3.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Heinz Mauelshagen <hei...@redhat.com>
commit 8b9d96666529a979acf4825391efcc7c8a3e9f12 upstream.
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 <hei...@redhat.com>
Acked-by: Joe Thornber <e...@redhat.com>
Signed-off-by: Mike Snitzer <snit...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/md/dm-cache-target.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -970,12 +970,13 @@ static void issue_copy_real(struct dm_ca
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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