block: Mark bdrv_(un)freeze_backing_chain() and callers GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_(un)freeze_backing_chain() need to hold a reader lock for the
graph because it calls bdrv_filter_or_cow_child(), which accesses
bs->file/backing.

Use the opportunity to make bdrv_is_backing_chain_frozen() static, it
has no external callers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231027155333.420094-10-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/block.c b/block.c
index 7e8b397..dc1980e 100644
--- a/block.c
+++ b/block.c
@@ -5843,8 +5843,9 @@ BlockDriverState *bdrv_find_base(BlockDriverState *bs)
  * between @bs and @base is frozen. @errp is set if that's the case.
  * @base must be reachable from @bs, or NULL.
  */
-bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
-                                  Error **errp)
+static bool GRAPH_RDLOCK
+bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
+                             Error **errp)
 {
     BlockDriverState *i;
     BdrvChild *child;