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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6B69BC433EF for ; Wed, 20 Apr 2022 05:36:45 +0000 (UTC) Received: from localhost ([::1]:53366 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nh31A-0002Px-DK for qemu-devel@archiver.kernel.org; Wed, 20 Apr 2022 01:36:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59484) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nh2yF-0000W4-Mv; Wed, 20 Apr 2022 01:33:43 -0400 Received: from verein.lst.de ([213.95.11.211]:41938) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nh2yE-0001gY-Bv; Wed, 20 Apr 2022 01:33:43 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 9154B68D06; Wed, 20 Apr 2022 07:33:37 +0200 (CEST) Date: Wed, 20 Apr 2022 07:33:36 +0200 From: Christoph Hellwig To: Klaus Jensen Subject: Re: [PATCH 4/5] hw/nvme: do not auto-generate uuid Message-ID: <20220420053336.GA2063@lst.de> References: <20220419121039.1259477-1-its@irrelevant.dk> <20220419121039.1259477-5-its@irrelevant.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220419121039.1259477-5-its@irrelevant.dk> User-Agent: Mutt/1.5.17 (2007-11-01) Received-SPF: none client-ip=213.95.11.211; envelope-from=hch@lst.de; helo=verein.lst.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_NONE=0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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: qemu-block@nongnu.org, Klaus Jensen , qemu-devel@nongnu.org, Luis Chamberlain , Keith Busch , Christoph Hellwig Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Apr 19, 2022 at 02:10:38PM +0200, Klaus Jensen wrote: > From: Klaus Jensen > > Do not default to generate an UUID for namespaces if it is not > explicitly specified. > > This is a technically a breaking change in behavior. However, since the > UUID changes on every VM launch, it is not spec compliant and is of > little use since the UUID cannot be used reliably anyway and the > behavior prior to this patch must be considered buggy. So unlike the EUI, UUIDs are designed to be autogenerated even if the current algorithm is completely broken. We'd just need to persist them. Note that NVMe at least in theory requires providing at least on of the unique identifiers, and the UUID is the only one designed to be autogenerated in a distributed fashion.