[PATCH v3 05/16] block: Don't attach inactive child to active node

[Kevin Wolf <kwolf@redhat.com>]

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>
---
 block.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/block.c b/block.c
index 9458c5e013..66a99e87c5 100644
--- 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,
-- 
2.48.1