migration/block-dirty-bitmap: fix add_bitmaps_to_list

We shouldn't fail when finding an unnamed bitmap in a unnamed node or
node with auto-generated node name, as bitmap migration ignores such
bitmaps in the first place.

Fixes: 82640ed
Fixes: 4ff5cc1
Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
[eblake: commit message grammar tweaks]
Signed-off-by: Eric Blake <[email protected]>

Author: Vladimir Sementsov-Ogievskiy

migration/block-dirty-bitmap.c

@@ -274,7 +274,11 @@ static int add_bitmaps_to_list(BlockDriverState *bs, const char *bs_name)
     DirtyBitmapMigBitmapState *dbms;
     Error *local_err = NULL;
 
-    bitmap = bdrv_dirty_bitmap_first(bs);
+    FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
+        if (bdrv_dirty_bitmap_name(bitmap)) {
+            break;
+        }
+    }
     if (!bitmap) {
         return 0;
     }