dm era: Verify the data block size hasn't changed

dm-era doesn't support changing the data block size of existing devices,
so check explicitly that the requested block size for a new target
matches the one stored in the metadata.

Fixes: b83b01ee643a86 ("dm: add era target")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Reviewed-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index 33c02b1f56785d7a2177c97a1b178ff6266202c5..da3d8ace23980cf57f16315130f840bdb1790f06 100644 (file)
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -564,6 +564,15 @@ static int open_metadata(struct era_metadata *md)
        }
 
        disk = dm_block_data(sblock);
+
+       /* Verify the data block size hasn't changed */
+       if (le32_to_cpu(disk->data_block_size) != md->block_size) {
+               DMERR("changing the data block size (from %u to %llu) is not supported",
+                     le32_to_cpu(disk->data_block_size), md->block_size);
+               r = -EINVAL;
+               goto bad;
+       }
+
        r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
                               disk->metadata_space_map_root,
                               sizeof(disk->metadata_space_map_root),
@@ -575,7 +584,6 @@ static int open_metadata(struct era_metadata *md)
 
        setup_infos(md);
 
-       md->block_size = le32_to_cpu(disk->data_block_size);
        md->nr_blocks = le32_to_cpu(disk->nr_blocks);
        md->current_era = le32_to_cpu(disk->current_era);