From e0d849fad746cb36a6822e4595d8ba9bf0adf7fa Mon Sep 17 00:00:00 2001 From: Heinz Mauelshagen Date: Thu, 27 Feb 2014 22:46:48 +0100 Subject: [PATCH] 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 Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org --- drivers/md/dm-cache-target.c | 5 +++-- 1 file 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)); } -- 2.30.2