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=-2.0 required=3.0 tests=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 B96D3C433E0 for ; Thu, 14 May 2020 18:30:18 +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 7ACDC2054F for ; Thu, 14 May 2020 18:30:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BkePE7xF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7ACDC2054F 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]:33508 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZIcb-00012A-Nb for qemu-devel@archiver.kernel.org; Thu, 14 May 2020 14:30:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48870) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZIbi-0007gM-17 for qemu-devel@nongnu.org; Thu, 14 May 2020 14:29:22 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:33200 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jZIbg-0002zX-Ij for qemu-devel@nongnu.org; Thu, 14 May 2020 14:29:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589480959; 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=+N9CjBMLLoI9lVw+zuDUt4jjNlaG7QZ55QrLColBzTY=; b=BkePE7xFbKwXurcYTPiUJxv55H0uh8MngCDEWtVCeau926Vvje0um/Ue0ORChPTRPX9QaB DtK+rrmOEa0pQb6+0NTlOhaM3ZWKbgULkR3O+7Ad974J1fpRT4JdfjFXG4UdbV4kEiNrlr L6JsDxYfwQhjpK2Jn58t57sgin43Etk= 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-210-mVjo3tVcObi9OtDSGo-gsw-1; Thu, 14 May 2020 14:29:13 -0400 X-MC-Unique: mVjo3tVcObi9OtDSGo-gsw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 07353107ACF9; Thu, 14 May 2020 18:29:12 +0000 (UTC) Received: from [10.3.116.145] (ovpn-116-145.phx2.redhat.com [10.3.116.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 164BF2E170; Thu, 14 May 2020 18:29:11 +0000 (UTC) Subject: Re: [PATCH v2 0/5] fix migration with bitmaps and mirror To: Peter Krempa , Vladimir Sementsov-Ogievskiy References: <20191219085106.22309-1-vsementsov@virtuozzo.com> <20191219103638.GJ4914@andariel.pipo.sk> <20200403112358.GV578401@andariel.pipo.sk> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Thu, 14 May 2020 13:29:10 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200403112358.GV578401@andariel.pipo.sk> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/14 11:41:05 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: fam@euphon.net, kwolf@redhat.com, qemu-block@nongnu.org, quintela@redhat.com, qemu-devel@nongnu.org, dgilbert@redhat.com, stefanha@redhat.com, den@openvz.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" reviving this thread... On 4/3/20 6:23 AM, Peter Krempa wrote: > On Fri, Apr 03, 2020 at 14:02:47 +0300, Vladimir Sementsov-Ogievskiy wrote: >> 19.12.2019 13:36, Peter Krempa wrote: >>> On Thu, Dec 19, 2019 at 11:51:01 +0300, Vladimir Sementsov-Ogievskiy wrote: >>>> Hi all! >>>> >>>> It's a continuation for >>>> "bitmap migration bug with -drive while block mirror runs" >>>> <315cff78-dcdb-a3ce-2742-da3cc9f0ca97@redhat.com> >>>> https://lists.gnu.org/archive/html/qemu-devel/2019-09/msg07241.html >>>> >>>> The problem is that bitmaps migrated to node with same node-name or >>>> blk-parent name. And currently only the latter actually work in libvirt. >>>> And with mirror-top filter it doesn't work, because >>>> bdrv_get_device_or_node_name don't go through filters. >>> >>> I want to point out that since libvirt-5.10 we use -blockdev to >>> configure the backend of storage devices with qemu-4.2 and later. This >>> means unfortunately that the BlockBackend of the drive does not have a >>> name any more and thus the above will not work even if you make the >>> lookup code to see through filters. >> >> Not that this series doesn't make things worse, as it loops through named >> block backends when trying to use their name for migration. So with these >> patches applied, qemu will just work in more possible scenarios. > > Okay, if that's so it's fair enough in this case. > > I'm just very firmly against baking in the assumption that > node names mean the same thing accross migration, because that will > create a precedent situation and more stuff may be baked in on top of > this in the future. It seems that it has already happened though and > it's wrong. And the worst part is that it's never mentioned that this > might occur. But again, don't do that and preferrably remove the > matching of node names for bitmaps altogether until we can control it > arbitrarily. > > We've also seen this already before with the backend name of memory > devices being baked in to the migration stream which creates an unwanted > dependancy. Max is trying to tackle the node-name issue: https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg03358.html And trying to apply that patch after staging this series hits a conflict in mnigration/block-dirty-bitmap.c. Which one should go in first? -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org