aha/fs
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
..
9p FS-Cache: Handle pages pending storage that get evicted under OOM conditions 2009-11-19 18:11:35 +00:00
adfs adfs: remove redundant test on unsigned 2009-09-24 07:21:05 -07:00
affs
afs FS-Cache: Handle pages pending storage that get evicted under OOM conditions 2009-11-19 18:11:35 +00:00
autofs trivial: remove unnecessary semicolons 2009-09-21 15:14:58 +02:00
autofs4 autofs4 - fix missed case when changing to use struct path 2009-08-31 17:44:05 -10:00
befs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
bfs
btrfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2009-11-11 13:38:59 -08:00
cachefiles CacheFiles: Catch an overly long wait for an old active object 2009-11-19 18:12:05 +00:00
cifs cifs: clear server inode number flag while autodisabling 2009-11-16 15:24:03 +00:00
coda headers: remove sched.h from poll.h 2009-10-04 15:05:10 -07:00
configfs writeback: add name to backing_dev_info 2009-09-11 09:20:26 +02:00
cramfs
debugfs
devpts Move magic numbers into magic.h 2009-09-23 07:39:28 -07:00
dlm dlm: fix socket fd translation 2009-09-30 12:19:44 -05:00
ecryptfs ima: ecryptfs fix imbalance message 2009-10-08 11:31:38 -05:00
efs
exofs exofs: remove BKL from super operations 2009-09-24 07:47:38 -04:00
exportfs
ext2 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
ext3 ext3: Wait for proper transaction commit on fsync 2009-11-11 15:22:49 +01:00
ext4 ext4: partial revert to fix double brelse WARNING() 2009-11-08 15:45:44 -05:00
fat Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6 2009-09-30 09:31:14 -07:00
freevxfs
fscache CacheFiles: Catch an overly long wait for an old active object 2009-11-19 18:12:05 +00:00
fuse fuse: invalidate target of rename 2009-11-04 10:24:52 +01:00
gfs2 SLOW_WORK: Wait for outstanding work items belonging to a module to clear 2009-11-19 18:10:23 +00:00
hfs hfs: fix oops on mount with corrupted btree extent records 2009-10-29 07:39:29 -07:00
hfsplus hfsplus: refuse to mount volumes larger than 2TB 2009-10-29 07:39:27 -07:00
hostfs
hpfs
hppfs
hugetlbfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-09-24 08:32:11 -07:00
isofs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
jbd fs/jbd: Export log_start_commit to fix ext3 build. 2009-11-12 10:24:12 +01:00
jbd2 JBD/JBD2: free j_wbuf if journal init fails. 2009-11-11 15:24:14 +01:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2009-09-23 10:07:49 -07:00
jfs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
lockd headers: utsname.h redux 2009-09-23 18:13:10 -07:00
minix V3 minixfs: add missing directory type checking 2009-09-23 07:39:57 -07:00
ncpfs const: mark struct vm_struct_operations 2009-09-27 11:39:25 -07:00
nfs FS-Cache: Handle pages pending storage that get evicted under OOM conditions 2009-11-19 18:11:35 +00:00
nfs_common
nfsd Fix memory corruption caused by nfsd readdir+ 2009-11-14 12:55:55 -08:00
nilfs2 nilfs2: deleted inconsistent comment in nilfs_load_inode_block() 2009-11-15 17:17:46 +09:00
nls Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6 2009-09-30 09:31:14 -07:00
notify dnotify: ignore FS_EVENT_ON_CHILD 2009-10-20 18:02:33 -04:00
ntfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-09-24 08:32:11 -07:00
ocfs2 const: constify remaining file_operations 2009-10-01 16:11:11 -07:00
omfs const: constify remaining file_operations 2009-10-01 16:11:11 -07:00
openpromfs
partitions block: Seperate read and write statistics of in_flight requests v2 2009-10-06 20:16:55 +02:00
proc procfs: fix /proc/<pid>/stat stack pointer for kernel threads 2009-11-17 17:40:33 -08:00
qnx4 qnx4: remove write support 2009-09-23 07:39:30 -07:00
quota const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
ramfs truncate: use new helpers 2009-09-24 08:41:47 -04:00
reiserfs const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
romfs ROMFS: fix length used with romfs_dev_strnlen() function 2009-10-11 11:33:56 -07:00
smbfs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
squashfs const: mark remaining super_operations const 2009-09-22 07:17:24 -07:00
sysfs sysfs: Don't leak secdata when a sysfs_dirent is freed. 2009-11-05 08:19:18 +11:00
sysv
ubifs const: mark struct vm_struct_operations 2009-09-27 11:39:25 -07:00
udf udf: Fix possible corruption when close races with write 2009-09-14 19:13:01 +02:00
ufs
xfs xfs: copy li_lsn before dropping AIL lock 2009-11-17 10:26:49 -06:00
aio.c aio.c: move EXPORT* macros to line after function 2009-09-23 07:39:29 -07:00
anon_inodes.c headers: remove sched.h from poll.h 2009-10-04 15:05:10 -07:00
attr.c truncate: new helpers 2009-09-24 08:41:47 -04:00
bad_inode.c
binfmt_aout.c
binfmt_elf.c elf: clean up fill_note_info() 2009-09-24 07:21:01 -07:00
binfmt_elf_fdpic.c fdpic: ignore the loader's PT_GNU_STACK when calculating the stack size 2009-09-24 07:21:02 -07:00
binfmt_em86.c
binfmt_flat.c flat: use IS_ERR_VALUE() helper macro 2009-09-24 07:21:03 -07:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c
bio.c Fix bio_alloc() and bio_kmalloc() documentation 2009-11-02 11:41:13 +01:00
block_dev.c block: use after free bug in __blkdev_get 2009-10-26 15:27:11 +01:00
buffer.c Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block 2009-09-25 09:27:30 -07:00
char_dev.c fs/char_dev.c: remove useless loop 2009-09-24 07:21:03 -07:00
compat.c x86, fs: Fix x86 procfs stack information for threads on 64-bit 2009-11-04 13:25:03 +01:00
compat_binfmt_elf.c
compat_ioctl.c fs: add missing compat_ptr handling for FS_IOC_RESVSP ioctl 2009-11-12 07:25:57 -08:00
dcache.c
dcookies.c [CVE-2009-0029] System call wrapper special cases 2009-01-14 14:15:18 +01:00
direct-io.c
drop_caches.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
eventfd.c anonfd: split interface into file creation and install 2009-09-23 07:39:29 -07:00
eventpoll.c
exec.c exec: setup_arg_pages() fails to return errors 2009-11-12 07:25:58 -08:00
fcntl.c fcntl: rename F_OWNER_GID to F_OWNER_PGRP 2009-11-17 17:40:33 -08:00
fifo.c
file.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
file_table.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
filesystems.c
fs-writeback.c writeback: pass in super_block to bdi_start_writeback() 2009-09-26 00:10:40 +02:00
fs_struct.c
generic_acl.c
inode.c vfs: optimize touch_time() too 2009-09-24 07:47:27 -04:00
internal.h fs: fix overflow in sys_mount() for in-kernel calls 2009-09-24 08:40:15 -04:00
ioctl.c __generic_block_fiemap(): fix for files bigger than 4GB 2009-11-12 07:26:01 -08:00
ioprio.c
Kconfig powerpc: Cleanup Kconfig selection of hugetlbfs support 2009-10-30 15:03:54 +11:00
Kconfig.binfmt
libfs.c libfs: return error code on failed attr set 2009-09-24 07:47:30 -04:00
locks.c const: make lock_manager_operations const 2009-09-22 07:17:25 -07:00
Makefile
mbcache.c
mpage.c
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-09-11 08:55:49 -07:00
namespace.c fs: fix overflow in sys_mount() for in-kernel calls 2009-09-24 08:40:15 -04:00
nfsctl.c
no-block.c
open.c fs: change sys_truncate length parameter type 2009-09-23 09:21:05 -07:00
pipe.c fs: pipe.c null pointer dereference 2009-10-22 08:11:44 +09:00
pnode.c
pnode.h
posix_acl.c
read_write.c vfs: remove redundant position check in do_sendfile 2009-09-24 07:47:34 -04:00
read_write.h
readdir.c
select.c headers: remove sched.h from poll.h 2009-10-04 15:05:10 -07:00
seq_file.c vfs: seq_file: add helpers for data filling 2009-09-24 07:47:35 -04:00
signalfd.c
splice.c Merge branch 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block 2009-09-14 17:55:15 -07:00
stack.c
stat.c
super.c freeze_bdev: grab active reference to frozen superblocks 2009-09-24 07:47:41 -04:00
sync.c fs/buffer.c: clean up EXPORT* macros 2009-09-23 07:39:29 -07:00
timerfd.c
utimes.c
xattr.c VFS: Factor out part of vfs_setxattr so it can be called from the SELinux hook for inode_setsecctx. 2009-09-10 10:11:22 +10:00
xattr_acl.c