path: root/mm
diff options
authorWeijie Yang <weijie.yang@samsung.com>2014-12-02 15:59:25 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-12-16 09:09:41 -0800
commit22fff283762550ddc75c2ae070e71321559a29ac (patch)
treeba75b2832c573e14724bf103be074a1571f6ba4a /mm
parent2f9ac85b35cce77eb36e415f8f7a36aefb7d977d (diff)
mm: frontswap: invalidate expired data on a dup-store failure
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>
Diffstat (limited to 'mm')
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 1b24bdcb3197..a55036a68487 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -244,8 +244,10 @@ int __frontswap_store(struct page *page)
the (older) page from frontswap
- 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 */