn_checksum;
ndn->dn_compress = odn->dn_compress;
ndn->dn_nlevels = odn->dn_nlevels;
ndn->dn_indblkshift = odn->dn_indblkshift;
ndn->dn_datablkshift = odn->dn_datablkshift;
ndn->dn_datablkszsec = odn->dn_datablkszsec;
ndn->dn_datablksz = odn->dn_datablksz;
ndn->dn_maxblkid = odn->dn_maxblkid;
ndn->dn_num_slots = odn->dn_num_slots;
bcopy(&odn->dn_next_nblkptr[0], &ndn->dn_next_nblkptr[0],
sizeof (odn->dn_next_nblkptr));
bcopy(&odn->dn_next_nlevels[0], &ndn->dn_next_nlevels[0],
sizeof (odn->dn_next_nlevels));
bcopy(&odn->dn_next_indblkshift[0], &ndn->dn_next_indblkshift[0],
sizeof (odn->dn_next_indblkshift));
bcopy(&odn->dn_next_bonustype[0], &ndn->dn_next_bonustype[0],
sizeof (odn->dn_next_bonustype));
bcopy(&odn->dn_rm_spillblk[0], &ndn->dn_rm_spillblk[0],
sizeof (odn->dn_rm_spillblk));
bcopy(&odn->dn_next_bonuslen[0], &ndn->dn_next_bonuslen[0],
sizeof (odn->dn_next_bonuslen));
bcopy(&odn->dn_next_blksz[0], &ndn->dn_next_blksz[0],
sizeof (odn->dn_next_blksz));
Encryption Stability and On-Disk Format Fixes The on-disk format for encrypted datasets protects not only the encrypted and authenticated blocks themselves, but also the order and interpretation of these blocks. In order to make this work while maintaining the ability to do raw sends, the indirect bps maintain a secure checksum of all the MACs in the block below it along with a few other fields that determine how the data is interpreted. Unfortunately, the current on-disk format erroneously includes some fields which are not portable and thus cannot support raw sends. It is not possible to easily work around this issue due to a separate and much smaller bug which causes indirect blocks for encrypted dnodes to not be compressed, which conflicts with the previous bug. In addition, the current code generates incompatible on-disk formats on big endian and little endian systems due to an issue with how block pointers are authenticated. Finally, raw send streams do not currently include dn_maxblkid when sending both the metadnode and normal dnodes which are needed in order to ensure that we are correctly maintaining the portable objset MAC. This patch zero's out the offending fields when computing the bp MAC and ensures that these MACs are always calculated in little endian order (regardless of the host system's byte order). This patch also registers an errata for the old on-disk format, which we detect by adding a "version" field to newly created DSL Crypto Keys. We allow datasets without a version (version 0) to only be mounted for read so that they can easily be migrated. We also now include dn_maxblkid in raw send streams to ensure the MAC can be maintained correctly. This patch also contains minor bug fixes and cleanups. Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #6845 Closes #6864 Closes #7052
2017-11-08 19:12:59 +00:00
bcopy(&odn->dn_next_maxblkid[0], &ndn->dn_next_maxblkid[0],
sizeof (odn->dn_next_maxblkid));
for (i = 0; i < TXG_SIZE; i++) {
list_move_tail(&ndn->dn_dirty_records[i],
&odn->dn_dirty_records[i]);
}
bcopy(&odn->dn_free_ranges[0], &ndn->dn_free_ranges[0],
sizeof (odn->dn_free_ranges));
ndn->dn_allocated_txg = odn->dn_allocated_txg;
ndn->dn_free_txg = odn->dn_free_txg;
ndn->dn_assigned_txg = odn->dn_assigned_txg;
ndn->dn_dirtyctx = odn->dn_dirtyctx;
ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset;
ASSERT(refcount_count(&odn->dn_tx_holds) == 0);
refcount_transfer(&ndn->dn_holds, &odn->dn_holds);
ASSERT(avl_is_empty(&ndn->dn_dbufs));
avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs);
ndn->dn_dbufs_count = odn->dn_dbufs_count;
ndn->dn_bonus = odn->dn_bonus;
ndn->dn_have_spill = odn->dn_have_spill;
ndn->dn_zio = odn->dn_zio;
ndn->dn_oldused = odn->dn_oldused;
ndn->dn_oldflags = odn->dn_oldflags;
ndn->dn_olduid = odn->dn_olduid;
ndn->dn_oldgid = odn->dn_oldgid;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
ndn->dn_oldprojid = odn->dn_oldprojid;
ndn->dn_newuid = odn->dn_newuid;
ndn->dn_newgid = odn->dn_newgid;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
ndn->dn_newprojid = odn->dn_newprojid;
ndn->dn_id_flags = odn->dn_id_flags;
dmu_zfetch_init(&ndn->dn_zfetch, NULL);
list_move_tail(&ndn->dn_zfetch.zf_stream, &odn->dn_zfetch.zf_stream);
ndn->dn_zfetch.zf_dnode = odn->dn_zfetch.zf_dnode;
/*
* Update back pointers. Updating the handle fixes the back pointer of
* every descendant dbuf as well as the bonus dbuf.
*/
ASSERT(ndn->dn_handle->dnh_dnode == odn);
ndn->dn_handle->dnh_dnode = ndn;
if (ndn->dn_zfetch.zf_dnode == odn) {
ndn->dn_zfetch.zf_dnode = ndn;
}
/*
* Invalidate the original dnode by clearing all of its back pointers.
*/
odn->dn_dbuf = NULL;
odn->dn_handle = NULL;
avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
odn->dn_dbufs_count = 0;
odn->dn_bonus = NULL;
odn->dn_zfetch.zf_dnode = NULL;
/*
* Set the low bit of the objset pointer to ensure that dnode_move()
* recognizes the dnode as invalid in any subsequent callback.
*/
POINTER_INVALIDATE(&odn->dn_objset);
/*
* Satisfy the destructor.
*/
for (i = 0; i < TXG_SIZE; i++) {
list_create(&odn->dn_dirty_records[i],
sizeof (dbuf_dirty_record_t),
offsetof(dbuf_dirty_record_t, dr_dirty_node));
odn->dn_free_ranges[i] = NULL;
odn->dn_next_nlevels[i] = 0;
odn->dn_next_indblkshift[i] = 0;
odn->dn_next_bonustype[i] = 0;
odn->dn_rm_spillblk[i] = 0;
odn->dn_next_bonuslen[i] = 0;
odn->dn_next_blksz[i] = 0;
}
odn->dn_allocated_txg = 0;
odn->dn_free_txg = 0;
odn->dn_assigned_txg = 0;
odn->dn_dirtyctx = 0;
odn->dn_dirtyctx_firstset = NULL;
odn->dn_have_spill = B_FALSE;
odn->dn_zio = NULL;
odn->dn_oldused = 0;
odn->dn_oldflags = 0;
odn->dn_olduid = 0;
odn->dn_oldgid = 0;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
odn->dn_oldprojid = ZFS_DEFAULT_PROJID;
odn->dn_newuid = 0;
odn->dn_newgid = 0;
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
odn->dn_newprojid = ZFS_DEFAULT_PROJID;
odn->dn_id_flags = 0;
/*
* Mark the dnode.
*/
ndn->dn_moved = 1;
odn->dn_moved = (uint8_t)-1;
}
/*ARGSUSED*/
static kmem_cbrc_t
dnode_move(void *buf, void *newbuf, size_t size, void *arg)
{
dnode_t *odn = buf, *ndn = newbuf;
objset_t *os;
int64_t refcount;
uint32_t dbufs;
/*
* The dnode is on the objset's list of known dnodes if the objset
* pointer is valid. We set the low bit of the objset pointer when
* freeing the dnode to invalidate it, and the memory patterns written
* by kmem (baddcafe and deadbeef) set at least one of the two low bits.
* A newly created dnode sets the objset pointer last of all to indicate
* that the dnode is known and in a valid state to be moved by this
* function.
*/
os = odn->dn_objset;
if (!POINTER_IS_VALID(os)) {
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_invalid);
return (KMEM_CBRC_DONT_KNOW);
}
/*
* Ensure that the objset does not go away during the move.
*/
rw_enter(&os_lock, RW_WRITER);
if (os != odn->dn_objset) {
rw_exit(&os_lock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_recheck1);
return (KMEM_CBRC_DONT_KNOW);
}
/*
* If the dnode is still valid, then so is the objset. We know that no
* valid objset can be freed while we hold os_lock, so we can safely
* ensure that the objset remains in use.
*/
mutex_enter(&os->os_lock);
/*
* Recheck the objset pointer in case the dnode was removed just before
* acquiring the lock.
*/
if (os != odn->dn_objset) {
mutex_exit(&os->os_lock);
rw_exit(&os_lock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_recheck2);
return (KMEM_CBRC_DONT_KNOW);
}
/*
* At this point we know that as long as we hold os->os_lock, the dnode
* cannot be freed and fields within the dnode can be safely accessed.
* The objset listing this dnode cannot go away as long as this dnode is
* on its list.
*/
rw_exit(&os_lock);
if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) {
mutex_exit(&os->os_lock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_special);
return (KMEM_CBRC_NO);
}
ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */
/*
* Lock the dnode handle to prevent the dnode from obtaining any new
* holds. This also prevents the descendant dbufs and the bonus dbuf
* from accessing the dnode, so that we can discount their holds. The
* handle is safe to access because we know that while the dnode cannot
* go away, neither can its handle. Once we hold dnh_zrlock, we can
* safely move any dnode referenced only by dbufs.
*/
if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) {
mutex_exit(&os->os_lock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_handle);
return (KMEM_CBRC_LATER);
}
/*
* Ensure a consistent view of the dnode's holds and the dnode's dbufs.
* We need to guarantee that there is a hold for every dbuf in order to
* determine whether the dnode is actively referenced. Falsely matching
* a dbuf to an active hold would lead to an unsafe move. It's possible
* that a thread already having an active dnode hold is about to add a
* dbuf, and we can't compare hold and dbuf counts while the add is in
* progress.
*/
if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) {
zrl_exit(&odn->dn_handle->dnh_zrlock);
mutex_exit(&os->os_lock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_rwlock);
return (KMEM_CBRC_LATER);
}
/*
* A dbuf may be removed (evicted) without an active dnode hold. In that
* case, the dbuf count is decremented under the handle lock before the
* dbuf's hold is released. This order ensures that if we count the hold
* after the dbuf is removed but before its hold is released, we will
* treat the unmatched hold as active and exit safely. If we count the
* hold before the dbuf is removed, the hold is discounted, and the
* removal is blocked until the move completes.
*/
refcount = refcount_count(&odn->dn_holds);
ASSERT(refcount >= 0);
dbufs = odn->dn_dbufs_count;
/* We can't have more dbufs than dnode holds. */
ASSERT3U(dbufs, <=, refcount);
DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount,
uint32_t, dbufs);
if (refcount > dbufs) {
rw_exit(&odn->dn_struct_rwlock);
zrl_exit(&odn->dn_handle->dnh_zrlock);
mutex_exit(&os->os_lock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_move_active);
return (KMEM_CBRC_LATER);
}
rw_exit(&odn->dn_struct_rwlock);
/*
* At this point we know that anyone with a hold on the dnode is not
* actively referencing it. The dnode is known and in a valid state to
* move. We're holding the locks needed to execute the critical section.
*/
dnode_move_impl(odn, ndn);
list_link_replace(&odn->dn_link, &ndn->dn_link);
/* If the dnode was safe to move, the refcount cannot have changed. */
ASSERT(refcount == refcount_count(&ndn->dn_holds));
ASSERT(dbufs == ndn->dn_dbufs_count);
zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */
mutex_exit(&os->os_lock);
return (KMEM_CBRC_YES);
}
#endif /* _KERNEL */
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
static void
dnode_slots_hold(dnode_children_t *children, int idx, int slots)
{
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
for (int i = idx; i < idx + slots; i++) {
dnode_handle_t *dnh = &children->dnc_children[i];
zrl_add(&dnh->dnh_zrlock);
}
}
static void
dnode_slots_rele(dnode_children_t *children, int idx, int slots)
{
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
for (int i = idx; i < idx + slots; i++) {
dnode_handle_t *dnh = &children->dnc_children[i];
if (zrl_is_locked(&dnh->dnh_zrlock))
zrl_exit(&dnh->dnh_zrlock);
else
zrl_remove(&dnh->dnh_zrlock);
}
}
static int
dnode_slots_tryenter(dnode_children_t *children, int idx, int slots)
{
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
for (int i = idx; i < idx + slots; i++) {
dnode_handle_t *dnh = &children->dnc_children[i];
if (!zrl_tryenter(&dnh->dnh_zrlock)) {
for (int j = idx; j < i; j++) {
dnh = &children->dnc_children[j];
zrl_exit(&dnh->dnh_zrlock);
}
return (0);
}
}
return (1);
}
static void
dnode_set_slots(dnode_children_t *children, int idx, int slots, void *ptr)
{
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
for (int i = idx; i < idx + slots; i++) {
dnode_handle_t *dnh = &children->dnc_children[i];
dnh->dnh_dnode = ptr;
}
}
static boolean_t
dnode_check_slots_free(dnode_children_t *children, int idx, int slots)
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
{
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
for (int i = idx; i < idx + slots; i++) {
dnode_handle_t *dnh = &children->dnc_children[i];
dnode_t *dn = dnh->dnh_dnode;
if (dn == DN_SLOT_FREE) {
continue;
} else if (DN_SLOT_IS_PTR(dn)) {
mutex_enter(&dn->dn_mtx);
dmu_object_type_t type = dn->dn_type;
mutex_exit(&dn->dn_mtx);
if (type != DMU_OT_NONE)
return (B_FALSE);
continue;
} else {
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
return (B_FALSE);
}
return (B_FALSE);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
}
return (B_TRUE);
}
static void
dnode_reclaim_slots(dnode_children_t *children, int idx, int slots)
{
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
for (int i = idx; i < idx + slots; i++) {
dnode_handle_t *dnh = &children->dnc_children[i];
ASSERT(zrl_is_locked(&dnh->dnh_zrlock));
if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) {
ASSERT3S(dnh->dnh_dnode->dn_type, ==, DMU_OT_NONE);
dnode_destroy(dnh->dnh_dnode);
dnh->dnh_dnode = DN_SLOT_FREE;
}
}
}
void
dnode_free_interior_slots(dnode_t *dn)
{
dnode_children_t *children = dmu_buf_get_user(&dn->dn_dbuf->db);
int epb = dn->dn_dbuf->db.db_size >> DNODE_SHIFT;
int idx = (dn->dn_object & (epb - 1)) + 1;
int slots = dn->dn_num_slots - 1;
if (slots == 0)
return;
ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK);
while (!dnode_slots_tryenter(children, idx, slots))
DNODE_STAT_BUMP(dnode_free_interior_lock_retry);
dnode_set_slots(children, idx, slots, DN_SLOT_FREE);
dnode_slots_rele(children, idx, slots);
}
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void
dnode_special_close(dnode_handle_t *dnh)
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{
dnode_t *dn = dnh->dnh_dnode;
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/*
* Wait for final references to the dnode to clear. This can
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
* only happen if the arc is asynchronously evicting state that
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* has a hold on this dnode while we are trying to evict this
* dnode.
*/
while (refcount_count(&dn->dn_holds) > 0)
delay(1);
ASSERT(dn->dn_dbuf == NULL ||
dmu_buf_get_user(&dn->dn_dbuf->db) == NULL);
zrl_add(&dnh->dnh_zrlock);
dnode_destroy(dn); /* implicit zrl_remove() */
zrl_destroy(&dnh->dnh_zrlock);
dnh->dnh_dnode = NULL;
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}
void
dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object,
dnode_handle_t *dnh)
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{
dnode_t *dn;
zrl_init(&dnh->dnh_zrlock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
zrl_tryenter(&dnh->dnh_zrlock);
dn = dnode_create(os, dnp, NULL, object, dnh);
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DNODE_VERIFY(dn);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
zrl_exit(&dnh->dnh_zrlock);
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}
static void
dnode_buf_evict_async(void *dbu)
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{
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_children_t *dnc = dbu;
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Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
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DNODE_STAT_BUMP(dnode_buf_evict);
for (int i = 0; i < dnc->dnc_count; i++) {
dnode_handle_t *dnh = &dnc->dnc_children[i];
dnode_t *dn;
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/*
* The dnode handle lock guards against the dnode moving to
* another valid address, so there is no need here to guard
* against changes to or from NULL.
*/
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
if (!DN_SLOT_IS_PTR(dnh->dnh_dnode)) {
zrl_destroy(&dnh->dnh_zrlock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnh->dnh_dnode = DN_SLOT_UNINIT;
2008-11-20 20:01:55 +00:00
continue;
}
zrl_add(&dnh->dnh_zrlock);
dn = dnh->dnh_dnode;
2008-11-20 20:01:55 +00:00
/*
* If there are holds on this dnode, then there should
* be holds on the dnode's containing dbuf as well; thus
* it wouldn't be eligible for eviction and this function
2008-11-20 20:01:55 +00:00
* would not have been called.
*/
ASSERT(refcount_is_zero(&dn->dn_holds));
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_destroy(dn); /* implicit zrl_remove() for first slot */
zrl_destroy(&dnh->dnh_zrlock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnh->dnh_dnode = DN_SLOT_UNINIT;
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
kmem_free(dnc, sizeof (dnode_children_t) +
dnc->dnc_count * sizeof (dnode_handle_t));
}
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/*
* When the DNODE_MUST_BE_FREE flag is set, the "slots" parameter is used
* to ensure the hole at the specified object offset is large enough to
* hold the dnode being created. The slots parameter is also used to ensure
* a dnode does not span multiple dnode blocks. In both of these cases, if
* a failure occurs, ENOSPC is returned. Keep in mind, these failure cases
* are only possible when using DNODE_MUST_BE_FREE.
*
* If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0.
* dnode_hold_impl() will check if the requested dnode is already consumed
* as an extra dnode slot by an large dnode, in which case it returns
* ENOENT.
*
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* errors:
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
* EINVAL - Invalid object number or flags.
* ENOSPC - Hole too small to fulfill "slots" request (DNODE_MUST_BE_FREE)
* EEXIST - Refers to an allocated dnode (DNODE_MUST_BE_FREE)
* - Refers to an interior dnode slot (DNODE_MUST_BE_ALLOCATED)
* ENOENT - The requested dnode is not allocated (DNODE_MUST_BE_ALLOCATED)
* EIO - I/O error when reading the meta dnode dbuf.
*
2008-11-20 20:01:55 +00:00
* succeeds even for free dnodes.
*/
int
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dnode_hold_impl(objset_t *os, uint64_t object, int flag, int slots,
2008-11-20 20:01:55 +00:00
void *tag, dnode_t **dnp)
{
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
int epb, idx, err;
2008-11-20 20:01:55 +00:00
int drop_struct_lock = FALSE;
int type;
uint64_t blk;
dnode_t *mdn, *dn;
dmu_buf_impl_t *db;
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_children_t *dnc;
dnode_phys_t *dn_block;
dnode_handle_t *dnh;
2008-11-20 20:01:55 +00:00
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT(!(flag & DNODE_MUST_BE_ALLOCATED) || (slots == 0));
ASSERT(!(flag & DNODE_MUST_BE_FREE) || (slots > 0));
/*
* If you are holding the spa config lock as writer, you shouldn't
* be asking the DMU to do *anything* unless it's the root pool
* which may require us to read from the root filesystem while
* holding some (not all) of the locks as writer.
*/
ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 ||
(spa_is_root(os->os_spa) &&
spa_config_held(os->os_spa, SCL_STATE, RW_WRITER)));
Project Quota on ZFS Project quota is a new ZFS system space/object usage accounting and enforcement mechanism. Similar as user/group quota, project quota is another dimension of system quota. It bases on the new object attribute - project ID. Project ID is a numerical value to indicate to which project an object belongs. An object only can belong to one project though you (the object owner or privileged user) can change the object project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly. The object also can inherit the project ID from its parent when created if the parent has the project inherit flag (that can be set via 'chattr +P' or 'zfs project -s [-p]'). By accounting the spaces/objects belong to the same project, we can know how many spaces/objects used by the project. And if we set the upper limit then we can control the spaces/objects that are consumed by such project. It is useful when multiple groups and users cooperate for the same project, or a user/group needs to participate in multiple projects. Support the following commands and functionalities: zfs set projectquota@project zfs set projectobjquota@project zfs get projectquota@project zfs get projectobjquota@project zfs get projectused@project zfs get projectobjused@project zfs projectspace zfs allow projectquota zfs allow projectobjquota zfs allow projectused zfs allow projectobjused zfs unallow projectquota zfs unallow projectobjquota zfs unallow projectused zfs unallow projectobjused chattr +/-P chattr -p project_id lsattr -p This patch also supports tree quota based on the project quota via "zfs project" commands set as following: zfs project [-d|-r] <file|directory ...> zfs project -C [-k] [-r] <file|directory ...> zfs project -c [-0] [-d|-r] [-p id] <file|directory ...> zfs project [-p id] [-r] [-s] <file|directory ...> For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on the $DIR, then the proejct [obj]quota and [obj]used values for the $DIR's project ID will be shown as the total/free (avail) resource. Keep the same behavior as EXT4/XFS does. Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by Ned Bass <bass6@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Fan Yong <fan.yong@intel.com> TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master" Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c Closes #6290
2018-02-13 22:54:54 +00:00
if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT ||
object == DMU_PROJECTUSED_OBJECT) {
if (object == DMU_USERUSED_OBJECT)
dn = DMU_USERUSED_DNODE(os);
else if (object == DMU_GROUPUSED_OBJECT)
dn = DMU_GROUPUSED_DNODE(os);
else
dn = DMU_PROJECTUSED_DNODE(os);
2009-07-02 22:44:48 +00:00
if (dn == NULL)
return (SET_ERROR(ENOENT));
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type = dn->dn_type;
if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE)
return (SET_ERROR(ENOENT));
2009-07-02 22:44:48 +00:00
if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)
return (SET_ERROR(EEXIST));
2009-07-02 22:44:48 +00:00
DNODE_VERIFY(dn);
(void) refcount_add(&dn->dn_holds, tag);
*dnp = dn;
return (0);
}
2008-11-20 20:01:55 +00:00
if (object == 0 || object >= DN_MAX_OBJECT)
return (SET_ERROR(EINVAL));
2008-11-20 20:01:55 +00:00
mdn = DMU_META_DNODE(os);
ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT);
2008-11-20 20:01:55 +00:00
DNODE_VERIFY(mdn);
if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) {
rw_enter(&mdn->dn_struct_rwlock, RW_READER);
drop_struct_lock = TRUE;
}
blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t));
2008-11-20 20:01:55 +00:00
db = dbuf_hold(mdn, blk, FTAG);
if (drop_struct_lock)
rw_exit(&mdn->dn_struct_rwlock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
if (db == NULL) {
DNODE_STAT_BUMP(dnode_hold_dbuf_hold);
return (SET_ERROR(EIO));
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
}
Native Encryption for ZFS on Linux This change incorporates three major pieces: The first change is a keystore that manages wrapping and encryption keys for encrypted datasets. These commands mostly involve manipulating the new DSL Crypto Key ZAP Objects that live in the MOS. Each encrypted dataset has its own DSL Crypto Key that is protected with a user's key. This level of indirection allows users to change their keys without re-encrypting their entire datasets. The change implements the new subcommands "zfs load-key", "zfs unload-key" and "zfs change-key" which allow the user to manage their encryption keys and settings. In addition, several new flags and properties have been added to allow dataset creation and to make mounting and unmounting more convenient. The second piece of this patch provides the ability to encrypt, decyrpt, and authenticate protected datasets. Each object set maintains a Merkel tree of Message Authentication Codes that protect the lower layers, similarly to how checksums are maintained. This part impacts the zio layer, which handles the actual encryption and generation of MACs, as well as the ARC and DMU, which need to be able to handle encrypted buffers and protected data. The last addition is the ability to do raw, encrypted sends and receives. The idea here is to send raw encrypted and compressed data and receive it exactly as is on a backup system. This means that the dataset on the receiving system is protected using the same user key that is in use on the sending side. By doing so, datasets can be efficiently backed up to an untrusted system without fear of data being compromised. Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #494 Closes #5769
2017-08-14 17:36:48 +00:00
/*
* We do not need to decrypt to read the dnode so it doesn't matter
* if we get the encrypted or decrypted version.
*/
err = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_NO_DECRYPT);
2008-11-20 20:01:55 +00:00
if (err) {
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_hold_dbuf_read);
2008-11-20 20:01:55 +00:00
dbuf_rele(db, FTAG);
return (err);
}
ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT);
epb = db->db.db_size >> DNODE_SHIFT;
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
idx = object & (epb - 1);
dn_block = (dnode_phys_t *)db->db.db_data;
ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnc = dmu_buf_get_user(&db->db);
dnh = NULL;
if (dnc == NULL) {
dnode_children_t *winner;
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
int skip = 0;
dnc = kmem_zalloc(sizeof (dnode_children_t) +
epb * sizeof (dnode_handle_t), KM_SLEEP);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnc->dnc_count = epb;
dnh = &dnc->dnc_children[0];
/* Initialize dnode slot status from dnode_phys_t */
for (int i = 0; i < epb; i++) {
zrl_init(&dnh[i].dnh_zrlock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
if (skip) {
skip--;
continue;
}
if (dn_block[i].dn_type != DMU_OT_NONE) {
int interior = dn_block[i].dn_extra_slots;
dnode_set_slots(dnc, i, 1, DN_SLOT_ALLOCATED);
dnode_set_slots(dnc, i + 1, interior,
DN_SLOT_INTERIOR);
skip = interior;
} else {
dnh[i].dnh_dnode = DN_SLOT_FREE;
skip = 0;
}
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dmu_buf_init_user(&dnc->dnc_dbu, NULL,
dnode_buf_evict_async, NULL);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
winner = dmu_buf_set_user(&db->db, &dnc->dnc_dbu);
if (winner != NULL) {
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
for (int i = 0; i < epb; i++)
zrl_destroy(&dnh[i].dnh_zrlock);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
kmem_free(dnc, sizeof (dnode_children_t) +
epb * sizeof (dnode_handle_t));
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnc = winner;
2008-11-20 20:01:55 +00:00
}
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
ASSERT(dnc->dnc_count == epb);
dn = DN_SLOT_UNINIT;
if (flag & DNODE_MUST_BE_ALLOCATED) {
slots = 1;
while (dn == DN_SLOT_UNINIT) {
dnode_slots_hold(dnc, idx, slots);
dnh = &dnc->dnc_children[idx];
if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) {
dn = dnh->dnh_dnode;
break;
} else if (dnh->dnh_dnode == DN_SLOT_INTERIOR) {
DNODE_STAT_BUMP(dnode_hold_alloc_interior);
dnode_slots_rele(dnc, idx, slots);
dbuf_rele(db, FTAG);
return (SET_ERROR(EEXIST));
} else if (dnh->dnh_dnode != DN_SLOT_ALLOCATED) {
DNODE_STAT_BUMP(dnode_hold_alloc_misses);
dnode_slots_rele(dnc, idx, slots);
dbuf_rele(db, FTAG);
return (SET_ERROR(ENOENT));
}
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_slots_rele(dnc, idx, slots);
if (!dnode_slots_tryenter(dnc, idx, slots)) {
DNODE_STAT_BUMP(dnode_hold_alloc_lock_retry);
continue;
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
/*
* Someone else won the race and called dnode_create()
* after we checked DN_SLOT_IS_PTR() above but before
* we acquired the lock.
*/
if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) {
DNODE_STAT_BUMP(dnode_hold_alloc_lock_misses);
dn = dnh->dnh_dnode;
} else {
dn = dnode_create(os, dn_block + idx, db,
object, dnh);
}
}
mutex_enter(&dn->dn_mtx);
if (dn->dn_type == DMU_OT_NONE) {
DNODE_STAT_BUMP(dnode_hold_alloc_type_none);
mutex_exit(&dn->dn_mtx);
dnode_slots_rele(dnc, idx, slots);
dbuf_rele(db, FTAG);
return (SET_ERROR(ENOENT));
}
DNODE_STAT_BUMP(dnode_hold_alloc_hits);
} else if (flag & DNODE_MUST_BE_FREE) {
if (idx + slots - 1 >= DNODES_PER_BLOCK) {
DNODE_STAT_BUMP(dnode_hold_free_overflow);
dbuf_rele(db, FTAG);
return (SET_ERROR(ENOSPC));
}
while (dn == DN_SLOT_UNINIT) {
dnode_slots_hold(dnc, idx, slots);
if (!dnode_check_slots_free(dnc, idx, slots)) {
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_hold_free_misses);
dnode_slots_rele(dnc, idx, slots);
dbuf_rele(db, FTAG);
return (SET_ERROR(ENOSPC));
}
dnode_slots_rele(dnc, idx, slots);
if (!dnode_slots_tryenter(dnc, idx, slots)) {
DNODE_STAT_BUMP(dnode_hold_free_lock_retry);
continue;
}
if (!dnode_check_slots_free(dnc, idx, slots)) {
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
DNODE_STAT_BUMP(dnode_hold_free_lock_misses);
dnode_slots_rele(dnc, idx, slots);
dbuf_rele(db, FTAG);
return (SET_ERROR(ENOSPC));
}
/*
* Allocated but otherwise free dnodes which would
* be in the interior of a multi-slot dnodes need
* to be freed. Single slot dnodes can be safely
* re-purposed as a performance optimization.
*/
if (slots > 1)
dnode_reclaim_slots(dnc, idx + 1, slots - 1);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnh = &dnc->dnc_children[idx];
if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) {
dn = dnh->dnh_dnode;
} else {
dn = dnode_create(os, dn_block + idx, db,
object, dnh);
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
}
mutex_enter(&dn->dn_mtx);
if (!refcount_is_zero(&dn->dn_holds)) {
DNODE_STAT_BUMP(dnode_hold_free_refcount);
mutex_exit(&dn->dn_mtx);
dnode_slots_rele(dnc, idx, slots);
dbuf_rele(db, FTAG);
return (SET_ERROR(EEXIST));
}
dnode_set_slots(dnc, idx + 1, slots - 1, DN_SLOT_INTERIOR);
DNODE_STAT_BUMP(dnode_hold_free_hits);
} else {
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
dbuf_rele(db, FTAG);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
return (SET_ERROR(EINVAL));
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
if (dn->dn_free_txg) {
DNODE_STAT_BUMP(dnode_hold_free_txg);
type = dn->dn_type;
2008-11-20 20:01:55 +00:00
mutex_exit(&dn->dn_mtx);
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_slots_rele(dnc, idx, slots);
2008-11-20 20:01:55 +00:00
dbuf_rele(db, FTAG);
return (SET_ERROR(type == DMU_OT_NONE ? ENOENT : EEXIST));
2008-11-20 20:01:55 +00:00
}
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
2008-11-20 20:01:55 +00:00
if (refcount_add(&dn->dn_holds, tag) == 1)
dbuf_add_ref(db, dnh);
mutex_exit(&dn->dn_mtx);
/* Now we can rely on the hold to prevent the dnode from moving. */
Improved dnode allocation and dmu_hold_impl() Refactor dmu_object_alloc_dnsize() and dnode_hold_impl() to simplify the code, fix errors introduced by commit dbeb879 (PR #6117) interacting badly with large dnodes, and improve performance. * When allocating a new dnode in dmu_object_alloc_dnsize(), update the percpu object ID for the core's metadnode chunk immediately. This eliminates most lock contention when taking the hold and creating the dnode. * Correct detection of the chunk boundary to work properly with large dnodes. * Separate the dmu_hold_impl() code for the FREE case from the code for the ALLOCATED case to make it easier to read. * Fully populate the dnode handle array immediately after reading a block of the metadnode from disk. Subsequently the dnode handle array provides enough information to determine which dnode slots are in use and which are free. * Add several kstats to allow the behavior of the code to be examined. * Verify dnode packing in large_dnode_008_pos.ksh. Since the test is purely creates, it should leave very few holes in the metadnode. * Add test large_dnode_009_pos.ksh, which performs concurrent creates and deletes, to complement existing test which does only creates. With the above fixes, there is very little contention in a test of about 200,000 racing dnode allocations produced by tests 'large_dnode_008_pos' and 'large_dnode_009_pos'. name type data dnode_hold_dbuf_hold 4 0 dnode_hold_dbuf_read 4 0 dnode_hold_alloc_hits 4 3804690 dnode_hold_alloc_misses 4 216 dnode_hold_alloc_interior 4 3 dnode_hold_alloc_lock_retry 4 0 dnode_hold_alloc_lock_misses 4 0 dnode_hold_alloc_type_none 4 0 dnode_hold_free_hits 4 203105 dnode_hold_free_misses 4 4 dnode_hold_free_lock_misses 4 0 dnode_hold_free_lock_retry 4 0 dnode_hold_free_overflow 4 0 dnode_hold_free_refcount 4 57 dnode_hold_free_txg 4 0 dnode_allocate 4 203154 dnode_reallocate 4 0 dnode_buf_evict 4 23918 dnode_alloc_next_chunk 4 4887 dnode_alloc_race 4 0 dnode_alloc_next_block 4 18 The performance is slightly improved for concurrent creates with 16+ threads, and unchanged for low thread counts. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Olaf Faaland <faaland1@llnl.gov> Closes #5396 Closes #6522 Closes #6414 Closes #6564
2017-09-05 23:15:04 +00:00
dnode_slots_rele(dnc, idx, slots);
2008-11-20 20:01:55 +00:00
DNODE_VERIFY(dn);
ASSERT3P(dn->dn_dbuf, ==, db);
ASSERT3U(dn->dn_object, ==, object);
dbuf_rele(db, FTAG);
*dnp = dn;
return (0);
}
/*
* Return held dnode if the object is allocated, NULL if not.
*/
int
dnode_hold(objset_t *os, uint64_t object, void *tag, dnode_t **dnp)
2008-11-20 20:01:55 +00:00
{
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0, tag,
dnp));
2008-11-20 20:01:55 +00:00
}
/*
* Can only add a reference if there is already at least one
* reference on the dnode. Returns FALSE if unable to add a
* new reference.
*/
boolean_t
dnode_add_ref(dnode_t *dn, void *tag)
{
mutex_enter(&dn->dn_mtx);
if (refcount_is_zero(&dn->dn_holds)) {
mutex_exit(&dn->dn_mtx);
return (FALSE);
}
VERIFY(1 < refcount_add(&dn->dn_holds, tag));
mutex_exit(&dn->dn_mtx);
return (TRUE);
}
void
dnode_rele(dnode_t *dn, void *tag)
{
mutex_enter(&dn->dn_mtx);
dnode_rele_and_unlock(dn, tag);
}
void
dnode_rele_and_unlock(dnode_t *dn, void *tag)
2008-11-20 20:01:55 +00:00
{
uint64_t refs;
/* Get while the hold prevents the dnode from moving. */
dmu_buf_impl_t *db = dn->dn_dbuf;
dnode_handle_t *dnh = dn->dn_handle;
2008-11-20 20:01:55 +00:00
refs = refcount_remove(&dn->dn_holds, tag);
mutex_exit(&dn->dn_mtx);
/*
* It's unsafe to release the last hold on a dnode by dnode_rele() or
* indirectly by dbuf_rele() while relying on the dnode handle to
* prevent the dnode from moving, since releasing the last hold could
* result in the dnode's parent dbuf evicting its dnode handles. For
* that reason anyone calling dnode_rele() or dbuf_rele() without some
* other direct or indirect hold on the dnode must first drop the dnode
* handle.
*/
ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread);
2008-11-20 20:01:55 +00:00
/* NOTE: the DNODE_DNODE does not have a dn_dbuf */
if (refs == 0 && db != NULL) {
/*
* Another thread could add a hold to the dnode handle in
* dnode_hold_impl() while holding the parent dbuf. Since the
* hold on the parent dbuf prevents the handle from being
* destroyed, the hold on the handle is OK. We can't yet assert
* that the handle has zero references, but that will be
* asserted anyway when the handle gets destroyed.
*/
dbuf_rele(db, dnh);
}
2008-11-20 20:01:55 +00:00
}
void
dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
{
objset_t *os = dn->dn_objset;
2008-11-20 20:01:55 +00:00
uint64_t txg = tx->tx_txg;
2009-07-02 22:44:48 +00:00
if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
dsl_dataset_dirty(os->os_dsl_dataset, tx);
2008-11-20 20:01:55 +00:00
return;
2009-07-02 22:44:48 +00:00
}
2008-11-20 20:01:55 +00:00
DNODE_VERIFY(dn);
#ifdef ZFS_DEBUG
mutex_enter(&dn->dn_mtx);
ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg);
ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg);
2008-11-20 20:01:55 +00:00
mutex_exit(&dn->dn_mtx);
#endif
/*
* Determine old uid/gid when necessary
*/
dmu_objset_userquota_get_ids(dn, B_TRUE, tx);
multilist_t *dirtylist = os->os_dirty_dnodes[txg & TXG_MASK];
multilist_sublist_t *mls = multilist_sublist_lock_obj(dirtylist, dn);
2008-11-20 20:01:55 +00:00
/*
* If we are already marked dirty, we're done.
*/
if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) {
multilist_sublist_unlock(mls);
2008-11-20 20:01:55 +00:00
return;
}
ASSERT(!refcount_is_zero(&dn->dn_holds) ||
!avl_is_empty(&dn->dn_dbufs));
2008-11-20 20:01:55 +00:00
ASSERT(dn->dn_datablksz != 0);
ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]);
ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]);
ASSERT0(dn->dn_next_bonustype[txg&TXG_MASK]);
2008-11-20 20:01:55 +00:00
dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n",
dn->dn_object, txg);
multilist_sublist_insert_head(mls, dn);
2008-11-20 20:01:55 +00:00
multilist_sublist_unlock(mls);
2008-11-20 20:01:55 +00:00
/*
* The dnode maintains a hold on its containing dbuf as
* long as there are holds on it. Each instantiated child
* dbuf maintains a hold on the dnode. When the last child
2008-11-20 20:01:55 +00:00
* drops its hold, the dnode will drop its hold on the
* containing dbuf. We add a "dirty hold" here so that the
* dnode will hang around after we finish processing its
* children.
*/
VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg));
(void) dbuf_dirty(dn->dn_dbuf, tx);
dsl_dataset_dirty(os->os_dsl_dataset, tx);
}
void
dnode_free(dnode_t *dn, dmu_tx_t *tx)
{
mutex_enter(&dn->dn_mtx);
if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) {
mutex_exit(&dn->dn_mtx);
return;
}
dn->dn_free_txg = tx->tx_txg;
mutex_exit(&dn->dn_mtx);
dnode_setdirty(dn, tx);
2008-11-20 20:01:55 +00:00
}
/*
* Try to change the block size for the indicated dnode. This can only
* succeed if there are no blocks allocated or dirty beyond first block
*/
int
dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
{
dmu_buf_impl_t *db;
int err;
2008-11-20 20:01:55 +00:00
Illumos 5027 - zfs large block support 5027 zfs large block support Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com> Reviewed by: Richard Elling <richard.elling@richardelling.com> Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@omniti.com> References: https://www.illumos.org/issues/5027 https://github.com/illumos/illumos-gate/commit/b515258 Porting Notes: * Included in this patch is a tiny ISP2() cleanup in zio_init() from Illumos 5255. * Unlike the upstream Illumos commit this patch does not impose an arbitrary 128K block size limit on volumes. Volumes, like filesystems, are limited by the zfs_max_recordsize=1M module option. * By default the maximum record size is limited to 1M by the module option zfs_max_recordsize. This value may be safely increased up to 16M which is the largest block size supported by the on-disk format. At the moment, 1M blocks clearly offer a significant performance improvement but the benefits of going beyond this for the majority of workloads are less clear. * The illumos version of this patch increased DMU_MAX_ACCESS to 32M. This was determined not to be large enough when using 16M blocks because the zfs_make_xattrdir() function will fail (EFBIG) when assigning a TX. This was immediately observed under Linux because all newly created files must have a security xattr created and that was failing. Therefore, we've set DMU_MAX_ACCESS to 64M. * On 32-bit platforms a hard limit of 1M is set for blocks due to the limited virtual address space. We should be able to relax this one the ABD patches are merged. Ported-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #354
2014-11-03 20:15:08 +00:00
ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
2008-11-20 20:01:55 +00:00
if (size == 0)
size = SPA_MINBLOCKSIZE;
else
size = P2ROUNDUP(size, SPA_MINBLOCKSIZE);
if (ibs == dn->dn_indblkshift)
ibs = 0;
if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0)
return (0);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
/* Check for any allocated blocks beyond the first */
Illumos #4101, #4102, #4103, #4105, #4106 4101 metaslab_debug should allow for fine-grained control 4102 space_maps should store more information about themselves 4103 space map object blocksize should be increased 4105 removing a mirrored log device results in a leaked object 4106 asynchronously load metaslab Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Adam Leventhal <ahl@delphix.com> Reviewed by: Sebastien Roy <seb@delphix.com> Approved by: Garrett D'Amore <garrett@damore.org> Prior to this patch, space_maps were preferred solely based on the amount of free space left in each. Unfortunately, this heuristic didn't contain any information about the make-up of that free space, which meant we could keep preferring and loading a highly fragmented space map that wouldn't actually have enough contiguous space to satisfy the allocation; then unloading that space_map and repeating the process. This change modifies the space_map's to store additional information about the contiguous space in the space_map, so that we can use this information to make a better decision about which space_map to load. This requires reallocating all space_map objects to increase their bonus buffer size sizes enough to fit the new metadata. The above feature can be enabled via a new feature flag introduced by this change: com.delphix:spacemap_histogram In addition to the above, this patch allows the space_map block size to be increase. Currently the block size is set to be 4K in size, which has certain implications including the following: * 4K sector devices will not see any compression benefit * large space_maps require more metadata on-disk * large space_maps require more time to load (typically random reads) Now the space_map block size can adjust as needed up to the maximum size set via the space_map_max_blksz variable. A bug was fixed which resulted in potentially leaking an object when removing a mirrored log device. The previous logic for vdev_remove() did not deal with removing top-level vdevs that are interior vdevs (i.e. mirror) correctly. The problem would occur when removing a mirrored log device, and result in the DTL space map object being leaked; because top-level vdevs don't have DTL space map objects associated with them. References: https://www.illumos.org/issues/4101 https://www.illumos.org/issues/4102 https://www.illumos.org/issues/4103 https://www.illumos.org/issues/4105 https://www.illumos.org/issues/4106 https://github.com/illumos/illumos-gate/commit/0713e23 Porting notes: A handful of kmem_alloc() calls were converted to kmem_zalloc(). Also, the KM_PUSHPAGE and TQ_PUSHPAGE flags were used as necessary. Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Prakash Surya <surya1@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #2488
2013-10-01 21:25:53 +00:00
if (dn->dn_maxblkid != 0)
2008-11-20 20:01:55 +00:00
goto fail;
mutex_enter(&dn->dn_dbufs_mtx);
for (db = avl_first(&dn->dn_dbufs); db != NULL;
db = AVL_NEXT(&dn->dn_dbufs, db)) {
if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID &&
db->db_blkid != DMU_SPILL_BLKID) {
2008-11-20 20:01:55 +00:00
mutex_exit(&dn->dn_dbufs_mtx);
goto fail;
}
}
mutex_exit(&dn->dn_dbufs_mtx);
if (ibs && dn->dn_nlevels != 1)
goto fail;
/* resize the old block */
err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, FTAG, &db);
if (err == 0)
2008-11-20 20:01:55 +00:00
dbuf_new_size(db, size, tx);
else if (err != ENOENT)
goto fail;
2008-11-20 20:01:55 +00:00
dnode_setdblksz(dn, size);
dnode_setdirty(dn, tx);
dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size;
if (ibs) {
dn->dn_indblkshift = ibs;
dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs;
}
/* rele after we have fixed the blocksize in the dnode */
2008-11-20 20:01:55 +00:00
if (db)
dbuf_rele(db, FTAG);
rw_exit(&dn->dn_struct_rwlock);
return (0);
fail:
rw_exit(&dn->dn_struct_rwlock);
return (SET_ERROR(ENOTSUP));
2008-11-20 20:01:55 +00:00
}
Native Encryption for ZFS on Linux This change incorporates three major pieces: The first change is a keystore that manages wrapping and encryption keys for encrypted datasets. These commands mostly involve manipulating the new DSL Crypto Key ZAP Objects that live in the MOS. Each encrypted dataset has its own DSL Crypto Key that is protected with a user's key. This level of indirection allows users to change their keys without re-encrypting their entire datasets. The change implements the new subcommands "zfs load-key", "zfs unload-key" and "zfs change-key" which allow the user to manage their encryption keys and settings. In addition, several new flags and properties have been added to allow dataset creation and to make mounting and unmounting more convenient. The second piece of this patch provides the ability to encrypt, decyrpt, and authenticate protected datasets. Each object set maintains a Merkel tree of Message Authentication Codes that protect the lower layers, similarly to how checksums are maintained. This part impacts the zio layer, which handles the actual encryption and generation of MACs, as well as the ARC and DMU, which need to be able to handle encrypted buffers and protected data. The last addition is the ability to do raw, encrypted sends and receives. The idea here is to send raw encrypted and compressed data and receive it exactly as is on a backup system. This means that the dataset on the receiving system is protected using the same user key that is in use on the sending side. By doing so, datasets can be efficiently backed up to an untrusted system without fear of data being compromised. Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #494 Closes #5769
2017-08-14 17:36:48 +00:00
static void
dnode_set_nlevels_impl(dnode_t *dn, int new_nlevels, dmu_tx_t *tx)
{
uint64_t txgoff = tx->tx_txg & TXG_MASK;
int old_nlevels = dn->dn_nlevels;
dmu_buf_impl_t *db;
list_t *list;
dbuf_dirty_record_t *new, *dr, *dr_next;
ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
dn->dn_nlevels = new_nlevels;
ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]);
dn->dn_next_nlevels[txgoff] = new_nlevels;
/* dirty the left indirects */
db = dbuf_hold_level(dn, old_nlevels, 0, FTAG);
ASSERT(db != NULL);
new = dbuf_dirty(db, tx);
dbuf_rele(db, FTAG);
/* transfer the dirty records to the new indirect */
mutex_enter(&dn->dn_mtx);
mutex_enter(&new->dt.di.dr_mtx);
list = &dn->dn_dirty_records[txgoff];
for (dr = list_head(list); dr; dr = dr_next) {
dr_next = list_next(&dn->dn_dirty_records[txgoff], dr);
if (dr->dr_dbuf->db_level != new_nlevels-1 &&
dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID &&
dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) {
ASSERT(dr->dr_dbuf->db_level == old_nlevels-1);
list_remove(&dn->dn_dirty_records[txgoff], dr);
list_insert_tail(&new->dt.di.dr_children, dr);
dr->dr_parent = new;
}
}
mutex_exit(&new->dt.di.dr_mtx);
mutex_exit(&dn->dn_mtx);
}
int
dnode_set_nlevels(dnode_t *dn, int nlevels, dmu_tx_t *tx)
{
int ret = 0;
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
if (dn->dn_nlevels == nlevels) {
ret = 0;
goto out;
} else if (nlevels < dn->dn_nlevels) {
ret = SET_ERROR(EINVAL);
goto out;
}
dnode_set_nlevels_impl(dn, nlevels, tx);
out:
rw_exit(&dn->dn_struct_rwlock);
return (ret);
}
/* read-holding callers must not rely on the lock being continuously held */
2008-11-20 20:01:55 +00:00
void
dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read)
2008-11-20 20:01:55 +00:00
{
int epbs, new_nlevels;
uint64_t sz;
ASSERT(blkid != DMU_BONUS_BLKID);
2008-11-20 20:01:55 +00:00
ASSERT(have_read ?
RW_READ_HELD(&dn->dn_struct_rwlock) :
RW_WRITE_HELD(&dn->dn_struct_rwlock));
/*
* if we have a read-lock, check to see if we need to do any work
* before upgrading to a write-lock.
*/
if (have_read) {
if (blkid <= dn->dn_maxblkid)
return;
if (!rw_tryupgrade(&dn->dn_struct_rwlock)) {
rw_exit(&dn->dn_struct_rwlock);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
}
2008-11-20 20:01:55 +00:00
}
if (blkid <= dn->dn_maxblkid)
goto out;
dn->dn_maxblkid = blkid;
Encryption Stability and On-Disk Format Fixes The on-disk format for encrypted datasets protects not only the encrypted and authenticated blocks themselves, but also the order and interpretation of these blocks. In order to make this work while maintaining the ability to do raw sends, the indirect bps maintain a secure checksum of all the MACs in the block below it along with a few other fields that determine how the data is interpreted. Unfortunately, the current on-disk format erroneously includes some fields which are not portable and thus cannot support raw sends. It is not possible to easily work around this issue due to a separate and much smaller bug which causes indirect blocks for encrypted dnodes to not be compressed, which conflicts with the previous bug. In addition, the current code generates incompatible on-disk formats on big endian and little endian systems due to an issue with how block pointers are authenticated. Finally, raw send streams do not currently include dn_maxblkid when sending both the metadnode and normal dnodes which are needed in order to ensure that we are correctly maintaining the portable objset MAC. This patch zero's out the offending fields when computing the bp MAC and ensures that these MACs are always calculated in little endian order (regardless of the host system's byte order). This patch also registers an errata for the old on-disk format, which we detect by adding a "version" field to newly created DSL Crypto Keys. We allow datasets without a version (version 0) to only be mounted for read so that they can easily be migrated. We also now include dn_maxblkid in raw send streams to ensure the MAC can be maintained correctly. This patch also contains minor bug fixes and cleanups. Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #6845 Closes #6864 Closes #7052
2017-11-08 19:12:59 +00:00
dn->dn_next_maxblkid[tx->tx_txg & TXG_MASK] = blkid;
2008-11-20 20:01:55 +00:00
/*
* Compute the number of levels necessary to support the new maxblkid.
*/
new_nlevels = 1;
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
for (sz = dn->dn_nblkptr;
sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs)
new_nlevels++;
ASSERT3U(new_nlevels, <=, DN_MAX_LEVELS);
Native Encryption for ZFS on Linux This change incorporates three major pieces: The first change is a keystore that manages wrapping and encryption keys for encrypted datasets. These commands mostly involve manipulating the new DSL Crypto Key ZAP Objects that live in the MOS. Each encrypted dataset has its own DSL Crypto Key that is protected with a user's key. This level of indirection allows users to change their keys without re-encrypting their entire datasets. The change implements the new subcommands "zfs load-key", "zfs unload-key" and "zfs change-key" which allow the user to manage their encryption keys and settings. In addition, several new flags and properties have been added to allow dataset creation and to make mounting and unmounting more convenient. The second piece of this patch provides the ability to encrypt, decyrpt, and authenticate protected datasets. Each object set maintains a Merkel tree of Message Authentication Codes that protect the lower layers, similarly to how checksums are maintained. This part impacts the zio layer, which handles the actual encryption and generation of MACs, as well as the ARC and DMU, which need to be able to handle encrypted buffers and protected data. The last addition is the ability to do raw, encrypted sends and receives. The idea here is to send raw encrypted and compressed data and receive it exactly as is on a backup system. This means that the dataset on the receiving system is protected using the same user key that is in use on the sending side. By doing so, datasets can be efficiently backed up to an untrusted system without fear of data being compromised. Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #494 Closes #5769
2017-08-14 17:36:48 +00:00
if (new_nlevels > dn->dn_nlevels)
dnode_set_nlevels_impl(dn, new_nlevels, tx);
2008-11-20 20:01:55 +00:00
out:
if (have_read)
rw_downgrade(&dn->dn_struct_rwlock);
2008-11-20 20:01:55 +00:00
}
static void
dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx)
{
dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG);
if (db != NULL) {
dmu_buf_will_dirty(&db->db, tx);
dbuf_rele(db, FTAG);
}
}
2008-11-20 20:01:55 +00:00
void
dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
{
dmu_buf_impl_t *db;
uint64_t blkoff, blkid, nblks;
int blksz, blkshift, head, tail;
2008-11-20 20:01:55 +00:00
int trunc = FALSE;
int epbs;
2008-11-20 20:01:55 +00:00
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
blksz = dn->dn_datablksz;
blkshift = dn->dn_datablkshift;
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
2008-11-20 20:01:55 +00:00
if (len == DMU_OBJECT_END) {
2008-11-20 20:01:55 +00:00
len = UINT64_MAX - off;
trunc = TRUE;
}
/*
* First, block align the region to free:
*/
if (ISP2(blksz)) {
head = P2NPHASE(off, blksz);
blkoff = P2PHASE(off, blksz);
if ((off >> blkshift) > dn->dn_maxblkid)
goto out;
2008-11-20 20:01:55 +00:00
} else {
ASSERT(dn->dn_maxblkid == 0);
if (off == 0 && len >= blksz) {
/*
* Freeing the whole block; fast-track this request.
* Note that we won't dirty any indirect blocks,
* which is fine because we will be freeing the entire
* file and thus all indirect blocks will be freed
* by free_children().
*/
blkid = 0;
nblks = 1;
goto done;
} else if (off >= blksz) {
/* Freeing past end-of-data */
goto out;
2008-11-20 20:01:55 +00:00
} else {
/* Freeing part of the block. */
head = blksz - off;
ASSERT3U(head, >, 0);
}
blkoff = off;
}
/* zero out any partial block data at the start of the range */
if (head) {
ASSERT3U(blkoff + head, ==, blksz);
if (len < head)
head = len;
if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off),
TRUE, FALSE, FTAG, &db) == 0) {
2008-11-20 20:01:55 +00:00
caddr_t data;
/* don't dirty if it isn't on disk and isn't dirty */
if (db->db_last_dirty ||
(db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
rw_exit(&dn->dn_struct_rwlock);
dmu_buf_will_dirty(&db->db, tx);
2008-11-20 20:01:55 +00:00
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
data = db->db.db_data;
bzero(data + blkoff, head);
}
dbuf_rele(db, FTAG);
}
off += head;
len -= head;
}
/* If the range was less than one block, we're done */
if (len == 0)
2008-11-20 20:01:55 +00:00
goto out;
/* If the remaining range is past end of file, we're done */
if ((off >> blkshift) > dn->dn_maxblkid)
goto out;
2008-11-20 20:01:55 +00:00
ASSERT(ISP2(blksz));
if (trunc)
tail = 0;
else
tail = P2PHASE(len, blksz);
ASSERT0(P2PHASE(off, blksz));
/* zero out any partial block data at the end of the range */
if (tail) {
if (len < tail)
tail = len;
if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off+len),
TRUE, FALSE, FTAG, &db) == 0) {
/* don't dirty if not on disk and not dirty */
if (db->db_last_dirty ||
(db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
rw_exit(&dn->dn_struct_rwlock);
dmu_buf_will_dirty(&db->db, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
bzero(db->db.db_data, tail);
2008-11-20 20:01:55 +00:00
}
dbuf_rele(db, FTAG);
2008-11-20 20:01:55 +00:00
}
len -= tail;
}
2008-11-20 20:01:55 +00:00
/* If the range did not include a full block, we are done */
if (len == 0)
goto out;
ASSERT(IS_P2ALIGNED(off, blksz));
ASSERT(trunc || IS_P2ALIGNED(len, blksz));
blkid = off >> blkshift;
nblks = len >> blkshift;
if (trunc)
nblks += 1;
/*
* Dirty all the indirect blocks in this range. Note that only
* the first and last indirect blocks can actually be written
* (if they were partially freed) -- they must be dirtied, even if
* they do not exist on disk yet. The interior blocks will
* be freed by free_children(), so they will not actually be written.
* Even though these interior blocks will not be written, we
* dirty them for two reasons:
*
* - It ensures that the indirect blocks remain in memory until
* syncing context. (They have already been prefetched by
* dmu_tx_hold_free(), so we don't have to worry about reading
* them serially here.)
*
* - The dirty space accounting will put pressure on the txg sync
* mechanism to begin syncing, and to delay transactions if there
* is a large amount of freeing. Even though these indirect
* blocks will not be written, we could need to write the same
* amount of space if we copy the freed BPs into deadlists.
*/
if (dn->dn_nlevels > 1) {
uint64_t first, last;
first = blkid >> epbs;
dnode_dirty_l1(dn, first, tx);
if (trunc)
last = dn->dn_maxblkid >> epbs;
else
last = (blkid + nblks - 1) >> epbs;
if (last != first)
dnode_dirty_l1(dn, last, tx);
int shift = dn->dn_datablkshift + dn->dn_indblkshift -
SPA_BLKPTRSHIFT;
for (uint64_t i = first + 1; i < last; i++) {
/*
* Set i to the blockid of the next non-hole
* level-1 indirect block at or after i. Note
* that dnode_next_offset() operates in terms of
* level-0-equivalent bytes.
*/
uint64_t ibyte = i << shift;
int err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK,
&ibyte, 2, 1, 0);
i = ibyte >> shift;
if (i >= last)
break;
/*
* Normally we should not see an error, either
* from dnode_next_offset() or dbuf_hold_level()
* (except for ESRCH from dnode_next_offset).
* If there is an i/o error, then when we read
* this block in syncing context, it will use
* ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according
* to the "failmode" property. dnode_next_offset()
* doesn't have a flag to indicate MUSTSUCCEED.
*/
if (err != 0)
break;
dnode_dirty_l1(dn, i, tx);
2008-11-20 20:01:55 +00:00
}
}
done:
/*
* Add this range to the dnode range list.
* We will finish up this free operation in the syncing phase.
*/
2008-11-20 20:01:55 +00:00
mutex_enter(&dn->dn_mtx);
{
int txgoff = tx->tx_txg & TXG_MASK;
if (dn->dn_free_ranges[txgoff] == NULL) {
dn->dn_free_ranges[txgoff] =
range_tree_create(NULL, NULL, &dn->dn_mtx);
}
range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks);
range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks);
2008-11-20 20:01:55 +00:00
}
dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n",
blkid, nblks, tx->tx_txg);
2008-11-20 20:01:55 +00:00
mutex_exit(&dn->dn_mtx);
dbuf_free_range(dn, blkid, blkid + nblks - 1, tx);
2008-11-20 20:01:55 +00:00
dnode_setdirty(dn, tx);
out:
2008-11-20 20:01:55 +00:00
rw_exit(&dn->dn_struct_rwlock);
}
static boolean_t
dnode_spill_freed(dnode_t *dn)
{
int i;
mutex_enter(&dn->dn_mtx);
for (i = 0; i < TXG_SIZE; i++) {
if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK)
break;
}
mutex_exit(&dn->dn_mtx);
return (i < TXG_SIZE);
}
2008-11-20 20:01:55 +00:00
/* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */
uint64_t
dnode_block_freed(dnode_t *dn, uint64_t blkid)
{
void *dp = spa_get_dsl(dn->dn_objset->os_spa);
int i;
if (blkid == DMU_BONUS_BLKID)
2008-11-20 20:01:55 +00:00
return (FALSE);
/*
* If we're in the process of opening the pool, dp will not be
* set yet, but there shouldn't be anything dirty.
*/
if (dp == NULL)
return (FALSE);
if (dn->dn_free_txg)
return (TRUE);
if (blkid == DMU_SPILL_BLKID)
return (dnode_spill_freed(dn));
2008-11-20 20:01:55 +00:00
mutex_enter(&dn->dn_mtx);
for (i = 0; i < TXG_SIZE; i++) {
if (dn->dn_free_ranges[i] != NULL &&
range_tree_contains(dn->dn_free_ranges[i], blkid, 1))
2008-11-20 20:01:55 +00:00
break;
}
mutex_exit(&dn->dn_mtx);
return (i < TXG_SIZE);
}
/* call from syncing context when we actually write/free space for this dnode */
void
dnode_diduse_space(dnode_t *dn, int64_t delta)
{
uint64_t space;
dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n",
dn, dn->dn_phys,
(u_longlong_t)dn->dn_phys->dn_used,
(longlong_t)delta);
mutex_enter(&dn->dn_mtx);
space = DN_USED_BYTES(dn->dn_phys);
if (delta > 0) {
ASSERT3U(space + delta, >=, space); /* no overflow */
} else {
ASSERT3U(space, >=, -delta); /* no underflow */
}
space += delta;
if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) {
ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0);
ASSERT0(P2PHASE(space, 1<<DEV_BSHIFT));
2008-11-20 20:01:55 +00:00
dn->dn_phys->dn_used = space >> DEV_BSHIFT;
} else {
dn->dn_phys->dn_used = space;
dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES;
}
mutex_exit(&dn->dn_mtx);
}
2009-08-18 18:43:27 +00:00
/*
* Scans a block at the indicated "level" looking for a hole or data,
* depending on 'flags'.
*
* If level > 0, then we are scanning an indirect block looking at its
* pointers. If level == 0, then we are looking at a block of dnodes.
*
* If we don't find what we are looking for in the block, we return ESRCH.
* Otherwise, return with *offset pointing to the beginning (if searching
* forwards) or end (if searching backwards) of the range covered by the
* block pointer we matched on (or dnode).
2009-08-18 18:43:27 +00:00
*
* The basic search algorithm used below by dnode_next_offset() is to
* use this function to search up the block tree (widen the search) until
* we find something (i.e., we don't return ESRCH) and then search back
* down the tree (narrow the search) until we reach our original search
* level.
*/
2008-11-20 20:01:55 +00:00
static int
dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
int lvl, uint64_t blkfill, uint64_t txg)
2008-11-20 20:01:55 +00:00
{
dmu_buf_impl_t *db = NULL;
void *data = NULL;
uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
uint64_t epb = 1ULL << epbs;
uint64_t minfill, maxfill;
boolean_t hole;
int i, inc, error, span;
2008-11-20 20:01:55 +00:00
2009-07-02 22:44:48 +00:00
hole = ((flags & DNODE_FIND_HOLE) != 0);
inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1;
ASSERT(txg == 0 || !hole);
2008-11-20 20:01:55 +00:00
if (lvl == dn->dn_phys->dn_nlevels) {
error = 0;
epb = dn->dn_phys->dn_nblkptr;
data = dn->dn_phys->dn_blkptr;
} else {
uint64_t blkid = dbuf_whichblock(dn, lvl, *offset);
error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db);
2008-11-20 20:01:55 +00:00
if (error) {
if (error != ENOENT)
return (error);
if (hole)
return (0);
/*
* This can only happen when we are searching up
* the block tree for data. We don't really need to
* adjust the offset, as we will just end up looking
* at the pointer to this block in its parent, and its
* going to be unallocated, so we will skip over it.
*/
return (SET_ERROR(ESRCH));
2008-11-20 20:01:55 +00:00
}
Native Encryption for ZFS on Linux This change incorporates three major pieces: The first change is a keystore that manages wrapping and encryption keys for encrypted datasets. These commands mostly involve manipulating the new DSL Crypto Key ZAP Objects that live in the MOS. Each encrypted dataset has its own DSL Crypto Key that is protected with a user's key. This level of indirection allows users to change their keys without re-encrypting their entire datasets. The change implements the new subcommands "zfs load-key", "zfs unload-key" and "zfs change-key" which allow the user to manage their encryption keys and settings. In addition, several new flags and properties have been added to allow dataset creation and to make mounting and unmounting more convenient. The second piece of this patch provides the ability to encrypt, decyrpt, and authenticate protected datasets. Each object set maintains a Merkel tree of Message Authentication Codes that protect the lower layers, similarly to how checksums are maintained. This part impacts the zio layer, which handles the actual encryption and generation of MACs, as well as the ARC and DMU, which need to be able to handle encrypted buffers and protected data. The last addition is the ability to do raw, encrypted sends and receives. The idea here is to send raw encrypted and compressed data and receive it exactly as is on a backup system. This means that the dataset on the receiving system is protected using the same user key that is in use on the sending side. By doing so, datasets can be efficiently backed up to an untrusted system without fear of data being compromised. Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #494 Closes #5769
2017-08-14 17:36:48 +00:00
error = dbuf_read(db, NULL,
DB_RF_CANFAIL | DB_RF_HAVESTRUCT | DB_RF_NO_DECRYPT);
2008-11-20 20:01:55 +00:00
if (error) {
dbuf_rele(db, FTAG);
return (error);
}
data = db->db.db_data;
}
if (db != NULL && txg != 0 && (db->db_blkptr == NULL ||
db->db_blkptr->blk_birth <= txg ||
BP_IS_HOLE(db->db_blkptr))) {
/*
* This can only happen when we are searching up the tree
* and these conditions mean that we need to keep climbing.
*/
error = SET_ERROR(ESRCH);
2008-11-20 20:01:55 +00:00
} else if (lvl == 0) {
dnode_phys_t *dnp = data;
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
2008-11-20 20:01:55 +00:00
ASSERT(dn->dn_type == DMU_OT_DNODE);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
ASSERT(!(flags & DNODE_FIND_BACKWARDS));
2008-11-20 20:01:55 +00:00
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
for (i = (*offset >> DNODE_SHIFT) & (blkfill - 1);
i < blkfill; i += dnp[i].dn_extra_slots + 1) {
2009-07-02 22:44:48 +00:00
if ((dnp[i].dn_type == DMU_OT_NONE) == hole)
2008-11-20 20:01:55 +00:00
break;
}
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
if (i == blkfill)
error = SET_ERROR(ESRCH);
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
2016-03-17 01:25:34 +00:00
*offset = (*offset & ~(DNODE_BLOCK_SIZE - 1)) +
(i << DNODE_SHIFT);
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} else {
blkptr_t *bp = data;
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uint64_t start = *offset;
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span = (lvl - 1) * epbs + dn->dn_datablkshift;
minfill = 0;
maxfill = blkfill << ((lvl - 1) * epbs);
if (hole)
maxfill--;
else
minfill++;
if (span >= 8 * sizeof (*offset)) {
/* This only happens on the highest indirection level */
ASSERT3U((lvl - 1), ==, dn->dn_phys->dn_nlevels - 1);
*offset = 0;
} else {
*offset = *offset >> span;
}
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for (i = BF64_GET(*offset, 0, epbs);
i >= 0 && i < epb; i += inc) {
if (BP_GET_FILL(&bp[i]) >= minfill &&
BP_GET_FILL(&bp[i]) <= maxfill &&
(hole || bp[i].blk_birth > txg))
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break;
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if (inc > 0 || *offset > 0)
*offset += inc;
}
if (span >= 8 * sizeof (*offset)) {
*offset = start;
} else {
*offset = *offset << span;
}
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if (inc < 0) {
/* traversing backwards; position offset at the end */
ASSERT3U(*offset, <=, start);
*offset = MIN(*offset + (1ULL << span) - 1, start);
} else if (*offset < start) {
*offset = start;
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}
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if (i < 0 || i >= epb)
error = SET_ERROR(ESRCH);
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}
if (db)
dbuf_rele(db, FTAG);
return (error);
}
/*
* Find the next hole, data, or sparse region at or after *offset.
* The value 'blkfill' tells us how many items we expect to find
* in an L0 data block; this value is 1 for normal objects,
* DNODES_PER_BLOCK for the meta dnode, and some fraction of
* DNODES_PER_BLOCK when searching for sparse regions thereof.
*
* Examples:
*
* dnode_next_offset(dn, flags, offset, 1, 1, 0);
* Finds the next/previous hole/data in a file.
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* Used in dmu_offset_next().
*
* dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg);
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* Finds the next free/allocated dnode an objset's meta-dnode.
* Only finds objects that have new contents since txg (ie.
* bonus buffer changes and content removal are ignored).
* Used in dmu_object_next().
*
* dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0);
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* Finds the next L2 meta-dnode bp that's at most 1/4 full.
* Used in dmu_object_alloc().
*/
int
dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset,
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int minlvl, uint64_t blkfill, uint64_t txg)
{
uint64_t initial_offset = *offset;
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int lvl, maxlvl;
int error = 0;
if (!(flags & DNODE_FIND_HAVELOCK))
rw_enter(&dn->dn_struct_rwlock, RW_READER);
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if (dn->dn_phys->dn_nlevels == 0) {
error = SET_ERROR(ESRCH);
goto out;
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}
if (dn->dn_datablkshift == 0) {
if (*offset < dn->dn_datablksz) {
if (flags & DNODE_FIND_HOLE)
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*offset = dn->dn_datablksz;
} else {
error = SET_ERROR(ESRCH);
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}
goto out;
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}
maxlvl = dn->dn_phys->dn_nlevels;
for (lvl = minlvl; lvl <= maxlvl; lvl++) {
error = dnode_next_offset_level(dn,
flags, offset, lvl, blkfill, txg);
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if (error != ESRCH)
break;
}
while (error == 0 && --lvl >= minlvl) {
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error = dnode_next_offset_level(dn,
flags, offset, lvl, blkfill, txg);
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}
/*
* There's always a "virtual hole" at the end of the object, even
* if all BP's which physically exist are non-holes.
*/
if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 &&
minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) {
error = 0;
}
if (error == 0 && (flags & DNODE_FIND_BACKWARDS ?
initial_offset < *offset : initial_offset > *offset))
error = SET_ERROR(ESRCH);
out:
if (!(flags & DNODE_FIND_HAVELOCK))
rw_exit(&dn->dn_struct_rwlock);
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return (error);
}