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=-6.8 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 83159C3A5A2 for ; Fri, 20 Sep 2019 15:38:23 +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 5A16520882 for ; Fri, 20 Sep 2019 15:38:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A16520882 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]:60958 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iBKzF-0007yV-Tw for qemu-devel@archiver.kernel.org; Fri, 20 Sep 2019 11:38:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44094) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iBKq3-00014T-QD for qemu-devel@nongnu.org; Fri, 20 Sep 2019 11:28:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iBKq1-0004fH-ON for qemu-devel@nongnu.org; Fri, 20 Sep 2019 11:28:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39978) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iBKpq-0004XO-2v; Fri, 20 Sep 2019 11:28:38 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3259C8A1C92; Fri, 20 Sep 2019 15:28:37 +0000 (UTC) Received: from localhost (unknown [10.40.205.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BFFD45D6A7; Fri, 20 Sep 2019 15:28:36 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH 13/22] mirror: Double-check immediately before replacing Date: Fri, 20 Sep 2019 17:27:55 +0200 Message-Id: <20190920152804.12875-14-mreitz@redhat.com> In-Reply-To: <20190920152804.12875-1-mreitz@redhat.com> References: <20190920152804.12875-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.69]); Fri, 20 Sep 2019 15:28:37 +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 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 , Alberto Garcia , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" There is no guarantee that we can still replace the node we want to replace at the end of the mirror job. Double-check by calling bdrv_recurse_can_replace(). Signed-off-by: Max Reitz --- block/mirror.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/block/mirror.c b/block/mirror.c index 706d80fced..d877637e1e 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -695,7 +695,19 @@ static int mirror_exit_common(Job *job) * drain potential other users of the BDS before changing the gr= aph. */ assert(s->in_drain); bdrv_drained_begin(target_bs); - bdrv_replace_node(to_replace, target_bs, &local_err); + /* + * Cannot use check_to_replace_node() here, because that would + * check for an op blocker on @to_replace, and we have our own + * there. + */ + if (bdrv_recurse_can_replace(src, to_replace)) { + bdrv_replace_node(to_replace, target_bs, &local_err); + } else { + error_setg(&local_err, "Can no longer replace '%s' by '%s', = " + "because it can no longer be guaranteed that doin= g so " + "would not lead to an abrupt change of visible da= ta", + to_replace->node_name, target_bs->node_name); + } bdrv_drained_end(target_bs); if (local_err) { error_report_err(local_err); --=20 2.21.0