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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 715D0C11F67 for ; Tue, 29 Jun 2021 14:49:02 +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 2645761DD1 for ; Tue, 29 Jun 2021 14:49:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2645761DD1 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]:44938 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lyF2r-0000rE-76 for qemu-devel@archiver.kernel.org; Tue, 29 Jun 2021 10:49:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58336) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lyEun-0003uU-MH for qemu-devel@nongnu.org; Tue, 29 Jun 2021 10:40:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53516) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lyEul-0008AX-TH for qemu-devel@nongnu.org; Tue, 29 Jun 2021 10:40:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624977638; 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: in-reply-to:in-reply-to:references:references; bh=JjDIMLLsBfABKh/xX/phtl52HKaLwAGax+urcAPocWs=; b=Lfe0ejyl7ExWzWQEvC9c34mP8SfKGh6LIDwYZQ0upuS9dX6Csc/M+LOcsOhhtx/mi1NtXA V2139UBhMW3YP2I24uK/IYlL8OpK1YEBHGGZsTYXB+XUmOr5lqmhlcYD4WY5DqRdVetVv5 IPIMraKlvafxdAPqvXkEWz/tZrnqoEg= 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-248-7wP5G6TbOhaktPPgRR8fyw-1; Tue, 29 Jun 2021 10:40:35 -0400 X-MC-Unique: 7wP5G6TbOhaktPPgRR8fyw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3ECB6804143; Tue, 29 Jun 2021 14:40:34 +0000 (UTC) Received: from redhat.com (ovpn-114-170.ams2.redhat.com [10.36.114.170]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CF62E18A77; Tue, 29 Jun 2021 14:40:32 +0000 (UTC) Date: Tue, 29 Jun 2021 16:40:31 +0200 From: Kevin Wolf To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH v2 2/1] qemu-img: Add "backing":true to unallocated map segments Message-ID: References: <20210611140157.1366738-1-eblake@redhat.com> <20210611190316.1424729-1-eblake@redhat.com> <20210628174216.25ybfzmtbiymgd6s@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.435, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: "open list:Block layer core" , Markus Armbruster , QEMU Developers , Max Reitz , Nir Soffer , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 29.06.2021 um 09:23 hat Vladimir Sementsov-Ogievskiy geschrieben: > 28.06.2021 20:42, Eric Blake wrote: > > On Wed, Jun 23, 2021 at 06:04:19PM +0200, Kevin Wolf wrote: > > > > This is fine, but it means that this flag will present in all ranges, > > > > instead of only in unallocated ranges (what this patch is doing). > > > > > > An argument for always having the flag would be that it's probably > > > useful for a tool to know whether a given block is actually absent or > > > whether it's just running an old qemu-img. > > > > > > If we didn't care about this, I would still define the actual value, but > > > also document a default. > > > > So to summarize, it looks like my v3 will have the best chance of > > approval if I go with always outputting the new field (instead of only > > on one of its two boolean values), and put it at the end of the JSON > > output. It also looks like we have consensus on spelling the new > > field "present":true for data found in the backing chain, and > > "present":false for places where we would defer to another file if a > > backing file is later added. > > > > I didn't follow the discussion carefully, but that sounds good to me. To me, too. > What's the decision about patch 1? I think we won't need patch 1 (and the potential backwards compatibility problems it would introduce) when we have this one. Kevin