lkml.org 
[lkml]   [2014]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.14 01/34] mm: frontswap: invalidate expired data on a dup-store failure
    Date
    3.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    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 */



    \
     
     \ /
      Last update: 2014-12-14 22:21    [W:4.250 / U:0.732 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site