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 E6C5FC433F5 for ; Fri, 5 Nov 2021 19:57:41 +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 7DB6B61131 for ; Fri, 5 Nov 2021 19:57:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7DB6B61131 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]:42684 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mj5LI-00029y-AK for qemu-devel@archiver.kernel.org; Fri, 05 Nov 2021 15:57:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55056) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mj5Kd-0001Ji-Fd for qemu-devel@nongnu.org; Fri, 05 Nov 2021 15:56:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:45618) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mj5KZ-0004AD-Ri for qemu-devel@nongnu.org; Fri, 05 Nov 2021 15:56:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636142214; 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=nPj3v0YMBa59wn+p64UvpVrfo+flqnWiMXR65nVzuZM=; b=K5x+W+OAsgJ7SqIQTzg1CA8VOGmz+5wNBzTinuNuFpXjdQtPL+vGrM9cQwHHPenL/CtGa0 lXe/1FLQn0knsvdGg1IinYjMiasBmRh+/GptMOhLUXz6pbBGD4/1P2Oat5wjIxzHkmjwh5 YGinvj85mBZ8I8NSgBkush9RN5l6NZo= 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-468-x5ws1FrUODOyuTwbvYDZRg-1; Fri, 05 Nov 2021 15:56:48 -0400 X-MC-Unique: x5ws1FrUODOyuTwbvYDZRg-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 C5145EC1A3; Fri, 5 Nov 2021 19:56:46 +0000 (UTC) Received: from redhat.com (ovpn-112-104.phx2.redhat.com [10.3.112.104]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 81AFD67843; Fri, 5 Nov 2021 19:56:30 +0000 (UTC) Date: Fri, 5 Nov 2021 14:56:28 -0500 From: Eric Blake To: Markus Armbruster Subject: Re: [PATCH v4 3/3] qapi: deprecate drive-backup Message-ID: <20211105195628.fwq7tdjvrmggf6ez@redhat.com> References: <20211104085811.1736654-1-armbru@redhat.com> <20211104085811.1736654-4-armbru@redhat.com> MIME-Version: 1.0 In-Reply-To: <20211104085811.1736654-4-armbru@redhat.com> User-Agent: NeoMutt/20211029-10-fe244a X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.648, 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=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: vsementsov@virtuozzo.com, qemu-block@nongnu.org, kchamart@redhat.com, libvir-list@redhat.com, wencongyang2@huawei.com, xiechanglong.d@gmail.com, qemu-devel@nongnu.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Nov 04, 2021 at 09:58:11AM +0100, Markus Armbruster wrote: > From: Vladimir Sementsov-Ogievskiy > > Modern way is using blockdev-add + blockdev-backup, which provides a > lot more control on how target is opened. > > As example of drive-backup problems consider the following: > > User of drive-backup expects that target will be opened in the same > cache and aio mode as source. Corresponding logic is in > drive_backup_prepare(), where we take bs->open_flags of source. > > It works rather bad if source was added by blockdev-add. Assume source > is qcow2 image. On blockdev-add we should specify aio and cache options > for file child of qcow2 node. What happens next: > > drive_backup_prepare() looks at bs->open_flags of qcow2 source node. > But there no BDRV_O_NOCAHE neither BDRV_O_NATIVE_AIO: BDRV_O_NOCAHE is > places in bs->file->bs->open_flags, and BDRV_O_NATIVE_AIO is nowhere, > as file-posix parse options and simply set s->use_linux_aio. > > The documentation is updated in a minimal way, so that drive-backup is > noted only as a deprecated command, and blockdev-backup used in most of > places. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > Reviewed-by: Kashyap Chamarthy > Signed-off-by: Markus Armbruster > --- Reviewed-by: Eric Blake I think this is appropriate for inclusion in 6.2, even if it did not quite make soft freeze, so that we aren't delaying the deprecation for an entire cycle. > docs/about/deprecated.rst | 11 ++++++ > docs/interop/live-block-operations.rst | 47 +++++++++++++++++--------- > qapi/block-core.json | 5 ++- > qapi/transaction.json | 6 +++- > 4 files changed, 51 insertions(+), 18 deletions(-) > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org