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 1965CC433F5 for ; Wed, 29 Sep 2021 11:38:21 +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 B89D761409 for ; Wed, 29 Sep 2021 11:38:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B89D761409 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]:41808 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mVXul-0007Bj-P1 for qemu-devel@archiver.kernel.org; Wed, 29 Sep 2021 07:38:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44444) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mVXsS-0005Va-6w for qemu-devel@nongnu.org; Wed, 29 Sep 2021 07:35:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:21232) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mVXsL-00080p-LB for qemu-devel@nongnu.org; Wed, 29 Sep 2021 07:35:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632915347; h=from:from:reply-to: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=slnn17+p6DbA1Y7VKEvWLQ2FLx4m+nfEWywltLk/IoQ=; b=FteS3tmdzoXsMttJFJfPFVzUFW6JYA/xJaWa9nzMReKUpx7WZBihfrL9WBQq3RZ6fvEP51 Ec0VgEo764yWNnjLdUATKf884b6Kd0gqIrUgCQqX2GqeVwqFGW8d8NVI+WxKQl50T9N3iR uii03lYQhy/9DTyrbt03tUSnv6OsS9Y= 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-373-5GyEROTSOSCJirDMRF8omA-1; Wed, 29 Sep 2021 07:35:27 -0400 X-MC-Unique: 5GyEROTSOSCJirDMRF8omA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CA9CE100C661; Wed, 29 Sep 2021 11:35:26 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.141]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 40B5D60BE5; Wed, 29 Sep 2021 11:35:25 +0000 (UTC) Date: Wed, 29 Sep 2021 12:35:22 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Michael Tokarev Subject: Re: blockdev driver=file,filename=/dev/block forbidden? Message-ID: References: MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@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, T_SPF_TEMPERROR=0.01 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Sep 29, 2021 at 02:21:58PM +0300, Michael Tokarev wrote: > Commit 8d17adf34f501ded65a106572740760f0a75577c > "block: remove support for using "file" driver with block/char devices" > explicitly forbids usage of file driver for block devices. > > But _why_? > > Hasn't we always used file for everything on *nix? And what's the _actual_ > difference between file and host_device? There are various things QEMU does differently for plain files vs block devices. The check for read-only volume, determining data transfer size, media geometry, supporting discard. This is seen in the BlockDriver structs that have different callbacks for each. > Please note this change has been added to qemu long before libvirt has > been adapted (I guess there's no released libvirt can be used with > qemu 6.0+). Can you show your libvirt guest XML config that is causing trouble, as it has done the right thing here for a long while AFAIK, so I suspect a mis-configuration. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|