From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57518) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ciRdd-0000PV-TB for qemu-devel@nongnu.org; Mon, 27 Feb 2017 15:11:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ciRdd-0003fw-3o for qemu-devel@nongnu.org; Mon, 27 Feb 2017 15:11:17 -0500 From: Kevin Wolf Date: Mon, 27 Feb 2017 21:09:31 +0100 Message-Id: <1488226184-9044-31-git-send-email-kwolf@redhat.com> In-Reply-To: <1488226184-9044-1-git-send-email-kwolf@redhat.com> References: <1488226184-9044-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH v2 30/43] block: Allow backing file links in change_parent_backing_link() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, mreitz@redhat.com, jcody@redhat.com, famz@redhat.com, qemu-devel@nongnu.org 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 Reviewed-by: Max Reitz --- block.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/block.c b/block.c index 86567a8..af2b8ff 100644 --- a/block.c +++ b/block.c @@ -2872,9 +2872,9 @@ 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; @@ -2885,7 +2885,6 @@ static void change_parent_backing_link(BlockDriverState *from, } } - assert(c->role != &child_backing); bdrv_ref(to); bdrv_replace_child(c, to); bdrv_unref(from); -- 1.8.3.1