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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0DA0CC433DF for ; Wed, 10 Jun 2020 20:05:32 +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 D2E94206F7 for ; Wed, 10 Jun 2020 20:05:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aFM8Uw5C" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2E94206F7 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]:47906 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jj6yY-0005uD-UU for qemu-devel@archiver.kernel.org; Wed, 10 Jun 2020 16:05:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40298) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jj6vZ-0002vg-14 for qemu-devel@nongnu.org; Wed, 10 Jun 2020 16:02:25 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:26749 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jj6vX-0000CS-80 for qemu-devel@nongnu.org; Wed, 10 Jun 2020 16:02:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591819342; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RjDaqfoc8uBUQyC6TA74CxQQrVEwQkkBfACH1VLW5mQ=; b=aFM8Uw5C0SFMug8YuqTm3ZkzKzwWp6Mb658fH6RblOYj6n2Cm4xr+Q+W5G86VbGKEABzhp olcC37QBMZlUdRwhB/IcmSuj0r+1VtpRPLmXGOXmLbJe0i3YLFFiaXjKEdkxVvrnWo3V5a F7VP1S8p1OSMheFKzxm6c1BIkN6oNi0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-340-hhgPWyOAMvKt5zxCdJdydg-1; Wed, 10 Jun 2020 16:02:20 -0400 X-MC-Unique: hhgPWyOAMvKt5zxCdJdydg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C638C461; Wed, 10 Jun 2020 20:02:18 +0000 (UTC) Received: from [10.3.113.22] (ovpn-113-22.phx2.redhat.com [10.3.113.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6618C5D9D3; Wed, 10 Jun 2020 20:02:18 +0000 (UTC) Subject: Re: [PATCH] qcow2: Fix preallocation on images with unaligned sizes To: Alberto Garcia , qemu-devel@nongnu.org References: <20200610094600.4029-1-berto@igalia.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Wed, 10 Jun 2020 15:02:17 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200610094600.4029-1-berto@igalia.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/10 15:44:05 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 6/10/20 4:46 AM, Alberto Garcia wrote: > When resizing an image with qcow2_co_truncate() using the falloc or > full preallocation modes the code assumes that both the old and new > sizes are cluster-aligned. > > There are two problems with this: > > 1) The calculation of how many clusters are involved does not always > get the right result. > > Example: creating a 60KB image and resizing it (with > preallocation=full) to 80KB won't allocate the second cluster. > > 2) No copy-on-write is performed, so in the previous example if > there is a backing file then the first 60KB of the first cluster > won't be filled with data from the backing file. > > This patch fixes both issues. > > Signed-off-by: Alberto Garcia > --- > block/qcow2.c | 17 ++++++++++++++--- > tests/qemu-iotests/125 | 21 +++++++++++++++++++++ > tests/qemu-iotests/125.out | 9 +++++++++ > 3 files changed, 44 insertions(+), 3 deletions(-) > Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org