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| author | Weijie Yang <weijie.yang@samsung.com> | 2014-12-02 15:59:25 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-12-16 09:09:41 -0800 |
| commit | 22fff283762550ddc75c2ae070e71321559a29ac (patch) | |
| tree | ba75b2832c573e14724bf103be074a1571f6ba4a | |
| parent | 2f9ac85b35cce77eb36e415f8f7a36aefb7d977d (diff) | |
| download | lwn-22fff283762550ddc75c2ae070e71321559a29ac.tar.gz lwn-22fff283762550ddc75c2ae070e71321559a29ac.zip | |
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>
| -rw-r--r-- | mm/frontswap.c | 4 |
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 */ 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 */ |