redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity
alistair23-linux/fs
History
Jan Kara b9543dac5b writeback: avoid livelocking WB_SYNC_ALL writeback 
When wb_writeback() is called in WB_SYNC_ALL mode, work->nr_to_write is
usually set to LONG_MAX.  The logic in wb_writeback() then calls
__writeback_inodes_sb() with nr_to_write == MAX_WRITEBACK_PAGES and we
easily end up with non-positive nr_to_write after the function returns, if
the inode has more than MAX_WRITEBACK_PAGES dirty pages at the moment.

When nr_to_write is <= 0 wb_writeback() decides we need another round of
writeback but this is wrong in some cases!  For example when a single
large file is continuously dirtied, we would never finish syncing it
because each pass would be able to write MAX_WRITEBACK_PAGES and inode
dirty timestamp never gets updated (as inode is never completely clean).
Thus __writeback_inodes_sb() would write the redirtied inode again and
again.

Fix the issue by setting nr_to_write to LONG_MAX in WB_SYNC_ALL mode.  We
do not need nr_to_write in WB_SYNC_ALL mode anyway since
write_cache_pages() does livelock avoidance using page tagging in
WB_SYNC_ALL mode.

This makes wb_writeback() call __writeback_inodes_sb() only once on
WB_SYNC_ALL.  The latter function won't livelock because it works on

- a finite set of files by doing queue_io() once at the beginning
- a finite set of pages by PAGECACHE_TAG_TOWRITE page tagging

After this patch, program from http://lkml.org/lkml/2010/10/24/154 is no
longer able to stall sync forever.

[fengguang.wu@intel.com: fix locking comment]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Engelhardt <jengelh@medozas.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2011-01-13 17:32:32 -08:00
..
9p switch 9p 2011-01-12 20:03:43 -05:00
adfs switch adfs 2011-01-12 20:02:45 -05:00
affs switch affs 2011-01-12 20:03:42 -05:00
afs switch afs 2011-01-12 20:04:20 -05:00
autofs4 fs: rcu-walk aware d_revalidate method 2011-01-07 17:50:29 +11:00
befs befs: don't pass huge structs by value 2011-01-13 08:03:15 -08:00
bfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
btrfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
cachefiles llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2011-01-13 10:25:24 -08:00
cifs switch cifs 2011-01-12 20:02:46 -05:00
coda Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2011-01-13 10:27:28 -08:00
configfs switch configfs 2011-01-12 20:03:12 -05:00
cramfs cramfs: generate unique inode number for better inode cache usage 2011-01-13 08:03:23 -08:00
debugfs convert get_sb_single() users 2010-10-29 04:16:28 -04:00
devpts convert get_sb_single() users 2010-10-29 04:16:28 -04:00
dlm dlm: sanitize work_start() in lowcomms.c 2010-12-13 13:42:24 -06:00
ecryptfs ecryptfs: fix broken build 2011-01-13 17:19:38 -08:00
efs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
exofs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
exportfs fs: dcache per-inode inode alias locking 2011-01-07 17:50:31 +11:00
ext2 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2011-01-11 14:37:31 -08:00
ext3 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
ext4 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
fat switch fat to ->s_d_op, close exportfs races there 2011-01-12 20:02:43 -05:00
freevxfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
fscache Add a dummy printk function for the maintenance of unused printks 2010-08-12 09:51:35 -07:00
fuse switch fuse 2011-01-12 20:02:44 -05:00
gfs2 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
hfs switch hfs 2011-01-12 20:02:45 -05:00
hfsplus switch hfsplus 2011-01-12 20:02:45 -05:00
hostfs switch hostfs 2011-01-12 20:03:42 -05:00
hpfs switch hpfs 2011-01-12 20:02:47 -05:00
hppfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
hugetlbfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
isofs fix isofs d_op handling 2011-01-12 20:02:43 -05:00
jbd fix comment typos concerning "consistent" 2010-12-10 16:04:28 +01:00
jbd2 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
jffs2 fs: provide rcu-walk aware permission i_ops 2011-01-07 17:50:29 +11:00
jfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
lockd lockd: double unlock in next_host_state() 2011-01-04 13:10:37 -05:00
logfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
minix minixfs: kill dead code 2011-01-12 20:02:44 -05:00
ncpfs move internal-only parts of ncpfs headers to fs/ncpfs 2011-01-12 20:03:43 -05:00
nfs NFS: Fix NFSv3 exclusive open semantics 2011-01-13 12:06:29 -08:00
nfs_common
…
nfsd Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
nilfs2 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
nls
…
notify Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
ntfs NTFS: writev() fix and maintenance/contact details update 2011-01-12 08:35:53 -08:00
ocfs2 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
omfs new helper: mount_bdev() 2010-10-29 04:16:13 -04:00
openpromfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
partitions Merge branch 'for-2.6.38/event-handling' into for-2.6.38/core 2011-01-13 14:47:54 +01:00
proc /proc/kcore: fix seeking 2011-01-13 08:03:17 -08:00
qnx4 fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
quota quota: Use %pV and __attribute__((format (printf in __quota_error and fix fallout 2011-01-10 19:04:05 +01:00
ramfs convert get_sb_nodev() users 2010-10-29 04:16:31 -04:00
reiserfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
romfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
squashfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
sysfs Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2011-01-10 16:10:33 -08:00
sysv switch sysv 2011-01-12 20:02:44 -05:00
ubifs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
udf Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-udf-2.6 2011-01-11 14:45:52 -08:00
ufs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
xfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
Kconfig Merge 'staging-next' to Linus's tree 2010-10-28 09:44:56 -07:00
Kconfig.binfmt coredump: default CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y 2010-10-27 18:03:12 -07:00
Makefile Merge 'staging-next' to Linus's tree 2010-10-28 09:44:56 -07:00
aio.c aio: remove unused aio_run_iocbs() 2011-01-13 08:03:22 -08:00
anon_inodes.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2011-01-13 10:27:28 -08:00
attr.c
…
bad_inode.c fs: provide rcu-walk aware permission i_ops 2011-01-07 17:50:29 +11:00
binfmt_aout.c Don't dump task struct in a.out core-dumps 2010-10-14 10:57:40 -07:00
binfmt_elf.c binfmt_elf: cleanups 2011-01-13 08:03:12 -08:00
binfmt_elf_fdpic.c
…
binfmt_em86.c
…
binfmt_flat.c
…
binfmt_misc.c convert get_sb_single() users 2010-10-29 04:16:28 -04:00
binfmt_script.c Make do_execve() take a const filename pointer 2010-08-17 18:07:43 -07:00
binfmt_som.c
…
bio-integrity.c bio-integrity: mark kintegrityd_wq highpri and CPU intensive 2011-01-03 15:01:48 +01:00
bio.c bio: take care not overflow page count when mapping/copying user data 2010-11-10 14:40:43 +01:00
block_dev.c Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
buffer.c fs: Use this_cpu_inc_return in buffer.c 2010-12-17 15:18:05 +01:00
char_dev.c Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
compat.c exec: copy-and-paste the fixes into compat_do_execve() paths 2010-11-30 17:56:38 -08:00
compat_binfmt_elf.c
…
compat_ioctl.c Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2011-01-07 14:39:20 -08:00
dcache.c fs: fix kernel-doc for dcache::prepend_path 2011-01-12 20:06:57 -05:00
dcookies.c
…
direct-io.c fs/direct-io.c: fix truncation error in dio_complete() return 2010-10-26 16:52:13 -07:00
drop_caches.c
…
eventfd.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
eventpoll.c epoll: convert max_user_watches to long 2011-01-13 08:03:12 -08:00
exec.c install_special_mapping skips security_file_mmap check. 2010-12-15 12:30:36 -08:00
fcntl.c fasync: Fix placement of FASYNC flag comment 2010-10-27 18:17:02 -07:00
fifo.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
file.c vfs: use kmalloc() to allocate fdmem if possible 2010-08-11 08:59:02 -07:00
file_table.c fs: allow for more than 2^31 files 2010-10-26 16:52:15 -07:00
filesystems.c fs: rcu-walk for path lookup 2011-01-07 17:50:27 +11:00
fs-writeback.c writeback: avoid livelocking WB_SYNC_ALL writeback 2011-01-13 17:32:32 -08:00
fs_struct.c fs: scale mntget/mntput 2011-01-07 17:50:33 +11:00
generic_acl.c fs: provide simple rcu-walk generic_check_acl implementation 2011-01-07 17:50:29 +11:00
inode.c fs: avoid inode RCU freeing for pseudo fs 2011-01-07 17:50:26 +11:00
internal.h fs: scale mntget/mntput 2011-01-07 17:50:33 +11:00
ioctl.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2010-11-19 19:46:45 -08:00
ioprio.c ioprio: grab rcu_read_lock in sys_ioprio_{set,get}() 2010-11-15 10:23:31 +01:00
libfs.c pass default dentry_operations to mount_pseudo() 2011-01-12 20:03:43 -05:00
locks.c fs: dcache scale dentry refcount 2011-01-07 17:50:21 +11:00
mbcache.c ext2: Resolve 'dereferencing pointer to incomplete type' when enabling EXT2_XATTR_DEBUG 2011-01-10 19:04:08 +01:00
mpage.c
…
namei.c vfs: pass struct file to do_truncate on O_TRUNC opens (try #2) 2011-01-12 20:06:59 -05:00
namespace.c fs: scale mntget/mntput 2011-01-07 17:50:33 +11:00
nfsctl.c
…
no-block.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
open.c fs: add hole punching to fallocate 2011-01-12 20:16:43 -05:00
pipe.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2011-01-13 10:27:28 -08:00
pnode.c fs: scale mntget/mntput 2011-01-07 17:50:33 +11:00
pnode.h
…
posix_acl.c
…
read_write.c fix signedness mess in rw_verify_area() on 64bit architectures 2011-01-12 20:06:58 -05:00
read_write.h
…
readdir.c vfs: fix warning: 'dirent' is used uninitialized in this function 2010-08-09 20:45:05 -07:00
select.c fs/select.c: fix information leak to userspace 2011-01-13 08:03:12 -08:00
seq_file.c fs: take dcache_lock inside __d_path 2010-10-25 21:26:12 -04:00
signalfd.c Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2010-10-26 10:13:10 -07:00
splice.c Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
stack.c
…
stat.c Mark arguments to certain syscalls as being const 2010-08-13 16:53:13 -07:00
statfs.c add f_flags to struct statfs(64) 2010-08-09 16:48:44 -04:00
super.c Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
sync.c
…
timerfd.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
utimes.c Mark arguments to certain syscalls as being const 2010-08-13 16:53:13 -07:00
xattr.c
…
xattr_acl.c
…