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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
parent7d48935eff401bb7970e73e822871a10e3643df1 (diff)
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
-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));
}