From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 160E4C0650E for ; Wed, 3 Jul 2019 17:30:41 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E13FB21882 for ; Wed, 3 Jul 2019 17:30:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E13FB21882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:38002 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hij5c-0000z6-27 for qemu-devel@archiver.kernel.org; Wed, 03 Jul 2019 13:30:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48821) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hij3o-0007SA-VR for qemu-devel@nongnu.org; Wed, 03 Jul 2019 13:28:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hij3n-0008JI-UA for qemu-devel@nongnu.org; Wed, 03 Jul 2019 13:28:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49794) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hij3g-0007ut-Ma; Wed, 03 Jul 2019 13:28:41 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CFE0286671; Wed, 3 Jul 2019 17:28:24 +0000 (UTC) Received: from localhost (ovpn-204-65.brq.redhat.com [10.40.204.65]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 69E6D19698; Wed, 3 Jul 2019 17:28:24 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 3 Jul 2019 19:28:05 +0200 Message-Id: <20190703172813.6868-5-mreitz@redhat.com> In-Reply-To: <20190703172813.6868-1-mreitz@redhat.com> References: <20190703172813.6868-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 03 Jul 2019 17:28:24 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 04/12] block: Keep subtree drained in drop_intermediate X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" bdrv_drop_intermediate() calls BdrvChildRole.update_filename(). That may poll, thus changing the graph, which potentially breaks the QLIST_FOREACH_SAFE() loop. Just keep the whole subtree drained. This is probably the right thing to do anyway (dropping nodes while the subtree is not drained seems wrong). Signed-off-by: Max Reitz --- block.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block.c b/block.c index a06f07347f..96b3dc7d53 100644 --- a/block.c +++ b/block.c @@ -4493,6 +4493,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, B= lockDriverState *base, int ret =3D -EIO; =20 bdrv_ref(top); + bdrv_subtree_drained_begin(top); =20 if (!top->drv || !base->drv) { goto exit; @@ -4564,6 +4565,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, B= lockDriverState *base, =20 ret =3D 0; exit: + bdrv_subtree_drained_end(top); bdrv_unref(top); return ret; } --=20 2.21.0