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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 0B846C433E0 for ; Thu, 11 Jun 2020 14:37:49 +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 C3E0C206C3 for ; Thu, 11 Jun 2020 14:37:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="A7V5c6jb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C3E0C206C3 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]:45458 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jjOKy-0005OH-4E for qemu-devel@archiver.kernel.org; Thu, 11 Jun 2020 10:37:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37636) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jjOK7-0004SM-WE for qemu-devel@nongnu.org; Thu, 11 Jun 2020 10:36:56 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:57482 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 1jjOK6-0001vQ-9y for qemu-devel@nongnu.org; Thu, 11 Jun 2020 10:36:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591886213; 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=R8iGEVR1kQQwsgaN0ZpVmjwYHpEbDiFbdqFaOwDYgTE=; b=A7V5c6jbX5uY/Dv4kSTlbl6tuZ/Gg5kT6T4tvdetLMucdTc/OnH+QB1ubX8IsAMvvtWwsr DinDSRO951pb6F8QE/yr/U3urvo+uBcL+0ktEuehlXoeN6eUB7d77Dy867lUs+MPbBnAUY 0RxE/pON8Il8HG3iHHahYAB3yxyA3iE= 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-169-vDfpWE7aPmKNghQaMSfkwA-1; Thu, 11 Jun 2020 10:36:51 -0400 X-MC-Unique: vDfpWE7aPmKNghQaMSfkwA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4A3BA18A8220; Thu, 11 Jun 2020 14:36:50 +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 BA0A18FF81; Thu, 11 Jun 2020 14:36:48 +0000 (UTC) Subject: Re: [PATCH v8 33/34] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters To: Alberto Garcia , qemu-devel@nongnu.org References: <19afb93b267b9698edf5e0253458c5db69ef91a2.1591801197.git.berto@igalia.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <033a2dc9-6dbf-dca8-9963-84f0a374e907@redhat.com> Date: Thu, 11 Jun 2020 09:36:48 -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: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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=207.211.31.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/11 08:37:10 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_H3=-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 , Derek Su , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 6/11/20 8:24 AM, Alberto Garcia wrote: > On Wed 10 Jun 2020 09:43:53 PM CEST, Eric Blake wrote: >> On 6/10/20 10:03 AM, Alberto Garcia wrote: >>> This function is only used by qcow2_expand_zero_clusters() to >>> downgrade a qcow2 image to a previous version. It is however not >>> possible to downgrade an image with extended L2 entries because older >>> versions of qcow2 do not have this feature. >> >> Well, it _is_ possible, but it would involve rewriting the entire >> L1/L2 tables (including all internal snapshots) > > Right :-) Let's try this way: > > This function is only used by qcow2_expand_zero_clusters() to > downgrade a qcow2 image to a previous version. This would require > transforming all extended L2 entries into normal L2 entries but > this is not a simple task and there are no plans to implement this > at the moment. Works for me. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org