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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 169EEC28CBC for ; Wed, 6 May 2020 18:10:11 +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 D505D20747 for ; Wed, 6 May 2020 18:10:10 +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="NmjKQ89M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D505D20747 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]:56524 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jWOUj-0002vH-TX for qemu-devel@archiver.kernel.org; Wed, 06 May 2020 14:10:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55314) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jWOTt-0002KD-7S for qemu-devel@nongnu.org; Wed, 06 May 2020 14:09:17 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:22241 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 1jWOTr-0001jV-I4 for qemu-devel@nongnu.org; Wed, 06 May 2020 14:09:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588788554; 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=YEmA1bcoNYxRJdB+2eSsoyZLzKj/F93sUwMOgeeW/34=; b=NmjKQ89MMlhNcHvmo65heO5xQTcL6DIU8QabOBXd4H5BEko7GguRQKrhRHrTh0v77Aql9J BNxELUe/gsBfo+A/MZL3Ok9EjBX0nrSWgOM9sxPCD4LFIh9PbDb6/Ujms6I1/vPnLvgeWB sdoS0ogsF0f6qqXt4qZwfiuMOm3NUs4= 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-179-tJ6j2C6YNuymL8Xl2z5dOg-1; Wed, 06 May 2020 14:09:09 -0400 X-MC-Unique: tJ6j2C6YNuymL8Xl2z5dOg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A12901B18BC5; Wed, 6 May 2020 18:09:08 +0000 (UTC) Received: from [10.3.114.73] (ovpn-114-73.phx2.redhat.com [10.3.114.73]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 14DB41001920; Wed, 6 May 2020 18:09:07 +0000 (UTC) Subject: Re: [PATCH v5 28/31] qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit To: Alberto Garcia , qemu-devel@nongnu.org References: From: Eric Blake Organization: Red Hat, Inc. Message-ID: <926a34f4-c629-fe8e-ed5a-b655b68d1265@redhat.com> Date: Wed, 6 May 2020 13:09:07 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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 = 2020/05/05 23:48:07 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, 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_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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 , 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 5/5/20 12:38 PM, Alberto Garcia wrote: > Now that the implementation of subclusters is complete we can finally > add the necessary options to create and read images with this feature, > which we call "extended L2 entries". > > Signed-off-by: Alberto Garcia > Reviewed-by: Max Reitz > --- What you have looks good, but I didn't notice anything affecting amend. The simplest option: amend can reject attempts to toggle the extended L2 option (the zstd compression patches take that path). More complicated is actually supporting it (in either direction, turning it on or off), which requires rewriting ALL L2 tables in the entry (including any in internal snapshots), which could be quite time-intensive, and where you must be careful to stage things so that failures during partial conversion merely leave leaked clusters rather than a header pointing to a half-converted state. Either way, one of the iotests should probably add coverage on what happens when you attempt to amend the bit on or off. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org