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freebsd-nq/module/zfs/spa_misc.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

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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.
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/spa_impl.h>
#include <sys/zio.h>
#include <sys/zio_checksum.h>
#include <sys/zio_compress.h>
#include <sys/dmu.h>
#include <sys/dmu_tx.h>
#include <sys/zap.h>
#include <sys/zil.h>
#include <sys/vdev_impl.h>
#include <sys/metaslab.h>
#include <sys/uberblock_impl.h>
#include <sys/txg.h>
#include <sys/avl.h>
#include <sys/unique.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_prop.h>
#include <sys/fm/util.h>
#include <sys/dsl_scan.h>
#include <sys/fs/zfs.h>
#include <sys/metaslab_impl.h>
#include <sys/arc.h>
#include <sys/ddt.h>
#include <sys/kstat.h>
#include "zfs_prop.h"
#include "zfeature_common.h"
/*
* SPA locking
*
* There are four basic locks for managing spa_t structures:
*
* spa_namespace_lock (global mutex)
*
* This lock must be acquired to do any of the following:
*
* - Lookup a spa_t by name
* - Add or remove a spa_t from the namespace
* - Increase spa_refcount from non-zero
* - Check if spa_refcount is zero
* - Rename a spa_t
* - add/remove/attach/detach devices
* - Held for the duration of create/destroy/import/export
*
* It does not need to handle recursion. A create or destroy may
* reference objects (files or zvols) in other pools, but by
* definition they must have an existing reference, and will never need
* to lookup a spa_t by name.
*
* spa_refcount (per-spa refcount_t protected by mutex)
*
* This reference count keep track of any active users of the spa_t. The
* spa_t cannot be destroyed or freed while this is non-zero. Internally,
* the refcount is never really 'zero' - opening a pool implicitly keeps
* some references in the DMU. Internally we check against spa_minref, but
* present the image of a zero/non-zero value to consumers.
*
* spa_config_lock[] (per-spa array of rwlocks)
*
* This protects the spa_t from config changes, and must be held in
* the following circumstances:
*
* - RW_READER to perform I/O to the spa
* - RW_WRITER to change the vdev config
*
* The locking order is fairly straightforward:
*
* spa_namespace_lock -> spa_refcount
*
* The namespace lock must be acquired to increase the refcount from 0
* or to check if it is zero.
*
* spa_refcount -> spa_config_lock[]
*
* There must be at least one valid reference on the spa_t to acquire
* the config lock.
*
* spa_namespace_lock -> spa_config_lock[]
*
* The namespace lock must always be taken before the config lock.
*
*
* The spa_namespace_lock can be acquired directly and is globally visible.
*
* The namespace is manipulated using the following functions, all of which
* require the spa_namespace_lock to be held.
*
* spa_lookup() Lookup a spa_t by name.
*
* spa_add() Create a new spa_t in the namespace.
*
* spa_remove() Remove a spa_t from the namespace. This also
* frees up any memory associated with the spa_t.
*
* spa_next() Returns the next spa_t in the system, or the
* first if NULL is passed.
*
* spa_evict_all() Shutdown and remove all spa_t structures in
* the system.
*
* spa_guid_exists() Determine whether a pool/device guid exists.
*
* The spa_refcount is manipulated using the following functions:
*
* spa_open_ref() Adds a reference to the given spa_t. Must be
* called with spa_namespace_lock held if the
* refcount is currently zero.
*
* spa_close() Remove a reference from the spa_t. This will
* not free the spa_t or remove it from the
* namespace. No locking is required.
*
* spa_refcount_zero() Returns true if the refcount is currently
* zero. Must be called with spa_namespace_lock
* held.
*
* The spa_config_lock[] is an array of rwlocks, ordered as follows:
* SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
* spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
*
* To read the configuration, it suffices to hold one of these locks as reader.
* To modify the configuration, you must hold all locks as writer. To modify
* vdev state without altering the vdev tree's topology (e.g. online/offline),
* you must hold SCL_STATE and SCL_ZIO as writer.
*
* We use these distinct config locks to avoid recursive lock entry.
* For example, spa_sync() (which holds SCL_CONFIG as reader) induces
* block allocations (SCL_ALLOC), which may require reading space maps
* from disk (dmu_read() -> zio_read() -> SCL_ZIO).
*
* The spa config locks cannot be normal rwlocks because we need the
* ability to hand off ownership. For example, SCL_ZIO is acquired
* by the issuing thread and later released by an interrupt thread.
* They do, however, obey the usual write-wanted semantics to prevent
* writer (i.e. system administrator) starvation.
*
* The lock acquisition rules are as follows:
*
* SCL_CONFIG
* Protects changes to the vdev tree topology, such as vdev
* add/remove/attach/detach. Protects the dirty config list
* (spa_config_dirty_list) and the set of spares and l2arc devices.
*
* SCL_STATE
* Protects changes to pool state and vdev state, such as vdev
* online/offline/fault/degrade/clear. Protects the dirty state list
* (spa_state_dirty_list) and global pool state (spa_state).
*
* SCL_ALLOC
* Protects changes to metaslab groups and classes.
* Held as reader by metaslab_alloc() and metaslab_claim().
*
* SCL_ZIO
* Held by bp-level zios (those which have no io_vd upon entry)
* to prevent changes to the vdev tree. The bp-level zio implicitly
* protects all of its vdev child zios, which do not hold SCL_ZIO.
*
* SCL_FREE
* Protects changes to metaslab groups and classes.
* Held as reader by metaslab_free(). SCL_FREE is distinct from
* SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
* blocks in zio_done() while another i/o that holds either
* SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
*
* SCL_VDEV
* Held as reader to prevent changes to the vdev tree during trivial
* inquiries such as bp_get_dsize(). SCL_VDEV is distinct from the
* other locks, and lower than all of them, to ensure that it's safe
* to acquire regardless of caller context.
*
* In addition, the following rules apply:
*
* (a) spa_props_lock protects pool properties, spa_config and spa_config_list.
* The lock ordering is SCL_CONFIG > spa_props_lock.
*
* (b) I/O operations on leaf vdevs. For any zio operation that takes
* an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
* or zio_write_phys() -- the caller must ensure that the config cannot
* cannot change in the interim, and that the vdev cannot be reopened.
* SCL_STATE as reader suffices for both.
*
* The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
*
* spa_vdev_enter() Acquire the namespace lock and the config lock
* for writing.
*
* spa_vdev_exit() Release the config lock, wait for all I/O
* to complete, sync the updated configs to the
* cache, and release the namespace lock.
*
* vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
* Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
* locking is, always, based on spa_namespace_lock and spa_config_lock[].
*
* spa_rename() is also implemented within this file since it requires
* manipulation of the namespace.
*/
static avl_tree_t spa_namespace_avl;
kmutex_t spa_namespace_lock;
static kcondvar_t spa_namespace_cv;
static int spa_active_count;
int spa_max_replication_override = SPA_DVAS_PER_BP;
static kmutex_t spa_spare_lock;
static avl_tree_t spa_spare_avl;
static kmutex_t spa_l2cache_lock;
static avl_tree_t spa_l2cache_avl;
kmem_cache_t *spa_buffer_pool;
int spa_mode_global;
/*
* Expiration time in milliseconds. This value has two meanings. First it is
* used to determine when the spa_deadman() logic should fire. By default the
* spa_deadman() will fire if spa_sync() has not completed in 1000 seconds.
* Secondly, the value determines if an I/O is considered "hung". Any I/O that
* has not completed in zfs_deadman_synctime_ms is considered "hung" resulting
* in a system panic.
*/
unsigned long zfs_deadman_synctime_ms = 1000000ULL;
/*
* By default the deadman is enabled.
*/
int zfs_deadman_enabled = 1;
/*
* The worst case is single-sector max-parity RAID-Z blocks, in which
* case the space requirement is exactly (VDEV_RAIDZ_MAXPARITY + 1)
* times the size; so just assume that. Add to this the fact that
* we can have up to 3 DVAs per bp, and one more factor of 2 because
* the block may be dittoed with up to 3 DVAs by ddt_sync(). All together,
* the worst case is:
* (VDEV_RAIDZ_MAXPARITY + 1) * SPA_DVAS_PER_BP * 2 == 24
*/
int spa_asize_inflation = 24;
/*
* ==========================================================================
* SPA config locking
* ==========================================================================
*/
static void
spa_config_lock_init(spa_t *spa)
{
int i;
for (i = 0; i < SCL_LOCKS; i++) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
refcount_create_untracked(&scl->scl_count);
scl->scl_writer = NULL;
scl->scl_write_wanted = 0;
}
}
static void
spa_config_lock_destroy(spa_t *spa)
{
int i;
for (i = 0; i < SCL_LOCKS; i++) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
mutex_destroy(&scl->scl_lock);
cv_destroy(&scl->scl_cv);
refcount_destroy(&scl->scl_count);
ASSERT(scl->scl_writer == NULL);
ASSERT(scl->scl_write_wanted == 0);
}
}
int
spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
{
int i;
for (i = 0; i < SCL_LOCKS; i++) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
if (!(locks & (1 << i)))
continue;
mutex_enter(&scl->scl_lock);
if (rw == RW_READER) {
if (scl->scl_writer || scl->scl_write_wanted) {
mutex_exit(&scl->scl_lock);
spa_config_exit(spa, locks ^ (1 << i), tag);
return (0);
}
} else {
ASSERT(scl->scl_writer != curthread);
if (!refcount_is_zero(&scl->scl_count)) {
mutex_exit(&scl->scl_lock);
spa_config_exit(spa, locks ^ (1 << i), tag);
return (0);
}
scl->scl_writer = curthread;
}
(void) refcount_add(&scl->scl_count, tag);
mutex_exit(&scl->scl_lock);
}
return (1);
}
void
spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
{
int wlocks_held = 0;
int i;
ASSERT3U(SCL_LOCKS, <, sizeof (wlocks_held) * NBBY);
for (i = 0; i < SCL_LOCKS; i++) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
if (scl->scl_writer == curthread)
wlocks_held |= (1 << i);
if (!(locks & (1 << i)))
continue;
mutex_enter(&scl->scl_lock);
if (rw == RW_READER) {
while (scl->scl_writer || scl->scl_write_wanted) {
cv_wait(&scl->scl_cv, &scl->scl_lock);
}
} else {
ASSERT(scl->scl_writer != curthread);
while (!refcount_is_zero(&scl->scl_count)) {
scl->scl_write_wanted++;
cv_wait(&scl->scl_cv, &scl->scl_lock);
scl->scl_write_wanted--;
}
scl->scl_writer = curthread;
}
(void) refcount_add(&scl->scl_count, tag);
mutex_exit(&scl->scl_lock);
}
ASSERT(wlocks_held <= locks);
}
void
spa_config_exit(spa_t *spa, int locks, void *tag)
{
int i;
for (i = SCL_LOCKS - 1; i >= 0; i--) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
if (!(locks & (1 << i)))
continue;
mutex_enter(&scl->scl_lock);
ASSERT(!refcount_is_zero(&scl->scl_count));
if (refcount_remove(&scl->scl_count, tag) == 0) {
ASSERT(scl->scl_writer == NULL ||
scl->scl_writer == curthread);
scl->scl_writer = NULL; /* OK in either case */
cv_broadcast(&scl->scl_cv);
}
mutex_exit(&scl->scl_lock);
}
}
int
spa_config_held(spa_t *spa, int locks, krw_t rw)
{
int i, locks_held = 0;
for (i = 0; i < SCL_LOCKS; i++) {
spa_config_lock_t *scl = &spa->spa_config_lock[i];
if (!(locks & (1 << i)))
continue;
if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
(rw == RW_WRITER && scl->scl_writer == curthread))
locks_held |= 1 << i;
}
return (locks_held);
}
/*
* ==========================================================================
* SPA namespace functions
* ==========================================================================
*/
/*
* Lookup the named spa_t in the AVL tree. The spa_namespace_lock must be held.
* Returns NULL if no matching spa_t is found.
*/
spa_t *
spa_lookup(const char *name)
{
static spa_t search; /* spa_t is large; don't allocate on stack */
spa_t *spa;
avl_index_t where;
char *cp;
ASSERT(MUTEX_HELD(&spa_namespace_lock));
(void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
/*
* If it's a full dataset name, figure out the pool name and
* just use that.
*/
cp = strpbrk(search.spa_name, "/@");
if (cp != NULL)
*cp = '\0';
spa = avl_find(&spa_namespace_avl, &search, &where);
return (spa);
}
/*
* Fires when spa_sync has not completed within zfs_deadman_synctime_ms.
* If the zfs_deadman_enabled flag is set then it inspects all vdev queues
* looking for potentially hung I/Os.
*/
void
spa_deadman(void *arg)
{
spa_t *spa = arg;
zfs_dbgmsg("slow spa_sync: started %llu seconds ago, calls %llu",
(gethrtime() - spa->spa_sync_starttime) / NANOSEC,
++spa->spa_deadman_calls);
if (zfs_deadman_enabled)
vdev_deadman(spa->spa_root_vdev);
spa->spa_deadman_tqid = taskq_dispatch_delay(system_taskq,
spa_deadman, spa, TQ_PUSHPAGE, ddi_get_lbolt() +
NSEC_TO_TICK(spa->spa_deadman_synctime));
}
/*
* Create an uninitialized spa_t with the given name. Requires
* spa_namespace_lock. The caller must ensure that the spa_t doesn't already
* exist by calling spa_lookup() first.
*/
spa_t *
spa_add(const char *name, nvlist_t *config, const char *altroot)
{
spa_t *spa;
spa_config_dirent_t *dp;
int t;
ASSERT(MUTEX_HELD(&spa_namespace_lock));
spa = kmem_zalloc(sizeof (spa_t), KM_PUSHPAGE | KM_NODEBUG);
mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_proc_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
cv_init(&spa->spa_proc_cv, NULL, CV_DEFAULT, NULL);
cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
for (t = 0; t < TXG_SIZE; t++)
bplist_create(&spa->spa_free_bplist[t]);
(void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
spa->spa_state = POOL_STATE_UNINITIALIZED;
spa->spa_freeze_txg = UINT64_MAX;
spa->spa_final_txg = UINT64_MAX;
spa->spa_load_max_txg = UINT64_MAX;
spa->spa_proc = &p0;
spa->spa_proc_state = SPA_PROC_NONE;
spa->spa_deadman_synctime = MSEC2NSEC(zfs_deadman_synctime_ms);
refcount_create(&spa->spa_refcount);
spa_config_lock_init(spa);
spa_stats_init(spa);
avl_add(&spa_namespace_avl, spa);
/*
* Set the alternate root, if there is one.
*/
if (altroot) {
spa->spa_root = spa_strdup(altroot);
spa_active_count++;
}
/*
* Every pool starts with the default cachefile
*/
list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
offsetof(spa_config_dirent_t, scd_link));
dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_PUSHPAGE);
dp->scd_path = altroot ? NULL : spa_strdup(spa_config_path);
list_insert_head(&spa->spa_config_list, dp);
VERIFY(nvlist_alloc(&spa->spa_load_info, NV_UNIQUE_NAME,
KM_PUSHPAGE) == 0);
if (config != NULL) {
nvlist_t *features;
if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
&features) == 0) {
VERIFY(nvlist_dup(features, &spa->spa_label_features,
0) == 0);
}
VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
}
if (spa->spa_label_features == NULL) {
VERIFY(nvlist_alloc(&spa->spa_label_features, NV_UNIQUE_NAME,
KM_SLEEP) == 0);
}
spa->spa_debug = ((zfs_flags & ZFS_DEBUG_SPA) != 0);
return (spa);
}
/*
* Removes a spa_t from the namespace, freeing up any memory used. Requires
* spa_namespace_lock. This is called only after the spa_t has been closed and
* deactivated.
*/
void
spa_remove(spa_t *spa)
{
spa_config_dirent_t *dp;
int t;
ASSERT(MUTEX_HELD(&spa_namespace_lock));
ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
nvlist_free(spa->spa_config_splitting);
avl_remove(&spa_namespace_avl, spa);
cv_broadcast(&spa_namespace_cv);
if (spa->spa_root) {
spa_strfree(spa->spa_root);
spa_active_count--;
}
while ((dp = list_head(&spa->spa_config_list)) != NULL) {
list_remove(&spa->spa_config_list, dp);
if (dp->scd_path != NULL)
spa_strfree(dp->scd_path);
kmem_free(dp, sizeof (spa_config_dirent_t));
}
list_destroy(&spa->spa_config_list);
nvlist_free(spa->spa_label_features);
nvlist_free(spa->spa_load_info);
spa_config_set(spa, NULL);
refcount_destroy(&spa->spa_refcount);
spa_stats_destroy(spa);
spa_config_lock_destroy(spa);
for (t = 0; t < TXG_SIZE; t++)
bplist_destroy(&spa->spa_free_bplist[t]);
cv_destroy(&spa->spa_async_cv);
cv_destroy(&spa->spa_proc_cv);
cv_destroy(&spa->spa_scrub_io_cv);
cv_destroy(&spa->spa_suspend_cv);
mutex_destroy(&spa->spa_async_lock);
mutex_destroy(&spa->spa_errlist_lock);
mutex_destroy(&spa->spa_errlog_lock);
mutex_destroy(&spa->spa_history_lock);
mutex_destroy(&spa->spa_proc_lock);
mutex_destroy(&spa->spa_props_lock);
mutex_destroy(&spa->spa_scrub_lock);
mutex_destroy(&spa->spa_suspend_lock);
mutex_destroy(&spa->spa_vdev_top_lock);
kmem_free(spa, sizeof (spa_t));
}
/*
* Given a pool, return the next pool in the namespace, or NULL if there is
* none. If 'prev' is NULL, return the first pool.
*/
spa_t *
spa_next(spa_t *prev)
{
ASSERT(MUTEX_HELD(&spa_namespace_lock));
if (prev)
return (AVL_NEXT(&spa_namespace_avl, prev));
else
return (avl_first(&spa_namespace_avl));
}
/*
* ==========================================================================
* SPA refcount functions
* ==========================================================================
*/
/*
* Add a reference to the given spa_t. Must have at least one reference, or
* have the namespace lock held.
*/
void
spa_open_ref(spa_t *spa, void *tag)
{
ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
MUTEX_HELD(&spa_namespace_lock));
(void) refcount_add(&spa->spa_refcount, tag);
}
/*
* Remove a reference to the given spa_t. Must have at least one reference, or
* have the namespace lock held.
*/
void
spa_close(spa_t *spa, void *tag)
{
ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
MUTEX_HELD(&spa_namespace_lock));
(void) refcount_remove(&spa->spa_refcount, tag);
}
/*
* Check to see if the spa refcount is zero. Must be called with
* spa_namespace_lock held. We really compare against spa_minref, which is the
* number of references acquired when opening a pool
*/
boolean_t
spa_refcount_zero(spa_t *spa)
{
ASSERT(MUTEX_HELD(&spa_namespace_lock));
return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
}
/*
* ==========================================================================
* SPA spare and l2cache tracking
* ==========================================================================
*/
/*
* Hot spares and cache devices are tracked using the same code below,
* for 'auxiliary' devices.
*/
typedef struct spa_aux {
uint64_t aux_guid;
uint64_t aux_pool;
avl_node_t aux_avl;
int aux_count;
} spa_aux_t;
static int
spa_aux_compare(const void *a, const void *b)
{
const spa_aux_t *sa = a;
const spa_aux_t *sb = b;
if (sa->aux_guid < sb->aux_guid)
return (-1);
else if (sa->aux_guid > sb->aux_guid)
return (1);
else
return (0);
}
void
spa_aux_add(vdev_t *vd, avl_tree_t *avl)
{
avl_index_t where;
spa_aux_t search;
spa_aux_t *aux;
search.aux_guid = vd->vdev_guid;
if ((aux = avl_find(avl, &search, &where)) != NULL) {
aux->aux_count++;
} else {
aux = kmem_zalloc(sizeof (spa_aux_t), KM_PUSHPAGE);
aux->aux_guid = vd->vdev_guid;
aux->aux_count = 1;
avl_insert(avl, aux, where);
}
}
void
spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
{
spa_aux_t search;
spa_aux_t *aux;
avl_index_t where;
search.aux_guid = vd->vdev_guid;
aux = avl_find(avl, &search, &where);
ASSERT(aux != NULL);
if (--aux->aux_count == 0) {
avl_remove(avl, aux);
kmem_free(aux, sizeof (spa_aux_t));
} else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
aux->aux_pool = 0ULL;
}
}
boolean_t
spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
{
spa_aux_t search, *found;
search.aux_guid = guid;
found = avl_find(avl, &search, NULL);
if (pool) {
if (found)
*pool = found->aux_pool;
else
*pool = 0ULL;
}
if (refcnt) {
if (found)
*refcnt = found->aux_count;
else
*refcnt = 0;
}
return (found != NULL);
}
void
spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
{
spa_aux_t search, *found;
avl_index_t where;
search.aux_guid = vd->vdev_guid;
found = avl_find(avl, &search, &where);
ASSERT(found != NULL);
ASSERT(found->aux_pool == 0ULL);
found->aux_pool = spa_guid(vd->vdev_spa);
}
/*
* Spares are tracked globally due to the following constraints:
*
* - A spare may be part of multiple pools.
* - A spare may be added to a pool even if it's actively in use within
* another pool.
* - A spare in use in any pool can only be the source of a replacement if
* the target is a spare in the same pool.
*
* We keep track of all spares on the system through the use of a reference
* counted AVL tree. When a vdev is added as a spare, or used as a replacement
* spare, then we bump the reference count in the AVL tree. In addition, we set
* the 'vdev_isspare' member to indicate that the device is a spare (active or
* inactive). When a spare is made active (used to replace a device in the
* pool), we also keep track of which pool its been made a part of.
*
* The 'spa_spare_lock' protects the AVL tree. These functions are normally
* called under the spa_namespace lock as part of vdev reconfiguration. The
* separate spare lock exists for the status query path, which does not need to
* be completely consistent with respect to other vdev configuration changes.
*/
static int
spa_spare_compare(const void *a, const void *b)
{
return (spa_aux_compare(a, b));
}
void
spa_spare_add(vdev_t *vd)
{
mutex_enter(&spa_spare_lock);
ASSERT(!vd->vdev_isspare);
spa_aux_add(vd, &spa_spare_avl);
vd->vdev_isspare = B_TRUE;
mutex_exit(&spa_spare_lock);
}
void
spa_spare_remove(vdev_t *vd)
{
mutex_enter(&spa_spare_lock);
ASSERT(vd->vdev_isspare);
spa_aux_remove(vd, &spa_spare_avl);
vd->vdev_isspare = B_FALSE;
mutex_exit(&spa_spare_lock);
}
boolean_t
spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
{
boolean_t found;
mutex_enter(&spa_spare_lock);
found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
mutex_exit(&spa_spare_lock);
return (found);
}
void
spa_spare_activate(vdev_t *vd)
{
mutex_enter(&spa_spare_lock);
ASSERT(vd->vdev_isspare);
spa_aux_activate(vd, &spa_spare_avl);
mutex_exit(&spa_spare_lock);
}
/*
* Level 2 ARC devices are tracked globally for the same reasons as spares.
* Cache devices currently only support one pool per cache device, and so
* for these devices the aux reference count is currently unused beyond 1.
*/
static int
spa_l2cache_compare(const void *a, const void *b)
{
return (spa_aux_compare(a, b));
}
void
spa_l2cache_add(vdev_t *vd)
{
mutex_enter(&spa_l2cache_lock);
ASSERT(!vd->vdev_isl2cache);
spa_aux_add(vd, &spa_l2cache_avl);
vd->vdev_isl2cache = B_TRUE;
mutex_exit(&spa_l2cache_lock);
}
void
spa_l2cache_remove(vdev_t *vd)
{
mutex_enter(&spa_l2cache_lock);
ASSERT(vd->vdev_isl2cache);
spa_aux_remove(vd, &spa_l2cache_avl);
vd->vdev_isl2cache = B_FALSE;
mutex_exit(&spa_l2cache_lock);
}
boolean_t
spa_l2cache_exists(uint64_t guid, uint64_t *pool)
{
boolean_t found;
mutex_enter(&spa_l2cache_lock);
found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
mutex_exit(&spa_l2cache_lock);
return (found);
}
void
spa_l2cache_activate(vdev_t *vd)
{
mutex_enter(&spa_l2cache_lock);
ASSERT(vd->vdev_isl2cache);
spa_aux_activate(vd, &spa_l2cache_avl);
mutex_exit(&spa_l2cache_lock);
}
/*
* ==========================================================================
* SPA vdev locking
* ==========================================================================
*/
/*
* Lock the given spa_t for the purpose of adding or removing a vdev.
* Grabs the global spa_namespace_lock plus the spa config lock for writing.
* It returns the next transaction group for the spa_t.
*/
uint64_t
spa_vdev_enter(spa_t *spa)
{
mutex_enter(&spa->spa_vdev_top_lock);
mutex_enter(&spa_namespace_lock);
return (spa_vdev_config_enter(spa));
}
/*
* Internal implementation for spa_vdev_enter(). Used when a vdev
* operation requires multiple syncs (i.e. removing a device) while
* keeping the spa_namespace_lock held.
*/
uint64_t
spa_vdev_config_enter(spa_t *spa)
{
ASSERT(MUTEX_HELD(&spa_namespace_lock));
spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
return (spa_last_synced_txg(spa) + 1);
}
/*
* Used in combination with spa_vdev_config_enter() to allow the syncing
* of multiple transactions without releasing the spa_namespace_lock.
*/
void
spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
{
int config_changed = B_FALSE;
ASSERT(MUTEX_HELD(&spa_namespace_lock));
ASSERT(txg > spa_last_synced_txg(spa));
spa->spa_pending_vdev = NULL;
/*
* Reassess the DTLs.
*/
vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
config_changed = B_TRUE;
spa->spa_config_generation++;
}
/*
* Verify the metaslab classes.
*/
ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0);
ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0);
spa_config_exit(spa, SCL_ALL, spa);
/*
* Panic the system if the specified tag requires it. This
* is useful for ensuring that configurations are updated
* transactionally.
*/
if (zio_injection_enabled)
zio_handle_panic_injection(spa, tag, 0);
/*
* Note: this txg_wait_synced() is important because it ensures
* that there won't be more than one config change per txg.
* This allows us to use the txg as the generation number.
*/
if (error == 0)
txg_wait_synced(spa->spa_dsl_pool, txg);
if (vd != NULL) {
ASSERT(!vd->vdev_detached || vd->vdev_dtl_smo.smo_object == 0);
spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
vdev_free(vd);
spa_config_exit(spa, SCL_ALL, spa);
}
/*
* If the config changed, update the config cache.
*/
if (config_changed)
spa_config_sync(spa, B_FALSE, B_TRUE);
}
/*
* Unlock the spa_t after adding or removing a vdev. Besides undoing the
* locking of spa_vdev_enter(), we also want make sure the transactions have
* synced to disk, and then update the global configuration cache with the new
* information.
*/
int
spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
{
spa_vdev_config_exit(spa, vd, txg, error, FTAG);
mutex_exit(&spa_namespace_lock);
mutex_exit(&spa->spa_vdev_top_lock);
return (error);
}
/*
* Lock the given spa_t for the purpose of changing vdev state.
*/
void
spa_vdev_state_enter(spa_t *spa, int oplocks)
{
int locks = SCL_STATE_ALL | oplocks;
/*
* Root pools may need to read of the underlying devfs filesystem
* when opening up a vdev. Unfortunately if we're holding the
* SCL_ZIO lock it will result in a deadlock when we try to issue
* the read from the root filesystem. Instead we "prefetch"
* the associated vnodes that we need prior to opening the
* underlying devices and cache them so that we can prevent
* any I/O when we are doing the actual open.
*/
if (spa_is_root(spa)) {
int low = locks & ~(SCL_ZIO - 1);
int high = locks & ~low;
spa_config_enter(spa, high, spa, RW_WRITER);
vdev_hold(spa->spa_root_vdev);
spa_config_enter(spa, low, spa, RW_WRITER);
} else {
spa_config_enter(spa, locks, spa, RW_WRITER);
}
spa->spa_vdev_locks = locks;
}
int
spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
{
boolean_t config_changed = B_FALSE;
if (vd != NULL || error == 0)
vdev_dtl_reassess(vd ? vd->vdev_top : spa->spa_root_vdev,
0, 0, B_FALSE);
if (vd != NULL) {
vdev_state_dirty(vd->vdev_top);
config_changed = B_TRUE;
spa->spa_config_generation++;
}
if (spa_is_root(spa))
vdev_rele(spa->spa_root_vdev);
ASSERT3U(spa->spa_vdev_locks, >=, SCL_STATE_ALL);
spa_config_exit(spa, spa->spa_vdev_locks, spa);
/*
* If anything changed, wait for it to sync. This ensures that,
* from the system administrator's perspective, zpool(1M) commands
* are synchronous. This is important for things like zpool offline:
* when the command completes, you expect no further I/O from ZFS.
*/
if (vd != NULL)
txg_wait_synced(spa->spa_dsl_pool, 0);
/*
* If the config changed, update the config cache.
*/
if (config_changed) {
mutex_enter(&spa_namespace_lock);
spa_config_sync(spa, B_FALSE, B_TRUE);
mutex_exit(&spa_namespace_lock);
}
return (error);
}
/*
* ==========================================================================
* Miscellaneous functions
* ==========================================================================
*/
void
spa_activate_mos_feature(spa_t *spa, const char *feature)
{
(void) nvlist_add_boolean(spa->spa_label_features, feature);
vdev_config_dirty(spa->spa_root_vdev);
}
void
spa_deactivate_mos_feature(spa_t *spa, const char *feature)
{
(void) nvlist_remove_all(spa->spa_label_features, feature);
vdev_config_dirty(spa->spa_root_vdev);
}
/*
* Rename a spa_t.
*/
int
spa_rename(const char *name, const char *newname)
{
spa_t *spa;
int err;
/*
* Lookup the spa_t and grab the config lock for writing. We need to
* actually open the pool so that we can sync out the necessary labels.
* It's OK to call spa_open() with the namespace lock held because we
* allow recursive calls for other reasons.
*/
mutex_enter(&spa_namespace_lock);
if ((err = spa_open(name, &spa, FTAG)) != 0) {
mutex_exit(&spa_namespace_lock);
return (err);
}
spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
avl_remove(&spa_namespace_avl, spa);
(void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
avl_add(&spa_namespace_avl, spa);
/*
* Sync all labels to disk with the new names by marking the root vdev
* dirty and waiting for it to sync. It will pick up the new pool name
* during the sync.
*/
vdev_config_dirty(spa->spa_root_vdev);
spa_config_exit(spa, SCL_ALL, FTAG);
txg_wait_synced(spa->spa_dsl_pool, 0);
/*
* Sync the updated config cache.
*/
spa_config_sync(spa, B_FALSE, B_TRUE);
spa_close(spa, FTAG);
mutex_exit(&spa_namespace_lock);
return (0);
}
/*
* Return the spa_t associated with given pool_guid, if it exists. If
* device_guid is non-zero, determine whether the pool exists *and* contains
* a device with the specified device_guid.
*/
spa_t *
spa_by_guid(uint64_t pool_guid, uint64_t device_guid)
{
spa_t *spa;
avl_tree_t *t = &spa_namespace_avl;
ASSERT(MUTEX_HELD(&spa_namespace_lock));
for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
if (spa->spa_state == POOL_STATE_UNINITIALIZED)
continue;
if (spa->spa_root_vdev == NULL)
continue;
if (spa_guid(spa) == pool_guid) {
if (device_guid == 0)
break;
if (vdev_lookup_by_guid(spa->spa_root_vdev,
device_guid) != NULL)
break;
/*
* Check any devices we may be in the process of adding.
*/
if (spa->spa_pending_vdev) {
if (vdev_lookup_by_guid(spa->spa_pending_vdev,
device_guid) != NULL)
break;
}
}
}
return (spa);
}
/*
* Determine whether a pool with the given pool_guid exists.
*/
boolean_t
spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
{
return (spa_by_guid(pool_guid, device_guid) != NULL);
}
char *
spa_strdup(const char *s)
{
size_t len;
char *new;
len = strlen(s);
new = kmem_alloc(len + 1, KM_PUSHPAGE);
bcopy(s, new, len);
new[len] = '\0';
return (new);
}
void
spa_strfree(char *s)
{
kmem_free(s, strlen(s) + 1);
}
uint64_t
spa_get_random(uint64_t range)
{
uint64_t r;
ASSERT(range != 0);
(void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
return (r % range);
}
uint64_t
spa_generate_guid(spa_t *spa)
{
uint64_t guid = spa_get_random(-1ULL);
if (spa != NULL) {
while (guid == 0 || spa_guid_exists(spa_guid(spa), guid))
guid = spa_get_random(-1ULL);
} else {
while (guid == 0 || spa_guid_exists(guid, 0))
guid = spa_get_random(-1ULL);
}
return (guid);
}
void
sprintf_blkptr(char *buf, const blkptr_t *bp)
{
char type[256];
char *checksum = NULL;
char *compress = NULL;
if (bp != NULL) {
if (BP_GET_TYPE(bp) & DMU_OT_NEWTYPE) {
dmu_object_byteswap_t bswap =
DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
(void) snprintf(type, sizeof (type), "bswap %s %s",
DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) ?
"metadata" : "data",
dmu_ot_byteswap[bswap].ob_name);
} else {
(void) strlcpy(type, dmu_ot[BP_GET_TYPE(bp)].ot_name,
sizeof (type));
}
checksum = zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name;
compress = zio_compress_table[BP_GET_COMPRESS(bp)].ci_name;
}
SPRINTF_BLKPTR(snprintf, ' ', buf, bp, type, checksum, compress);
}
void
spa_freeze(spa_t *spa)
{
uint64_t freeze_txg = 0;
spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
if (spa->spa_freeze_txg == UINT64_MAX) {
freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
spa->spa_freeze_txg = freeze_txg;
}
spa_config_exit(spa, SCL_ALL, FTAG);
if (freeze_txg != 0)
txg_wait_synced(spa_get_dsl(spa), freeze_txg);
}
/*
* This is a stripped-down version of strtoull, suitable only for converting
* lowercase hexadecimal numbers that don't overflow.
*/
uint64_t
strtonum(const char *str, char **nptr)
{
uint64_t val = 0;
char c;
int digit;
while ((c = *str) != '\0') {
if (c >= '0' && c <= '9')
digit = c - '0';
else if (c >= 'a' && c <= 'f')
digit = 10 + c - 'a';
else
break;
val *= 16;
val += digit;
str++;
}
if (nptr)
*nptr = (char *)str;
return (val);
}
/*
* ==========================================================================
* Accessor functions
* ==========================================================================
*/
boolean_t
spa_shutting_down(spa_t *spa)
{
return (spa->spa_async_suspended);
}
dsl_pool_t *
spa_get_dsl(spa_t *spa)
{
return (spa->spa_dsl_pool);
}
boolean_t
spa_is_initializing(spa_t *spa)
{
return (spa->spa_is_initializing);
}
blkptr_t *
spa_get_rootblkptr(spa_t *spa)
{
return (&spa->spa_ubsync.ub_rootbp);
}
void
spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
{
spa->spa_uberblock.ub_rootbp = *bp;
}
void
spa_altroot(spa_t *spa, char *buf, size_t buflen)
{
if (spa->spa_root == NULL)
buf[0] = '\0';
else
(void) strncpy(buf, spa->spa_root, buflen);
}
int
spa_sync_pass(spa_t *spa)
{
return (spa->spa_sync_pass);
}
char *
spa_name(spa_t *spa)
{
return (spa->spa_name);
}
uint64_t
spa_guid(spa_t *spa)
{
dsl_pool_t *dp = spa_get_dsl(spa);
uint64_t guid;
/*
* If we fail to parse the config during spa_load(), we can go through
* the error path (which posts an ereport) and end up here with no root
* vdev. We stash the original pool guid in 'spa_config_guid' to handle
* this case.
*/
if (spa->spa_root_vdev == NULL)
return (spa->spa_config_guid);
guid = spa->spa_last_synced_guid != 0 ?
spa->spa_last_synced_guid : spa->spa_root_vdev->vdev_guid;
/*
* Return the most recently synced out guid unless we're
* in syncing context.
*/
if (dp && dsl_pool_sync_context(dp))
return (spa->spa_root_vdev->vdev_guid);
else
return (guid);
}
uint64_t
spa_load_guid(spa_t *spa)
{
/*
* This is a GUID that exists solely as a reference for the
* purposes of the arc. It is generated at load time, and
* is never written to persistent storage.
*/
return (spa->spa_load_guid);
}
uint64_t
spa_last_synced_txg(spa_t *spa)
{
return (spa->spa_ubsync.ub_txg);
}
uint64_t
spa_first_txg(spa_t *spa)
{
return (spa->spa_first_txg);
}
uint64_t
spa_syncing_txg(spa_t *spa)
{
return (spa->spa_syncing_txg);
}
pool_state_t
spa_state(spa_t *spa)
{
return (spa->spa_state);
}
spa_load_state_t
spa_load_state(spa_t *spa)
{
return (spa->spa_load_state);
}
uint64_t
spa_freeze_txg(spa_t *spa)
{
return (spa->spa_freeze_txg);
}
/* ARGSUSED */
uint64_t
spa_get_asize(spa_t *spa, uint64_t lsize)
{
return (lsize * spa_asize_inflation);
}
uint64_t
spa_get_dspace(spa_t *spa)
{
return (spa->spa_dspace);
}
void
spa_update_dspace(spa_t *spa)
{
spa->spa_dspace = metaslab_class_get_dspace(spa_normal_class(spa)) +
ddt_get_dedup_dspace(spa);
}
/*
* Return the failure mode that has been set to this pool. The default
* behavior will be to block all I/Os when a complete failure occurs.
*/
uint8_t
spa_get_failmode(spa_t *spa)
{
return (spa->spa_failmode);
}
boolean_t
spa_suspended(spa_t *spa)
{
return (spa->spa_suspended);
}
uint64_t
spa_version(spa_t *spa)
{
return (spa->spa_ubsync.ub_version);
}
boolean_t
spa_deflate(spa_t *spa)
{
return (spa->spa_deflate);
}
metaslab_class_t *
spa_normal_class(spa_t *spa)
{
return (spa->spa_normal_class);
}
metaslab_class_t *
spa_log_class(spa_t *spa)
{
return (spa->spa_log_class);
}
int
spa_max_replication(spa_t *spa)
{
/*
* As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
* handle BPs with more than one DVA allocated. Set our max
* replication level accordingly.
*/
if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
return (1);
return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
}
int
spa_prev_software_version(spa_t *spa)
{
return (spa->spa_prev_software_version);
}
uint64_t
spa_deadman_synctime(spa_t *spa)
{
return (spa->spa_deadman_synctime);
}
uint64_t
dva_get_dsize_sync(spa_t *spa, const dva_t *dva)
{
uint64_t asize = DVA_GET_ASIZE(dva);
uint64_t dsize = asize;
ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
if (asize != 0 && spa->spa_deflate) {
vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
dsize = (asize >> SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
}
return (dsize);
}
uint64_t
bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
{
uint64_t dsize = 0;
int d;
for (d = 0; d < SPA_DVAS_PER_BP; d++)
dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
return (dsize);
}
uint64_t
bp_get_dsize(spa_t *spa, const blkptr_t *bp)
{
uint64_t dsize = 0;
int d;
spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
for (d = 0; d < SPA_DVAS_PER_BP; d++)
dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
spa_config_exit(spa, SCL_VDEV, FTAG);
return (dsize);
}
/*
* ==========================================================================
* Initialization and Termination
* ==========================================================================
*/
static int
spa_name_compare(const void *a1, const void *a2)
{
const spa_t *s1 = a1;
const spa_t *s2 = a2;
int s;
s = strcmp(s1->spa_name, s2->spa_name);
if (s > 0)
return (1);
if (s < 0)
return (-1);
return (0);
}
void
spa_boot_init(void)
{
spa_config_load();
}
void
spa_init(int mode)
{
mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
offsetof(spa_t, spa_avl));
avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
offsetof(spa_aux_t, aux_avl));
avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
offsetof(spa_aux_t, aux_avl));
spa_mode_global = mode;
#ifndef _KERNEL
if (spa_mode_global != FREAD && dprintf_find_string("watch")) {
struct sigaction sa;
sa.sa_flags = SA_SIGINFO;
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = arc_buf_sigsegv;
if (sigaction(SIGSEGV, &sa, NULL) == -1) {
perror("could not enable watchpoints: "
"sigaction(SIGSEGV, ...) = ");
} else {
arc_watch = B_TRUE;
}
}
#endif
fm_init();
refcount_init();
unique_init();
space_map_init();
zio_init();
dmu_init();
zil_init();
vdev_cache_stat_init();
zfs_prop_init();
zpool_prop_init();
zpool_feature_init();
spa_config_load();
l2arc_start();
}
void
spa_fini(void)
{
l2arc_stop();
spa_evict_all();
vdev_cache_stat_fini();
zil_fini();
dmu_fini();
zio_fini();
space_map_fini();
unique_fini();
refcount_fini();
fm_fini();
avl_destroy(&spa_namespace_avl);
avl_destroy(&spa_spare_avl);
avl_destroy(&spa_l2cache_avl);
cv_destroy(&spa_namespace_cv);
mutex_destroy(&spa_namespace_lock);
mutex_destroy(&spa_spare_lock);
mutex_destroy(&spa_l2cache_lock);
}
/*
* Return whether this pool has slogs. No locking needed.
* It's not a problem if the wrong answer is returned as it's only for
* performance and not correctness
*/
boolean_t
spa_has_slogs(spa_t *spa)
{
return (spa->spa_log_class->mc_rotor != NULL);
}
spa_log_state_t
spa_get_log_state(spa_t *spa)
{
return (spa->spa_log_state);
}
void
spa_set_log_state(spa_t *spa, spa_log_state_t state)
{
spa->spa_log_state = state;
}
boolean_t
spa_is_root(spa_t *spa)
{
return (spa->spa_is_root);
}
boolean_t
spa_writeable(spa_t *spa)
{
return (!!(spa->spa_mode & FWRITE));
}
int
spa_mode(spa_t *spa)
{
return (spa->spa_mode);
}
uint64_t
spa_bootfs(spa_t *spa)
{
return (spa->spa_bootfs);
}
uint64_t
spa_delegation(spa_t *spa)
{
return (spa->spa_delegation);
}
objset_t *
spa_meta_objset(spa_t *spa)
{
return (spa->spa_meta_objset);
}
enum zio_checksum
spa_dedup_checksum(spa_t *spa)
{
return (spa->spa_dedup_checksum);
}
/*
* Reset pool scan stat per scan pass (or reboot).
*/
void
spa_scan_stat_init(spa_t *spa)
{
/* data not stored on disk */
spa->spa_scan_pass_start = gethrestime_sec();
spa->spa_scan_pass_exam = 0;
vdev_scan_stat_init(spa->spa_root_vdev);
}
/*
* Get scan stats for zpool status reports
*/
int
spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
{
dsl_scan_t *scn = spa->spa_dsl_pool ? spa->spa_dsl_pool->dp_scan : NULL;
if (scn == NULL || scn->scn_phys.scn_func == POOL_SCAN_NONE)
return (SET_ERROR(ENOENT));
bzero(ps, sizeof (pool_scan_stat_t));
/* data stored on disk */
ps->pss_func = scn->scn_phys.scn_func;
ps->pss_start_time = scn->scn_phys.scn_start_time;
ps->pss_end_time = scn->scn_phys.scn_end_time;
ps->pss_to_examine = scn->scn_phys.scn_to_examine;
ps->pss_examined = scn->scn_phys.scn_examined;
ps->pss_to_process = scn->scn_phys.scn_to_process;
ps->pss_processed = scn->scn_phys.scn_processed;
ps->pss_errors = scn->scn_phys.scn_errors;
ps->pss_state = scn->scn_phys.scn_state;
/* data not stored on disk */
ps->pss_pass_start = spa->spa_scan_pass_start;
ps->pss_pass_exam = spa->spa_scan_pass_exam;
return (0);
}
boolean_t
spa_debug_enabled(spa_t *spa)
{
return (spa->spa_debug);
}
#if defined(_KERNEL) && defined(HAVE_SPL)
/* Namespace manipulation */
EXPORT_SYMBOL(spa_lookup);
EXPORT_SYMBOL(spa_add);
EXPORT_SYMBOL(spa_remove);
EXPORT_SYMBOL(spa_next);
/* Refcount functions */
EXPORT_SYMBOL(spa_open_ref);
EXPORT_SYMBOL(spa_close);
EXPORT_SYMBOL(spa_refcount_zero);
/* Pool configuration lock */
EXPORT_SYMBOL(spa_config_tryenter);
EXPORT_SYMBOL(spa_config_enter);
EXPORT_SYMBOL(spa_config_exit);
EXPORT_SYMBOL(spa_config_held);
/* Pool vdev add/remove lock */
EXPORT_SYMBOL(spa_vdev_enter);
EXPORT_SYMBOL(spa_vdev_exit);
/* Pool vdev state change lock */
EXPORT_SYMBOL(spa_vdev_state_enter);
EXPORT_SYMBOL(spa_vdev_state_exit);
/* Accessor functions */
EXPORT_SYMBOL(spa_shutting_down);
EXPORT_SYMBOL(spa_get_dsl);
EXPORT_SYMBOL(spa_get_rootblkptr);
EXPORT_SYMBOL(spa_set_rootblkptr);
EXPORT_SYMBOL(spa_altroot);
EXPORT_SYMBOL(spa_sync_pass);
EXPORT_SYMBOL(spa_name);
EXPORT_SYMBOL(spa_guid);
EXPORT_SYMBOL(spa_last_synced_txg);
EXPORT_SYMBOL(spa_first_txg);
EXPORT_SYMBOL(spa_syncing_txg);
EXPORT_SYMBOL(spa_version);
EXPORT_SYMBOL(spa_state);
EXPORT_SYMBOL(spa_load_state);
EXPORT_SYMBOL(spa_freeze_txg);
EXPORT_SYMBOL(spa_get_asize);
EXPORT_SYMBOL(spa_get_dspace);
EXPORT_SYMBOL(spa_update_dspace);
EXPORT_SYMBOL(spa_deflate);
EXPORT_SYMBOL(spa_normal_class);
EXPORT_SYMBOL(spa_log_class);
EXPORT_SYMBOL(spa_max_replication);
EXPORT_SYMBOL(spa_prev_software_version);
EXPORT_SYMBOL(spa_get_failmode);
EXPORT_SYMBOL(spa_suspended);
EXPORT_SYMBOL(spa_bootfs);
EXPORT_SYMBOL(spa_delegation);
EXPORT_SYMBOL(spa_meta_objset);
/* Miscellaneous support routines */
EXPORT_SYMBOL(spa_rename);
EXPORT_SYMBOL(spa_guid_exists);
EXPORT_SYMBOL(spa_strdup);
EXPORT_SYMBOL(spa_strfree);
EXPORT_SYMBOL(spa_get_random);
EXPORT_SYMBOL(spa_generate_guid);
EXPORT_SYMBOL(sprintf_blkptr);
EXPORT_SYMBOL(spa_freeze);
EXPORT_SYMBOL(spa_upgrade);
EXPORT_SYMBOL(spa_evict_all);
EXPORT_SYMBOL(spa_lookup_by_guid);
EXPORT_SYMBOL(spa_has_spare);
EXPORT_SYMBOL(dva_get_dsize_sync);
EXPORT_SYMBOL(bp_get_dsize_sync);
EXPORT_SYMBOL(bp_get_dsize);
EXPORT_SYMBOL(spa_has_slogs);
EXPORT_SYMBOL(spa_is_root);
EXPORT_SYMBOL(spa_writeable);
EXPORT_SYMBOL(spa_mode);
EXPORT_SYMBOL(spa_namespace_lock);
module_param(zfs_deadman_synctime_ms, ulong, 0644);
MODULE_PARM_DESC(zfs_deadman_synctime_ms,"Expiration time in milliseconds");
module_param(zfs_deadman_enabled, int, 0644);
MODULE_PARM_DESC(zfs_deadman_enabled, "Enable deadman timer");
module_param(spa_asize_inflation, int, 0644);
MODULE_PARM_DESC(spa_asize_inflation,
"SPA size estimate multiplication factor");
#endif
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