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authorHeinz Mauelshagen <heinzm@redhat.com>2014-03-12 00:40:05 +0100
committerMike Snitzer <snitzer@redhat.com>2014-03-12 13:49:27 -0400
commit8b9d96666529a979acf4825391efcc7c8a3e9f12 (patch)
tree142c3205b54a86c96cba376f1dd689463b1d6548
parentcebc2de44d3bce53e46476e774126c298ca2c8a9 (diff)
downloadop-kernel-dev-8b9d96666529a979acf4825391efcc7c8a3e9f12.zip
op-kernel-dev-8b9d96666529a979acf4825391efcc7c8a3e9f12.tar.gz
dm cache: fix truncation bug when copying a block to/from >2TB fast device
During demotion or promotion to a cache's >2TB fast device we must not truncate the cache block's associated sector to 32bits. The 32bit temporary result of from_cblock() caused a 32bit multiplication when calculating the sector of the fast device in issue_copy_real(). Use an intermediate 64bit type to store the 32bit from_cblock() to allow for proper 64bit multiplication. Here is an example of how this bug manifests on an ext4 filesystem: EXT4-fs error (device dm-0): ext4_mb_generate_buddy:756: group 17136, 32768 clusters in bitmap, 30688 in gd; block bitmap corrupt. JBD2: Spotted dirty metadata buffer (dev = dm-0, blocknr = 0). There's a risk of filesystem corruption in case of system crash. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
-rw-r--r--drivers/md/dm-cache-target.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1af7014..354bbc1 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -979,12 +979,13 @@ static void issue_copy_real(struct dm_cache_migration *mg)
int r;
struct dm_io_region o_region, c_region;
struct cache *cache = mg->cache;
+ sector_t cblock = from_cblock(mg->cblock);
o_region.bdev = cache->origin_dev->bdev;
o_region.count = cache->sectors_per_block;
c_region.bdev = cache->cache_dev->bdev;
- c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block;
+ c_region.sector = cblock * cache->sectors_per_block;
c_region.count = cache->sectors_per_block;
if (mg->writeback || mg->demote) {
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