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=-2.3 required=3.0 tests=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 92E14CA9EA0 for ; Fri, 18 Oct 2019 14:18:53 +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 6B5A9222C6 for ; Fri, 18 Oct 2019 14:18:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B5A9222C6 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]:40744 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLT5g-0004HB-DN for qemu-devel@archiver.kernel.org; Fri, 18 Oct 2019 10:18:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59668) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLT3i-00030D-C4 for qemu-devel@nongnu.org; Fri, 18 Oct 2019 10:16:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iLT3h-000286-4b for qemu-devel@nongnu.org; Fri, 18 Oct 2019 10:16:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36572) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iLT3g-000260-ST for qemu-devel@nongnu.org; Fri, 18 Oct 2019 10:16:49 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 06CA63D966; Fri, 18 Oct 2019 14:16:48 +0000 (UTC) Received: from localhost.localdomain (ovpn-117-198.ams2.redhat.com [10.36.117.198]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F1F255C1B5; Fri, 18 Oct 2019 14:16:38 +0000 (UTC) Date: Fri, 18 Oct 2019 16:16:37 +0200 From: Kevin Wolf To: Pavel Dovgalyuk Subject: Re: [for-4.2 PATCH 3/6] replay: update docs for record/replay with block devices Message-ID: <20191018141637.GG6122@localhost.localdomain> References: <20190919112702.GC10163@localhost.localdomain> <001a01d56ee3$4354a530$c9fdef90$@ru> <20190919130005.GF10163@localhost.localdomain> <002401d56f84$83900e40$8ab02ac0$@ru> <20190920100150.GD5458@localhost.localdomain> <001601d57380$002b3f20$0081bd60$@ru> <20191010152830.GF7616@localhost.localdomain> <002401d57ffa$927ffab0$b77ff010$@ru> <20191011091232.GB5158@localhost.localdomain> <003901d585ac$6a9b9d30$3fd2d790$@ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <003901d585ac$6a9b9d30$3fd2d790$@ru> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 18 Oct 2019 14:16:48 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: peter.maydell@linaro.org, pavel.dovgaluk@ispras.ru, quintela@redhat.com, ciro.santilli@gmail.com, jasowang@redhat.com, crosthwaite.peter@gmail.com, qemu-devel@nongnu.org, armbru@redhat.com, alex.bennee@linaro.org, maria.klimushenkova@ispras.ru, mst@redhat.com, kraxel@redhat.com, boost.lists@gmail.com, thomas.dullien@googlemail.com, pbonzini@redhat.com, mreitz@redhat.com, artem.k.pisarenko@gmail.com, dgilbert@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 18.10.2019 um 14:06 hat Pavel Dovgalyuk geschrieben: > > From: Kevin Wolf [mailto:kwolf@redhat.com] > > Am 11.10.2019 um 08:10 hat Pavel Dovgalyuk geschrieben: > > > > From: Kevin Wolf [mailto:kwolf@redhat.com] > > > > Am 25.09.2019 um 11:02 hat Pavel Dovgalyuk geschrieben: > > > > > I started playing with -blockdev: added new blockdev for blkreplay and > > > > > constructed the following command line: > > > > > > > > > > -blockdev driver=file,filename=disk.img,node-name=hd0 > > > > > -blockdev driver=blkreplay,file=hd0,node-name=hd0-rr > > > > > -device virtio-blk-device,drive=hd0-rr > > > > > > > > > > However, I get an error: "Could not open 'disk.img': Permission denied" > > > > > Everything works when I use this file in '-drive' parameter. > > > > > What am I doing wrong? > > > > > > > > The reason why I didn't reply immediately is because I don't see > > > > anything wrong in the options you used. > > > > > > > > Just to confirm, do you still get the same error when you use only the > > > > first -blockdev option and no other options at all? > > > > > > Ok, I tried again and got different error, which was caused by incorrect > > > QAPI schema for blkreplay. > > > Now it seems ok, but I still can't boot. > > > > Hm... Are you actually using a raw image? If not, you need the format > > driver, too, and would end up with something like: > > > > -blockdev driver=file,filename=disk.qcow2,node-name=hd0 > > -blockdev driver=qcow2,file=hd0,node-name=hd0-qcow2 > > -blockdev driver=blkreplay,file=hd0-qcow2,node-name=hd0-rr > > -device virtio-blk-device,drive=hd0-rr > > > > (The first two can be combined into a single option by using a syntax > > like file.driver=file,file.filename=disk.qcow2, but defining each node > > separately is a bit cleaner.) > > Ok, this works. > Now I'm trying to check root of the nodes in blk_insert_bs. > This command line leads to 2 invocations of this function: > 1. bs->drv is file > 2. bs->drv is blkreplay > > How then can we check "snapshot" node attachment? Ah, I see what's going on there... :-/ bdrv_open_inherit() creates an internal temporary BlockBackend for image format probing. And it creates that BlockBackend even when we don't need to do image probing because we already explicitly selected a driver. It would be better if it didn't do that. Kevin