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authorHeinz Mauelshagen <heinzm@redhat.com>2014-02-27 22:46:48 +0100
committerMike Snitzer <snitzer@redhat.com>2014-02-28 09:23:02 -0500
commite0d849fad746cb36a6822e4595d8ba9bf0adf7fa (patch)
treed5ea46f6692bc8de0260843a59d386db4bb9030c /drivers/md/dm-cache-target.c
parent7d48935eff401bb7970e73e822871a10e3643df1 (diff)
downloadlinux-e0d849fad746cb36a6822e4595d8ba9bf0adf7fa.tar.gz
dm cache: fix truncation bug when mapping I/O to >2TB fast device
When remapping a block to the cache's fast device that is larger than
2TB we must not truncate the destination sector to 32bits.  The 32bit
temporary result of from_cblock() was being overflowed in
remap_to_cache() due to the logical left shift.

Use an intermediate 64bit type to store the 32bit from_cblock() result
to fix the overflow.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/md/dm-cache-target.c')
-rw-r--r--drivers/md/dm-cache-target.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index db0944465127..1af70145fab9 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -671,15 +671,16 @@ static void remap_to_cache(struct cache *cache, struct bio *bio,
 			   dm_cblock_t cblock)
 {
 	sector_t bi_sector = bio->bi_iter.bi_sector;
+	sector_t block = from_cblock(cblock);
 
 	bio->bi_bdev = cache->cache_dev->bdev;
 	if (!block_size_is_power_of_two(cache))
 		bio->bi_iter.bi_sector =
-			(from_cblock(cblock) * cache->sectors_per_block) +
+			(block * cache->sectors_per_block) +
 			sector_div(bi_sector, cache->sectors_per_block);
 	else
 		bio->bi_iter.bi_sector =
-			(from_cblock(cblock) << cache->sectors_per_block_shift) |
+			(block << cache->sectors_per_block_shift) |
 			(bi_sector & (cache->sectors_per_block - 1));
 }