block: Mark bdrv_query_block_graph_info() and callers GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_query_block_graph_info() need to hold a reader lock for the graph
because it accesses the children list of a node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230504115750.54437-19-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/qemu-img.c b/qemu-img.c
index 9aeac69..9f9f0a7 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2938,6 +2938,8 @@ static BlockGraphInfoList *collect_image_info_list(bool image_opts,
         }
         bs = blk_bs(blk);
 
+        GRAPH_RDLOCK_GUARD_MAINLOOP();
+
         /*
          * Note that the returned BlockGraphInfo object will not have
          * information about this image's backing node, because we have opened