]> git.baikalelectronics.ru Git - kernel.git/commit
tmpfs: allow filepage alongside swappage
authorHugh Dickins <hugh@veritas.com>
Tue, 5 Feb 2008 06:28:51 +0000 (22:28 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Tue, 5 Feb 2008 17:44:15 +0000 (09:44 -0800)
commitabf539049c5f36864abdfbdb8c18c88774527063
treeaecb9dbd92108915ba255df8f04d106c2099bf48
parent4a9c012a060c461daf649c7854b8c09a58333a5f
tmpfs: allow filepage alongside swappage

tmpfs has long allowed for a fresh filepage to be created in pagecache, just
before shmem_getpage gets the chance to match it up with the swappage which
already belongs to that offset.  But unionfs_writepage now does a
find_or_create_page, divorced from shmem_getpage, which leaves conflicting
filepage and swappage outstanding indefinitely, when unionfs is over tmpfs.

Therefore shmem_writepage (where a page is swizzled from file to swap) must
now be on the lookout for existing swap, ready to free it in favour of the
more uptodate filepage, instead of BUGging on that clash.  And when the
add_to_page_cache fails in shmem_unuse_inode, it must defer to an uptodate
filepage, otherwise swapoff would hang.  Whereas when add_to_page_cache fails
in shmem_getpage, it should retry in the same way it already does.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/shmem.c