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=BAYES_00,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 AF4EBC11F64 for ; Mon, 28 Jun 2021 17:44:11 +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 7359C61C65 for ; Mon, 28 Jun 2021 17:44:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7359C61C65 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]:58478 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxvIo-0007hX-N4 for qemu-devel@archiver.kernel.org; Mon, 28 Jun 2021 13:44:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39674) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxvH7-0005NY-Pi for qemu-devel@nongnu.org; Mon, 28 Jun 2021 13:42:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:51864) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxvH5-0003e2-U7 for qemu-devel@nongnu.org; Mon, 28 Jun 2021 13:42:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624902143; 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=lm8U4n09Vw04OSvpdQ6CmtpJcOTb0HoMlVRQRJDxilA=; b=QPWKXwWm5pffse4aPwrwa6rYOmfqW1UEPQotcoUyGn7i4761Trw3mL5o1JZ1HYuc23GG5I cY9dZYylLne/1lYTq1hMXjCaXib5OWnvVrdfhBZNXNCxf/HVD2WIUTLoqqZdcuuEkPvvTB JeTxAXpUrNG4XT4ibdVWRU77BHoDCo0= 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-331-xW4Lj4kJMUOHcErzzmOeJw-1; Mon, 28 Jun 2021 13:42:20 -0400 X-MC-Unique: xW4Lj4kJMUOHcErzzmOeJw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C33C0106B7DA; Mon, 28 Jun 2021 17:42:18 +0000 (UTC) Received: from redhat.com (ovpn-113-39.phx2.redhat.com [10.3.113.39]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2F2CD6267C; Mon, 28 Jun 2021 17:42:18 +0000 (UTC) Date: Mon, 28 Jun 2021 12:42:16 -0500 From: Eric Blake To: Kevin Wolf Subject: Re: [PATCH v2 2/1] qemu-img: Add "backing":true to unallocated map segments Message-ID: <20210628174216.25ybfzmtbiymgd6s@redhat.com> References: <20210611140157.1366738-1-eblake@redhat.com> <20210611190316.1424729-1-eblake@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: NeoMutt/20210205 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@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=216.205.24.124; envelope-from=eblake@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=-0.375, 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: Vladimir Sementsov-Ogievskiy , "open list:Block layer core" , Markus Armbruster , QEMU Developers , Max Reitz , Nir Soffer Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org