From nobody Tue Feb 10 01:19:59 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1487691563313642.7198504239291; Tue, 21 Feb 2017 07:39:23 -0800 (PST) Received: from localhost ([::1]:46397 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgCXA-0003rq-Td for importer@patchew.org; Tue, 21 Feb 2017 10:39:20 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43537) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgBv8-0000xT-MI for qemu-devel@nongnu.org; Tue, 21 Feb 2017 10:00:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cgBv7-0008EQ-UQ for qemu-devel@nongnu.org; Tue, 21 Feb 2017 10:00:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48560) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cgBv5-0008CZ-Mi; Tue, 21 Feb 2017 09:59:59 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BC82E7E9F7; Tue, 21 Feb 2017 14:59:59 +0000 (UTC) Received: from noname.str.redhat.com (dhcp-192-197.str.redhat.com [10.33.192.197]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1LEwudP030565; Tue, 21 Feb 2017 09:59:58 -0500 From: Kevin Wolf To: qemu-block@nongnu.org Date: Tue, 21 Feb 2017 15:58:37 +0100 Message-Id: <1487689130-30373-42-git-send-email-kwolf@redhat.com> In-Reply-To: <1487689130-30373-1-git-send-email-kwolf@redhat.com> References: <1487689130-30373-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 21 Feb 2017 14:59:59 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 41/54] block: Allow backing file links in change_parent_backing_link() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, jcody@redhat.com, famz@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 97694fa..560e84a 100644 --- a/block.c +++ b/block.c @@ -2860,9 +2860,9 @@ static void change_parent_backing_link(BlockDriverSta= te *from, continue; } if (c->role =3D=3D &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 rep= laced - * 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 =3D=3D c) { break; @@ -2873,7 +2873,6 @@ static void change_parent_backing_link(BlockDriverSta= te *from, } } =20 - assert(c->role !=3D &child_backing); bdrv_ref(to); bdrv_replace_child(c, to); bdrv_unref(from); --=20 1.8.3.1