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c96c36fa22
freebsd-dev/module/zfs
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Brian Behlendorf c96c36fa22 Fix zsb->z_hold_mtx deadlock 
The zfs_znode_hold_enter() / zfs_znode_hold_exit() functions are used to
serialize access to a znode and its SA buffer while the object is being
created or destroyed.  This kind of locking would normally reside in the
znode itself but in this case that's impossible because the znode and SA
buffer may not yet exist.  Therefore the locking is handled externally
with an array of mutexs and AVLs trees which contain per-object locks.

In zfs_znode_hold_enter() a per-object lock is created as needed, inserted
in to the correct AVL tree and finally the per-object lock is held.  In
zfs_znode_hold_exit() the process is reversed.  The per-object lock is
released, removed from the AVL tree and destroyed if there are no waiters.

This scheme has two important properties:

1) No memory allocations are performed while holding one of the z_hold_locks.
   This ensures evict(), which can be called from direct memory reclaim, will
   never block waiting on a z_hold_locks which just happens to have hashed
   to the same index.

2) All locks used to serialize access to an object are per-object and never
   shared.  This minimizes lock contention without creating a large number
   of dedicated locks.

On the downside it does require znode_lock_t structures to be frequently
allocated and freed.  However, because these are backed by a kmem cache
and very short lived this cost is minimal.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4106
2016-01-15 15:33:45 -08:00
..
arc.c Illumos 5987 - zfs prefetch code needs work 2016-01-12 09:02:33 -08:00
blkptr.c Illumos 4757, 4913 2014-08-01 14:28:05 -07:00
bplist.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
bpobj.c Illumos 5810 - zdb should print details of bpobj 2015-05-11 15:10:24 -07:00
bptree.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
bqueue.c Allow 16M send/recv blocks 2016-01-08 20:23:23 -05:00
dbuf_stats.c Illumos 5497 - lock contention on arcs_mtx 2015-06-11 10:27:25 -07:00
dbuf.c Illumos 6288 - dmu_buf_will_dirty could be faster 2016-01-12 09:13:52 -08:00
ddt_zap.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
ddt.c Handle zap_lookup() failure in ddt_object_load() 2015-08-19 14:32:50 -07:00
dmu_diff.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dmu_object.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dmu_objset.c Illumos 6171 - dsl_prop_unregister() slows down dataset eviction. 2016-01-12 10:53:12 -08:00
dmu_send.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dmu_traverse.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dmu_tx.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dmu_zfetch.c Illumos 6281 - prefetching should apply to 1MB reads 2016-01-12 13:51:27 -08:00
dmu.c Illumos 6281 - prefetching should apply to 1MB reads 2016-01-12 13:51:27 -08:00
dnode_sync.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dnode.c Illumos 5987 - zfs prefetch code needs work 2016-01-12 09:02:33 -08:00
dsl_bookmark.c Illumos 4951 - ZFS administrative commands should use reserved space 2015-05-04 09:41:10 -07:00
dsl_dataset.c Illumos 6171 - dsl_prop_unregister() slows down dataset eviction. 2016-01-12 10:53:12 -08:00
dsl_deadlist.c Handle damaged blk_birth in dsl_deadlist_insert() 2015-12-15 16:12:31 -08:00
dsl_deleg.c Illumos 4951 - ZFS administrative commands should use reserved space 2015-05-04 09:41:10 -07:00
dsl_destroy.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
dsl_dir.c Illumos 6171 - dsl_prop_unregister() slows down dataset eviction. 2016-01-12 10:53:12 -08:00
dsl_pool.c Align thread priority with Linux defaults 2015-07-28 13:36:47 -07:00
dsl_prop.c Illumos 6171 - dsl_prop_unregister() slows down dataset eviction. 2016-01-12 10:53:12 -08:00
dsl_scan.c Illumos 6292 - exporting a pool while an async destroy 2016-01-12 09:10:52 -08:00
dsl_synctask.c Illumos 4951 - ZFS administrative commands should use reserved space 2015-05-04 09:41:10 -07:00
dsl_userhold.c Illumos 4951 - ZFS administrative commands should use reserved space 2015-05-04 09:41:10 -07:00
fm.c zfsdev_getminor() should check for invalid file handles 2015-06-22 17:02:13 -07:00
gzip.c cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
lz4.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
lzjb.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
Makefile.in Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
metaslab.c Illumos 6295 - metaslab_condense's dbgmsg should include vdev id 2016-01-12 11:02:07 -08:00
multilist.c Identify locks flagged by lockdep 2015-12-22 10:21:33 -08:00
range_tree.c Illumos 5163 - arc should reap range_seg_cache 2015-06-25 08:58:16 -07:00
refcount.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
rrwlock.c Illumos 5008 - lock contention (rrw_exit) while running a read only load 2015-07-06 09:34:13 -07:00
sa.c Prevent SA length overflow 2015-12-30 13:20:12 -08:00
sha256.c Add linux sha2 support 2010-08-31 13:41:59 -07:00
spa_boot.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
spa_config.c Illumos 3749 - zfs event processing should work on R/O root filesystems 2016-01-12 14:42:32 -08:00
spa_errlog.c Illumos 4914 - zfs on-disk bookmark structure should be named *_phys_t 2014-08-06 14:48:41 -07:00
spa_history.c Illumos 5027 - zfs large block support 2015-05-11 12:23:16 -07:00
spa_misc.c Illumos 6367 - spa_config_tryenter incorrectly handles the multiple-lock case 2016-01-12 11:05:28 -08:00
spa_stats.c Illumos 5369 - arc flags should be an enum 2015-06-11 10:27:25 -07:00
spa.c Illumos 3749 - zfs event processing should work on R/O root filesystems 2016-01-12 14:42:32 -08:00
space_map.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
space_reftree.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
trace.c Illumos 5497 - lock contention on arcs_mtx 2015-06-11 10:27:25 -07:00
txg.c Increase default user space stack size 2016-01-13 13:55:12 -08:00
uberblock.c Illumos 5347 - idle pool may run itself out of space 2015-07-14 10:35:21 -07:00
unique.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
vdev_cache.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
vdev_disk.c Fix use-after-free in vdev_disk_physio_completion 2015-10-13 15:25:33 -07:00
vdev_file.c Disable LBA weighting on files and SSDs 2015-09-01 15:22:07 -07:00
vdev_label.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
vdev_mirror.c Illumos #5244 - zio pipeline callers should explicitly invoke next stage 2015-04-30 15:07:47 -07:00
vdev_missing.c Illumos #5244 - zio pipeline callers should explicitly invoke next stage 2015-04-30 15:07:47 -07:00
vdev_queue.c Fix zfs_vdev_aggregation_limit bounds checking 2015-12-18 13:32:06 -08:00
vdev_raidz.c Illumos #5244 - zio pipeline callers should explicitly invoke next stage 2015-04-30 15:07:47 -07:00
vdev_root.c Illumos #3598 2013-10-31 14:58:04 -07:00
vdev.c Identify locks flagged by lockdep 2015-12-22 10:21:33 -08:00
zap_leaf.c Illumos 5314 - Remove "dbuf phys" db->db_data pointer aliases in ZFS 2015-04-28 16:25:20 -07:00
zap_micro.c Add zap_prefetch() interface 2015-12-04 09:39:20 -08:00
zap.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00
zfeature_common.c Illumos 5959 - clean up per-dataset feature count code 2015-12-04 14:20:20 -08:00
zfeature.c Illumos 5959 - clean up per-dataset feature count code 2015-12-04 14:20:20 -08:00
zfs_acl.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
zfs_byteswap.c Add linux kernel module support 2010-08-31 13:41:58 -07:00
zfs_ctldir.c Hold the zfs_snapentry_t before dispatch 2015-12-14 12:06:31 -08:00
zfs_debug.c Add dbgmsg kstat 2015-09-04 16:08:14 -07:00
zfs_dir.c Make xattr dir truncate and remove in one tx 2015-12-28 09:48:26 -08:00
zfs_fm.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
zfs_fuid.c Illumos #3522 2013-10-30 14:51:27 -07:00
zfs_ioctl.c Illumos 5515 - dataset user hold doesn't reject empty tags 2016-01-12 13:52:26 -08:00
zfs_log.c Illumos 5027 - zfs large block support 2015-05-11 12:23:16 -07:00
zfs_onexit.c zfsdev_getminor() should check for invalid file handles 2015-06-22 17:02:13 -07:00
zfs_replay.c Linux AIO Support 2014-09-05 15:11:43 -07:00
zfs_rlock.c Change KM_PUSHPAGE -> KM_SLEEP 2015-01-16 14:41:26 -08:00
zfs_sa.c Prevent SA length overflow 2015-12-30 13:20:12 -08:00
zfs_vfsops.c Fix zsb->z_hold_mtx deadlock 2016-01-15 15:33:45 -08:00
zfs_vnops.c Illumos 4638 - Panic in ZFS via rfs3_setattr()/rfs3_write(): dirtying snapshot! 2016-01-11 10:29:48 -08:00
zfs_znode.c Fix zsb->z_hold_mtx deadlock 2016-01-15 15:33:45 -08:00
zil.c Align thread priority with Linux defaults 2015-07-28 13:36:47 -07:00
zio_checksum.c Illumos 4757, 4913 2014-08-01 14:28:05 -07:00
zio_compress.c Illumos 5661 - ZFS: "compression = on" should use lz4 if feature is enabled 2015-07-10 12:11:45 -07:00
zio_inject.c Illumos 5497 - lock contention on arcs_mtx 2015-06-11 10:27:25 -07:00
zio.c Illumos 5438 - zfs_blkptr_verify should continue after zfs_panic_recover 2016-01-12 13:54:05 -08:00
zle.c Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00
zpl_ctldir.c Linux 3.18 compat: Snapshot auto-mounting 2015-08-31 13:54:39 -07:00
zpl_export.c zfsctl: No need to sync ctldir inodes 2015-08-31 13:54:39 -07:00
zpl_file.c Linux 4.1 compat: loop device on ZFS 2015-08-24 10:17:06 -07:00
zpl_inode.c Fix casesensitivity=insensitive deadlock 2016-01-08 11:05:07 -08:00
zpl_super.c Disable zpl_nr_cached_objects() callback 2015-09-25 12:45:42 -07:00
zpl_xattr.c Prevent SA length overflow 2015-12-30 13:20:12 -08:00
zrlock.c Illumos 5812 - assertion failed in zrl_tryenter(): zr_owner==NULL 2015-04-30 14:43:40 -07:00
zvol.c Illumos 5960, 5925 2016-01-08 15:08:19 -08:00