dm cache metadata: do not allow the data block size to change
The block size for the dm-cache's data device must remained fixed for
the life of the cache. Disallow any attempt to change the cache's data
block size.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 4ead4ba..d2899e7 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -425,6 +425,15 @@
disk_super = dm_block_data(sblock);
+ /* Verify the data block size hasn't changed */
+ if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
+ DMERR("changing the data block size (from %u to %llu) is not supported",
+ le32_to_cpu(disk_super->data_block_size),
+ (unsigned long long)cmd->data_block_size);
+ r = -EINVAL;
+ goto bad;
+ }
+
r = __check_incompat_features(disk_super, cmd);
if (r < 0)
goto bad;