linux/include
Jan Kara 08142579b6 mm: fix assertion mapping->nrpages == 0 in end_writeback()
Under heavy memory and filesystem load, users observe the assertion
mapping->nrpages == 0 in end_writeback() trigger.  This can be caused by
page reclaim reclaiming the last page from a mapping in the following
race:

	CPU0				CPU1
  ...
  shrink_page_list()
    __remove_mapping()
      __delete_from_page_cache()
        radix_tree_delete()
					evict_inode()
					  truncate_inode_pages()
					    truncate_inode_pages_range()
					      pagevec_lookup() - finds nothing
					  end_writeback()
					    mapping->nrpages != 0 -> BUG
        page->mapping = NULL
        mapping->nrpages--

Fix the problem by doing a reliable check of mapping->nrpages under
mapping->tree_lock in end_writeback().

Analyzed by Jay <jinshan.xiong@whamcloud.com>, lost in LKML, and dug out
by Miklos Szeredi <mszeredi@suse.de>.

Cc: Jay <jinshan.xiong@whamcloud.com>
Cc: Miklos Szeredi <mszeredi@suse.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-27 18:00:13 -07:00
..
acpi
asm-generic Merge branches 'gpio/merge' and 'spi/merge' of git://git.secretlab.ca/git/linux-2.6 2011-06-17 10:36:32 -07:00
crypto
drm drm/radeon: workaround a hw bug on some radeon chipsets with all-0 EDIDs. 2011-06-16 16:30:54 +10:00
keys
linux mm: fix assertion mapping->nrpages == 0 in end_writeback() 2011-06-27 18:00:13 -07:00
math-emu
media
mtd
net Fix some kernel-doc warnings 2011-06-27 16:06:19 -07:00
pcmcia
rdma
rxrpc
scsi
sound
target
trace Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2011-06-21 10:22:35 -07:00
video
xen
Kbuild