block: Don't attach inactive child to active node

An active node makes unrestricted use of its children and would possibly
run into assertion failures when it operates on an inactive child node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20250204211407.381505-6-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/block.c b/block.c
index 9458c5e01318c2263bcea0b339d729f2afbfb0a6..66a99e87c5f5ea9bab4189a9f5d335c5c04e03e6 100644 (file)
--- a/block.c
+++ b/block.c
@@ -3183,6 +3183,11 @@ bdrv_attach_child_noperm(BlockDriverState *parent_bs,
                    child_bs->node_name, child_name, parent_bs->node_name);
         return NULL;
     }
+    if (bdrv_is_inactive(child_bs) && !bdrv_is_inactive(parent_bs)) {
+        error_setg(errp, "Inactive '%s' can't be a %s child of active '%s'",
+                   child_bs->node_name, child_name, parent_bs->node_name);
+        return NULL;
+    }
 
     bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
     bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,