Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 01/34] mm: frontswap: invalidate expired data on a dup-store failure | Date | Sun, 14 Dec 2014 12:20:39 -0800 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Weijie Yang <weijie.yang@samsung.com>
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>
--- mm/frontswap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- 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 */
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