From nobody Mon Feb 9 06:00:33 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 1488901486840867.9358565498586; Tue, 7 Mar 2017 07:44:46 -0800 (PST) Received: from localhost ([::1]:51255 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1clHI3-0004Ve-Ft for importer@patchew.org; Tue, 07 Mar 2017 10:44:43 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42393) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1clHEa-000227-Bm for qemu-devel@nongnu.org; Tue, 07 Mar 2017 10:41:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1clHEZ-0002Xl-H1 for qemu-devel@nongnu.org; Tue, 07 Mar 2017 10:41:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35552) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1clHEX-0002U4-0l; Tue, 07 Mar 2017 10:41:05 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (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 261DA64DA8; Tue, 7 Mar 2017 15:41:05 +0000 (UTC) Received: from noname.str.redhat.com (dhcp-192-197.str.redhat.com [10.33.192.197]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v27FeuUY032123; Tue, 7 Mar 2017 10:41:04 -0500 From: Kevin Wolf To: qemu-block@nongnu.org Date: Tue, 7 Mar 2017 16:40:29 +0100 Message-Id: <1488901251-16214-6-git-send-email-kwolf@redhat.com> In-Reply-To: <1488901251-16214-1-git-send-email-kwolf@redhat.com> References: <1488901251-16214-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 07 Mar 2017 15:41:05 +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] [PULL 05/27] block: Fix blockdev-snapshot error handling 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, qemu-devel@nongnu.org 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" For blockdev-snapshot, external_snapshot_prepare() accepts an arbitrary node reference at first and only checks later whether it already has a backing file. Between those places, other errors can occur. Therefore checking in external_snapshot_abort() whether state->new_bs has a backing file is not sufficient to tell whether bdrv_append() was already completed or not. Trying to undo the bdrv_append() when it wasn't even executed is wrong. Introduce a new boolean flag in the state to fix this. Signed-off-by: Kevin Wolf Reviewed-by: Fam Zheng Reviewed-by: Eric Blake --- blockdev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/blockdev.c b/blockdev.c index 8eb4e84..af67ce4 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1614,6 +1614,7 @@ typedef struct ExternalSnapshotState { BlockDriverState *old_bs; BlockDriverState *new_bs; AioContext *aio_context; + bool overlay_appended; } ExternalSnapshotState; =20 static void external_snapshot_prepare(BlkActionState *common, @@ -1780,6 +1781,7 @@ static void external_snapshot_prepare(BlkActionState = *common, error_propagate(errp, local_err); return; } + state->overlay_appended =3D true; } =20 static void external_snapshot_commit(BlkActionState *common) @@ -1803,7 +1805,7 @@ static void external_snapshot_abort(BlkActionState *c= ommon) ExternalSnapshotState *state =3D DO_UPCAST(ExternalSnapshotState, common, comm= on); if (state->new_bs) { - if (state->new_bs->backing) { + if (state->overlay_appended) { bdrv_replace_in_backing_chain(state->new_bs, state->old_bs); } } --=20 1.8.3.1