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authorWeijie Yang <weijie.yang@samsung.com>2014-06-04 16:11:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:54:13 -0700
commit38515c73398a4c58059ecf1087e844561b58ee0f (patch)
tree12f67883a423232403194cf1823fb04b19e59fc8 /drivers/block
parent2a7a0e0fdc49a08740a69d51ef44ef09763072b0 (diff)
downloadlinux-38515c73398a4c58059ecf1087e844561b58ee0f.tar.bz2
zram: correct offset usage in zram_bio_discard
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: Weijie Yang <weijie.yang@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: Joonsoo 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/zram/zram_drv.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9849b5233bf4..48eccb350180 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -572,10 +572,10 @@ static void zram_bio_discard(struct zram *zram, u32 index,
* skipping this logical block is appropriate here.
*/
if (offset) {
- if (n < offset)
+ if (n <= (PAGE_SIZE - offset))
return;
- n -= offset;
+ n -= (PAGE_SIZE - offset);
index++;
}