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Glauber Costa 4e717f5c10 list_lru: remove special case function list_lru_dispose_all.
The list_lru implementation has one function, list_lru_dispose_all, with
only one user (the dentry code).  At first, such function appears to make
sense because we are really not interested in the result of isolating each
dentry separately - all of them are going away anyway.  However, it's
implementation is buggy in the following way:

When we call list_lru_dispose_all in fs/dcache.c, we scan all dentries
marking them with DCACHE_SHRINK_LIST.  However, this is done without the
nlru->lock taken.  The imediate result of that is that someone else may
add or remove the dentry from the LRU at the same time.  When list_lru_del
happens in that scenario we will see an element that is not yet marked
with DCACHE_SHRINK_LIST (even though it will be in the future) and
obviously remove it from an lru where the element no longer is.  Since
list_lru_dispose_all will in effect count down nlru's nr_items and
list_lru_del will do the same, this will lead to an imbalance.

The solution for this would not be so simple: we can obviously just keep
the lru_lock taken, but then we have no guarantees that we will be able to
acquire the dentry lock (dentry->d_lock).  To properly solve this, we need
a communication mechanism between the lru and dentry code, so they can
coordinate this with each other.

Such mechanism already exists in the form of the list_lru_walk_cb
callback.  So it is possible to construct a dcache-side prune function
that does the right thing only by calling list_lru_walk in a loop until no
more dentries are available.

With only one user, plus the fact that a sane solution for the problem
would involve boucing between dcache and list_lru anyway, I see little
justification to keep the special case list_lru_dispose_all in tree.

Signed-off-by: Glauber Costa <glommer@openvz.org>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-10 18:56:31 -04:00
..
9p Second round of 9p patches for the 3.11 merge window. 2013-07-11 10:21:23 -07:00
adfs Don't pass inode to ->d_hash() and ->d_compare() 2013-06-29 12:57:36 +04:00
affs Don't pass inode to ->d_hash() and ->d_compare() 2013-06-29 12:57:36 +04:00
afs afs: get rid of redundant ->d_name.len checks 2013-09-07 19:54:55 -04:00
autofs4 autofs4 - fix device ioctl mount lookup 2013-09-08 22:07:47 -04:00
befs [readdir] convert befs 2013-06-29 12:56:55 +04:00
bfs bfs: iget_locked() doesn't return an ERR_PTR 2013-08-24 12:10:22 -04:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-09-06 09:36:28 -07:00
cachefiles CacheFiles: Implement interface to check cache consistency 2013-09-06 09:17:30 +01:00
ceph ceph: use d_invalidate() to invalidate aliases 2013-09-06 12:55:29 -07:00
cifs direct-io: Handle O_(D)SYNC AIO 2013-09-04 09:23:46 -04:00
coda helper for reading ->d_count 2013-07-05 18:59:33 +04:00
configfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-07-14 11:42:26 -07:00
cramfs [readdir] convert f2fs 2013-06-29 12:56:46 +04:00
debugfs debugfs: debugfs_remove_recursive() must not rely on list_empty(d_subdirs) 2013-07-31 12:16:31 -04:00
devpts fs: Limit sys_mount to only request filesystem modules (Part 2). 2013-03-07 01:08:55 -08:00
dlm dlm: remove signal blocking 2013-08-12 15:22:43 -05:00
ecryptfs Code cleanups and improved buffer handling during page crypto operations 2013-07-11 10:20:18 -07:00
efivarfs efivarfs: we can use simple_lookup() now 2013-07-14 17:48:35 +04:00
efs efs: iget_locked() doesn't return an ERR_PTR() 2013-08-24 12:10:22 -04:00
exofs Lots of bug fixes, cleanups and optimizations. In the bug fixes 2013-07-02 09:39:34 -07:00
exportfs exportfs: don't assume that ->iterate() won't feed us too long entries 2013-09-07 19:54:55 -04:00
ext2 [O_TMPFILE] it's still short a few helpers, but infrastructure should be OK now... 2013-06-29 12:57:10 +04:00
ext3 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2013-09-06 09:06:02 -07:00
ext4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-09-06 09:36:28 -07:00
f2fs f2fs: optimize gc for better performance 2013-09-05 13:50:32 +09:00
fat fatfs: add FAT_IOCTL_GET_VOLUME_ID 2013-07-09 10:33:25 -07:00
freevxfs [readdir] convert freevxfs 2013-06-29 12:56:53 +04:00
fscache fscache: Netfs function for cleanup post readpages 2013-09-06 09:17:30 +01:00
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 2013-09-09 09:18:23 -07:00
gfs2 super: fix calculation of shrinkable objects for small numbers 2013-09-10 18:56:29 -04:00
hfs Don't pass inode to ->d_hash() and ->d_compare() 2013-06-29 12:57:36 +04:00
hfsplus Don't pass inode to ->d_hash() and ->d_compare() 2013-06-29 12:57:36 +04:00
hostfs um: hostfs: Fix writeback 2013-09-07 10:38:29 +02:00
hpfs Merge branch 'hpfs' from Mikulas Patocka 2013-07-04 11:22:55 -07:00
hppfs clean up scary strncpy(dst, src, strlen(src)) uses 2013-07-03 16:07:41 -07:00
hugetlbfs cope with potentially long ->d_dname() output for shmem/hugetlb 2013-08-24 12:10:17 -04:00
isofs isofs: Refuse RW mount of the filesystem instead of making it RO 2013-07-31 22:14:50 +02:00
jbd jbd: use a single printk for jbd_debug() 2013-08-09 10:49:00 +02:00
jbd2 jbd2: Fix endian mixing problems in the checksumming code 2013-08-28 14:59:58 -04:00
jffs2 [readdir] convert jffs2 2013-06-29 12:56:47 +04:00
jfs jfs: fix readdir cookie incompatibility with NFSv4 2013-08-15 17:22:29 -05:00
lockd LOCKD: Don't call utsname()->nodename from nlmclnt_setlockargs 2013-08-05 15:03:46 -04:00
logfs Lots of bug fixes, cleanups and optimizations. In the bug fixes 2013-07-02 09:39:34 -07:00
minix minix: bug widening a binary "not" operation 2013-06-29 12:57:35 +04:00
ncpfs ncpfs: fix error return code in ncp_parse_options() 2013-07-09 10:33:25 -07:00
nfs super: fix calculation of shrinkable objects for small numbers 2013-09-10 18:56:29 -04:00
nfs_common nfs_common: Update the translation between nfsv3 acls linux posix acls 2013-02-13 06:15:14 -08:00
nfsd nfsd: racy access to ->d_name in nsfd4_encode_path() 2013-09-03 22:50:28 -04:00
nilfs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-09-05 08:50:26 -07:00
nls
notify fsnotify: update comments concerning locking scheme 2013-07-09 10:33:20 -07:00
ntfs Lots of bug fixes, cleanups and optimizations. In the bug fixes 2013-07-02 09:39:34 -07:00
ocfs2 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-09-07 14:34:07 -07:00
omfs [readdir] convert omfs 2013-06-29 12:56:37 +04:00
openpromfs [readdir] convert openpromfs 2013-06-29 12:56:32 +04:00
proc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
pstore pstore/ram: (really) fix undefined usage of rounddown_pow_of_two 2013-08-30 15:57:01 -07:00
qnx4 [readdir] convert qnx4 2013-06-29 12:56:38 +04:00
qnx6 [readdir] convert qnx6 2013-06-29 12:56:39 +04:00
quota super: fix calculation of shrinkable objects for small numbers 2013-09-10 18:56:29 -04:00
ramfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
reiserfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2013-09-06 09:06:02 -07:00
romfs [readdir] convert romfs 2013-06-29 12:56:29 +04:00
squashfs [readdir] convert squashfs 2013-06-29 12:56:28 +04:00
sysfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-09-07 14:36:57 -07:00
sysv Don't pass inode to ->d_hash() and ->d_compare() 2013-06-29 12:57:36 +04:00
ubifs Only a single patch which fixes a message. 2013-07-05 12:08:47 -07:00
udf udf: Refuse RW mount of the filesystem instead of making it RO 2013-07-31 22:14:51 +02:00
ufs [readdir] simple local unixlike: switch to ->iterate() 2013-06-29 12:46:47 +04:00
xfs shrinker: convert superblock shrinkers to new API 2013-09-10 18:56:30 -04:00
Kconfig efivarfs: Move to fs/efivarfs 2013-04-17 13:25:09 +01:00
Kconfig.binfmt fs: make binfmt support for #! scripts modular and removable 2013-04-30 17:04:04 -07:00
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
aio.c aio: fix wrong comment in aio_complete() 2013-07-03 16:08:06 -07:00
anon_inodes.c get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero 2013-02-26 02:46:11 -05:00
attr.c
bad_inode.c [readdir] ->readdir() is gone 2013-06-29 12:57:04 +04:00
binfmt_aout.c mm: remove free_area_cache 2013-07-10 18:11:34 -07:00
binfmt_elf.c mm: remove free_area_cache 2013-07-10 18:11:34 -07:00
binfmt_elf_fdpic.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-05-02 10:16:16 -07:00
binfmt_em86.c
binfmt_flat.c new helper: read_code() 2013-04-29 15:40:23 -04:00
binfmt_misc.c binfmt_misc: reuse string_unescape_inplace() 2013-04-30 17:04:03 -07:00
binfmt_script.c
binfmt_som.c
bio-integrity.c bio-integrity: Add explicit field for owner of bip_buf 2013-03-23 14:26:34 -07:00
bio.c Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2013-09-03 18:25:03 -07:00
block_dev.c direct-io: Handle O_(D)SYNC AIO 2013-09-04 09:23:46 -04:00
buffer.c mm: vmscan: take page buffers dirty and locked state into account 2013-07-03 16:07:29 -07:00
char_dev.c
compat.c [readdir] constify ->actor 2013-06-29 12:57:05 +04:00
compat_binfmt_elf.c
compat_ioctl.c compat.c: LOOP_CLR_FD is taken care of in loop.c itself... 2013-06-29 12:46:44 +04:00
coredump.c coredump: '% at the end' shouldn't bypass core_uses_pid logic 2013-07-03 16:08:02 -07:00
coredump.h
dcache.c list_lru: remove special case function list_lru_dispose_all. 2013-09-10 18:56:31 -04:00
dcookies.c consolidate compat lookup_dcookie() 2013-03-03 23:00:23 -05:00
direct-io.c direct-io: Use return from cmpxchg to decide of assignment happened 2013-09-09 10:47:42 -07:00
drop_caches.c
eventfd.c
eventpoll.c switch epoll_ctl() to fdget 2013-09-03 23:04:44 -04:00
exec.c Fix TLB gather virtual address range invalidation corner cases 2013-08-16 08:52:46 -07:00
fcntl.c vfs: add missing check for __O_TMPFILE in fcntl_init() 2013-08-05 18:25:32 +04:00
fhandle.c
file.c don't bother with deferred freeing of fdtables 2013-05-01 17:31:42 -04:00
file_table.c only regular files with FMODE_WRITE need to be on s_files 2013-09-03 22:50:28 -04:00
filesystems.c fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
fs-writeback.c mm/writeback: don't check force_wait to handle bdi->work_list 2013-07-09 10:33:22 -07:00
fs_struct.c constify path_get/path_put and fs_struct.c stuff 2013-03-01 23:51:07 -05:00
generic_acl.c
inode.c inode: move inode to a different list inside lock 2013-09-10 18:56:30 -04:00
internal.h shrinker: convert superblock shrinkers to new API 2013-09-10 18:56:30 -04:00
ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
ioprio.c
libfs.c make simple_lookup() usable for filesystems that set ->s_d_op 2013-07-14 17:43:25 +04:00
locks.c locks: move file_lock_list to a set of percpu hlist_heads and convert file_lock_lock to an lglock 2013-07-08 13:36:42 +04:00
mbcache.c super: fix calculation of shrinkable objects for small numbers 2013-09-10 18:56:29 -04:00
mount.h get rid of full-hash scan on detaching vfsmounts 2013-04-09 14:12:52 -04:00
mpage.c
namei.c Add missing unlocks to error paths of mountpoint_last. 2013-09-10 18:56:29 -04:00
namespace.c rename user_path_umountat() to user_path_mountpoint_at() 2013-09-08 20:20:21 -04:00
no-block.c
open.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
pipe.c aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
pnode.c vfs: Fix invalid ida_remove() call 2013-05-31 15:16:33 -04:00
pnode.h vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces 2013-08-26 18:42:15 -07:00
posix_acl.c
proc_namespace.c
read_write.c vfs: export lseek_execute() to modules 2013-07-03 16:23:27 +04:00
readdir.c [readdir] constify ->actor 2013-06-29 12:57:05 +04:00
select.c net: rename include/net/ll_poll.h to include/net/busy_poll.h 2013-07-10 17:08:27 -07:00
seq_file.c seq_file: add seq_list_*_percpu helpers 2013-07-08 13:36:41 +04:00
signalfd.c switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE 2013-03-03 22:58:46 -05:00
splice.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-07-03 09:10:19 -07:00
stack.c
stat.c quota: provide interface for readding allocated space into reserved space 2013-08-17 09:32:32 -04:00
statfs.c
super.c dcache: convert to use new lru list infrastructure 2013-09-10 18:56:30 -04:00
sync.c teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long 2013-03-03 22:46:22 -05:00
timerfd.c timerfd: Add alarm timers 2013-05-29 12:57:34 -07:00
utimes.c
xattr.c
xattr_acl.c