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=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 5E3BAC10F27 for ; Mon, 9 Mar 2020 15:37:22 +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 2CB7420578 for ; Mon, 9 Mar 2020 15:37:22 +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="M3ElGOfW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CB7420578 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]:45146 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jBKT3-0005Ju-9s for qemu-devel@archiver.kernel.org; Mon, 09 Mar 2020 11:37:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36162) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jBKDf-0000CA-SX for qemu-devel@nongnu.org; Mon, 09 Mar 2020 11:21:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jBKDe-0003vs-O2 for qemu-devel@nongnu.org; Mon, 09 Mar 2020 11:21:27 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:54417 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jBKDe-0003va-Kx for qemu-devel@nongnu.org; Mon, 09 Mar 2020 11:21:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583767286; 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=5LbgiGGlJQ3AL4Gec/ApZifD2V3O4x1g104VF59gBMI=; b=M3ElGOfWh0av3ofH0bjUK7F5OB8G+PieauacY4hyTERC3OnfBr5GBkn3/QzOvLHCrmcr3K CArA4Zc6Ny/0l550MLl0VWCfwu1/f5sbCBCM020SJhd5XpwgrN9rB+GOvkgOmlqnyXJm4I ryPfyVUlFXlDl9INIzgnSJwrZSlAmls= 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-143-NVrN1dDSOL2aiJ5ImoulCg-1; Mon, 09 Mar 2020 11:21:22 -0400 X-MC-Unique: NVrN1dDSOL2aiJ5ImoulCg-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id E9982107ACC9; Mon, 9 Mar 2020 15:21:20 +0000 (UTC) Received: from linux.fritz.box (ovpn-116-162.ams2.redhat.com [10.36.116.162]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9744B5C3F8; Mon, 9 Mar 2020 15:21:13 +0000 (UTC) Date: Mon, 9 Mar 2020 16:21:12 +0100 From: Kevin Wolf To: Eric Blake Subject: Re: [PATCH v3 1/4] block: Add trivial backing_fmt support to qcow, sheepdog, vmdk Message-ID: <20200309152112.GC6478@linux.fritz.box> References: <20200306225121.3199279-1-eblake@redhat.com> <20200306225121.3199279-2-eblake@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200306225121.3199279-2-eblake@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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 Zheng , pkrempa@redhat.com, "open list:Sheepdog" , qemu-block@nongnu.org, libvir-list@redhat.com, Michael Tokarev , qemu-devel@nongnu.org, mreitz@redhat.com, "open list:Trivial patches" , Liu Yuan , Laurent Vivier Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 06.03.2020 um 23:51 hat Eric Blake geschrieben: > For qcow2 and qed, we want to encourage the use of -F always, as these > formats can suffer from data corruption or security holes if backing > format is probed. But for other formats, the backing format cannot be > recorded. Making the user decide on a per-format basis whether to > supply a backing format string is awkward, better is to just blindly > accept a backing format argument even if it is ignored by the > contraints of the format at hand. >=20 > Signed-off-by: Eric Blake I'm not sure if I agree with this reasoning. Accepting and silently ignoring -F could give users a false sense of security. If I specify a -F raw and QEMU later probes qcow2, that would be very surprising. Kevin