Commit Graph

15830 Commits

Author SHA1 Message Date
Frederic Weisbecker
4dd859697f reiserfs: Fix journal mutex <-> inode mutex lock inversion
We need to relax the reiserfs lock before locking the inode mutex
from xattr_unlink(), otherwise we'll face the usual bad dependencies:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #178
-------------------------------------------------------
rm/3202 is trying to acquire lock:
 (&journal->j_mutex){+.+...}, at: [<c113c234>] do_journal_begin_r+0x94/0x360

but task is already holding lock:
 (&sb->s_type->i_mutex_key#4/2){+.+...}, at: [<c1142a67>] xattr_unlink+0x57/0xb0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (&sb->s_type->i_mutex_key#4/2){+.+...}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a7b>] mutex_lock_nested+0x5b/0x340
       [<c1142a67>] xattr_unlink+0x57/0xb0
       [<c1143179>] delete_one_xattr+0x29/0x100
       [<c11427bb>] reiserfs_for_each_xattr+0x10b/0x290
       [<c11429ba>] reiserfs_delete_xattrs+0x1a/0x60
       [<c111ea2f>] reiserfs_delete_inode+0x9f/0x150
       [<c10c9c32>] generic_delete_inode+0xa2/0x170
       [<c10c9d4f>] generic_drop_inode+0x4f/0x70
       [<c10c8b07>] iput+0x47/0x50
       [<c10c0965>] do_unlinkat+0xd5/0x160
       [<c10c0b13>] sys_unlinkat+0x23/0x40
       [<c1002ec4>] sysenter_do_call+0x12/0x32

-> #1 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a7b>] mutex_lock_nested+0x5b/0x340
       [<c1143359>] reiserfs_write_lock+0x29/0x40
       [<c113c23c>] do_journal_begin_r+0x9c/0x360
       [<c113c680>] journal_begin+0x80/0x130
       [<c1127363>] reiserfs_remount+0x223/0x4e0
       [<c10b6dd6>] do_remount_sb+0xa6/0x140
       [<c10ce6a0>] do_mount+0x560/0x750
       [<c10ce914>] sys_mount+0x84/0xb0
       [<c1002ec4>] sysenter_do_call+0x12/0x32

-> #0 (&journal->j_mutex){+.+...}:
       [<c105f176>] __lock_acquire+0x18f6/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a7b>] mutex_lock_nested+0x5b/0x340
       [<c113c234>] do_journal_begin_r+0x94/0x360
       [<c113c680>] journal_begin+0x80/0x130
       [<c1116d63>] reiserfs_unlink+0x83/0x2e0
       [<c1142a74>] xattr_unlink+0x64/0xb0
       [<c1143179>] delete_one_xattr+0x29/0x100
       [<c11427bb>] reiserfs_for_each_xattr+0x10b/0x290
       [<c11429ba>] reiserfs_delete_xattrs+0x1a/0x60
       [<c111ea2f>] reiserfs_delete_inode+0x9f/0x150
       [<c10c9c32>] generic_delete_inode+0xa2/0x170
       [<c10c9d4f>] generic_drop_inode+0x4f/0x70
       [<c10c8b07>] iput+0x47/0x50
       [<c10c0965>] do_unlinkat+0xd5/0x160
       [<c10c0b13>] sys_unlinkat+0x23/0x40
       [<c1002ec4>] sysenter_do_call+0x12/0x32

other info that might help us debug this:

2 locks held by rm/3202:
 #0:  (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c114274b>] reiserfs_for_each_xattr+0x9b/0x290
 #1:  (&sb->s_type->i_mutex_key#4/2){+.+...}, at: [<c1142a67>] xattr_unlink+0x57/0xb0

stack backtrace:
Pid: 3202, comm: rm Not tainted 2.6.32-atom #178
Call Trace:
 [<c13ff9e3>] ? printk+0x18/0x1a
 [<c105d33a>] print_circular_bug+0xca/0xd0
 [<c105f176>] __lock_acquire+0x18f6/0x19e0
 [<c1142a67>] ? xattr_unlink+0x57/0xb0
 [<c105f2c8>] lock_acquire+0x68/0x90
 [<c113c234>] ? do_journal_begin_r+0x94/0x360
 [<c113c234>] ? do_journal_begin_r+0x94/0x360
 [<c1401a7b>] mutex_lock_nested+0x5b/0x340
 [<c113c234>] ? do_journal_begin_r+0x94/0x360
 [<c113c234>] do_journal_begin_r+0x94/0x360
 [<c10411b6>] ? run_timer_softirq+0x1a6/0x220
 [<c103cb00>] ? __do_softirq+0x50/0x140
 [<c113c680>] journal_begin+0x80/0x130
 [<c103cba2>] ? __do_softirq+0xf2/0x140
 [<c104f72f>] ? hrtimer_interrupt+0xdf/0x220
 [<c1116d63>] reiserfs_unlink+0x83/0x2e0
 [<c105c932>] ? mark_held_locks+0x62/0x80
 [<c11b8d08>] ? trace_hardirqs_on_thunk+0xc/0x10
 [<c1002fd8>] ? restore_all_notrace+0x0/0x18
 [<c1142a67>] ? xattr_unlink+0x57/0xb0
 [<c1142a74>] xattr_unlink+0x64/0xb0
 [<c1143179>] delete_one_xattr+0x29/0x100
 [<c11427bb>] reiserfs_for_each_xattr+0x10b/0x290
 [<c1143150>] ? delete_one_xattr+0x0/0x100
 [<c1401cb9>] ? mutex_lock_nested+0x299/0x340
 [<c11429ba>] reiserfs_delete_xattrs+0x1a/0x60
 [<c1143309>] ? reiserfs_write_lock_once+0x29/0x50
 [<c111ea2f>] reiserfs_delete_inode+0x9f/0x150
 [<c11b0d1f>] ? _atomic_dec_and_lock+0x4f/0x70
 [<c111e990>] ? reiserfs_delete_inode+0x0/0x150
 [<c10c9c32>] generic_delete_inode+0xa2/0x170
 [<c10c9d4f>] generic_drop_inode+0x4f/0x70
 [<c10c8b07>] iput+0x47/0x50
 [<c10c0965>] do_unlinkat+0xd5/0x160
 [<c1401068>] ? mutex_unlock+0x8/0x10
 [<c10c3e0d>] ? vfs_readdir+0x7d/0xb0
 [<c10c3af0>] ? filldir64+0x0/0xf0
 [<c1002ef3>] ? sysenter_exit+0xf/0x16
 [<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10c0b13>] sys_unlinkat+0x23/0x40
 [<c1002ec4>] sysenter_do_call+0x12/0x32

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:58:32 +01:00
Frederic Weisbecker
c674905ca7 reiserfs: Fix unwanted recursive reiserfs lock in reiserfs_unlink()
reiserfs_unlink() may or may not be called under the reiserfs
lock.
But it also takes the reiserfs lock and can then acquire it
recursively which leads to do_journal_begin_r() that fails to
relax the reiserfs lock before grabbing the journal mutex,
creating an unexpected lock inversion.

We need to ensure reiserfs_unlink() won't get the reiserfs lock
recursively using reiserfs_write_lock_once().

This fixes the following warning that precedes a lock inversion
report (reiserfs lock <-> journal mutex).

------------[ cut here ]------------
WARNING: at fs/reiserfs/lock.c:95 reiserfs_lock_check_recursive+0x3a/0x50()
Hardware name: MS-7418
Unwanted recursive reiserfs lock!
Pid: 3208, comm: dbench Not tainted 2.6.32-atom #177
Call Trace:
 [<c114327a>] ? reiserfs_lock_check_recursive+0x3a/0x50
 [<c114327a>] ? reiserfs_lock_check_recursive+0x3a/0x50
 [<c10373a7>] warn_slowpath_common+0x67/0xc0
 [<c114327a>] ? reiserfs_lock_check_recursive+0x3a/0x50
 [<c1037446>] warn_slowpath_fmt+0x26/0x30
 [<c114327a>] reiserfs_lock_check_recursive+0x3a/0x50
 [<c113c213>] do_journal_begin_r+0x83/0x360
 [<c105eb16>] ? __lock_acquire+0x1296/0x19e0
 [<c1142a57>] ? xattr_unlink+0x57/0xb0
 [<c113c670>] journal_begin+0x80/0x130
 [<c1116d5d>] reiserfs_unlink+0x7d/0x2d0
 [<c1142a57>] ? xattr_unlink+0x57/0xb0
 [<c1142a57>] ? xattr_unlink+0x57/0xb0
 [<c1142a57>] ? xattr_unlink+0x57/0xb0
 [<c1142a64>] xattr_unlink+0x64/0xb0
 [<c1143169>] delete_one_xattr+0x29/0x100
 [<c11427ab>] reiserfs_for_each_xattr+0x10b/0x290
 [<c1143140>] ? delete_one_xattr+0x0/0x100
 [<c1401ca9>] ? mutex_lock_nested+0x299/0x340
 [<c11429aa>] reiserfs_delete_xattrs+0x1a/0x60
 [<c11432f9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c111ea1f>] reiserfs_delete_inode+0x9f/0x150
 [<c11b0d0f>] ? _atomic_dec_and_lock+0x4f/0x70
 [<c111e980>] ? reiserfs_delete_inode+0x0/0x150
 [<c10c9c32>] generic_delete_inode+0xa2/0x170
 [<c10c9d4f>] generic_drop_inode+0x4f/0x70
 [<c10c8b07>] iput+0x47/0x50
 [<c10c0965>] do_unlinkat+0xd5/0x160
 [<c10505c6>] ? up_read+0x16/0x30
 [<c1022ab7>] ? do_page_fault+0x187/0x330
 [<c1002fd8>] ? restore_all_notrace+0x0/0x18
 [<c1022930>] ? do_page_fault+0x0/0x330
 [<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10c0a00>] sys_unlink+0x10/0x20
 [<c1002ec4>] sysenter_do_call+0x12/0x32
---[ end trace 2e35d71a6cc69d0c ]---

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:57:32 +01:00
Frederic Weisbecker
3f14fea6bb reiserfs: Relax lock before open xattr dir in reiserfs_xattr_set_handle()
We call xattr_lookup() from reiserfs_xattr_get(). We then hold
the reiserfs lock when we grab the i_mutex. But later, we may
relax the reiserfs lock, creating dependency inversion between
both locks.

The lookups and creation jobs ar already protected by the
inode mutex, so we can safely relax the reiserfs lock, dropping
the unwanted reiserfs lock -> i_mutex dependency, as shown
in the following lockdep report:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #173
-------------------------------------------------------
cp/3204 is trying to acquire lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11432b9>] reiserfs_write_lock_once+0x29/0x50

but task is already holding lock:
 (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#4/3){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a2b>] mutex_lock_nested+0x5b/0x340
       [<c1141d83>] open_xa_dir+0x43/0x1b0
       [<c1142722>] reiserfs_for_each_xattr+0x62/0x260
       [<c114299a>] reiserfs_delete_xattrs+0x1a/0x60
       [<c111ea1f>] reiserfs_delete_inode+0x9f/0x150
       [<c10c9c32>] generic_delete_inode+0xa2/0x170
       [<c10c9d4f>] generic_drop_inode+0x4f/0x70
       [<c10c8b07>] iput+0x47/0x50
       [<c10c0965>] do_unlinkat+0xd5/0x160
       [<c10c0a00>] sys_unlink+0x10/0x20
       [<c1002ec4>] sysenter_do_call+0x12/0x32

-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c105f176>] __lock_acquire+0x18f6/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a2b>] mutex_lock_nested+0x5b/0x340
       [<c11432b9>] reiserfs_write_lock_once+0x29/0x50
       [<c1117012>] reiserfs_lookup+0x62/0x140
       [<c10bd85f>] __lookup_hash+0xef/0x110
       [<c10bf21d>] lookup_one_len+0x8d/0xc0
       [<c1141e2a>] open_xa_dir+0xea/0x1b0
       [<c1141fe5>] xattr_lookup+0x15/0x160
       [<c1142476>] reiserfs_xattr_get+0x56/0x2a0
       [<c1144042>] reiserfs_get_acl+0xa2/0x360
       [<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
       [<c111789c>] reiserfs_mkdir+0x6c/0x2c0
       [<c10bea96>] vfs_mkdir+0xd6/0x180
       [<c10c0c10>] sys_mkdirat+0xc0/0xd0
       [<c10c0c40>] sys_mkdir+0x20/0x30
       [<c1002ec4>] sysenter_do_call+0x12/0x32

other info that might help us debug this:

2 locks held by cp/3204:
 #0:  (&sb->s_type->i_mutex_key#4/1){+.+.+.}, at: [<c10bd8d6>] lookup_create+0x26/0xa0
 #1:  (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0

stack backtrace:
Pid: 3204, comm: cp Not tainted 2.6.32-atom #173
Call Trace:
 [<c13ff993>] ? printk+0x18/0x1a
 [<c105d33a>] print_circular_bug+0xca/0xd0
 [<c105f176>] __lock_acquire+0x18f6/0x19e0
 [<c105d3aa>] ? check_usage+0x6a/0x460
 [<c105f2c8>] lock_acquire+0x68/0x90
 [<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c1401a2b>] mutex_lock_nested+0x5b/0x340
 [<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c11432b9>] reiserfs_write_lock_once+0x29/0x50
 [<c1117012>] reiserfs_lookup+0x62/0x140
 [<c105ccca>] ? debug_check_no_locks_freed+0x8a/0x140
 [<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10bd85f>] __lookup_hash+0xef/0x110
 [<c10bf21d>] lookup_one_len+0x8d/0xc0
 [<c1141e2a>] open_xa_dir+0xea/0x1b0
 [<c1141fe5>] xattr_lookup+0x15/0x160
 [<c1142476>] reiserfs_xattr_get+0x56/0x2a0
 [<c1144042>] reiserfs_get_acl+0xa2/0x360
 [<c10ca2e7>] ? new_inode+0x27/0xa0
 [<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
 [<c1402eb7>] ? _spin_unlock+0x27/0x40
 [<c111789c>] reiserfs_mkdir+0x6c/0x2c0
 [<c10c7cb8>] ? __d_lookup+0x108/0x190
 [<c105c932>] ? mark_held_locks+0x62/0x80
 [<c1401c8d>] ? mutex_lock_nested+0x2bd/0x340
 [<c10bd17a>] ? generic_permission+0x1a/0xa0
 [<c11788fe>] ? security_inode_permission+0x1e/0x20
 [<c10bea96>] vfs_mkdir+0xd6/0x180
 [<c10c0c10>] sys_mkdirat+0xc0/0xd0
 [<c10505c6>] ? up_read+0x16/0x30
 [<c1002fd8>] ? restore_all_notrace+0x0/0x18
 [<c10c0c40>] sys_mkdir+0x20/0x30
 [<c1002ec4>] sysenter_do_call+0x12/0x32

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:57:01 +01:00
Frederic Weisbecker
0523676d3f reiserfs: Relax reiserfs lock while freeing the journal
Keeping the reiserfs lock while freeing the journal on
umount path triggers a lock inversion between bdev->bd_mutex
and the reiserfs lock.

We don't need the reiserfs lock at this stage. The filesystem
is not usable anymore, and there are no more pending commits,
everything got flushed (even this operation was done in parallel
and didn't required the reiserfs lock from the current process).

This fixes the following lockdep report:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #172
-------------------------------------------------------
umount/3904 is trying to acquire lock:
 (&bdev->bd_mutex){+.+.+.}, at: [<c10de2c2>] __blkdev_put+0x22/0x160

but task is already holding lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1143279>] reiserfs_write_lock+0x29/0x40

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c140199b>] mutex_lock_nested+0x5b/0x340
       [<c1143229>] reiserfs_write_lock_once+0x29/0x50
       [<c111c485>] reiserfs_get_block+0x85/0x1620
       [<c10e1040>] do_mpage_readpage+0x1f0/0x6d0
       [<c10e1640>] mpage_readpages+0xc0/0x100
       [<c1119b89>] reiserfs_readpages+0x19/0x20
       [<c108f1ec>] __do_page_cache_readahead+0x1bc/0x260
       [<c108f2b8>] ra_submit+0x28/0x40
       [<c1087e3e>] filemap_fault+0x40e/0x420
       [<c109b5fd>] __do_fault+0x3d/0x430
       [<c109d47e>] handle_mm_fault+0x12e/0x790
       [<c1022a65>] do_page_fault+0x135/0x330
       [<c1403663>] error_code+0x6b/0x70
       [<c10ef9ca>] load_elf_binary+0x82a/0x1a10
       [<c10ba130>] search_binary_handler+0x90/0x1d0
       [<c10bb70f>] do_execve+0x1df/0x250
       [<c1001746>] sys_execve+0x46/0x70
       [<c1002fa5>] syscall_call+0x7/0xb

-> #2 (&mm->mmap_sem){++++++}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c109b1ab>] might_fault+0x8b/0xb0
       [<c11b8f52>] copy_to_user+0x32/0x70
       [<c10c3b94>] filldir64+0xa4/0xf0
       [<c1109116>] sysfs_readdir+0x116/0x210
       [<c10c3e1d>] vfs_readdir+0x8d/0xb0
       [<c10c3ea9>] sys_getdents64+0x69/0xb0
       [<c1002ec4>] sysenter_do_call+0x12/0x32

-> #1 (sysfs_mutex){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c140199b>] mutex_lock_nested+0x5b/0x340
       [<c110951c>] sysfs_addrm_start+0x2c/0xb0
       [<c1109aa0>] create_dir+0x40/0x90
       [<c1109b1b>] sysfs_create_dir+0x2b/0x50
       [<c11b2352>] kobject_add_internal+0xc2/0x1b0
       [<c11b2531>] kobject_add_varg+0x31/0x50
       [<c11b25ac>] kobject_add+0x2c/0x60
       [<c1258294>] device_add+0x94/0x560
       [<c11036ea>] add_partition+0x18a/0x2a0
       [<c110418a>] rescan_partitions+0x33a/0x450
       [<c10de5bf>] __blkdev_get+0x12f/0x2d0
       [<c10de76a>] blkdev_get+0xa/0x10
       [<c11034b8>] register_disk+0x108/0x130
       [<c11a87a9>] add_disk+0xd9/0x130
       [<c12998e5>] sd_probe_async+0x105/0x1d0
       [<c10528af>] async_thread+0xcf/0x230
       [<c104bfd4>] kthread+0x74/0x80
       [<c1003aab>] kernel_thread_helper+0x7/0x3c

-> #0 (&bdev->bd_mutex){+.+.+.}:
       [<c105f176>] __lock_acquire+0x18f6/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c140199b>] mutex_lock_nested+0x5b/0x340
       [<c10de2c2>] __blkdev_put+0x22/0x160
       [<c10de40a>] blkdev_put+0xa/0x10
       [<c113ce22>] free_journal_ram+0xd2/0x130
       [<c113ea18>] do_journal_release+0x98/0x190
       [<c113eb2a>] journal_release+0xa/0x10
       [<c1128eb6>] reiserfs_put_super+0x36/0x130
       [<c10b776f>] generic_shutdown_super+0x4f/0xe0
       [<c10b7825>] kill_block_super+0x25/0x40
       [<c11255df>] reiserfs_kill_sb+0x7f/0x90
       [<c10b7f4a>] deactivate_super+0x7a/0x90
       [<c10cccd8>] mntput_no_expire+0x98/0xd0
       [<c10ccfcc>] sys_umount+0x4c/0x310
       [<c10cd2a9>] sys_oldumount+0x19/0x20
       [<c1002ec4>] sysenter_do_call+0x12/0x32

other info that might help us debug this:

2 locks held by umount/3904:
 #0:  (&type->s_umount_key#30){+++++.}, at: [<c10b7f45>] deactivate_super+0x75/0x90
 #1:  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1143279>] reiserfs_write_lock+0x29/0x40

stack backtrace:
Pid: 3904, comm: umount Not tainted 2.6.32-atom #172
Call Trace:
 [<c13ff903>] ? printk+0x18/0x1a
 [<c105d33a>] print_circular_bug+0xca/0xd0
 [<c105f176>] __lock_acquire+0x18f6/0x19e0
 [<c108b66f>] ? free_pcppages_bulk+0x1f/0x250
 [<c105f2c8>] lock_acquire+0x68/0x90
 [<c10de2c2>] ? __blkdev_put+0x22/0x160
 [<c10de2c2>] ? __blkdev_put+0x22/0x160
 [<c140199b>] mutex_lock_nested+0x5b/0x340
 [<c10de2c2>] ? __blkdev_put+0x22/0x160
 [<c105c932>] ? mark_held_locks+0x62/0x80
 [<c10afe12>] ? kfree+0x92/0xd0
 [<c10de2c2>] __blkdev_put+0x22/0x160
 [<c105cc3b>] ? trace_hardirqs_on+0xb/0x10
 [<c10de40a>] blkdev_put+0xa/0x10
 [<c113ce22>] free_journal_ram+0xd2/0x130
 [<c113ea18>] do_journal_release+0x98/0x190
 [<c113eb2a>] journal_release+0xa/0x10
 [<c1128eb6>] reiserfs_put_super+0x36/0x130
 [<c1050596>] ? up_write+0x16/0x30
 [<c10b776f>] generic_shutdown_super+0x4f/0xe0
 [<c10b7825>] kill_block_super+0x25/0x40
 [<c10f41e0>] ? vfs_quota_off+0x0/0x20
 [<c11255df>] reiserfs_kill_sb+0x7f/0x90
 [<c10b7f4a>] deactivate_super+0x7a/0x90
 [<c10cccd8>] mntput_no_expire+0x98/0xd0
 [<c10ccfcc>] sys_umount+0x4c/0x310
 [<c10cd2a9>] sys_oldumount+0x19/0x20
 [<c1002ec4>] sysenter_do_call+0x12/0x32

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:56:54 +01:00
Frederic Weisbecker
27026a05bb reiserfs: Fix reiserfs lock <-> i_mutex dependency inversion on xattr
While deleting the xattrs of an inode, we hold the reiserfs lock
and grab the inode->i_mutex of the targeted inode and the root
private xattr directory.

Later on, we may relax the reiserfs lock for various reasons, this
creates inverted dependencies.

We can remove the reiserfs lock -> i_mutex dependency by relaxing
the former before calling open_xa_dir(). This is fine because the
lookup and creation of xattr private directories done in
open_xa_dir() are covered by the targeted inode mutexes. And deeper
operations in the tree are still done under the write lock.

This fixes the following lockdep report:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #173
-------------------------------------------------------
cp/3204 is trying to acquire lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11432b9>] reiserfs_write_lock_once+0x29/0x50

but task is already holding lock:
 (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#4/3){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a2b>] mutex_lock_nested+0x5b/0x340
       [<c1141d83>] open_xa_dir+0x43/0x1b0
       [<c1142722>] reiserfs_for_each_xattr+0x62/0x260
       [<c114299a>] reiserfs_delete_xattrs+0x1a/0x60
       [<c111ea1f>] reiserfs_delete_inode+0x9f/0x150
       [<c10c9c32>] generic_delete_inode+0xa2/0x170
       [<c10c9d4f>] generic_drop_inode+0x4f/0x70
       [<c10c8b07>] iput+0x47/0x50
       [<c10c0965>] do_unlinkat+0xd5/0x160
       [<c10c0a00>] sys_unlink+0x10/0x20
       [<c1002ec4>] sysenter_do_call+0x12/0x32

-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c105f176>] __lock_acquire+0x18f6/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c1401a2b>] mutex_lock_nested+0x5b/0x340
       [<c11432b9>] reiserfs_write_lock_once+0x29/0x50
       [<c1117012>] reiserfs_lookup+0x62/0x140
       [<c10bd85f>] __lookup_hash+0xef/0x110
       [<c10bf21d>] lookup_one_len+0x8d/0xc0
       [<c1141e2a>] open_xa_dir+0xea/0x1b0
       [<c1141fe5>] xattr_lookup+0x15/0x160
       [<c1142476>] reiserfs_xattr_get+0x56/0x2a0
       [<c1144042>] reiserfs_get_acl+0xa2/0x360
       [<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
       [<c111789c>] reiserfs_mkdir+0x6c/0x2c0
       [<c10bea96>] vfs_mkdir+0xd6/0x180
       [<c10c0c10>] sys_mkdirat+0xc0/0xd0
       [<c10c0c40>] sys_mkdir+0x20/0x30
       [<c1002ec4>] sysenter_do_call+0x12/0x32

other info that might help us debug this:

2 locks held by cp/3204:
 #0:  (&sb->s_type->i_mutex_key#4/1){+.+.+.}, at: [<c10bd8d6>] lookup_create+0x26/0xa0
 #1:  (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0

stack backtrace:
Pid: 3204, comm: cp Not tainted 2.6.32-atom #173
Call Trace:
 [<c13ff993>] ? printk+0x18/0x1a
 [<c105d33a>] print_circular_bug+0xca/0xd0
 [<c105f176>] __lock_acquire+0x18f6/0x19e0
 [<c105d3aa>] ? check_usage+0x6a/0x460
 [<c105f2c8>] lock_acquire+0x68/0x90
 [<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c1401a2b>] mutex_lock_nested+0x5b/0x340
 [<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
 [<c11432b9>] reiserfs_write_lock_once+0x29/0x50
 [<c1117012>] reiserfs_lookup+0x62/0x140
 [<c105ccca>] ? debug_check_no_locks_freed+0x8a/0x140
 [<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10bd85f>] __lookup_hash+0xef/0x110
 [<c10bf21d>] lookup_one_len+0x8d/0xc0
 [<c1141e2a>] open_xa_dir+0xea/0x1b0
 [<c1141fe5>] xattr_lookup+0x15/0x160
 [<c1142476>] reiserfs_xattr_get+0x56/0x2a0
 [<c1144042>] reiserfs_get_acl+0xa2/0x360
 [<c10ca2e7>] ? new_inode+0x27/0xa0
 [<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
 [<c1402eb7>] ? _spin_unlock+0x27/0x40
 [<c111789c>] reiserfs_mkdir+0x6c/0x2c0
 [<c10c7cb8>] ? __d_lookup+0x108/0x190
 [<c105c932>] ? mark_held_locks+0x62/0x80
 [<c1401c8d>] ? mutex_lock_nested+0x2bd/0x340
 [<c10bd17a>] ? generic_permission+0x1a/0xa0
 [<c11788fe>] ? security_inode_permission+0x1e/0x20
 [<c10bea96>] vfs_mkdir+0xd6/0x180
 [<c10c0c10>] sys_mkdirat+0xc0/0xd0
 [<c10505c6>] ? up_read+0x16/0x30
 [<c1002fd8>] ? restore_all_notrace+0x0/0x18
 [<c10c0c40>] sys_mkdir+0x20/0x30
 [<c1002ec4>] sysenter_do_call+0x12/0x32

v2: Don't drop reiserfs_mutex_lock_nested_safe() as we'll still
    need it later

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:54:47 +01:00
Frederic Weisbecker
c4a62ca362 reiserfs: Warn on lock relax if taken recursively
When we relax the reiserfs lock to avoid creating unwanted
dependencies against others locks while grabbing these,
we want to ensure it has not been taken recursively, otherwise
the lock won't be really relaxed. Only its depth will be decreased.
The unwanted dependency would then actually happen.

To prevent from that, add a reiserfs_lock_check_recursive() call
in the places that need it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:54:37 +01:00
Frederic Weisbecker
0719d34347 reiserfs: Fix reiserfs lock <-> i_xattr_sem dependency inversion
i_xattr_sem depends on the reiserfs lock. But after we grab
i_xattr_sem, we may relax/relock the reiserfs lock while waiting
on a freezed filesystem, creating a dependency inversion between
the two locks.

In order to avoid the i_xattr_sem -> reiserfs lock dependency, let's
create a reiserfs_down_read_safe() that acts like
reiserfs_mutex_lock_safe(): relax the reiserfs lock while grabbing
another lock to avoid undesired dependencies induced by the
heivyweight reiserfs lock.

This fixes the following warning:

[  990.005931] =======================================================
[  990.012373] [ INFO: possible circular locking dependency detected ]
[  990.013233] 2.6.33-rc1 #1
[  990.013233] -------------------------------------------------------
[  990.013233] dbench/1891 is trying to acquire lock:
[  990.013233]  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[  990.013233]
[  990.013233] but task is already holding lock:
[  990.013233]  (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}, at: [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]
[  990.013233] which lock already depends on the new lock.
[  990.013233]
[  990.013233]
[  990.013233] the existing dependency chain (in reverse order) is:
[  990.013233]
[  990.013233] -> #1 (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}:
[  990.013233]        [<ffffffff81063afc>] __lock_acquire+0xf9c/0x1560
[  990.013233]        [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[  990.013233]        [<ffffffff814ac194>] down_write+0x44/0x80
[  990.013233]        [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]        [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[  990.013233]        [<ffffffff8115a6aa>] user_set+0x8a/0x90
[  990.013233]        [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[  990.013233]        [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[  990.013233]        [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[  990.013233]        [<ffffffff810e2780>] setxattr+0xc0/0x150
[  990.013233]        [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[  990.013233]        [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
[  990.013233]
[  990.013233] -> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
[  990.013233]        [<ffffffff81063e30>] __lock_acquire+0x12d0/0x1560
[  990.013233]        [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[  990.013233]        [<ffffffff814aba77>] __mutex_lock_common+0x47/0x3b0
[  990.013233]        [<ffffffff814abebe>] mutex_lock_nested+0x3e/0x50
[  990.013233]        [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[  990.013233]        [<ffffffff811340e5>] reiserfs_prepare_write+0x45/0x180
[  990.013233]        [<ffffffff81158bb6>] reiserfs_xattr_set_handle+0x2a6/0x470
[  990.013233]        [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[  990.013233]        [<ffffffff8115a6aa>] user_set+0x8a/0x90
[  990.013233]        [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[  990.013233]        [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[  990.013233]        [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[  990.013233]        [<ffffffff810e2780>] setxattr+0xc0/0x150
[  990.013233]        [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[  990.013233]        [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
[  990.013233]
[  990.013233] other info that might help us debug this:
[  990.013233]
[  990.013233] 2 locks held by dbench/1891:
[  990.013233]  #0:  (&sb->s_type->i_mutex_key#12){+.+.+.}, at: [<ffffffff810e2678>] vfs_setxattr+0x78/0xc0
[  990.013233]  #1:  (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}, at: [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]
[  990.013233] stack backtrace:
[  990.013233] Pid: 1891, comm: dbench Not tainted 2.6.33-rc1 #1
[  990.013233] Call Trace:
[  990.013233]  [<ffffffff81061639>] print_circular_bug+0xe9/0xf0
[  990.013233]  [<ffffffff81063e30>] __lock_acquire+0x12d0/0x1560
[  990.013233]  [<ffffffff8115899a>] ? reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]  [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[  990.013233]  [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff8115899a>] ? reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]  [<ffffffff814aba77>] __mutex_lock_common+0x47/0x3b0
[  990.013233]  [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff81062592>] ? mark_held_locks+0x72/0xa0
[  990.013233]  [<ffffffff814ab81d>] ? __mutex_unlock_slowpath+0xbd/0x140
[  990.013233]  [<ffffffff810628ad>] ? trace_hardirqs_on_caller+0x14d/0x1a0
[  990.013233]  [<ffffffff814abebe>] mutex_lock_nested+0x3e/0x50
[  990.013233]  [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff811340e5>] reiserfs_prepare_write+0x45/0x180
[  990.013233]  [<ffffffff81158bb6>] reiserfs_xattr_set_handle+0x2a6/0x470
[  990.013233]  [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[  990.013233]  [<ffffffff814abcb4>] ? __mutex_lock_common+0x284/0x3b0
[  990.013233]  [<ffffffff8115a6aa>] user_set+0x8a/0x90
[  990.013233]  [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[  990.013233]  [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[  990.013233]  [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[  990.013233]  [<ffffffff810e2780>] setxattr+0xc0/0x150
[  990.013233]  [<ffffffff81056018>] ? sched_clock_cpu+0xb8/0x100
[  990.013233]  [<ffffffff8105eded>] ? trace_hardirqs_off+0xd/0x10
[  990.013233]  [<ffffffff810560a3>] ? cpu_clock+0x43/0x50
[  990.013233]  [<ffffffff810c6820>] ? fget+0xb0/0x110
[  990.013233]  [<ffffffff810c6770>] ? fget+0x0/0x110
[  990.013233]  [<ffffffff81002ddc>] ? sysret_check+0x27/0x62
[  990.013233]  [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[  990.013233]  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b

Reported-and-tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:54:04 +01:00
Frederic Weisbecker
98ea3f50bc reiserfs: Fix remaining in-reclaim-fs <-> reclaim-fs-on locking inversion
Commit 500f5a0bf5
(reiserfs: Fix possible recursive lock) fixed a vmalloc under reiserfs
lock that triggered a lockdep warning because of a
IN-FS-RECLAIM <-> RECLAIM-FS-ON locking dependency inversion.

But this patch has ommitted another vmalloc call in the same path
that allocates the journal. Relax the lock for this one too.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2009-12-29 22:34:59 +01:00
Frederic Weisbecker
47376ceba5 reiserfs: Fix reiserfs lock <-> inode mutex dependency inversion
The reiserfs lock -> inode mutex dependency gets inverted when we
relax the lock while walking to the tree.

To fix this, use a specialized version of reiserfs_mutex_lock_safe
that takes care of mutex subclasses. Then we can grab the inode
mutex with I_MUTEX_XATTR subclass without any reiserfs lock
dependency.

This fixes the following report:

[ INFO: possible circular locking dependency detected ]
2.6.32-06793-gf405425-dirty #2
-------------------------------------------------------
mv/18566 is trying to acquire lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1110708>] reiserfs_write_lock+0x28=
/0x40

but task is already holding lock:
 (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [<c111033c>]
reiserfs_for_each_xattr+0x10c/0x380

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#5/3){+.+.+.}:
       [<c104f723>] validate_chain+0xa23/0xf70
       [<c1050155>] __lock_acquire+0x4e5/0xa70
       [<c105075a>] lock_acquire+0x7a/0xa0
       [<c134c76f>] mutex_lock_nested+0x5f/0x2b0
       [<c11102b4>] reiserfs_for_each_xattr+0x84/0x380
       [<c1110615>] reiserfs_delete_xattrs+0x15/0x50
       [<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
       [<c10a565c>] generic_delete_inode+0x9c/0x150
       [<c10a574d>] generic_drop_inode+0x3d/0x60
       [<c10a4667>] iput+0x47/0x50
       [<c109cc0b>] do_unlinkat+0xdb/0x160
       [<c109cca0>] sys_unlink+0x10/0x20
       [<c1002c50>] sysenter_do_call+0x12/0x36

-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c104fc68>] validate_chain+0xf68/0xf70
       [<c1050155>] __lock_acquire+0x4e5/0xa70
       [<c105075a>] lock_acquire+0x7a/0xa0
       [<c134c76f>] mutex_lock_nested+0x5f/0x2b0
       [<c1110708>] reiserfs_write_lock+0x28/0x40
       [<c1103d6b>] search_by_key+0x1f7b/0x21b0
       [<c10e73ef>] search_by_entry_key+0x1f/0x3b0
       [<c10e77f7>] reiserfs_find_entry+0x77/0x400
       [<c10e81e5>] reiserfs_lookup+0x85/0x130
       [<c109a144>] __lookup_hash+0xb4/0x110
       [<c109b763>] lookup_one_len+0xb3/0x100
       [<c1110350>] reiserfs_for_each_xattr+0x120/0x380
       [<c1110615>] reiserfs_delete_xattrs+0x15/0x50
       [<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
       [<c10a565c>] generic_delete_inode+0x9c/0x150
       [<c10a574d>] generic_drop_inode+0x3d/0x60
       [<c10a4667>] iput+0x47/0x50
       [<c10a1c4f>] dentry_iput+0x6f/0xf0
       [<c10a1d74>] d_kill+0x24/0x50
       [<c10a396b>] dput+0x5b/0x120
       [<c109ca89>] sys_renameat+0x1b9/0x230
       [<c109cb28>] sys_rename+0x28/0x30
       [<c1002c50>] sysenter_do_call+0x12/0x36

other info that might help us debug this:

2 locks held by mv/18566:
 #0:  (&sb->s_type->i_mutex_key#5/1){+.+.+.}, at: [<c109b6ac>]
lock_rename+0xcc/0xd0
 #1:  (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [<c111033c>]
reiserfs_for_each_xattr+0x10c/0x380

stack backtrace:
Pid: 18566, comm: mv Tainted: G         C 2.6.32-06793-gf405425-dirty #2
Call Trace:
 [<c134b252>] ? printk+0x18/0x1e
 [<c104e790>] print_circular_bug+0xc0/0xd0
 [<c104fc68>] validate_chain+0xf68/0xf70
 [<c104c8cb>] ? trace_hardirqs_off+0xb/0x10
 [<c1050155>] __lock_acquire+0x4e5/0xa70
 [<c105075a>] lock_acquire+0x7a/0xa0
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c134c76f>] mutex_lock_nested+0x5f/0x2b0
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c134b60a>] ? schedule+0x27a/0x440
 [<c1110708>] reiserfs_write_lock+0x28/0x40
 [<c1103d6b>] search_by_key+0x1f7b/0x21b0
 [<c1050176>] ? __lock_acquire+0x506/0xa70
 [<c1051267>] ? lock_release_non_nested+0x1e7/0x340
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c104e354>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c104e3ab>] ? trace_hardirqs_on+0xb/0x10
 [<c1042a55>] ? T.316+0x15/0x1a0
 [<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
 [<c10e73ef>] search_by_entry_key+0x1f/0x3b0
 [<c134bf2a>] ? __mutex_unlock_slowpath+0x9a/0x120
 [<c104e354>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10e77f7>] reiserfs_find_entry+0x77/0x400
 [<c10e81e5>] reiserfs_lookup+0x85/0x130
 [<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
 [<c109a144>] __lookup_hash+0xb4/0x110
 [<c109b763>] lookup_one_len+0xb3/0x100
 [<c1110350>] reiserfs_for_each_xattr+0x120/0x380
 [<c110ffe0>] ? delete_one_xattr+0x0/0x1c0
 [<c1003342>] ? math_error+0x22/0x150
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c1110615>] reiserfs_delete_xattrs+0x15/0x50
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
 [<c10a561f>] ? generic_delete_inode+0x5f/0x150
 [<c10ef4f0>] ? reiserfs_delete_inode+0x0/0x140
 [<c10a565c>] generic_delete_inode+0x9c/0x150
 [<c10a574d>] generic_drop_inode+0x3d/0x60
 [<c10a4667>] iput+0x47/0x50
 [<c10a1c4f>] dentry_iput+0x6f/0xf0
 [<c10a1d74>] d_kill+0x24/0x50
 [<c10a396b>] dput+0x5b/0x120
 [<c109ca89>] sys_renameat+0x1b9/0x230
 [<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
 [<c104c8cb>] ? trace_hardirqs_off+0xb/0x10
 [<c1042dde>] ? cpu_clock+0x4e/0x60
 [<c1350825>] ? do_page_fault+0x155/0x370
 [<c1041816>] ? up_read+0x16/0x30
 [<c1350825>] ? do_page_fault+0x155/0x370
 [<c109cb28>] sys_rename+0x28/0x30
 [<c1002c50>] sysenter_do_call+0x12/0x36

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
2009-12-16 23:25:50 +01:00
Frederic Weisbecker
cb1c2e51c5 reiserfs: Fix reiserfs lock and journal lock inversion dependency
When we were using the bkl, we didn't care about dependencies against
other locks, but the mutex conversion created new ones, which is why
we have reiserfs_mutex_lock_safe(), which unlocks the reiserfs lock
before acquiring another mutex.

But this trick actually fails if we have acquired the reiserfs lock
recursively, as we try to unlock it to acquire the new mutex without
inverted dependency, but we eventually only decrease its depth.

This happens in the case of a nested inode creation/deletion.
Say we have no space left on the device, we create an inode
and tak the lock but fail to create its entry, then we release the
inode using iput(), which calls reiserfs_delete_inode() that takes
the reiserfs lock recursively. The path eventually ends up in
journal_begin() where we try to take the journal safely but we
fail because of the reiserfs lock recursion:

[ INFO: possible circular locking dependency detected ]
2.6.32-06486-g053fe57 #2
-------------------------------------------------------
vi/23454 is trying to acquire lock:
 (&journal->j_mutex){+.+...}, at: [<c110dac4>] do_journal_begin_r+0x64/0x2f0

but task is already holding lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11106a8>] reiserfs_write_lock+0x28/0x40

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c104f8f3>] validate_chain+0xa23/0xf70
       [<c1050325>] __lock_acquire+0x4e5/0xa70
       [<c105092a>] lock_acquire+0x7a/0xa0
       [<c134c78f>] mutex_lock_nested+0x5f/0x2b0
       [<c11106a8>] reiserfs_write_lock+0x28/0x40
       [<c110dacb>] do_journal_begin_r+0x6b/0x2f0
       [<c110ddcf>] journal_begin+0x7f/0x120
       [<c10f76c2>] reiserfs_remount+0x212/0x4d0
       [<c1093997>] do_remount_sb+0x67/0x140
       [<c10a9ca6>] do_mount+0x436/0x6b0
       [<c10a9f86>] sys_mount+0x66/0xa0
       [<c1002c50>] sysenter_do_call+0x12/0x36

-> #0 (&journal->j_mutex){+.+...}:
       [<c104fe38>] validate_chain+0xf68/0xf70
       [<c1050325>] __lock_acquire+0x4e5/0xa70
       [<c105092a>] lock_acquire+0x7a/0xa0
       [<c134c78f>] mutex_lock_nested+0x5f/0x2b0
       [<c110dac4>] do_journal_begin_r+0x64/0x2f0
       [<c110ddcf>] journal_begin+0x7f/0x120
       [<c10ef52f>] reiserfs_delete_inode+0x9f/0x140
       [<c10a55fc>] generic_delete_inode+0x9c/0x150
       [<c10a56ed>] generic_drop_inode+0x3d/0x60
       [<c10a4607>] iput+0x47/0x50
       [<c10e915c>] reiserfs_create+0x16c/0x1c0
       [<c109a9c1>] vfs_create+0xc1/0x130
       [<c109dbec>] do_filp_open+0x81c/0x920
       [<c109004f>] do_sys_open+0x4f/0x110
       [<c1090179>] sys_open+0x29/0x40
       [<c1002c50>] sysenter_do_call+0x12/0x36

other info that might help us debug this:

2 locks held by vi/23454:
 #0:  (&sb->s_type->i_mutex_key#5){+.+.+.}, at: [<c109d64e>]
do_filp_open+0x27e/0x920
 #1:  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11106a8>]
reiserfs_write_lock+0x28/0x40

stack backtrace:
Pid: 23454, comm: vi Not tainted 2.6.32-06486-g053fe57 #2
Call Trace:
 [<c134b202>] ? printk+0x18/0x1e
 [<c104e960>] print_circular_bug+0xc0/0xd0
 [<c104fe38>] validate_chain+0xf68/0xf70
 [<c104ca9b>] ? trace_hardirqs_off+0xb/0x10
 [<c1050325>] __lock_acquire+0x4e5/0xa70
 [<c105092a>] lock_acquire+0x7a/0xa0
 [<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
 [<c134c78f>] mutex_lock_nested+0x5f/0x2b0
 [<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
 [<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
 [<c110ff80>] ? delete_one_xattr+0x0/0x1c0
 [<c110dac4>] do_journal_begin_r+0x64/0x2f0
 [<c110ddcf>] journal_begin+0x7f/0x120
 [<c11105b5>] ? reiserfs_delete_xattrs+0x15/0x50
 [<c10ef52f>] reiserfs_delete_inode+0x9f/0x140
 [<c10a55bf>] ? generic_delete_inode+0x5f/0x150
 [<c10ef490>] ? reiserfs_delete_inode+0x0/0x140
 [<c10a55fc>] generic_delete_inode+0x9c/0x150
 [<c10a56ed>] generic_drop_inode+0x3d/0x60
 [<c10a4607>] iput+0x47/0x50
 [<c10e915c>] reiserfs_create+0x16c/0x1c0
 [<c1099a5d>] ? inode_permission+0x7d/0xa0
 [<c109a9c1>] vfs_create+0xc1/0x130
 [<c10e8ff0>] ? reiserfs_create+0x0/0x1c0
 [<c109dbec>] do_filp_open+0x81c/0x920
 [<c104ca9b>] ? trace_hardirqs_off+0xb/0x10
 [<c134dc0d>] ? _spin_unlock+0x1d/0x20
 [<c10a6eea>] ? alloc_fd+0xba/0xf0
 [<c109004f>] do_sys_open+0x4f/0x110
 [<c1090179>] sys_open+0x29/0x40
 [<c1002c50>] sysenter_do_call+0x12/0x36

To fix this, use reiserfs_lock_once() from reiserfs_delete_inode()
which prevents from adding reiserfs lock recursion.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
2009-12-14 11:47:11 +01:00
Frederic Weisbecker
500f5a0bf5 reiserfs: Fix possible recursive lock
While allocating the bitmap using vmalloc, we hold the reiserfs lock,
which makes lockdep later reporting a possible deadlock as we may
swap out pages to allocate memory and then take the reiserfs lock
recursively:

inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/312 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&REISERFS_SB(s)->lock){+.+.?.}, at: [<c11108a8>] reiserfs_write_lock+0x28/0x40
{RECLAIM_FS-ON-W} state was registered at:
  [<c104e1c2>] mark_held_locks+0x62/0x90
  [<c104e28a>] lockdep_trace_alloc+0x9a/0xc0
  [<c108e396>] kmem_cache_alloc+0x26/0xf0
  [<c10850ec>] __get_vm_area_node+0x6c/0xf0
  [<c10857de>] __vmalloc_node+0x7e/0xa0
  [<c108597b>] vmalloc+0x2b/0x30
  [<c10e00b9>] reiserfs_init_bitmap_cache+0x39/0x70
  [<c10f8178>] reiserfs_fill_super+0x2e8/0xb90
  [<c1094345>] get_sb_bdev+0x145/0x180
  [<c10f5a11>] get_super_block+0x21/0x30
  [<c10931f0>] vfs_kern_mount+0x40/0xd0
  [<c10932d9>] do_kern_mount+0x39/0xd0
  [<c10a9857>] do_mount+0x2c7/0x6b0
  [<c10a9ca6>] sys_mount+0x66/0xa0
  [<c161589b>] mount_block_root+0xc4/0x245
  [<c1615a75>] mount_root+0x59/0x5f
  [<c1615b8c>] prepare_namespace+0x111/0x14b
  [<c1615269>] kernel_init+0xcf/0xdb
  [<c10031fb>] kernel_thread_helper+0x7/0x1c

This is actually fine for two reasons: we call vmalloc at mount time
then it's not in the swapping out path. Also the reiserfs lock can be
acquired recursively, but since its implementation depends on a mutex,
it's hard and not necessary worth it to teach that to lockdep.

The lock is useless at mount time anyway, at least until we replay the
journal. But let's remove it from this path later as this needs
more thinking and is a sensible change.

For now we can just relax the lock around vmalloc,

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
2009-12-14 11:43:09 +01:00
Frederic Weisbecker
6548698f92 Merge commit 'v2.6.32' into reiserfs/kill-bkl
Merge-reason: The tree was based 2.6.31. It's better to be up to date
with 2.6.32. Although no conflicting changes were made in between,
it gives benchmarking results closer to the lastest kernel behaviour.
2009-12-07 07:29:22 +01:00
Marc Dionne
3350b2acdd CacheFiles: Update IMA counters when using dentry_open
When IMA is active, using dentry_open without updating the
IMA counters will result in free/open imbalance errors when
fput is eventually called.

Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-01 07:35:11 -08:00
David Howells
6f05416432 9p: fix build breakage introduced by FS-Cache
While building 2.6.32-rc8-git2 for Fedora I noticed the following thinko
in commit 201a15428b ("FS-Cache: Handle
pages pending storage that get evicted under OOM conditions"):

  fs/9p/cache.c: In function '__v9fs_fscache_release_page':
  fs/9p/cache.c:346: error: 'vnode' undeclared (first use in this function)
  fs/9p/cache.c:346: error: (Each undeclared identifier is reported only once
  fs/9p/cache.c:346: error: for each function it appears in.)
  make[2]: *** [fs/9p/cache.o] Error 1

Fix the 9P filesystem to correctly construct the argument to
fscache_maybe_release_page().

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com> [from identical patch]
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> [from identical patch]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-01 07:35:11 -08:00
Linus Torvalds
99d7832c0e Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  [CIFS] Fix sparse warning
  [CIFS] Duplicate data on appending to some Samba servers
  [CIFS] fix oops in cifs_lookup during net boot
2009-11-30 14:51:01 -08:00
Linus Torvalds
d0964c37b5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: reject O_DIRECT flag also in fuse_create
2009-11-30 14:00:09 -08:00
David Woodhouse
199bc9ff5c jffs2: Fix memory corruption in jffs2_read_inode_range()
In 2.6.23 kernel, commit a32ea1e1f9
("Fix read/truncate race") fixed a race in the generic code, and as a
side effect, now do_generic_file_read() can ask us to readpage() past
the i_size. This seems to be correctly handled by the block routines
(e.g. block_read_full_page() fills the page with zeroes in case if
somebody is trying to read past the last inode's block).

JFFS2 doesn't handle this; it assumes that it won't be asked to read
pages which don't exist -- and thus that there will be at least _one_
valid 'frag' on the page it's being asked to read. It will fill any
holes with the following memset:

  memset(buf, 0, min(end, frag->ofs + frag->size) - offset);

When the 'closest smaller match' returned by jffs2_lookup_node_frag() is
actually on a previous page and ends before 'offset', that results in:

  memset(buf, 0, <huge unsigned negative>);

Hopefully, in most cases the corruption is fatal, and quickly causing
random oopses, like this:

  root@10.0.0.4:~/ltp-fs-20090531# ./testcases/kernel/fs/ftest/ftest01
  Unable to handle kernel paging request for data at address 0x00000008
  Faulting instruction address: 0xc01cd980
  Oops: Kernel access of bad area, sig: 11 [#1]
  [...]
  NIP [c01cd980] rb_insert_color+0x38/0x184
  LR [c0043978] enqueue_hrtimer+0x88/0xc4
  Call Trace:
  [c6c63b60] [c004f9a8] tick_sched_timer+0xa0/0xe4 (unreliable)
  [c6c63b80] [c0043978] enqueue_hrtimer+0x88/0xc4
  [c6c63b90] [c0043a48] __run_hrtimer+0x94/0xbc
  [c6c63bb0] [c0044628] hrtimer_interrupt+0x140/0x2b8
  [c6c63c10] [c000f8e8] timer_interrupt+0x13c/0x254
  [c6c63c30] [c001352c] ret_from_except+0x0/0x14
  --- Exception: 901 at memset+0x38/0x5c
      LR = jffs2_read_inode_range+0x144/0x17c
  [c6c63cf0] [00000000] (null) (unreliable)

This patch fixes the issue, plus fixes all LTP tests on NAND/UBI with
JFFS2 filesystem that were failing since 2.6.23 (seems like the bug
above also broke the truncation).

Reported-By: Anton Vorontsov <avorontsov@ru.mvista.com>
Tested-By: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-30 13:52:40 -08:00
Linus Torvalds
6e80133f7f Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-fscache
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-fscache: (31 commits)
  FS-Cache: Provide nop fscache_stat_d() if CONFIG_FSCACHE_STATS=n
  SLOW_WORK: Fix GFS2 to #include <linux/module.h> before using THIS_MODULE
  SLOW_WORK: Fix CIFS to pass THIS_MODULE to slow_work_register_user()
  CacheFiles: Don't log lookup/create failing with ENOBUFS
  CacheFiles: Catch an overly long wait for an old active object
  CacheFiles: Better showing of debugging information in active object problems
  CacheFiles: Mark parent directory locks as I_MUTEX_PARENT to keep lockdep happy
  CacheFiles: Handle truncate unlocking the page we're reading
  CacheFiles: Don't write a full page if there's only a partial page to cache
  FS-Cache: Actually requeue an object when requested
  FS-Cache: Start processing an object's operations on that object's death
  FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure
  FS-Cache: Add a retirement stat counter
  FS-Cache: Handle pages pending storage that get evicted under OOM conditions
  FS-Cache: Handle read request vs lookup, creation or other cache failure
  FS-Cache: Don't delete pending pages from the page-store tracking tree
  FS-Cache: Fix lock misorder in fscache_write_op()
  FS-Cache: The object-available state can't rely on the cookie to be available
  FS-Cache: Permit cache retrieval ops to be interrupted in the initial wait phase
  FS-Cache: Use radix tree preload correctly in tracking of pages to be stored
  ...
2009-11-30 13:33:48 -08:00
Csaba Henk
1b7323965a fuse: reject O_DIRECT flag also in fuse_create
The comment in fuse_open about O_DIRECT:

  "VFS checks this, but only _after_ ->open()"

also holds for fuse_create, however, the same kind of check was missing there.

As an impact of this bug, open(newfile, O_RDWR|O_CREAT|O_DIRECT) fails, but a
stub newfile will remain if the fuse server handled the implied FUSE_CREATE
request appropriately.

Other impact: in the above situation ima_file_free() will complain to open/free
imbalance if CONFIG_IMA is set.

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Harshavardhana <harsha@gluster.com>
Cc: stable@kernel.org
2009-11-27 16:37:13 +01:00
Steve French
2f81e752da [CIFS] Fix sparse warning
Also update CHANGES file

Signed-off-by: Steve French <sfrench@us.ibm.com>
2009-11-25 00:11:31 +00:00
Steve French
cea6234395 [CIFS] Duplicate data on appending to some Samba servers
SMB writes are sent with a starting offset and length. When the server
supports the newer SMB trans2 posix open (rather than using the SMB
NTCreateX) a file can be opened with SMB_O_APPEND flag, and for that
case Samba server assumes that the offset sent in SMBWriteX is unneeded
since the write should go to the end of the file - which can cause
problems if the write was cached (since the beginning part of a
page could be written twice by the client mm).  Jeff suggested that
masking the flag on posix open on the client is easiest for the time
being. Note that recent Samba server also had an unrelated problem with
SMB NTCreateX and append (see samba bugzilla bug number 6898) which
should not affect current Linux clients (unless cifs Unix Extensions
are disabled).

The cifs client did not send the O_APPEND flag on posix open
before 2.6.29 so the fix is unneeded on early kernels.

In the future, for the non-cached case (O_DIRECT, and forcedirectio mounts)
it would be possible and useful to send O_APPEND on posix open (for Windows
case: FILE_APPEND_DATA but not FILE_WRITE_DATA on SMB NTCreateX) but for
cached writes although the vfs sets the offset to end of file it
may fragment a write across pages - so we can't send O_APPEND on
open (could result in sending part of a page twice).

CC: Stable <stable@kernel.org>
Reviewed-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2009-11-24 22:52:13 +00:00
Steve French
8e6c0332d5 [CIFS] fix oops in cifs_lookup during net boot
Fixes bugzilla.kernel.org bug number 14641

Lookup called during network boot (network root filesystem
for diskless workstation) has case where nd is null in
lookup.  This patch fixes that in cifs_lookup.

(Shirish noted that 2.6.30 and 2.6.31 stable need the same check)

Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Tested-by:  Vladimir Stavrinov <vs@inist.ru>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2009-11-24 22:17:59 +00:00
David Howells
4fa9f4ede8 FS-Cache: Provide nop fscache_stat_d() if CONFIG_FSCACHE_STATS=n
Provide nop fscache_stat_d() macro if CONFIG_FSCACHE_STATS=n lest errors like
the following occur:

	fs/fscache/cache.c: In function 'fscache_withdraw_cache':
	fs/fscache/cache.c:386: error: implicit declaration of function 'fscache_stat_d'
	fs/fscache/cache.c:386: error: 'fscache_n_cop_sync_cache' undeclared (first use in this function)
	fs/fscache/cache.c:386: error: (Each undeclared identifier is reported only once
	fs/fscache/cache.c:386: error: for each function it appears in.)
	fs/fscache/cache.c:392: error: 'fscache_n_cop_dissociate_pages' undeclared (first use in this function)

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-20 21:50:44 +00:00
David Howells
1c2ea8a2c0 SLOW_WORK: Fix GFS2 to #include <linux/module.h> before using THIS_MODULE
GFS2 has been altered to pass THIS_MODULE to slow_work_register_user(), but
hasn't been altered to #include <linux/module.h> to provide it, resulting in
the following error:

	fs/gfs2/recovery.c:596: error: 'THIS_MODULE' undeclared here (not in a function)

Add the missing #include.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-20 21:50:40 +00:00
David Howells
0109d7e614 SLOW_WORK: Fix CIFS to pass THIS_MODULE to slow_work_register_user()
As of the patch:

	SLOW_WORK: Wait for outstanding work items belonging to a module to clear

	Wait for outstanding slow work items belonging to a module to clear
	when unregistering that module as a user of the facility.  This
	prevents the put_ref code of a work item from being taken away before
	it returns.

slow_work_register_user() takes a module pointer as an argument.  CIFS must now
pass THIS_MODULE as that argument, lest the following error be observed:

	fs/cifs/cifsfs.c: In function 'init_cifs':
	fs/cifs/cifsfs.c:1040: error: too few arguments to function 'slow_work_register_user'

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-20 21:50:36 +00:00
Frederic Weisbecker
1d2c6cfd40 kill-the-bkl/reiserfs: turn GFP_ATOMIC flag to GFP_NOFS in reiserfs_get_block()
GFP_ATOMIC was used in reiserfs_get_block to not lose the Bkl so that
nobody can modify the tree in the middle of its work. Now that we
kicked out the bkl, we can use a more friendly flag. We use GFP_NOFS
here because we already hold the reiserfs lock.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Laurent Riffard <laurent.riffard@free.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>
2009-11-20 18:25:02 +01:00
Linus Torvalds
931ed94430 Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
  ocfs2: Trivial cleanup of jbd compatibility layer removal
  ocfs2: Refresh documentation
  ocfs2: return f_fsid info in ocfs2_statfs()
  ocfs2: duplicate inline data properly during reflink.
  ocfs2: Move ocfs2_complete_reflink to the right place.
  ocfs2: Return -EINVAL when a device is not ocfs2.
2009-11-19 20:29:05 -08:00
Linus Torvalds
e6236f781c Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
  SUNRPC: Address buffer overrun in rpc_uaddr2sockaddr()
  NFSv4: Fix a cache validation bug which causes getcwd() to return ENOENT
2009-11-19 13:43:19 -08:00
David Howells
14e69647c8 CacheFiles: Don't log lookup/create failing with ENOBUFS
Don't log the CacheFiles lookup/create object routined failing with ENOBUFS as
under high memory load or high cache load they can do this quite a lot.  This
error simply means that the requested object cannot be created on disk due to
lack of space, or due to failure of the backing filesystem to find sufficient
resources.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:12:08 +00:00
David Howells
fee096deb4 CacheFiles: Catch an overly long wait for an old active object
Catch an overly long wait for an old, dying active object when we want to
replace it with a new one.  The probability is that all the slow-work threads
are hogged, and the delete can't get a look in.

What we do instead is:

 (1) if there's nothing in the slow work queue, we sleep until either the dying
     object has finished dying or there is something in the slow work queue
     behind which we can queue our object.

 (2) if there is something in the slow work queue, we return ETIMEDOUT to
     fscache_lookup_object(), which then puts us back on the slow work queue,
     presumably behind the deletion that we're blocked by.  We are then
     deferred for a while until we work our way back through the queue -
     without blocking a slow-work thread unnecessarily.

A backtrace similar to the following may appear in the log without this patch:

	INFO: task kslowd004:5711 blocked for more than 120 seconds.
	"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
	kslowd004     D 0000000000000000     0  5711      2 0x00000080
	 ffff88000340bb80 0000000000000046 ffff88002550d000 0000000000000000
	 ffff88002550d000 0000000000000007 ffff88000340bfd8 ffff88002550d2a8
	 000000000000ddf0 00000000000118c0 00000000000118c0 ffff88002550d2a8
	Call Trace:
	 [<ffffffff81058e21>] ? trace_hardirqs_on+0xd/0xf
	 [<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
	 [<ffffffffa011c4e1>] cachefiles_wait_bit+0x9/0xd [cachefiles]
	 [<ffffffff81353153>] __wait_on_bit+0x43/0x76
	 [<ffffffff8111ae39>] ? ext3_xattr_get+0x1ec/0x270
	 [<ffffffff813531ef>] out_of_line_wait_on_bit+0x69/0x74
	 [<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
	 [<ffffffff8104c125>] ? wake_bit_function+0x0/0x2e
	 [<ffffffffa011bc79>] cachefiles_mark_object_active+0x203/0x23b [cachefiles]
	 [<ffffffffa011c209>] cachefiles_walk_to_object+0x558/0x827 [cachefiles]
	 [<ffffffffa011a429>] cachefiles_lookup_object+0xac/0x12a [cachefiles]
	 [<ffffffffa00aa1e9>] fscache_lookup_object+0x1c7/0x214 [fscache]
	 [<ffffffffa00aafc5>] fscache_object_state_machine+0xa5/0x52d [fscache]
	 [<ffffffffa00ab4ac>] fscache_object_slow_work_execute+0x5f/0xa0 [fscache]
	 [<ffffffff81082093>] slow_work_execute+0x18f/0x2d1
	 [<ffffffff8108239a>] slow_work_thread+0x1c5/0x308
	 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
	 [<ffffffff810821d5>] ? slow_work_thread+0x0/0x308
	 [<ffffffff8104be91>] kthread+0x7a/0x82
	 [<ffffffff8100beda>] child_rip+0xa/0x20
	 [<ffffffff8100b87c>] ? restore_args+0x0/0x30
	 [<ffffffff8104be17>] ? kthread+0x0/0x82
	 [<ffffffff8100bed0>] ? child_rip+0x0/0x20
	1 lock held by kslowd004/5711:
	 #0:  (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [<ffffffffa011be64>] cachefiles_walk_to_object+0x1b3/0x827 [cachefiles]

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:12:05 +00:00
David Howells
d0e27b7808 CacheFiles: Better showing of debugging information in active object problems
Show more debugging information if cachefiles_mark_object_active() is asked to
activate an active object.

This may happen, for instance, if the netfs tries to register an object with
the same key multiple times.

The code is changed to (a) get the appropriate object lock to protect the
cookie pointer whilst we dereference it, and (b) get and display the cookie key
if available.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:12:02 +00:00
David Howells
6511de33c8 CacheFiles: Mark parent directory locks as I_MUTEX_PARENT to keep lockdep happy
Mark parent directory locks as I_MUTEX_PARENT in the callers of
cachefiles_bury_object() so that lockdep doesn't complain when that invokes
vfs_unlink():

=============================================
[ INFO: possible recursive locking detected ]
2.6.32-rc6-cachefs #47
---------------------------------------------
kslowd002/3089 is trying to acquire lock:
 (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff810bbf72>] vfs_unlink+0x8b/0x128

but task is already holding lock:
 (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffffa00e4e61>] cachefiles_walk_to_object+0x1b0/0x831 [cachefiles]

other info that might help us debug this:
1 lock held by kslowd002/3089:
 #0:  (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffffa00e4e61>] cachefiles_walk_to_object+0x1b0/0x831 [cachefiles]

stack backtrace:
Pid: 3089, comm: kslowd002 Not tainted 2.6.32-rc6-cachefs #47
Call Trace:
 [<ffffffff8105ad7b>] __lock_acquire+0x1649/0x16e3
 [<ffffffff8118170e>] ? inode_has_perm+0x5f/0x61
 [<ffffffff8105ae6c>] lock_acquire+0x57/0x6d
 [<ffffffff810bbf72>] ? vfs_unlink+0x8b/0x128
 [<ffffffff81353ac3>] mutex_lock_nested+0x54/0x292
 [<ffffffff810bbf72>] ? vfs_unlink+0x8b/0x128
 [<ffffffff8118179e>] ? selinux_inode_permission+0x8e/0x90
 [<ffffffff8117e271>] ? security_inode_permission+0x1c/0x1e
 [<ffffffff810bb4fb>] ? inode_permission+0x99/0xa5
 [<ffffffff810bbf72>] vfs_unlink+0x8b/0x128
 [<ffffffff810adb19>] ? kfree+0xed/0xf9
 [<ffffffffa00e3f00>] cachefiles_bury_object+0xb6/0x420 [cachefiles]
 [<ffffffff81058e21>] ? trace_hardirqs_on+0xd/0xf
 [<ffffffffa00e7e24>] ? cachefiles_check_object_xattr+0x233/0x293 [cachefiles]
 [<ffffffffa00e51b0>] cachefiles_walk_to_object+0x4ff/0x831 [cachefiles]
 [<ffffffff81032238>] ? finish_task_switch+0x0/0xb2
 [<ffffffffa00e3429>] cachefiles_lookup_object+0xac/0x12a [cachefiles]
 [<ffffffffa00741e9>] fscache_lookup_object+0x1c7/0x214 [fscache]
 [<ffffffffa0074fc5>] fscache_object_state_machine+0xa5/0x52d [fscache]
 [<ffffffffa00754ac>] fscache_object_slow_work_execute+0x5f/0xa0 [fscache]
 [<ffffffff81082093>] slow_work_execute+0x18f/0x2d1
 [<ffffffff8108239a>] slow_work_thread+0x1c5/0x308
 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
 [<ffffffff810821d5>] ? slow_work_thread+0x0/0x308
 [<ffffffff8104be91>] kthread+0x7a/0x82
 [<ffffffff8100beda>] child_rip+0xa/0x20
 [<ffffffff8100b87c>] ? restore_args+0x0/0x30
 [<ffffffff8104be17>] ? kthread+0x0/0x82
 [<ffffffff8100bed0>] ? child_rip+0x0/0x20

Signed-off-by: Daivd Howells <dhowells@redhat.com>
2009-11-19 18:11:58 +00:00
David Howells
5e929b33c3 CacheFiles: Handle truncate unlocking the page we're reading
Handle truncate unlocking the page we're attempting to read from the backing
device before the read has completed.

This was causing reports like the following to occur:

	Pid: 4765, comm: kslowd Not tainted 2.6.30.1 #1
	Call Trace:
	 [<ffffffffa0331d7a>] ? cachefiles_read_waiter+0xd9/0x147 [cachefiles]
	 [<ffffffff804b74bd>] ? __wait_on_bit+0x60/0x6f
	 [<ffffffff8022bbbb>] ? __wake_up_common+0x3f/0x71
	 [<ffffffff8022cc32>] ? __wake_up+0x30/0x44
	 [<ffffffff8024a41f>] ? __wake_up_bit+0x28/0x2d
	 [<ffffffffa003a793>] ? ext3_truncate+0x4d7/0x8ed [ext3]
	 [<ffffffff80281f90>] ? pagevec_lookup+0x17/0x1f
	 [<ffffffff8028c2ff>] ? unmap_mapping_range+0x59/0x1ff
	 [<ffffffff8022cc32>] ? __wake_up+0x30/0x44
	 [<ffffffff8028e286>] ? vmtruncate+0xc2/0xe2
	 [<ffffffff802b82cf>] ? inode_setattr+0x22/0x10a
	 [<ffffffffa003baa5>] ? ext3_setattr+0x17b/0x1e6 [ext3]
	 [<ffffffff802b853d>] ? notify_change+0x186/0x2c9
	 [<ffffffffa032d9de>] ? cachefiles_attr_changed+0x133/0x1cd [cachefiles]
	 [<ffffffffa032df7f>] ? cachefiles_lookup_object+0xcf/0x12a [cachefiles]
	 [<ffffffffa0318165>] ? fscache_lookup_object+0x110/0x122 [fscache]
	 [<ffffffffa03188c3>] ? fscache_object_slow_work_execute+0x590/0x6bc
	[fscache]
	 [<ffffffff80278f82>] ? slow_work_thread+0x285/0x43a
	 [<ffffffff8024a446>] ? autoremove_wake_function+0x0/0x2e
	 [<ffffffff80278cfd>] ? slow_work_thread+0x0/0x43a
	 [<ffffffff8024a317>] ? kthread+0x54/0x81
	 [<ffffffff8020c93a>] ? child_rip+0xa/0x20
	 [<ffffffff8024a2c3>] ? kthread+0x0/0x81
	 [<ffffffff8020c930>] ? child_rip+0x0/0x20
	CacheFiles: I/O Error: Readpage failed on backing file 200000000000810
	FS-Cache: Cache cachefiles stopped due to I/O error

Reported-by: Christian Kujau <lists@nerdbynature.de>
Reported-by: Takashi Iwai <tiwai@suse.de>
Reported-by: Duc Le Minh <duclm.vn@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:55 +00:00
David Howells
a17754fb8c CacheFiles: Don't write a full page if there's only a partial page to cache
cachefiles_write_page() writes a full page to the backing file for the last
page of the netfs file, even if the netfs file's last page is only a partial
page.

This causes the EOF on the backing file to be extended beyond the EOF of the
netfs, and thus the backing file will be truncated by cachefiles_attr_changed()
called from cachefiles_lookup_object().

So we need to limit the write we make to the backing file on that last page
such that it doesn't push the EOF too far.

Also, if a backing file that has a partial page at the end is expanded, we
discard the partial page and refetch it on the basis that we then have a hole
in the file with invalid data, and should the power go out...  A better way to
deal with this could be to record a note that the partial page contains invalid
data until the correct data is written into it.

This isn't a problem for netfs's that discard the whole backing file if the
file size changes (such as NFS).

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:52 +00:00
David Howells
868411be3f FS-Cache: Actually requeue an object when requested
FS-Cache objects have an FSCACHE_OBJECT_EV_REQUEUE event that can theoretically
be raised to ask the state machine to requeue the object for further processing
before the work function returns to the slow-work facility.

However, fscache_object_work_execute() was clearing that bit before checking
the event mask to see whether the object has any pending events that require it
to be requeued immediately.

Instead, the bit should be cleared after the check and enqueue.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:48 +00:00
David Howells
60d543ca72 FS-Cache: Start processing an object's operations on that object's death
Start processing an object's operations when that object moves into the DYING
state as the object cannot be destroyed until all its outstanding operations
have completed.

Furthermore, make sure that read and allocation operations handle being woken
up on a dead object.  Such events are recorded in the Allocs.abt and
Retrvls.abt statistics as viewable through /proc/fs/fscache/stats.

The code for waiting for object activation for the read and allocation
operations is also extracted into its own function as it is much the same in
all cases, differing only in the stats incremented.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:45 +00:00
David Howells
d461d26dde FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure
We must make sure that FSCACHE_COOKIE_LOOKING_UP is cleared on lookup failure
(if an object reaches the LC_DYING state), and we should clear it before
clearing FSCACHE_COOKIE_CREATING.

If this doesn't happen then fscache_wait_for_deferred_lookup() may hold
allocation and retrieval operations indefinitely until they're interrupted by
signals - which in turn pins the dying object until they go away.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:41 +00:00
David Howells
2175bb06dc FS-Cache: Add a retirement stat counter
Add a stat counter to count retirement events rather than ordinary release
events (the retire argument to fscache_relinquish_cookie()).

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:38 +00:00
David Howells
201a15428b FS-Cache: Handle pages pending storage that get evicted under OOM conditions
Handle netfs pages that the vmscan algorithm wants to evict from the pagecache
under OOM conditions, but that are waiting for write to the cache.  Under these
conditions, vmscan calls the releasepage() function of the netfs, asking if a
page can be discarded.

The problem is typified by the following trace of a stuck process:

	kslowd005     D 0000000000000000     0  4253      2 0x00000080
	 ffff88001b14f370 0000000000000046 ffff880020d0d000 0000000000000007
	 0000000000000006 0000000000000001 ffff88001b14ffd8 ffff880020d0d2a8
	 000000000000ddf0 00000000000118c0 00000000000118c0 ffff880020d0d2a8
	Call Trace:
	 [<ffffffffa00782d8>] __fscache_wait_on_page_write+0x8b/0xa7 [fscache]
	 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
	 [<ffffffffa0078240>] ? __fscache_check_page_write+0x63/0x70 [fscache]
	 [<ffffffffa00b671d>] nfs_fscache_release_page+0x4e/0xc4 [nfs]
	 [<ffffffffa00927f0>] nfs_release_page+0x3c/0x41 [nfs]
	 [<ffffffff810885d3>] try_to_release_page+0x32/0x3b
	 [<ffffffff81093203>] shrink_page_list+0x316/0x4ac
	 [<ffffffff8109372b>] shrink_inactive_list+0x392/0x67c
	 [<ffffffff813532fa>] ? __mutex_unlock_slowpath+0x100/0x10b
	 [<ffffffff81058df0>] ? trace_hardirqs_on_caller+0x10c/0x130
	 [<ffffffff8135330e>] ? mutex_unlock+0x9/0xb
	 [<ffffffff81093aa2>] shrink_list+0x8d/0x8f
	 [<ffffffff81093d1c>] shrink_zone+0x278/0x33c
	 [<ffffffff81052d6c>] ? ktime_get_ts+0xad/0xba
	 [<ffffffff81094b13>] try_to_free_pages+0x22e/0x392
	 [<ffffffff81091e24>] ? isolate_pages_global+0x0/0x212
	 [<ffffffff8108e743>] __alloc_pages_nodemask+0x3dc/0x5cf
	 [<ffffffff81089529>] grab_cache_page_write_begin+0x65/0xaa
	 [<ffffffff8110f8c0>] ext3_write_begin+0x78/0x1eb
	 [<ffffffff81089ec5>] generic_file_buffered_write+0x109/0x28c
	 [<ffffffff8103cb69>] ? current_fs_time+0x22/0x29
	 [<ffffffff8108a509>] __generic_file_aio_write+0x350/0x385
	 [<ffffffff8108a588>] ? generic_file_aio_write+0x4a/0xae
	 [<ffffffff8108a59e>] generic_file_aio_write+0x60/0xae
	 [<ffffffff810b2e82>] do_sync_write+0xe3/0x120
	 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
	 [<ffffffff810b18e1>] ? __dentry_open+0x1a5/0x2b8
	 [<ffffffff810b1a76>] ? dentry_open+0x82/0x89
	 [<ffffffffa00e693c>] cachefiles_write_page+0x298/0x335 [cachefiles]
	 [<ffffffffa0077147>] fscache_write_op+0x178/0x2c2 [fscache]
	 [<ffffffffa0075656>] fscache_op_execute+0x7a/0xd1 [fscache]
	 [<ffffffff81082093>] slow_work_execute+0x18f/0x2d1
	 [<ffffffff8108239a>] slow_work_thread+0x1c5/0x308
	 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
	 [<ffffffff810821d5>] ? slow_work_thread+0x0/0x308
	 [<ffffffff8104be91>] kthread+0x7a/0x82
	 [<ffffffff8100beda>] child_rip+0xa/0x20
	 [<ffffffff8100b87c>] ? restore_args+0x0/0x30
	 [<ffffffff8102ef83>] ? tg_shares_up+0x171/0x227
	 [<ffffffff8104be17>] ? kthread+0x0/0x82
	 [<ffffffff8100bed0>] ? child_rip+0x0/0x20

In the above backtrace, the following is happening:

 (1) A page storage operation is being executed by a slow-work thread
     (fscache_write_op()).

 (2) FS-Cache farms the operation out to the cache to perform
     (cachefiles_write_page()).

 (3) CacheFiles is then calling Ext3 to perform the actual write, using Ext3's
     standard write (do_sync_write()) under KERNEL_DS directly from the netfs
     page.

 (4) However, for Ext3 to perform the write, it must allocate some memory, in
     particular, it must allocate at least one page cache page into which it
     can copy the data from the netfs page.

 (5) Under OOM conditions, the memory allocator can't immediately come up with
     a page, so it uses vmscan to find something to discard
     (try_to_free_pages()).

 (6) vmscan finds a clean netfs page it might be able to discard (possibly the
     one it's trying to write out).

 (7) The netfs is called to throw the page away (nfs_release_page()) - but it's
     called with __GFP_WAIT, so the netfs decides to wait for the store to
     complete (__fscache_wait_on_page_write()).

 (8) This blocks a slow-work processing thread - possibly against itself.

The system ends up stuck because it can't write out any netfs pages to the
cache without allocating more memory.

To avoid this, we make FS-Cache cancel some writes that aren't in the middle of
actually being performed.  This means that some data won't make it into the
cache this time.  To support this, a new FS-Cache function is added
fscache_maybe_release_page() that replaces what the netfs releasepage()
functions used to do with respect to the cache.

The decisions fscache_maybe_release_page() makes are counted and displayed
through /proc/fs/fscache/stats on a line labelled "VmScan".  There are four
counters provided: "nos=N" - pages that weren't pending storage; "gon=N" -
pages that were pending storage when we first looked, but weren't by the time
we got the object lock; "bsy=N" - pages that we ignored as they were actively
being written when we looked; and "can=N" - pages that we cancelled the storage
of.

What I'd really like to do is alter the behaviour of the cancellation
heuristics, depending on how necessary it is to expel pages.  If there are
plenty of other pages that aren't waiting to be written to the cache that
could be ejected first, then it would be nice to hold up on immediate
cancellation of cache writes - but I don't see a way of doing that.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:35 +00:00
David Howells
e3d4d28b1c FS-Cache: Handle read request vs lookup, creation or other cache failure
FS-Cache doesn't correctly handle the netfs requesting a read from the cache
on an object that failed or was withdrawn by the cache.  A trace similar to
the following might be seen:

	CacheFiles: Lookup failed error -105
	[exe   ] unexpected submission OP165afe [OBJ6cac OBJECT_LC_DYING]
	[exe   ] objstate=OBJECT_LC_DYING [OBJECT_LC_DYING]
	[exe   ] objflags=0
	[exe   ] objevent=9 [fffffffffffffffb]
	[exe   ] ops=0 inp=0 exc=0
	Pid: 6970, comm: exe Not tainted 2.6.32-rc6-cachefs #50
	Call Trace:
	 [<ffffffffa0076477>] fscache_submit_op+0x3ff/0x45a [fscache]
	 [<ffffffffa0077997>] __fscache_read_or_alloc_pages+0x187/0x3c4 [fscache]
	 [<ffffffffa00b6480>] ? nfs_readpage_from_fscache_complete+0x0/0x66 [nfs]
	 [<ffffffffa00b6388>] __nfs_readpages_from_fscache+0x7e/0x176 [nfs]
	 [<ffffffff8108e483>] ? __alloc_pages_nodemask+0x11c/0x5cf
	 [<ffffffffa009d796>] nfs_readpages+0x114/0x1d7 [nfs]
	 [<ffffffff81090314>] __do_page_cache_readahead+0x15f/0x1ec
	 [<ffffffff81090228>] ? __do_page_cache_readahead+0x73/0x1ec
	 [<ffffffff810903bd>] ra_submit+0x1c/0x20
	 [<ffffffff810906bb>] ondemand_readahead+0x227/0x23a
	 [<ffffffff81090762>] page_cache_sync_readahead+0x17/0x19
	 [<ffffffff8108a99e>] generic_file_aio_read+0x236/0x5a0
	 [<ffffffffa00937bd>] nfs_file_read+0xe4/0xf3 [nfs]
	 [<ffffffff810b2fa2>] do_sync_read+0xe3/0x120
	 [<ffffffff81354cc3>] ? _spin_unlock_irq+0x2b/0x31
	 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
	 [<ffffffff811848e5>] ? selinux_file_permission+0x5d/0x10f
	 [<ffffffff81352bdb>] ? thread_return+0x3e/0x101
	 [<ffffffff8117d7b0>] ? security_file_permission+0x11/0x13
	 [<ffffffff810b3b06>] vfs_read+0xaa/0x16f
	 [<ffffffff81058df0>] ? trace_hardirqs_on_caller+0x10c/0x130
	 [<ffffffff810b3c84>] sys_read+0x45/0x6c
	 [<ffffffff8100ae2b>] system_call_fastpath+0x16/0x1b

The object state might also be OBJECT_DYING or OBJECT_WITHDRAWING.

This should be handled by simply rejecting the new operation with ENOBUFS.
There's no need to log an error for it.  Events of this type now appear in the
stats file under Ops:rej.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:32 +00:00
David Howells
285e728b0a FS-Cache: Don't delete pending pages from the page-store tracking tree
Don't delete pending pages from the page-store tracking tree, but rather send
them for another write as they've presumably been updated.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:29 +00:00
David Howells
1bccf513ac FS-Cache: Fix lock misorder in fscache_write_op()
FS-Cache has two structs internally for keeping track of the internal state of
a cached file: the fscache_cookie struct, which represents the netfs's state,
and fscache_object struct, which represents the cache's state.  Each has a
pointer that points to the other (when both are in existence), and each has a
spinlock for pointer maintenance.

Since netfs operations approach these structures from the cookie side, they get
the cookie lock first, then the object lock.  Cache operations, on the other
hand, approach from the object side, and get the object lock first.  It is not
then permitted for a cache operation to get the cookie lock whilst it is
holding the object lock lest deadlock occur; instead, it must do one of two
things:

 (1) increment the cookie usage counter, drop the object lock and then get both
     locks in order, or

 (2) simply hold the object lock as certain parts of the cookie may not be
     altered whilst the object lock is held.

It is also not permitted to follow either pointer without holding the lock at
the end you start with.  To break the pointers between the cookie and the
object, both locks must be held.

fscache_write_op(), however, violates the locking rules: It attempts to get the
cookie lock without (a) checking that the cookie pointer is a valid pointer,
and (b) holding the object lock to protect the cookie pointer whilst it follows
it.  This is so that it can access the pending page store tree without
interference from __fscache_write_page().

This is fixed by splitting the cookie lock, such that the page store tracking
tree is protected by its own lock, and checking that the cookie pointer is
non-NULL before we attempt to follow it whilst holding the object lock.

The new lock is subordinate to both the cookie lock and the object lock, and so
should be taken after those.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:25 +00:00
David Howells
6897e3df8f FS-Cache: The object-available state can't rely on the cookie to be available
The object-available state in the object processing state machine (as
processed by fscache_object_available()) can't rely on the cookie to be
available because the FSCACHE_COOKIE_CREATING bit may have been cleared by
fscache_obtained_object() prior to the object being put into the
FSCACHE_OBJECT_AVAILABLE state.

Clearing the FSCACHE_COOKIE_CREATING bit on a cookie permits
__fscache_relinquish_cookie() to proceed and detach the cookie from the
object.

To deal with this, we don't dereference object->cookie in
fscache_object_available() if the object has already been detached.

In addition, a couple of assertions are added into fscache_drop_object() to
make sure the object is unbound from the cookie before it gets there.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:22 +00:00
David Howells
5753c44188 FS-Cache: Permit cache retrieval ops to be interrupted in the initial wait phase
Permit the operations to retrieve data from the cache or to allocate space in
the cache for future writes to be interrupted whilst they're waiting for
permission for the operation to proceed.  Typically this wait occurs whilst the
cache object is being looked up on disk in the background.

If an interruption occurs, and the operation has not yet been given the
go-ahead to run, the operation is dequeued and cancelled, and control returns
to the read operation of the netfs routine with none of the requested pages
having been read or in any way marked as known by the cache.

This means that the initial wait is done interruptibly rather than
uninterruptibly.

In addition, extra stats values are made available to show the number of ops
cancelled and the number of cache space allocations interrupted.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:19 +00:00
David Howells
b34df792b4 FS-Cache: Use radix tree preload correctly in tracking of pages to be stored
__fscache_write_page() attempts to load the radix tree preallocation pool for
the CPU it is on before calling radix_tree_insert(), as the insertion must be
done inside a pair of spinlocks.

Use of the preallocation pool, however, is contingent on the radix tree being
initialised without __GFP_WAIT specified.  __fscache_acquire_cookie() was
passing GFP_NOFS to INIT_RADIX_TREE() - but that includes __GFP_WAIT.

The solution is to AND out __GFP_WAIT.

Additionally, the banner comment to radix_tree_preload() is altered to make
note of this prerequisite.  Possibly there should be a WARN_ON() too.

Without this fix, I have seen the following recursive deadlock caused by
radix_tree_insert() attempting to allocate memory inside the spinlocked
region, which resulted in FS-Cache being called back into to release memory -
which required the spinlock already held.

=============================================
[ INFO: possible recursive locking detected ]
2.6.32-rc6-cachefs #24
---------------------------------------------
nfsiod/7916 is trying to acquire lock:
 (&cookie->lock){+.+.-.}, at: [<ffffffffa0076872>] __fscache_uncache_page+0xdb/0x160 [fscache]

but task is already holding lock:
 (&cookie->lock){+.+.-.}, at: [<ffffffffa0076acc>] __fscache_write_page+0x15c/0x3f3 [fscache]

other info that might help us debug this:
5 locks held by nfsiod/7916:
 #0:  (nfsiod){+.+.+.}, at: [<ffffffff81048290>] worker_thread+0x19a/0x2e2
 #1:  (&task->u.tk_work#2){+.+.+.}, at: [<ffffffff81048290>] worker_thread+0x19a/0x2e2
 #2:  (&cookie->lock){+.+.-.}, at: [<ffffffffa0076acc>] __fscache_write_page+0x15c/0x3f3 [fscache]
 #3:  (&object->lock#2){+.+.-.}, at: [<ffffffffa0076b07>] __fscache_write_page+0x197/0x3f3 [fscache]
 #4:  (&cookie->stores_lock){+.+...}, at: [<ffffffffa0076b0f>] __fscache_write_page+0x19f/0x3f3 [fscache]

stack backtrace:
Pid: 7916, comm: nfsiod Not tainted 2.6.32-rc6-cachefs #24
Call Trace:
 [<ffffffff8105ac7f>] __lock_acquire+0x1649/0x16e3
 [<ffffffff81059ded>] ? __lock_acquire+0x7b7/0x16e3
 [<ffffffff8100e27d>] ? dump_trace+0x248/0x257
 [<ffffffff8105ad70>] lock_acquire+0x57/0x6d
 [<ffffffffa0076872>] ? __fscache_uncache_page+0xdb/0x160 [fscache]
 [<ffffffff8135467c>] _spin_lock+0x2c/0x3b
 [<ffffffffa0076872>] ? __fscache_uncache_page+0xdb/0x160 [fscache]
 [<ffffffffa0076872>] __fscache_uncache_page+0xdb/0x160 [fscache]
 [<ffffffffa0077eb7>] ? __fscache_check_page_write+0x0/0x71 [fscache]
 [<ffffffffa00b4755>] nfs_fscache_release_page+0x86/0xc4 [nfs]
 [<ffffffffa00907f0>] nfs_release_page+0x3c/0x41 [nfs]
 [<ffffffff81087ffb>] try_to_release_page+0x32/0x3b
 [<ffffffff81092c2b>] shrink_page_list+0x316/0x4ac
 [<ffffffff81058a9b>] ? mark_held_locks+0x52/0x70
 [<ffffffff8135451b>] ? _spin_unlock_irq+0x2b/0x31
 [<ffffffff81093153>] shrink_inactive_list+0x392/0x67c
 [<ffffffff81058a9b>] ? mark_held_locks+0x52/0x70
 [<ffffffff810934ca>] shrink_list+0x8d/0x8f
 [<ffffffff81093744>] shrink_zone+0x278/0x33c
 [<ffffffff81052c70>] ? ktime_get_ts+0xad/0xba
 [<ffffffff8109453b>] try_to_free_pages+0x22e/0x392
 [<ffffffff8109184c>] ? isolate_pages_global+0x0/0x212
 [<ffffffff8108e16b>] __alloc_pages_nodemask+0x3dc/0x5cf
 [<ffffffff810ae24a>] cache_alloc_refill+0x34d/0x6c1
 [<ffffffff811bcf74>] ? radix_tree_node_alloc+0x52/0x5c
 [<ffffffff810ae929>] kmem_cache_alloc+0xb2/0x118
 [<ffffffff811bcf74>] radix_tree_node_alloc+0x52/0x5c
 [<ffffffff811bcfd5>] radix_tree_insert+0x57/0x19c
 [<ffffffffa0076b53>] __fscache_write_page+0x1e3/0x3f3 [fscache]
 [<ffffffffa00b4248>] __nfs_readpage_to_fscache+0x58/0x11e [nfs]
 [<ffffffffa009bb77>] nfs_readpage_release+0x34/0x9b [nfs]
 [<ffffffffa009c0d9>] nfs_readpage_release_full+0x32/0x4b [nfs]
 [<ffffffffa0006cff>] rpc_release_calldata+0x12/0x14 [sunrpc]
 [<ffffffffa0006e2d>] rpc_free_task+0x59/0x61 [sunrpc]
 [<ffffffffa0006f03>] rpc_async_release+0x10/0x12 [sunrpc]
 [<ffffffff810482e5>] worker_thread+0x1ef/0x2e2
 [<ffffffff81048290>] ? worker_thread+0x19a/0x2e2
 [<ffffffff81352433>] ? thread_return+0x3e/0x101
 [<ffffffffa0006ef3>] ? rpc_async_release+0x0/0x12 [sunrpc]
 [<ffffffff8104bff5>] ? autoremove_wake_function+0x0/0x34
 [<ffffffff81058d25>] ? trace_hardirqs_on+0xd/0xf
 [<ffffffff810480f6>] ? worker_thread+0x0/0x2e2
 [<ffffffff8104bd21>] kthread+0x7a/0x82
 [<ffffffff8100beda>] child_rip+0xa/0x20
 [<ffffffff8100b87c>] ? restore_args+0x0/0x30
 [<ffffffff8104c2b9>] ? add_wait_queue+0x15/0x44
 [<ffffffff8104bca7>] ? kthread+0x0/0x82
 [<ffffffff8100bed0>] ? child_rip+0x0/0x20

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:14 +00:00
David Howells
7e311a207d FS-Cache: Clear netfs pointers in cookie after detaching object, not before
Clear the pointers from the fscache_cookie struct to netfs private data after
clearing the pointer to the cookie from the fscache_object struct and
releasing the object lock, rather than before.

This allows the netfs private data pointers to be relied on simply by holding
the object lock, rather than having to hold the cookie lock.  This is makes
things simpler as the cookie lock has to be taken before the object lock, but
sometimes the object pointer is all that the code has.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:11 +00:00
David Howells
52bd75fdb1 FS-Cache: Add counters for entry/exit to/from cache operation functions
Count entries to and exits from cache operation table functions.  Maintain
these as a single counter that's added to or removed from as appropriate.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:08 +00:00
David Howells
4fbf4291aa FS-Cache: Allow the current state of all objects to be dumped
Allow the current state of all fscache objects to be dumped by doing:

	cat /proc/fs/fscache/objects

By default, all objects and all fields will be shown.  This can be restricted
by adding a suitable key to one of the caller's keyrings (such as the session
keyring):

	keyctl add user fscache:objlist "<restrictions>" @s

The <restrictions> are:

	K	Show hexdump of object key (don't show if not given)
	A	Show hexdump of object aux data (don't show if not given)

And paired restrictions:

	C	Show objects that have a cookie
	c	Show objects that don't have a cookie
	B	Show objects that are busy
	b	Show objects that aren't busy
	W	Show objects that have pending writes
	w	Show objects that don't have pending writes
	R	Show objects that have outstanding reads
	r	Show objects that don't have outstanding reads
	S	Show objects that have slow work queued
	s	Show objects that don't have slow work queued

If neither side of a restriction pair is given, then both are implied.  For
example:

	keyctl add user fscache:objlist KB @s

shows objects that are busy, and lists their object keys, but does not dump
their auxiliary data.  It also implies "CcWwRrSs", but as 'B' is given, 'b' is
not implied.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:04 +00:00
David Howells
440f0affe2 FS-Cache: Annotate slow-work runqueue proc lines for FS-Cache work items
Annotate slow-work runqueue proc lines for FS-Cache work items.  Objects
include the object ID and the state.  Operations include the object ID, the
operation ID and the operation type and state.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:11:01 +00:00
David Howells
3d7a641e54 SLOW_WORK: Wait for outstanding work items belonging to a module to clear
Wait for outstanding slow work items belonging to a module to clear when
unregistering that module as a user of the facility.  This prevents the put_ref
code of a work item from being taken away before it returns.

Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19 18:10:23 +00:00