[Qemu-block] [PATCH] blockdev: fix bitmap clear undo

[John Snow]

Only undo the action if we actually prepared the action.

Signed-off-by: John Snow <js...@redhat.com>
---
 blockdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index f1f49bd..c5b2c2c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2047,7 +2047,9 @@ static void block_dirty_bitmap_clear_abort(BlkActionState 
*common)
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
                                              common, common);
 
-    bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
+    if (state->backup) {
+        bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
+    }
 }
 
 static void block_dirty_bitmap_clear_commit(BlkActionState *common)
-- 
2.9.3