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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 710EAC433EF for ; Fri, 29 Oct 2021 20:55:20 +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 37D2861056 for ; Fri, 29 Oct 2021 20:55:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 37D2861056 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:36522 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mgYuF-0002wX-70 for qemu-devel@archiver.kernel.org; Fri, 29 Oct 2021 16:55:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48644) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mgYja-0004TJ-1q for qemu-devel@nongnu.org; Fri, 29 Oct 2021 16:44:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:26941) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mgYjW-0002Lh-KH for qemu-devel@nongnu.org; Fri, 29 Oct 2021 16:44:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635540253; 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=l2d72+vgyYCZ1XSxK2vdAGa87Y7rw7GJ0KQomShvCCs=; b=QVtoh9aZ1e+pwK15lPVrFYQNmBIFKhmpet9lSZWDngLz3igM8s7ftu8XXx5SGEBr/XaTCr qPuaNT14A4vimRLxeQ2/okoxKdH/Ny0Dq58Z9rqzBTSfJrvYtNYEBMny/LtG9pg836TwJ/ B2hNavA/YKxaWCv/L/Iid7Qd985E6ZI= 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-368--IY4L6rJO5KtGI4cu9btGA-1; Fri, 29 Oct 2021 16:44:10 -0400 X-MC-Unique: -IY4L6rJO5KtGI4cu9btGA-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 A4F88362F9; Fri, 29 Oct 2021 20:44:09 +0000 (UTC) Received: from redhat.com (ovpn-112-232.phx2.redhat.com [10.3.112.232]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9AC26100EBAD; Fri, 29 Oct 2021 20:44:08 +0000 (UTC) Date: Fri, 29 Oct 2021 15:44:02 -0500 From: Eric Blake To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH v3 3/4] qemu-img: add --shallow option for qemu-img compare Message-ID: <20211029204402.flo6xeps4pexlujg@redhat.com> References: <20211028102441.1878668-1-vsementsov@virtuozzo.com> <20211028102441.1878668-4-vsementsov@virtuozzo.com> MIME-Version: 1.0 In-Reply-To: <20211028102441.1878668-4-vsementsov@virtuozzo.com> User-Agent: NeoMutt/20211022 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: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: kwolf@redhat.com, qemu-block@nongnu.org, nikita.lapshin@virtuozzo.com, qemu-devel@nongnu.org, nsoffer@redhat.com, hreitz@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Oct 28, 2021 at 12:24:40PM +0200, Vladimir Sementsov-Ogievskiy wrote: > Allow compare only top images of backing chains. This is useful to Allow the comparison of only the top image of backing chains. > compare images with same backing file or to compare incremental images > from the chain of incremental backups with "--stat" option. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > Reviewed-by: Hanna Reitz > --- > docs/tools/qemu-img.rst | 9 ++++++++- > qemu-img.c | 8 ++++++-- > qemu-img-cmds.hx | 4 ++-- > 3 files changed, 16 insertions(+), 5 deletions(-) > > diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst > index 9bfdd93d6c..c6e9306c70 100644 > --- a/docs/tools/qemu-img.rst > +++ b/docs/tools/qemu-img.rst > @@ -176,6 +176,13 @@ Parameters to compare subcommand: > - If both files don't specify cluster-size, use default of 64K > - If only one file specifies cluster-size, just use that. > > +.. option:: --shallow > + > + This option prevents opening and comparing any backing files. > + This is useful to compare images with same backing file or to compare > + incremental images from the chain of incremental backups with > + ``--stat`` option. If I understand correctly, your implementation makes --shallow an all-or-none option (either both images are compared shallow, or neither is). Does it make sense to make it a per-image option (--shallow-source, --shallow-dest), where --shallow is a synonym for the more verbose --shallow-source --shallow-dest? -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org