From patchwork Wed Jun 3 20:13:38 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 480144 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)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id A15901401F6 for ; Thu, 4 Jun 2015 06:17:05 +1000 (AEST) Received: from localhost ([::1]:37810 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z0F5z-0007Yh-NP for incoming@patchwork.ozlabs.org; Wed, 03 Jun 2015 16:17:03 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43224) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z0F3F-0002h7-5r for qemu-devel@nongnu.org; Wed, 03 Jun 2015 16:14:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z0F3E-0008N3-2k for qemu-devel@nongnu.org; Wed, 03 Jun 2015 16:14:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56576) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z0F3A-0008JQ-MJ; Wed, 03 Jun 2015 16:14:08 -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 (Postfix) with ESMTPS id 69CA7B6F3D; Wed, 3 Jun 2015 20:14:08 +0000 (UTC) Received: from localhost (ovpn-116-32.ams2.redhat.com [10.36.116.32]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t53KE6N4012380 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 3 Jun 2015 16:14:07 -0400 From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 3 Jun 2015 22:13:38 +0200 Message-Id: <1433362419-15033-10-git-send-email-mreitz@redhat.com> In-Reply-To: <1433362419-15033-1-git-send-email-mreitz@redhat.com> References: <1433362419-15033-1-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 , qemu-devel@nongnu.org, Stefan Hajnoczi , Max Reitz Subject: [Qemu-devel] [PATCH v8 09/10] qcow2: Point to amend function in 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 If a reference count is not representable with the current refcount order, the image check should point to qemu-img amend for increasing the refcount order. However, qemu-img amend needs write access to the image which cannot be provided if the image is marked corrupt; and the image check will not mark the image consistent unless everything actually is consistent. Therefore, if an image is marked corrupt and the image check encounters a reference count overflow, it cannot be fixed by using qemu-img amend to increase the refcount order. Instead, one has to use qemu-img convert to create a completely new copy of the image in this case. Alternatively, we may want to give the user a way of manually removing the corrupt flag, maybe through qemu-img amend, but this is not part of this patch. Signed-off-by: Max Reitz Reviewed-by: Eric Blake Reviewed-by: Stefan Hajnoczi --- block/qcow2-refcount.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 13397a9..38091c6 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1328,6 +1328,9 @@ static int inc_refcounts(BlockDriverState *bs, if (refcount == s->refcount_max) { fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 "\n", cluster_offset); + fprintf(stderr, "Use qemu-img amend to increase the refcount entry " + "width or qemu-img convert to create a clean copy if the " + "image cannot be opened for writing\n"); res->corruptions++; continue; }