Sage Weil ac14aed665 Btrfs: do not take cleanup_work_sem in btrfs_run_delayed_iputs() ... Josef has suggested that this is not necessary. Removing it also avoids this lockdep splat (after the new sb_internal locking stuff was added): [ 604.090449] ====================================================== [ 604.114819] [ INFO: possible circular locking dependency detected ] [ 604.139262] 3.6.0-rc2-ceph-00144-g463b030 #1 Not tainted [ 604.162193] ------------------------------------------------------- [ 604.186139] btrfs-cleaner/6669 is trying to acquire lock: [ 604.209555] (sb_internal#2){.+.+..}, at: [<ffffffffa0042b84>] start_transaction+0x124/0x430 [btrfs] [ 604.257100] [ 604.257100] but task is already holding lock: [ 604.300366] (&fs_info->cleanup_work_sem){.+.+..}, at: [<ffffffffa0048002>] btrfs_run_delayed_iputs+0x72/0x130 [btrfs] [ 604.352989] [ 604.352989] which lock already depends on the new lock. [ 604.352989] [ 604.427104] [ 604.427104] the existing dependency chain (in reverse order) is: [ 604.478493] [ 604.478493] -> #1 (&fs_info->cleanup_work_sem){.+.+..}: [ 604.529313] [<ffffffff810b2c82>] lock_acquire+0xa2/0x140 [ 604.559621] [<ffffffff81632b69>] down_read+0x39/0x4e [ 604.589382] [<ffffffffa004db98>] btrfs_lookup_dentry+0x218/0x550 [btrfs] [ 604.596161] btrfs: unlinked 1 orphans [ 604.675002] [<ffffffffa006aadd>] create_subvol+0x62d/0x690 [btrfs] [ 604.708859] [<ffffffffa006d666>] btrfs_mksubvol.isra.52+0x346/0x3a0 [btrfs] [ 604.772466] [<ffffffffa006d7f2>] btrfs_ioctl_snap_create_transid+0x132/0x190 [btrfs] [ 604.842245] [<ffffffffa006d8ae>] btrfs_ioctl_snap_create+0x5e/0x80 [btrfs] [ 604.912852] [<ffffffffa00708ae>] btrfs_ioctl+0x138e/0x1990 [btrfs] [ 604.951888] [<ffffffff8118e9b8>] do_vfs_ioctl+0x98/0x560 [ 604.989961] [<ffffffff8118ef11>] sys_ioctl+0x91/0xa0 [ 605.026628] [<ffffffff8163d569>] system_call_fastpath+0x16/0x1b [ 605.064404] [ 605.064404] -> #0 (sb_internal#2){.+.+..}: [ 605.126832] [<ffffffff810b25e8>] __lock_acquire+0x1ac8/0x1b90 [ 605.163671] [<ffffffff810b2c82>] lock_acquire+0xa2/0x140 [ 605.200228] [<ffffffff8117dac6>] __sb_start_write+0xc6/0x1b0 [ 605.236818] [<ffffffffa0042b84>] start_transaction+0x124/0x430 [btrfs] [ 605.274029] [<ffffffffa00431a3>] btrfs_start_transaction+0x13/0x20 [btrfs] [ 605.340520] [<ffffffffa004ccfa>] btrfs_evict_inode+0x19a/0x330 [btrfs] [ 605.378720] [<ffffffff811972c8>] evict+0xb8/0x1c0 [ 605.416057] [<ffffffff811974d5>] iput+0x105/0x210 [ 605.452373] [<ffffffffa0048082>] btrfs_run_delayed_iputs+0xf2/0x130 [btrfs] [ 605.521627] [<ffffffffa003b5e1>] cleaner_kthread+0xa1/0x120 [btrfs] [ 605.560520] [<ffffffff810791ee>] kthread+0xae/0xc0 [ 605.598094] [<ffffffff8163e744>] kernel_thread_helper+0x4/0x10 [ 605.636499] [ 605.636499] other info that might help us debug this: [ 605.636499] [ 605.736504] Possible unsafe locking scenario: [ 605.736504] [ 605.801931] CPU0 CPU1 [ 605.835126] ---- ---- [ 605.867093] lock(&fs_info->cleanup_work_sem); [ 605.898594] lock(sb_internal#2); [ 605.931954] lock(&fs_info->cleanup_work_sem); [ 605.965359] lock(sb_internal#2); [ 605.994758] [ 605.994758] *** DEADLOCK *** [ 605.994758] [ 606.075281] 2 locks held by btrfs-cleaner/6669: [ 606.104528] #0: (&fs_info->cleaner_mutex){+.+...}, at: [<ffffffffa003b5d5>] cleaner_kthread+0x95/0x120 [btrfs] [ 606.165626] #1: (&fs_info->cleanup_work_sem){.+.+..}, at: [<ffffffffa0048002>] btrfs_run_delayed_iputs+0x72/0x130 [btrfs] [ 606.231297] [ 606.231297] stack backtrace: [ 606.287723] Pid: 6669, comm: btrfs-cleaner Not tainted 3.6.0-rc2-ceph-00144-g463b030 #1 [ 606.347823] Call Trace: [ 606.376184] [<ffffffff8162a77c>] print_circular_bug+0x1fb/0x20c [ 606.409243] [<ffffffff810b25e8>] __lock_acquire+0x1ac8/0x1b90 [ 606.441343] [<ffffffffa0042b84>] ? start_transaction+0x124/0x430 [btrfs] [ 606.474583] [<ffffffff810b2c82>] lock_acquire+0xa2/0x140 [ 606.505934] [<ffffffffa0042b84>] ? start_transaction+0x124/0x430 [btrfs] [ 606.539429] [<ffffffff8132babd>] ? do_raw_spin_unlock+0x5d/0xb0 [ 606.571719] [<ffffffff8117dac6>] __sb_start_write+0xc6/0x1b0 [ 606.603498] [<ffffffffa0042b84>] ? start_transaction+0x124/0x430 [btrfs] [ 606.637405] [<ffffffffa0042b84>] ? start_transaction+0x124/0x430 [btrfs] [ 606.670165] [<ffffffff81172e75>] ? kmem_cache_alloc+0xb5/0x160 [ 606.702144] [<ffffffffa0042b84>] start_transaction+0x124/0x430 [btrfs] [ 606.735562] [<ffffffffa00256a6>] ? block_rsv_add_bytes+0x56/0x80 [btrfs] [ 606.769861] [<ffffffffa00431a3>] btrfs_start_transaction+0x13/0x20 [btrfs] [ 606.804575] [<ffffffffa004ccfa>] btrfs_evict_inode+0x19a/0x330 [btrfs] [ 606.838756] [<ffffffff81634c6b>] ? _raw_spin_unlock+0x2b/0x40 [ 606.872010] [<ffffffff811972c8>] evict+0xb8/0x1c0 [ 606.903800] [<ffffffff811974d5>] iput+0x105/0x210 [ 606.935416] [<ffffffffa0048082>] btrfs_run_delayed_iputs+0xf2/0x130 [btrfs] [ 606.970510] [<ffffffffa003b5d5>] ? cleaner_kthread+0x95/0x120 [btrfs] [ 607.005648] [<ffffffffa003b5e1>] cleaner_kthread+0xa1/0x120 [btrfs] [ 607.040724] [<ffffffffa003b540>] ? btrfs_destroy_delayed_refs.isra.102+0x220/0x220 [btrfs] [ 607.104740] [<ffffffff810791ee>] kthread+0xae/0xc0 [ 607.137119] [<ffffffff810b379d>] ? trace_hardirqs_on+0xd/0x10 [ 607.169797] [<ffffffff8163e744>] kernel_thread_helper+0x4/0x10 [ 607.202472] [<ffffffff81635430>] ? retint_restore_args+0x13/0x13 [ 607.235884] [<ffffffff81079140>] ? flush_kthread_work+0x1a0/0x1a0 [ 607.268731] [<ffffffff8163e740>] ? gs_change+0x13/0x13 Signed-off-by: Sage Weil <sage@inktank.com>		2012-10-01 15:19:08 -04:00
..
acl.c	Btrfs: cache no acl on new inodes	2012-05-30 10:23:27 -04:00
async-thread.c	Btrfs: call the ordered free operation without any locks held	2012-07-25 16:15:07 -04:00
async-thread.h	btrfs: return void in functions without error conditions	2012-03-22 01:45:34 +01:00
backref.c	Btrfs: fix gcc warnings for 32bit compiles	2012-10-01 15:19:01 -04:00
backref.h	Merge branch 'send-v2' of git://github.com/ablock84/linux-btrfs into for-linus	2012-07-25 19:19:10 -04:00
btrfs_inode.h	Btrfs: fix a bug in checking whether a inode is already in log	2012-10-01 15:19:06 -04:00
check-integrity.c	Btrfs: introduce subvol uuids and times	2012-07-25 23:28:38 +02:00
check-integrity.h	Btrfs: add optional integrity check code	2011-12-21 19:14:09 +01:00
compat.h
compression.c	Btrfs: barrier before waitqueue_active	2012-08-28 16:53:33 -04:00
compression.h	btrfs: return void in functions without error conditions	2012-03-22 01:45:34 +01:00
ctree.c	Btrfs: fix btrfs send for inline items and compression	2012-10-01 15:19:00 -04:00
ctree.h	Btrfs: add hole punching	2012-10-01 15:19:07 -04:00
delayed-inode.c	Btrfs: barrier before waitqueue_active	2012-08-28 16:53:33 -04:00
delayed-inode.h	Btrfs: flush delayed inodes if we're short on space	2012-07-23 15:41:40 -04:00
delayed-ref.c	Btrfs: allow delayed refs to be merged	2012-08-28 16:53:38 -04:00
delayed-ref.h	Btrfs: allow delayed refs to be merged	2012-08-28 16:53:38 -04:00
dir-item.c	btrfs: replace many BUG_ONs with proper error handling	2012-03-22 11:52:54 +01:00
disk-io.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2012-08-29 11:36:22 -07:00
disk-io.h	Btrfs: remove superblock writing after fatal error	2012-08-28 16:53:38 -04:00
export.c	->encode_fh() API change	2012-05-29 23:28:33 -04:00
export.h
extent-tree.c	Btrfs: add hole punching	2012-10-01 15:19:07 -04:00
extent_io.c	Btrfs: fix btrfs send for inline items and compression	2012-10-01 15:19:00 -04:00
extent_io.h	Merge branch 'for-chris' of git://git.jan-o-sch.net/btrfs-unstable into for-linus	2012-05-31 16:49:53 -04:00
extent_map.c	Btrfs: improve fsync by filtering extents that we want	2012-10-01 15:19:05 -04:00
extent_map.h	Btrfs: improve fsync by filtering extents that we want	2012-10-01 15:19:05 -04:00
file-item.c	Btrfs: fix gcc warnings for 32bit compiles	2012-10-01 15:19:01 -04:00
file.c	Btrfs: add hole punching	2012-10-01 15:19:07 -04:00
free-space-cache.c	Btrfs: do not count in readonly bytes	2012-07-23 16:28:03 -04:00
free-space-cache.h	btrfs: remove all unused functions	2011-05-06 12:34:03 +02:00
hash.h
inode-item.c	Merge branch 'error-handling' into for-linus	2012-03-28 20:31:37 -04:00
inode-map.c	Btrfs: show useful info in space reservation tracepoint	2012-03-29 09:57:44 -04:00
inode-map.h	Btrfs: Support reading/writing on disk free ino cache	2011-04-25 16:46:11 +08:00
inode.c	Btrfs: do not take cleanup_work_sem in btrfs_run_delayed_iputs()	2012-10-01 15:19:08 -04:00
ioctl.c	Btrfs: remove unused hint byte argument for btrfs_drop_extents	2012-10-01 15:19:06 -04:00
ioctl.h	Merge branch 'send-v2' of git://github.com/ablock84/linux-btrfs into for-linus	2012-07-25 19:19:10 -04:00
Kconfig	Btrfs: add config option to enable btrfs integrity check	2011-12-21 19:14:16 +01:00
locking.c	Btrfs: fix a misplaced address operator in a condition	2012-08-28 16:53:23 -04:00
locking.h	btrfs: return void in functions without error conditions	2012-03-22 01:45:34 +01:00
lzo.c	btrfs: remove the second argument of k[un]map_atomic()	2012-03-20 21:48:21 +08:00
Makefile	Merge branch 'send-v2' of git://github.com/ablock84/linux-btrfs into for-linus	2012-07-25 19:19:10 -04:00
ordered-data.c	btrfs: nuke pdflush from comments	2012-08-04 12:15:35 +04:00
ordered-data.h	Btrfs: finish ordered extents in their own thread	2012-05-30 10:23:33 -04:00
orphan.c	btrfs: replace many BUG_ONs with proper error handling	2012-03-22 11:52:54 +01:00
print-tree.c	Btrfs: read device stats on mount, write modified ones during commit	2012-05-30 10:23:41 -04:00
print-tree.h
qgroup.c	Btrfs: fix gcc warnings for 32bit compiles	2012-10-01 15:19:01 -04:00
rcu-string.h	Btrfs: use rcu to protect device->name	2012-06-14 21:29:16 -04:00
reada.c	Btrfs: set ioprio of scrub readahead to idle	2012-05-30 10:23:43 -04:00
relocation.c	btrfs: use printk_get_level and printk_skip_level, add __printf, fix fallout	2012-07-30 17:25:14 -07:00
root-tree.c	Btrfs: fix some endian bugs handling the root times	2012-08-28 16:53:26 -04:00
scrub.c	Btrfs: use rcu to protect device->name	2012-06-14 21:29:16 -04:00
send.c	Btrfs: fix gcc warnings for 32bit compiles	2012-10-01 15:19:01 -04:00
send.h	Btrfs: introduce BTRFS_IOC_SEND for btrfs send/receive	2012-07-25 23:30:19 +02:00
struct-funcs.c	Btrfs: rewrite BTRFS_SETGET_FUNCS	2012-07-23 16:28:06 -04:00
super.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2012-08-29 11:36:22 -07:00
sysfs.c	btrfs: Remove unused sysfs code	2011-06-17 14:54:18 -04:00
transaction.c	Btrfs: set journal_info in async trans commit worker	2012-10-01 15:19:08 -04:00
transaction.h	Btrfs: fix a bug in checking whether a inode is already in log	2012-10-01 15:19:06 -04:00
tree-defrag.c	btrfs: drop unused parameter from btrfs_release_path	2011-05-02 13:57:22 +02:00
tree-log.c	Btrfs: add hole punching	2012-10-01 15:19:07 -04:00
tree-log.h	btrfs: return void in functions without error conditions	2012-03-22 01:45:34 +01:00
ulist.c	Btrfs: make aux field of ulist 64 bit	2012-10-01 15:18:53 -04:00
ulist.h	Btrfs: make aux field of ulist 64 bit	2012-10-01 15:18:53 -04:00
version.h
volumes.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2012-08-29 11:36:22 -07:00
volumes.h	Btrfs: revert checksum error statistic which can cause a BUG()	2012-08-28 16:53:39 -04:00
xattr.c	Btrfs: use i_version instead of our own sequence	2012-05-30 10:23:27 -04:00
xattr.h	fs/vfs/security: pass last path component to LSM on inode creation	2011-02-01 11:12:29 -05:00
zlib.c	btrfs: remove the second argument of k[un]map_atomic()	2012-03-20 21:48:21 +08:00