Merge tag 'dm-3.16-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Fix the dm-thinp and dm-cache targets to disallow changing the data
  device's block size"

* tag 'dm-3.16-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache metadata: do not allow the data block size to change
  dm thin metadata: do not allow the data block size to change

2 files changed, 18 insertions, 0 deletions

diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 4ead4ba60656..d2899e7eb3aa 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -425,6 +425,15 @@ static int __open_metadata(struct dm_cache_metadata *cmd)
 
         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;
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index b086a945edcb..e9d33ad59df5 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -613,6 +613,15 @@ static int __open_metadata(struct dm_pool_metadata *pmd)
 
         disk_super = dm_block_data(sblock);
 
+        /* Verify the data block size hasn't changed */
+        if (le32_to_cpu(disk_super->data_block_size) != pmd->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)pmd->data_block_size);
+                r = -EINVAL;
+                goto bad_unlock_sblock;
+        }
+
         r = __check_incompat_features(disk_super, pmd);
         if (r < 0)
                 goto bad_unlock_sblock;