+ commit_top_backing_bs = s->commit_top_bs->backing->bs;
+ bdrv_drained_begin(commit_top_backing_bs);
+ bdrv_graph_wrlock(commit_top_backing_bs);
+ bdrv_replace_node(s->commit_top_bs, commit_top_backing_bs, &error_abort);
+ bdrv_graph_wrunlock();
+ bdrv_drained_end(commit_top_backing_bs);