block: Fix pending requests check in bdrv_append()

bdrv_append() cares about isolation of the node that it modifies, but
not about activity in some subtree below it. Instead of using the
recursive bdrv_requests_pending(), directly check bs->in_flight, which
considers only the node in question.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>

diff --git a/block.c b/block.c
index 9e538a5d4101b3e611f80d87cfdab122788e4a5c..5189c7c55ca2cded87c11d623a35bd348fd643d3 100644 (file)
--- a/block.c
+++ b/block.c
@@ -2897,8 +2897,8 @@ static void change_parent_backing_link(BlockDriverState *from,
  */
 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
 {
-    assert(!bdrv_requests_pending(bs_top));
-    assert(!bdrv_requests_pending(bs_new));
+    assert(!atomic_read(&bs_top->in_flight));
+    assert(!atomic_read(&bs_new->in_flight));
 
     bdrv_ref(bs_top);