1 files changed, 5 insertions, 1 deletions
diff --git a/block/dmg.c b/block/dmg.c
index 27ce4a62d1..900ae5a678 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -419,8 +419,12 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
+    ret = bdrv_set_read_only(bs, true, errp);
+    if (ret < 0) {
+        return ret;
+    }
+
     block_module_load_one("dmg-bz2");
-    bdrv_set_read_only(bs, true);
 
     s->n_chunks = 0;
     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;