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authorWeijie Yang <weijie.yang@samsung.com>2014-12-02 15:59:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-02 17:32:07 -0800
commitfb993fa1a2f669215fa03a09eed7848f2663e336 (patch)
tree0dedcd7d311b0ad5d1edca205b827e10e304c474
parentbc127bda37db2792fa7f02a8d258731ecf3e4b8b (diff)
downloadlinux-linaro-stable-fb993fa1a2f669215fa03a09eed7848f2663e336.tar.gz
mm: frontswap: invalidate expired data on a dup-store failure
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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/frontswap.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/frontswap.c b/mm/frontswap.c
index c30eec536f03..f2a3571c6e22 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -244,8 +244,10 @@ int __frontswap_store(struct page *page)
the (older) page from frontswap
*/
inc_frontswap_failed_stores();
- if (dup)
+ if (dup) {
__frontswap_clear(sis, offset);
+ frontswap_ops->invalidate_page(type, offset);
+ }
}
if (frontswap_writethrough_enabled)
/* report failure so swap also writes to swap device */