Piteball/android_kernel_samsung_msm8976
1
1
Fork 0
mirror of https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git synced 2024-10-31 18:09:19 +00:00
Code Issues Projects Releases Wiki Activity

mm: frontswap: invalidate expired data on a dup-store failure

Browse source 
commit fb993fa1a2f669215fa03a09eed7848f2663e336 upstream.

If a frontswap dup-store failed, it should invalidate the expired page
in the backend, or it could trigger some data corruption issue.
Such as:
 1. use zswap as the frontswap backend with writeback feature
 2. store a swap page(version_1) to entry A, success
 3. dup-store a newer page(version_2) to the same entry A, fail
 4. use __swap_writepage() write version_2 page to swapfile, success
 5. zswap do shrink, writeback version_1 page to swapfile
 6. version_2 page is overwrited by version_1, data corrupt.

This patch fixes this issue by invalidating expired data immediately
when meet a dup-store failure.

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Weijie Yang 2014-12-02 15:59:25 -08:00 committed by Greg Kroah-Hartman
parent 2f9ac85b35
commit 22fff28376
1 changed files with 3 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
mm/frontswap.c
View file

@ -244,8 +244,10 @@ int __frontswap_store(struct page *page)
the (older) page from frontswap the (older) page from frontswap
*/ */
inc_frontswap_failed_stores(); inc_frontswap_failed_stores();
if (dup) if (dup) {
__frontswap_clear(sis, offset); __frontswap_clear(sis, offset);
frontswap_ops->invalidate_page(type, offset);
}
} }
if (frontswap_writethrough_enabled) if (frontswap_writethrough_enabled)
/* report failure so swap also writes to swap device */ /* report failure so swap also writes to swap device */