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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 269FFC35247 for ; Thu, 6 Feb 2020 01:47:56 +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 E425D20658 for ; Thu, 6 Feb 2020 01:47:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="I45g5i2z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E425D20658 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]:59596 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1izWGp-0004lQ-0o for qemu-devel@archiver.kernel.org; Wed, 05 Feb 2020 20:47:55 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43983) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1izWEk-0003Rd-Hn for qemu-devel@nongnu.org; Wed, 05 Feb 2020 20:45:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1izWEi-0002Zy-FI for qemu-devel@nongnu.org; Wed, 05 Feb 2020 20:45:45 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:42249 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1izWEi-0002Tr-55 for qemu-devel@nongnu.org; Wed, 05 Feb 2020 20:45:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580953542; 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=8Uqz30hoaa5iJuXtZDEdpoq+vfR+s2EyhrOC6OyBeqA=; b=I45g5i2zzRpkOq+yBLfMfZKnsnhmtb5ygNdevpO4LdL4cThsrG4Z9n/M0pdjhPQkxe9ZUq oIukbmDXPO5Ft8weXTaGeoh9zq7AO/XC/FpLasLF91yWa2sfFzz3Gcvp7lTjiOaCKBsROb FPK3K7UBAn+E0l6UrOd3i5+1zNy5Q2E= 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-239-7yfkDo-zOHuxRIUruct2xw-1; Wed, 05 Feb 2020 20:45:38 -0500 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 32D8D8018C8; Thu, 6 Feb 2020 01:45:37 +0000 (UTC) Received: from [10.3.116.181] (ovpn-116-181.phx2.redhat.com [10.3.116.181]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D449186C4A; Thu, 6 Feb 2020 01:45:36 +0000 (UTC) Subject: Re: [PATCH v4 1/1] qemu-img: Add --target-is-zero to convert To: David Edmondson , qemu-devel@nongnu.org References: <20200205110248.2009589-1-david.edmondson@oracle.com> <20200205110248.2009589-2-david.edmondson@oracle.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <973eb8bc-fafa-a31f-e4b4-eb4e8ee868f0@redhat.com> Date: Wed, 5 Feb 2020 19:45:36 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200205110248.2009589-2-david.edmondson@oracle.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: 7yfkDo-zOHuxRIUruct2xw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2/5/20 5:02 AM, David Edmondson wrote: > In many cases the target of a convert operation is a newly provisioned > target that the user knows is blank (reads as zero). In this situation > there is no requirement for qemu-img to wastefully zero out the entire > device. > > Add a new option, --target-is-zero, allowing the user to indicate that > an existing target device will return zeros for all reads. > > Signed-off-by: David Edmondson > --- > docs/interop/qemu-img.rst | 9 ++++++++- > qemu-img-cmds.hx | 4 ++-- > qemu-img.c | 26 +++++++++++++++++++++++--- > 3 files changed, 33 insertions(+), 6 deletions(-) Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org