udf: Don't BUG on missing metadata partition descriptor

Currently, if a metadata partition map is missing its partition descriptor,
then udf_get_pblock_meta25() will BUG() out the first time it is called.
This is rather drastic for a corrupted filesystem, so just treat this case
as an invalid mapping instead.

Signed-off-by: Alden Tondettar <alden.tondettar@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/udf/partition.c b/fs/udf/partition.c
index 5f861ed287c3..e4e9e70c37f2 100644
--- a/fs/udf/partition.c
+++ b/fs/udf/partition.c
@@ -317,8 +317,9 @@ uint32_t udf_get_pblock_meta25(struct super_block *sb, uint32_t block,
         mdata = &map->s_type_specific.s_metadata;
         inode = mdata->s_metadata_fe ? : mdata->s_mirror_fe;
 
-        /* We shouldn't mount such media... */
-        BUG_ON(!inode);
+        if (!inode)
+                return 0xFFFFFFFF;
+
         retblk = udf_try_read_meta(inode, block, partition, offset);
         if (retblk == 0xFFFFFFFF && mdata->s_metadata_fe) {
                 udf_warn(sb, "error reading from METADATA, trying to read from MIRROR\n");