This is a note to let you know that I've just added the patch titled
dm cache: fix truncation bug when copying a block to/from >2TB fast device
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-cache-fix-truncation-bug-when-copying-a-block-to-from-2tb-fast-device.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8b9d96666529a979acf4825391efcc7c8a3e9f12 Mon Sep 17 00:00:00 2001
From: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
Date: Wed, 12 Mar 2014 00:40:05 +0100
Subject: dm cache: fix truncation bug when copying a block to/from >2TB fast device
From: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
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 <heinzm@xxxxxxxxxx>
Acked-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -861,12 +861,13 @@ 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) {
Patches currently in stable-queue which might be from heinzm@xxxxxxxxxx are
queue-3.10/dm-cache-fix-access-beyond-end-of-origin-device.patch
queue-3.10/dm-cache-fix-truncation-bug-when-copying-a-block-to-from-2tb-fast-device.patch
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