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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 81F27C48BD1 for ; Fri, 11 Jun 2021 13:32:02 +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 2862D60FE9 for ; Fri, 11 Jun 2021 13:32:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2862D60FE9 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]:53192 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lrhGT-0005Nq-CT for qemu-devel@archiver.kernel.org; Fri, 11 Jun 2021 09:32:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49582) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrhFq-0004c6-LO for qemu-devel@nongnu.org; Fri, 11 Jun 2021 09:31:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:36611) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrhFp-0007xX-1O for qemu-devel@nongnu.org; Fri, 11 Jun 2021 09:31:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623418280; 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=qIDZ8XOKyyZOPlW9MM+CVpWlwqLBkYGenn7V06DJyVI=; b=PVaVP/lcDghYqOqmeFzoJYJR+Bqf10ay0aIt8arUN+7AadsVVJBwFxhU6q8FZOSmSALA/8 LjZjBlO4NkRalWF5jBcdCcg5WnjuVvCbYgFQ9B/I5wixBNjGUqdGUAX31+fwQsF6hEl7lN rkHb8vd4AXKMEzWzYgSdPCG7oCRhQbk= 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-448-0FGYCBo6NOmXR5BLsPCNsg-1; Fri, 11 Jun 2021 09:31:14 -0400 X-MC-Unique: 0FGYCBo6NOmXR5BLsPCNsg-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 2E4901940927; Fri, 11 Jun 2021 13:31:13 +0000 (UTC) Received: from redhat.com (ovpn-113-53.phx2.redhat.com [10.3.113.53]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 937E11002EF0; Fri, 11 Jun 2021 13:31:12 +0000 (UTC) Date: Fri, 11 Jun 2021 08:31:10 -0500 From: Eric Blake To: Kevin Wolf Subject: Re: [PATCH] qemu-{img,nbd}: Don't report zeroed cluster as a hole Message-ID: <20210611133110.dy2arokoux63m3n7@redhat.com> References: <20210607202204.1805199-1-nsoffer@redhat.com> <20210607212224.tiqjvvdwosvhrvz7@redhat.com> <20210610183443.clk43ngkobzyjopy@redhat.com> <20210610204617.fuj4ivqrixpz4qfj@redhat.com> <49ed9c03-eb24-4e8a-1b5f-8a291466a7b9@virtuozzo.com> MIME-Version: 1.0 In-Reply-To: User-Agent: NeoMutt/20210205 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.199, 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 , Nir Soffer , qemu-block , QEMU Developers , Max Reitz , Nir Soffer Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Jun 11, 2021 at 01:21:45PM +0200, Kevin Wolf wrote: > > Did you consider just add a new field? > > > > So, "depth" keeps its meaning "which level provides data". > > > > And we add additional optional field like > > > > absolutely-completely-absent: bool > > > > Which is true if data is nowhere in the backing chain. > > Or how about exposing BDRV_BLOCK_ALLOCATED as 'allocated': 'bool'? Which > I think is what the conclusion was already for NBD, so doing the same in > 'qemu-img map' would be consistent. > > This is, of course, almost the same as 'absolutely-completely-absent', > just without the negating the flag. If we want to bikeshed on a new name, I think "allocated" is going to cause more confusion than it solves. And "hole" is wrong. Better would be "backing":true for portions of the file that would derive from a backing file, if a backing file had been present. But that still feels like more work than just exposing n+1 in depth. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org