diff options
authorWeijie Yang <weijie.yang@samsung.com>2014-06-04 16:11:06 -0700
committerAlex Shi <alex.shi@linaro.org>2015-05-11 21:03:18 +0800
commitce58d51a0e9b366876270f03555c209917d3b80d (patch)
parent6de155507ea389d7863f34fe53b41a86a59228bf (diff)
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> (cherry picked from commit 38515c73398a4c58059ecf1087e844561b58ee0f) Signed-off-by: Alex Shi <alex.shi@linaro.org>
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 19cf51ad48ef..efb6ff2a3735 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -571,10 +571,10 @@ 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))
- n -= offset;
+ n -= (PAGE_SIZE - offset);