linux/fs/ext4
Linus Torvalds 6268b325c3 Revert "ext4: don't release page refs in ext4_end_bio()"
This reverts commit b43d17f319.

Dave Jones reports that it causes lockups on his laptop, and his debug
output showed a lot of processes hung waiting for page_writeback (or
more commonly - processes hung waiting for a lock that was held during
that writeback wait).

The page_writeback hint made Ted suggest that Dave look at this commit,
and Dave verified that reverting it makes his problems go away.

Ted says:
 "That commit fixes a race which is seen when you write into fallocated
  (and hence uninitialized) disk blocks under *very* heavy memory
  pressure.  Furthermore, although theoretically it could trigger under
  normal direct I/O writes, it only seems to trigger if you are issuing
  a huge number of AIO writes, such that a just-written page can get
  evicted from memory, and then read back into memory, before the
  workqueue has a chance to update the extent tree.

  This race has been around for a little over a year, and no one noticed
  until two months ago; it only happens under fairly exotic conditions,
  and in fact even after trying very hard to create a simple repro under
  lab conditions, we could only reproduce the problem and confirm the
  fix on production servers running MySQL on very fast PCIe-attached
  flash devices.

  Given that Dave was able to hit this problem pretty quickly, if we
  confirm that this commit is at fault, the only reasonable thing to do
  is to revert it IMO."

Reported-and-tested-by: Dave Jones <davej@redhat.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-29 17:00:56 -07:00
..
acl.c switch posix_acl_equiv_mode() to umode_t * 2011-08-01 02:10:06 -04:00
acl.h fs: take the ACL checks to common code 2011-07-25 14:30:23 -04:00
balloc.c ext4: fix balloc.c printk-format-warning 2012-02-20 17:57:24 -05:00
bitmap.c ext4: Change unsigned long to unsigned int 2008-11-05 00:14:04 -05:00
block_validity.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
dir.c Merge branch 'for-3.4' of git://linux-nfs.org/~bfields/linux 2012-03-29 14:53:25 -07:00
ext4.h Merge branch 'for-3.4' of git://linux-nfs.org/~bfields/linux 2012-03-29 14:53:25 -07:00
ext4_extents.h ext4: add no_printk argument validation, fix fallout 2012-03-19 23:11:43 -04:00
ext4_jbd2.c jbd2: add debugging information to jbd2_journal_dirty_metadata() 2011-09-04 10:18:14 -04:00
ext4_jbd2.h ext4: expand commit callback and 2012-02-20 17:53:02 -05:00
extents.c ext4: remove restrictive checks for EOFBLOCKS_FL 2012-03-21 21:47:55 -04:00
file.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2011-11-02 10:06:20 -07:00
fsync.c ext4: fix race between sync and completed io work 2012-03-05 10:29:52 -05:00
hash.c ext4: return 32/64-bit dir name hash according to usage type 2012-03-18 22:44:40 -04:00
ialloc.c ext4: change some printk() calls to use ext4_msg() instead 2012-03-19 23:41:49 -04:00
indirect.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
inode.c ext4: do not mark superblock as dirty unnecessarily 2012-03-21 22:28:29 -04:00
ioctl.c Merge branch 'for_linus' into for_linus_merged 2012-01-10 11:54:07 -05:00
Kconfig ext4: Don't ask about supporting ext2/3 in ext4 if ext4 is not configured 2009-12-21 10:54:09 -05:00
Makefile ext4: move ext4_ind_* functions from inode.c to indirect.c 2011-06-27 19:40:50 -04:00
mballoc.c ext4: always set then trimmed blocks count into len 2012-03-21 21:26:22 -04:00
mballoc.h ext4: remove EXT4_MB_{BITMAP,BUDDY} macros 2012-02-20 17:54:06 -05:00
migrate.c ext4: using PTR_ERR() on the wrong variable in ext4_ext_migrate() 2012-02-20 17:53:06 -05:00
mmp.c ext4: Fix endianness bug when reading the MMP block 2012-02-27 01:09:03 -05:00
move_extent.c ext4: add some tracepoints in ext4/extents.c 2011-09-09 19:18:51 -04:00
namei.c ext4: format flag in dx_probe() 2012-02-20 23:09:36 -05:00
page-io.c Revert "ext4: don't release page refs in ext4_end_bio()" 2012-03-29 17:00:56 -07:00
resize.c ext4: update s_free_{inodes,blocks}_count during online resize 2012-03-20 15:46:11 -04:00
super.c Ext4 commits for 3.3 merge window; mostly cleanups and bug fixes 2012-03-28 10:02:55 -07:00
symlink.c ext4: symlink must be handled via filesystem specific operation 2010-05-16 02:00:00 -04:00
truncate.h ext4: move common truncate functions to header file 2011-06-27 19:16:04 -04:00
xattr.c ext4: add no_printk argument validation, fix fallout 2012-03-19 23:11:43 -04:00
xattr.h fs/vfs/security: pass last path component to LSM on inode creation 2011-02-01 11:12:29 -05:00
xattr_security.c Merge branch 'for_linus' into for_linus_merged 2012-01-10 11:54:07 -05:00
xattr_trusted.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
xattr_user.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00