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freebsd-nq/module/zfs/dnode.c
Matthew Ahrens e8b96c6007 Illumos #4045 write throttle & i/o scheduler performance work 
4045 zfs write throttle & i/o scheduler performance work

1. The ZFS i/o scheduler (vdev_queue.c) now divides i/os into 5 classes: sync
read, sync write, async read, async write, and scrub/resilver.  The scheduler
issues a number of concurrent i/os from each class to the device.  Once a class
has been selected, an i/o is selected from this class using either an elevator
algorithem (async, scrub classes) or FIFO (sync classes).  The number of
concurrent async write i/os is tuned dynamically based on i/o load, to achieve
good sync i/o latency when there is not a high load of writes, and good write
throughput when there is.  See the block comment in vdev_queue.c (reproduced
below) for more details.

2. The write throttle (dsl_pool_tempreserve_space() and
txg_constrain_throughput()) is rewritten to produce much more consistent delays
when under constant load.  The new write throttle is based on the amount of
dirty data, rather than guesses about future performance of the system.  When
there is a lot of dirty data, each transaction (e.g. write() syscall) will be
delayed by the same small amount.  This eliminates the "brick wall of wait"
that the old write throttle could hit, causing all transactions to wait several
seconds until the next txg opens.  One of the keys to the new write throttle is
decrementing the amount of dirty data as i/o completes, rather than at the end
of spa_sync().  Note that the write throttle is only applied once the i/o
scheduler is issuing the maximum number of outstanding async writes.  See the
block comments in dsl_pool.c and above dmu_tx_delay() (reproduced below) for
more details.

This diff has several other effects, including:

 * the commonly-tuned global variable zfs_vdev_max_pending has been removed;
use per-class zfs_vdev_*_max_active values or zfs_vdev_max_active instead.

 * the size of each txg (meaning the amount of dirty data written, and thus the
time it takes to write out) is now controlled differently.  There is no longer
an explicit time goal; the primary determinant is amount of dirty data.
Systems that are under light or medium load will now often see that a txg is
always syncing, but the impact to performance (e.g. read latency) is minimal.
Tune zfs_dirty_data_max and zfs_dirty_data_sync to control this.

 * zio_taskq_batch_pct = 75 -- Only use 75% of all CPUs for compression,
checksum, etc.  This improves latency by not allowing these CPU-intensive tasks
to consume all CPU (on machines with at least 4 CPU's; the percentage is
rounded up).

--matt

APPENDIX: problems with the current i/o scheduler

The current ZFS i/o scheduler (vdev_queue.c) is deadline based.  The problem
with this is that if there are always i/os pending, then certain classes of
i/os can see very long delays.

For example, if there are always synchronous reads outstanding, then no async
writes will be serviced until they become "past due".  One symptom of this
situation is that each pass of the txg sync takes at least several seconds
(typically 3 seconds).

If many i/os become "past due" (their deadline is in the past), then we must
service all of these overdue i/os before any new i/os.  This happens when we
enqueue a batch of async writes for the txg sync, with deadlines 2.5 seconds in
the future.  If we can't complete all the i/os in 2.5 seconds (e.g. because
there were always reads pending), then these i/os will become past due.  Now we
must service all the "async" writes (which could be hundreds of megabytes)
before we service any reads, introducing considerable latency to synchronous
i/os (reads or ZIL writes).

Notes on porting to ZFS on Linux:

- zio_t gained new members io_physdone and io_phys_children.  Because
  object caches in the Linux port call the constructor only once at
  allocation time, objects may contain residual data when retrieved
  from the cache. Therefore zio_create() was updated to zero out the two
  new fields.

- vdev_mirror_pending() relied on the depth of the per-vdev pending queue
  (vq->vq_pending_tree) to select the least-busy leaf vdev to read from.
  This tree has been replaced by vq->vq_active_tree which is now used
  for the same purpose.

- vdev_queue_init() used the value of zfs_vdev_max_pending to determine
  the number of vdev I/O buffers to pre-allocate.  That global no longer
  exists, so we instead use the sum of the *_max_active values for each of
  the five I/O classes described above.

- The Illumos implementation of dmu_tx_delay() delays a transaction by
  sleeping in condition variable embedded in the thread
  (curthread->t_delay_cv).  We do not have an equivalent CV to use in
  Linux, so this change replaced the delay logic with a wrapper called
  zfs_sleep_until(). This wrapper could be adopted upstream and in other
  downstream ports to abstract away operating system-specific delay logic.

- These tunables are added as module parameters, and descriptions added
  to the zfs-module-parameters.5 man page.

  spa_asize_inflation
  zfs_deadman_synctime_ms
  zfs_vdev_max_active
  zfs_vdev_async_write_active_min_dirty_percent
  zfs_vdev_async_write_active_max_dirty_percent
  zfs_vdev_async_read_max_active
  zfs_vdev_async_read_min_active
  zfs_vdev_async_write_max_active
  zfs_vdev_async_write_min_active
  zfs_vdev_scrub_max_active
  zfs_vdev_scrub_min_active
  zfs_vdev_sync_read_max_active
  zfs_vdev_sync_read_min_active
  zfs_vdev_sync_write_max_active
  zfs_vdev_sync_write_min_active
  zfs_dirty_data_max_percent
  zfs_delay_min_dirty_percent
  zfs_dirty_data_max_max_percent
  zfs_dirty_data_max
  zfs_dirty_data_max_max
  zfs_dirty_data_sync
  zfs_delay_scale

  The latter four have type unsigned long, whereas they are uint64_t in
  Illumos.  This accommodates Linux's module_param() supported types, but
  means they may overflow on 32-bit architectures.

  The values zfs_dirty_data_max and zfs_dirty_data_max_max are the most
  likely to overflow on 32-bit systems, since they express physical RAM
  sizes in bytes.  In fact, Illumos initializes zfs_dirty_data_max_max to
  2^32 which does overflow. To resolve that, this port instead initializes
  it in arc_init() to 25% of physical RAM, and adds the tunable
  zfs_dirty_data_max_max_percent to override that percentage.  While this
  solution doesn't completely avoid the overflow issue, it should be a
  reasonable default for most systems, and the minority of affected
  systems can work around the issue by overriding the defaults.

- Fixed reversed logic in comment above zfs_delay_scale declaration.

- Clarified comments in vdev_queue.c regarding when per-queue minimums take
  effect.

- Replaced dmu_tx_write_limit in the dmu_tx kstat file
  with dmu_tx_dirty_delay and dmu_tx_dirty_over_max.  The first counts
  how many times a transaction has been delayed because the pool dirty
  data has exceeded zfs_delay_min_dirty_percent.  The latter counts how
  many times the pool dirty data has exceeded zfs_dirty_data_max (which
  we expect to never happen).

- The original patch would have regressed the bug fixed in
  zfsonlinux/zfs@c418410, which prevented users from setting the
  zfs_vdev_aggregation_limit tuning larger than SPA_MAXBLOCKSIZE.
  A similar fix is added to vdev_queue_aggregate().

- In vdev_queue_io_to_issue(), dynamically allocate 'zio_t search' on the
  heap instead of the stack.  In Linux we can't afford such large
  structures on the stack.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Ned Bass <bass6@llnl.gov>
Reviewed by: Brendan Gregg <brendan.gregg@joyent.com>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  http://www.illumos.org/issues/4045
  illumos/illumos-gate@69962b5647

Ported-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1913
2013-12-06 09:32:43 -08:00

2008 lines
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/*
* 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) 2013 by Delphix. All rights reserved.
*/
#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>
static int free_range_compar(const void *node1, const void *node2);
static kmem_cache_t *dnode_cache;
/*
* Define DNODE_STATS to turn on statistic gathering. By default, it is only
* turned on when DEBUG is also defined.
*/
#ifdef DEBUG
#define DNODE_STATS
#endif /* DEBUG */
#ifdef DNODE_STATS
#define DNODE_STAT_ADD(stat) ((stat)++)
#else
#define DNODE_STAT_ADD(stat) /* nothing */
#endif /* DNODE_STATS */
ASSERTV(static dnode_phys_t dnode_phys_zero);
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 */
/* ARGSUSED */
static int
dnode_cons(void *arg, void *unused, int kmflag)
{
dnode_t *dn = arg;
int i;
rw_init(&dn->dn_struct_rwlock, NULL, RW_DEFAULT, NULL);
mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL);
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);
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));
for (i = 0; i < TXG_SIZE; i++) {
list_link_init(&dn->dn_dirty_link[i]);
avl_create(&dn->dn_ranges[i], free_range_compar,
sizeof (free_range_t),
offsetof(struct free_range, fr_node));
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;
dn->dn_newuid = 0;
dn->dn_newgid = 0;
dn->dn_id_flags = 0;
dn->dn_dbufs_count = 0;
dn->dn_unlisted_l0_blkid = 0;
list_create(&dn->dn_dbufs, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
dn->dn_moved = 0;
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);
cv_destroy(&dn->dn_notxholds);
refcount_destroy(&dn->dn_holds);
refcount_destroy(&dn->dn_tx_holds);
ASSERT(!list_link_active(&dn->dn_link));
for (i = 0; i < TXG_SIZE; i++) {
ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
avl_destroy(&dn->dn_ranges[i]);
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]);
}
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);
ASSERT0(dn->dn_newuid);
ASSERT0(dn->dn_newgid);
ASSERT0(dn->dn_id_flags);
ASSERT0(dn->dn_dbufs_count);
ASSERT0(dn->dn_unlisted_l0_blkid);
list_destroy(&dn->dn_dbufs);
}
void
dnode_init(void)
{
ASSERT(dnode_cache == NULL);
dnode_cache = kmem_cache_create("dnode_t", sizeof (dnode_t),
0, dnode_cons, dnode_dest, NULL, NULL, NULL, KMC_KMEM);
kmem_cache_set_move(dnode_cache, dnode_move);
}
void
dnode_fini(void)
{
kmem_cache_destroy(dnode_cache);
dnode_cache = NULL;
}
#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);
ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
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;
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));
ASSERT3U(dn->dn_nblkptr, >=, 1);
ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
ASSERT3U(dn->dn_bonuslen, <=, DN_MAX_BONUSLEN);
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) +
dn->dn_bonuslen, <=, DN_MAX_BONUSLEN);
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);
ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL);
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);
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);
size_t len = DN_MAX_BONUSLEN - 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);
}
/* Swap SPILL block if we have one */
if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)
byteswap_uint64_array(&dnp->dn_spill, sizeof (blkptr_t));
}
void
dnode_buf_byteswap(void *vbuf, size_t size)
{
dnode_phys_t *buf = vbuf;
int i;
ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT));
ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0);
size >>= DNODE_SHIFT;
for (i = 0; i < size; i++) {
dnode_byteswap(buf);
buf++;
}
}
static int
free_range_compar(const void *node1, const void *node2)
{
const free_range_t *rp1 = node1;
const free_range_t *rp2 = node2;
if (rp1->fr_blkid < rp2->fr_blkid)
return (-1);
else if (rp1->fr_blkid > rp2->fr_blkid)
return (1);
else return (0);
}
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);
ASSERT3U(newsize, <=, DN_MAX_BONUSLEN -
(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;
}
static void
dnode_setdblksz(dnode_t *dn, int size)
{
ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE));
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) ? highbit(size - 1) : 0;
}
static dnode_t *
dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db,
uint64_t object, dnode_handle_t *dnh)
{
dnode_t *dn = kmem_cache_alloc(dnode_cache, KM_PUSHPAGE);
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.
*/
dn->dn_object = object;
dn->dn_dbuf = db;
dn->dn_handle = dnh;
dn->dn_phys = dnp;
if (dnp->dn_datablkszsec) {
dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
} else {
dn->dn_datablksz = 0;
dn->dn_datablkszsec = 0;
dn->dn_datablkshift = 0;
}
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;
dn->dn_maxblkid = dnp->dn_maxblkid;
dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0);
dn->dn_id_flags = 0;
dmu_zfetch_init(&dn->dn_zfetch, dn);
ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
mutex_enter(&os->os_lock);
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;
mutex_exit(&os->os_lock);
arc_space_consume(sizeof (dnode_t), ARC_SPACE_OTHER);
return (dn);
}
/*
* Caller must be holding the dnode handle, which is released upon return.
*/
static void
dnode_destroy(dnode_t *dn)
{
objset_t *os = dn->dn_objset;
ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0);
mutex_enter(&os->os_lock);
POINTER_INVALIDATE(&dn->dn_objset);
list_remove(&os->os_dnodes, dn);
mutex_exit(&os->os_lock);
/* the dnode can no longer move, so we can release the handle */
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) {
kmem_free(dn->dn_dirtyctx_firstset, 1);
dn->dn_dirtyctx_firstset = NULL;
}
if (dn->dn_bonus != NULL) {
mutex_enter(&dn->dn_bonus->db_mtx);
dbuf_evict(dn->dn_bonus);
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;
dn->dn_newuid = 0;
dn->dn_newgid = 0;
dn->dn_id_flags = 0;
dn->dn_unlisted_l0_blkid = 0;
dmu_zfetch_rele(&dn->dn_zfetch);
kmem_cache_free(dnode_cache, dn);
arc_space_return(sizeof (dnode_t), ARC_SPACE_OTHER);
}
void
dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
int i;
if (blocksize == 0)
blocksize = 1 << zfs_default_bs;
else if (blocksize > SPA_MAXBLOCKSIZE)
blocksize = SPA_MAXBLOCKSIZE;
else
blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE);
if (ibs == 0)
ibs = zfs_default_ibs;
ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT);
dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d\n", dn->dn_objset,
dn->dn_object, tx->tx_txg, blocksize, ibs);
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));
ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
(bonustype == DMU_OT_SA && bonuslen == 0) ||
(bonustype != DMU_OT_NONE && bonuslen != 0));
ASSERT(DMU_OT_IS_VALID(bonustype));
ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN);
ASSERT(dn->dn_type == DMU_OT_NONE);
ASSERT0(dn->dn_maxblkid);
ASSERT0(dn->dn_allocated_txg);
ASSERT0(dn->dn_assigned_txg);
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
ASSERT3U(refcount_count(&dn->dn_holds), <=, 1);
ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
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]);
ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL);
ASSERT0(avl_numnodes(&dn->dn_ranges[i]));
}
dn->dn_type = ot;
dnode_setdblksz(dn, blocksize);
dn->dn_indblkshift = ibs;
dn->dn_nlevels = 1;
if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
dn->dn_nblkptr = 1;
else
dn->dn_nblkptr = 1 +
((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
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;
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;
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,
dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
int nblkptr;
ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
ASSERT3U(blocksize, <=, SPA_MAXBLOCKSIZE);
ASSERT0(blocksize % SPA_MINBLOCKSIZE);
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));
ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN);
/* clean up any unreferenced dbufs */
dnode_evict_dbufs(dn);
dn->dn_id_flags = 0;
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
dnode_setdirty(dn, tx);
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
nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
if (dn->dn_bonustype != bonustype)
dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype;
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);
}
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;
dn->dn_nblkptr = nblkptr;
dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
dn->dn_compress = ZIO_COMPRESS_INHERIT;
ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
/* fix up the bonus db_size */
if (dn->dn_bonus) {
dn->dn_bonus->db.db_size =
DN_MAX_BONUSLEN - (dn->dn_nblkptr-1) * sizeof (blkptr_t);
ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size);
}
dn->dn_allocated_txg = tx->tx_txg;
mutex_exit(&dn->dn_mtx);
}
#ifdef _KERNEL
#ifdef DNODE_STATS
static struct {
uint64_t dms_dnode_invalid;
uint64_t dms_dnode_recheck1;
uint64_t dms_dnode_recheck2;
uint64_t dms_dnode_special;
uint64_t dms_dnode_handle;
uint64_t dms_dnode_rwlock;
uint64_t dms_dnode_active;
} dnode_move_stats;
#endif /* DNODE_STATS */
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;
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));
for (i = 0; i < TXG_SIZE; i++) {
list_move_tail(&ndn->dn_dirty_records[i],
&odn->dn_dirty_records[i]);
}
bcopy(&odn->dn_ranges[0], &ndn->dn_ranges[0], sizeof (odn->dn_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(list_is_empty(&ndn->dn_dbufs));
list_move_tail(&ndn->dn_dbufs, &odn->dn_dbufs);
ndn->dn_dbufs_count = odn->dn_dbufs_count;
ndn->dn_unlisted_l0_blkid = odn->dn_unlisted_l0_blkid;
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;
ndn->dn_newuid = odn->dn_newuid;
ndn->dn_newgid = odn->dn_newgid;
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;
ndn->dn_zfetch.zf_stream_cnt = odn->dn_zfetch.zf_stream_cnt;
ndn->dn_zfetch.zf_alloc_fail = odn->dn_zfetch.zf_alloc_fail;
/*
* 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;
list_create(&odn->dn_dbufs, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
odn->dn_dbufs_count = 0;
odn->dn_unlisted_l0_blkid = 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_ranges[i].avl_root = NULL;
odn->dn_ranges[i].avl_numnodes = 0;
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;
odn->dn_newuid = 0;
odn->dn_newgid = 0;
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)) {
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_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 */
void
dnode_special_close(dnode_handle_t *dnh)
{
dnode_t *dn = dnh->dnh_dnode;
/*
* Wait for final references to the dnode to clear. This can
* only happen if the arc is asyncronously evicting state that
* has a hold on this dnode while we are trying to evict this
* dnode.
*/
while (refcount_count(&dn->dn_holds) > 0)
delay(1);
zrl_add(&dnh->dnh_zrlock);
dnode_destroy(dn); /* implicit zrl_remove() */
zrl_destroy(&dnh->dnh_zrlock);
dnh->dnh_dnode = NULL;
}
dnode_t *
dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object,
dnode_handle_t *dnh)
{
dnode_t *dn = dnode_create(os, dnp, NULL, object, dnh);
dnh->dnh_dnode = dn;
zrl_init(&dnh->dnh_zrlock);
DNODE_VERIFY(dn);
return (dn);
}
static void
dnode_buf_pageout(dmu_buf_t *db, void *arg)
{
dnode_children_t *children_dnodes = arg;
int i;
int epb = db->db_size >> DNODE_SHIFT;
ASSERT(epb == children_dnodes->dnc_count);
for (i = 0; i < epb; i++) {
dnode_handle_t *dnh = &children_dnodes->dnc_children[i];
dnode_t *dn;
/*
* 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.
*/
if (dnh->dnh_dnode == NULL) {
zrl_destroy(&dnh->dnh_zrlock);
continue;
}
zrl_add(&dnh->dnh_zrlock);
dn = dnh->dnh_dnode;
/*
* 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
* would not have been called.
*/
ASSERT(refcount_is_zero(&dn->dn_holds));
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
dnode_destroy(dn); /* implicit zrl_remove() */
zrl_destroy(&dnh->dnh_zrlock);
dnh->dnh_dnode = NULL;
}
kmem_free(children_dnodes, sizeof (dnode_children_t) +
(epb - 1) * sizeof (dnode_handle_t));
}
/*
* errors:
* EINVAL - invalid object number.
* EIO - i/o error.
* succeeds even for free dnodes.
*/
int
dnode_hold_impl(objset_t *os, uint64_t object, int flag,
void *tag, dnode_t **dnp)
{
int epb, idx, err;
int drop_struct_lock = FALSE;
int type;
uint64_t blk;
dnode_t *mdn, *dn;
dmu_buf_impl_t *db;
dnode_children_t *children_dnodes;
dnode_handle_t *dnh;
/*
* 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)));
if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) {
dn = (object == DMU_USERUSED_OBJECT) ?
DMU_USERUSED_DNODE(os) : DMU_GROUPUSED_DNODE(os);
if (dn == NULL)
return (SET_ERROR(ENOENT));
type = dn->dn_type;
if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE)
return (SET_ERROR(ENOENT));
if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)
return (SET_ERROR(EEXIST));
DNODE_VERIFY(dn);
(void) refcount_add(&dn->dn_holds, tag);
*dnp = dn;
return (0);
}
if (object == 0 || object >= DN_MAX_OBJECT)
return (SET_ERROR(EINVAL));
mdn = DMU_META_DNODE(os);
ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT);
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, object * sizeof (dnode_phys_t));
db = dbuf_hold(mdn, blk, FTAG);
if (drop_struct_lock)
rw_exit(&mdn->dn_struct_rwlock);
if (db == NULL)
return (SET_ERROR(EIO));
err = dbuf_read(db, NULL, DB_RF_CANFAIL);
if (err) {
dbuf_rele(db, FTAG);
return (err);
}
ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT);
epb = db->db.db_size >> DNODE_SHIFT;
idx = object & (epb-1);
ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE);
children_dnodes = dmu_buf_get_user(&db->db);
if (children_dnodes == NULL) {
int i;
dnode_children_t *winner;
children_dnodes = kmem_alloc(sizeof (dnode_children_t) +
(epb - 1) * sizeof (dnode_handle_t),
KM_PUSHPAGE | KM_NODEBUG);
children_dnodes->dnc_count = epb;
dnh = &children_dnodes->dnc_children[0];
for (i = 0; i < epb; i++) {
zrl_init(&dnh[i].dnh_zrlock);
dnh[i].dnh_dnode = NULL;
}
if ((winner = dmu_buf_set_user(&db->db, children_dnodes, NULL,
dnode_buf_pageout))) {
kmem_free(children_dnodes, sizeof (dnode_children_t) +
(epb - 1) * sizeof (dnode_handle_t));
children_dnodes = winner;
}
}
ASSERT(children_dnodes->dnc_count == epb);
dnh = &children_dnodes->dnc_children[idx];
zrl_add(&dnh->dnh_zrlock);
if ((dn = dnh->dnh_dnode) == NULL) {
dnode_phys_t *phys = (dnode_phys_t *)db->db.db_data+idx;
dnode_t *winner;
dn = dnode_create(os, phys, db, object, dnh);
winner = atomic_cas_ptr(&dnh->dnh_dnode, NULL, dn);
if (winner != NULL) {
zrl_add(&dnh->dnh_zrlock);
dnode_destroy(dn); /* implicit zrl_remove() */
dn = winner;
}
}
mutex_enter(&dn->dn_mtx);
type = dn->dn_type;
if (dn->dn_free_txg ||
((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) ||
((flag & DNODE_MUST_BE_FREE) &&
(type != DMU_OT_NONE || !refcount_is_zero(&dn->dn_holds)))) {
mutex_exit(&dn->dn_mtx);
zrl_remove(&dnh->dnh_zrlock);
dbuf_rele(db, FTAG);
return (type == DMU_OT_NONE ? ENOENT : EEXIST);
}
mutex_exit(&dn->dn_mtx);
if (refcount_add(&dn->dn_holds, tag) == 1)
dbuf_add_ref(db, dnh);
/* Now we can rely on the hold to prevent the dnode from moving. */
zrl_remove(&dnh->dnh_zrlock);
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)
{
return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, tag, dnp));
}
/*
* 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)
{
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;
mutex_enter(&dn->dn_mtx);
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);
/* 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);
}
}
void
dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
{
objset_t *os = dn->dn_objset;
uint64_t txg = tx->tx_txg;
if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
dsl_dataset_dirty(os->os_dsl_dataset, tx);
return;
}
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);
mutex_exit(&dn->dn_mtx);
#endif
/*
* Determine old uid/gid when necessary
*/
dmu_objset_userquota_get_ids(dn, B_TRUE, tx);
mutex_enter(&os->os_lock);
/*
* If we are already marked dirty, we're done.
*/
if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) {
mutex_exit(&os->os_lock);
return;
}
ASSERT(!refcount_is_zero(&dn->dn_holds) || list_head(&dn->dn_dbufs));
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]);
dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n",
dn->dn_object, txg);
if (dn->dn_free_txg > 0 && dn->dn_free_txg <= txg) {
list_insert_tail(&os->os_free_dnodes[txg&TXG_MASK], dn);
} else {
list_insert_tail(&os->os_dirty_dnodes[txg&TXG_MASK], dn);
}
mutex_exit(&os->os_lock);
/*
* 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
* 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)
{
int txgoff = tx->tx_txg & TXG_MASK;
dprintf("dn=%p txg=%llu\n", dn, tx->tx_txg);
/* we should be the only holder... hopefully */
/* ASSERT3U(refcount_count(&dn->dn_holds), ==, 1); */
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);
/*
* If the dnode is already dirty, it needs to be moved from
* the dirty list to the free list.
*/
mutex_enter(&dn->dn_objset->os_lock);
if (list_link_active(&dn->dn_dirty_link[txgoff])) {
list_remove(&dn->dn_objset->os_dirty_dnodes[txgoff], dn);
list_insert_tail(&dn->dn_objset->os_free_dnodes[txgoff], dn);
mutex_exit(&dn->dn_objset->os_lock);
} else {
mutex_exit(&dn->dn_objset->os_lock);
dnode_setdirty(dn, tx);
}
}
/*
* 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, *db_next;
int err;
if (size == 0)
size = SPA_MINBLOCKSIZE;
if (size > SPA_MAXBLOCKSIZE)
size = SPA_MAXBLOCKSIZE;
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 */
if (dn->dn_phys->dn_maxblkid != 0)
goto fail;
mutex_enter(&dn->dn_dbufs_mtx);
for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
db_next = list_next(&dn->dn_dbufs, db);
if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID &&
db->db_blkid != DMU_SPILL_BLKID) {
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, FTAG, &db);
if (err == 0)
dbuf_new_size(db, size, tx);
else if (err != ENOENT)
goto fail;
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 */
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));
}
/* read-holding callers must not rely on the lock being continuously held */
void
dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read)
{
uint64_t txgoff = tx->tx_txg & TXG_MASK;
int epbs, new_nlevels;
uint64_t sz;
ASSERT(blkid != DMU_BONUS_BLKID);
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);
}
}
if (blkid <= dn->dn_maxblkid)
goto out;
dn->dn_maxblkid = blkid;
/*
* 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++;
if (new_nlevels > dn->dn_nlevels) {
int old_nlevels = dn->dn_nlevels;
dmu_buf_impl_t *db;
list_t *list;
dbuf_dirty_record_t *new, *dr, *dr_next;
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);
}
out:
if (have_read)
rw_downgrade(&dn->dn_struct_rwlock);
}
void
dnode_clear_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
{
avl_tree_t *tree = &dn->dn_ranges[tx->tx_txg&TXG_MASK];
avl_index_t where;
free_range_t *rp;
free_range_t rp_tofind;
uint64_t endblk = blkid + nblks;
ASSERT(MUTEX_HELD(&dn->dn_mtx));
ASSERT(nblks <= UINT64_MAX - blkid); /* no overflow */
dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n",
blkid, nblks, tx->tx_txg);
rp_tofind.fr_blkid = blkid;
rp = avl_find(tree, &rp_tofind, &where);
if (rp == NULL)
rp = avl_nearest(tree, where, AVL_BEFORE);
if (rp == NULL)
rp = avl_nearest(tree, where, AVL_AFTER);
while (rp && (rp->fr_blkid <= blkid + nblks)) {
uint64_t fr_endblk = rp->fr_blkid + rp->fr_nblks;
free_range_t *nrp = AVL_NEXT(tree, rp);
if (blkid <= rp->fr_blkid && endblk >= fr_endblk) {
/* clear this entire range */
avl_remove(tree, rp);
kmem_free(rp, sizeof (free_range_t));
} else if (blkid <= rp->fr_blkid &&
endblk > rp->fr_blkid && endblk < fr_endblk) {
/* clear the beginning of this range */
rp->fr_blkid = endblk;
rp->fr_nblks = fr_endblk - endblk;
} else if (blkid > rp->fr_blkid && blkid < fr_endblk &&
endblk >= fr_endblk) {
/* clear the end of this range */
rp->fr_nblks = blkid - rp->fr_blkid;
} else if (blkid > rp->fr_blkid && endblk < fr_endblk) {
/* clear a chunk out of this range */
free_range_t *new_rp =
kmem_alloc(sizeof (free_range_t), KM_PUSHPAGE);
new_rp->fr_blkid = endblk;
new_rp->fr_nblks = fr_endblk - endblk;
avl_insert_here(tree, new_rp, rp, AVL_AFTER);
rp->fr_nblks = blkid - rp->fr_blkid;
}
/* there may be no overlap */
rp = nrp;
}
}
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;
int trunc = FALSE;
int epbs;
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
blksz = dn->dn_datablksz;
blkshift = dn->dn_datablkshift;
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
if (len == DMU_OBJECT_END) {
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;
} else {
ASSERT(dn->dn_maxblkid == 0);
if (off == 0 && len >= blksz) {
/* Freeing the whole block; fast-track this request */
blkid = 0;
nblks = 1;
goto done;
} else if (off >= blksz) {
/* Freeing past end-of-data */
goto out;
} 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, off), TRUE,
FTAG, &db) == 0) {
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);
dbuf_will_dirty(db, tx);
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)
goto out;
/* If the remaining range is past end of file, we're done */
if ((off >> blkshift) > dn->dn_maxblkid)
goto out;
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, off+len),
TRUE, 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);
dbuf_will_dirty(db, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
bzero(db->db.db_data, tail);
}
dbuf_rele(db, FTAG);
}
len -= tail;
}
/* 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;
/*
* Read in and mark all the level-1 indirects dirty,
* so that they will stay in memory until syncing phase.
* Always dirty the first and last indirect to make sure
* we dirty all the partial indirects.
*/
if (dn->dn_nlevels > 1) {
uint64_t i, first, last;
int shift = epbs + dn->dn_datablkshift;
first = blkid >> epbs;
if ((db = dbuf_hold_level(dn, 1, first, FTAG))) {
dbuf_will_dirty(db, tx);
dbuf_rele(db, FTAG);
}
if (trunc)
last = dn->dn_maxblkid >> epbs;
else
last = (blkid + nblks - 1) >> epbs;
if (last > first && (db = dbuf_hold_level(dn, 1, last, FTAG))) {
dbuf_will_dirty(db, tx);
dbuf_rele(db, FTAG);
}
for (i = first + 1; i < last; i++) {
uint64_t ibyte = i << shift;
int err;
err = dnode_next_offset(dn,
DNODE_FIND_HAVELOCK, &ibyte, 1, 1, 0);
i = ibyte >> shift;
if (err == ESRCH || i >= last)
break;
ASSERT(err == 0);
db = dbuf_hold_level(dn, 1, i, FTAG);
if (db) {
dbuf_will_dirty(db, tx);
dbuf_rele(db, FTAG);
}
}
}
done:
/*
* Add this range to the dnode range list.
* We will finish up this free operation in the syncing phase.
*/
mutex_enter(&dn->dn_mtx);
dnode_clear_range(dn, blkid, nblks, tx);
{
free_range_t *rp, *found;
avl_index_t where;
avl_tree_t *tree = &dn->dn_ranges[tx->tx_txg&TXG_MASK];
/* Add new range to dn_ranges */
rp = kmem_alloc(sizeof (free_range_t), KM_PUSHPAGE);
rp->fr_blkid = blkid;
rp->fr_nblks = nblks;
found = avl_find(tree, rp, &where);
ASSERT(found == NULL);
avl_insert(tree, rp, where);
dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n",
blkid, nblks, tx->tx_txg);
}
mutex_exit(&dn->dn_mtx);
dbuf_free_range(dn, blkid, blkid + nblks - 1, tx);
dnode_setdirty(dn, tx);
out:
if (trunc && dn->dn_maxblkid >= (off >> blkshift))
dn->dn_maxblkid = (off >> blkshift ? (off >> blkshift) - 1 : 0);
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);
}
/* 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)
{
free_range_t range_tofind;
void *dp = spa_get_dsl(dn->dn_objset->os_spa);
int i;
if (blkid == DMU_BONUS_BLKID)
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));
range_tofind.fr_blkid = blkid;
mutex_enter(&dn->dn_mtx);
for (i = 0; i < TXG_SIZE; i++) {
free_range_t *range_found;
avl_index_t idx;
range_found = avl_find(&dn->dn_ranges[i], &range_tofind, &idx);
if (range_found) {
ASSERT(range_found->fr_nblks > 0);
break;
}
range_found = avl_nearest(&dn->dn_ranges[i], idx, AVL_BEFORE);
if (range_found &&
range_found->fr_blkid + range_found->fr_nblks > blkid)
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));
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);
}
/*
* Call when we think we're going to write/free space in open context to track
* the amount of memory in use by the currently open txg.
*/
void
dnode_willuse_space(dnode_t *dn, int64_t space, dmu_tx_t *tx)
{
objset_t *os = dn->dn_objset;
dsl_dataset_t *ds = os->os_dsl_dataset;
int64_t aspace = spa_get_asize(os->os_spa, space);
if (ds != NULL) {
dsl_dir_willuse_space(ds->ds_dir, aspace, tx);
dsl_pool_dirty_space(dmu_tx_pool(tx), space, tx);
}
dmu_tx_willuse_space(tx, aspace);
}
/*
* 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).
*
* 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.
*/
static int
dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
int lvl, uint64_t blkfill, uint64_t txg)
{
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;
dprintf("probing object %llu offset %llx level %d of %u\n",
dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels);
hole = ((flags & DNODE_FIND_HOLE) != 0);
inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1;
ASSERT(txg == 0 || !hole);
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, *offset) >> (epbs * lvl);
error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FTAG, &db);
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));
}
error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT);
if (error) {
dbuf_rele(db, FTAG);
return (error);
}
data = db->db.db_data;
}
if (db && txg &&
(db->db_blkptr == NULL || db->db_blkptr->blk_birth <= txg)) {
/*
* 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);
} else if (lvl == 0) {
dnode_phys_t *dnp = data;
span = DNODE_SHIFT;
ASSERT(dn->dn_type == DMU_OT_DNODE);
for (i = (*offset >> span) & (blkfill - 1);
i >= 0 && i < blkfill; i += inc) {
if ((dnp[i].dn_type == DMU_OT_NONE) == hole)
break;
*offset += (1ULL << span) * inc;
}
if (i < 0 || i == blkfill)
error = SET_ERROR(ESRCH);
} else {
blkptr_t *bp = data;
uint64_t start = *offset;
span = (lvl - 1) * epbs + dn->dn_datablkshift;
minfill = 0;
maxfill = blkfill << ((lvl - 1) * epbs);
if (hole)
maxfill--;
else
minfill++;
*offset = *offset >> span;
for (i = BF64_GET(*offset, 0, epbs);
i >= 0 && i < epb; i += inc) {
if (bp[i].blk_fill >= minfill &&
bp[i].blk_fill <= maxfill &&
(hole || bp[i].blk_birth > txg))
break;
if (inc > 0 || *offset > 0)
*offset += inc;
}
*offset = *offset << span;
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;
}
if (i < 0 || i >= epb)
error = SET_ERROR(ESRCH);
}
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.
* Used in dmu_offset_next().
*
* dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg);
* 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);
* 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,
int minlvl, uint64_t blkfill, uint64_t txg)
{
uint64_t initial_offset = *offset;
int lvl, maxlvl;
int error = 0;
if (!(flags & DNODE_FIND_HAVELOCK))
rw_enter(&dn->dn_struct_rwlock, RW_READER);
if (dn->dn_phys->dn_nlevels == 0) {
error = SET_ERROR(ESRCH);
goto out;
}
if (dn->dn_datablkshift == 0) {
if (*offset < dn->dn_datablksz) {
if (flags & DNODE_FIND_HOLE)
*offset = dn->dn_datablksz;
} else {
error = SET_ERROR(ESRCH);
}
goto out;
}
maxlvl = dn->dn_phys->dn_nlevels;
for (lvl = minlvl; lvl <= maxlvl; lvl++) {
error = dnode_next_offset_level(dn,
flags, offset, lvl, blkfill, txg);
if (error != ESRCH)
break;
}
while (error == 0 && --lvl >= minlvl) {
error = dnode_next_offset_level(dn,
flags, offset, lvl, blkfill, txg);
}
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);
return (error);
}
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