ext4: fix wrong assert in ext4_mb_normalize_request()

commit b5b60778 upstream.

The variable "size" is expressed as number of blocks and not as
number of clusters, this could trigger a kernel panic when using
ext4 with the size of a cluster different from the size of a block.
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

fs/ext4/mballoc.c

@@ -3067,7 +3067,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
 	}
 	BUG_ON(start + size <= ac->ac_o_ex.fe_logical &&
 			start > ac->ac_o_ex.fe_logical);
-	BUG_ON(size <= 0 || size > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
+	BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
 
 	/* now prepare goal request */