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
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index db09444..1af7014 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -671,15 +671,16 @@
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));
}