block: Allow backing file links in change_parent_backing_link()

Now that the backing file child role implements .attach/.detach
callbacks, nothing prevents us from modifying the graph even if that
involves changing backing file links.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Kevin Wolf 2017-02-09 12:51:18 +01:00
parent db95dbba3b
commit 3e44c8e08a

View File

@ -2882,9 +2882,9 @@ static void change_parent_backing_link(BlockDriverState *from,
continue;
}
if (c->role == &child_backing) {
/* @from is generally not allowed to be a backing file, except for
* when @to is the overlay. In that case, @from may not be replaced
* by @to as @to's backing node. */
/* If @from is a backing file of @to, ignore the child to avoid
* creating a loop. We only want to change the pointer of other
* parents. */
QLIST_FOREACH(to_c, &to->children, next) {
if (to_c == c) {
break;
@ -2895,7 +2895,6 @@ static void change_parent_backing_link(BlockDriverState *from,
}
}
assert(c->role != &child_backing);
bdrv_ref(to);
/* FIXME Are we sure that bdrv_replace_child() can't run into
* &error_abort because of permissions? */