[PULL 1/1] migration/block-dirty-bitmap: fix add_bitmaps_to_list

[Eric Blake <eblake@redhat.com>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

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: 82640edb88faa
Fixes: 4ff5cc121b089
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200626130658.76498-1-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: commit message grammar tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 migration/block-dirty-bitmap.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
index 47bc0f650c1e..b0dbf9eeed43 100644
--- a/migration/block-dirty-bitmap.c
+++ b/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;
     }
-- 
2.27.0