From patchwork Thu Sep 19 10:29:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 275934 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 127BF2C010C for ; Thu, 19 Sep 2013 20:29:49 +1000 (EST) Received: from localhost ([::1]:50451 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMbUY-0002RH-D9 for incoming@patchwork.ozlabs.org; Thu, 19 Sep 2013 06:29:46 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51100) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMbUE-0002Qy-6X for qemu-devel@nongnu.org; Thu, 19 Sep 2013 06:29:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VMbU8-0001du-7F for qemu-devel@nongnu.org; Thu, 19 Sep 2013 06:29:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50688) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMbU7-0001dk-W9 for qemu-devel@nongnu.org; Thu, 19 Sep 2013 06:29:20 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r8JATIou012398 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 19 Sep 2013 06:29:18 -0400 Received: from localhost (ovpn-116-68.ams2.redhat.com [10.36.116.68]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r8JATGEM007160 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Thu, 19 Sep 2013 06:29:17 -0400 From: Max Reitz To: qemu-devel@nongnu.org Date: Thu, 19 Sep 2013 12:29:15 +0200 Message-Id: <1379586555-1479-1-git-send-email-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , Stefan Hajnoczi , Max Reitz Subject: [Qemu-devel] [PATCH] qcow2: Correct snapshots size for overlap check X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Using s->snapshots_size instead of snapshots_size for the metadata overlap check in qcow2_write_snapshots leads to the detection of an overlap with the main qcow2 image header when deleting the last snapshot, since s->snapshots_size has not yet been updated and is therefore non-zero. However, the offset returned by qcow2_alloc_clusters will be zero since snapshots_size is zero. Therefore, an overlap is detected albeit no such will occur. This patch fixes this by replacing s->snapshots_size by snapshots_size when calling qcow2_pre_write_overlap_check. Signed-off-by: Max Reitz --- block/qcow2-snapshot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 7d14420..5e8a779 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -192,7 +192,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) /* The snapshot list position has not yet been updated, so these clusters * must indeed be completely free */ ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset, - s->snapshots_size); + snapshots_size); if (ret < 0) { return ret; }