• Weijie Yang's avatar
    zram: correct offset usage in zram_bio_discard · 38515c73
    Weijie Yang authored
    We want to skip the physical block(PAGE_SIZE) which is partially covered
    by the discard bio, so we check the remaining size and subtract it if
    there is a need to goto the next physical block.
    
    The current offset usage in zram_bio_discard is incorrect, it will cause
    its upper filesystem breakdown.  Consider the following scenario:
    
    On some architecture or config, PAGE_SIZE is 64K for example, filesystem
    is set up on zram disk without PAGE_SIZE aligned, a discard bio leads to a
    offset = 4K and size=72K, normally, it should not really discard any
    physical block as it partially cover two physical blocks.  However, with
    the current offset usage, it will discard the second physical block and
    free its memory, which will cause filesystem breakdown.
    
    This patch corrects the offset usage in zram_bio_discard.
    Signed-off-by: default avatarWeijie Yang <weijie.yang@samsung.com>
    Cc: Minchan Kim <minchan@kernel.org>
    Cc: Nitin Gupta <ngupta@vflare.org>
    Acked-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
    Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
    Cc: Bob Liu <bob.liu@oracle.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    38515c73
zram_drv.c 23.8 KB