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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 BE1CBC4361B for ; Fri, 11 Dec 2020 19:41:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C3B923D5A for ; Fri, 11 Dec 2020 19:41:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392543AbgLKSEc (ORCPT ); Fri, 11 Dec 2020 13:04:32 -0500 Received: from mx2.suse.de ([195.135.220.15]:45346 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390628AbgLKSET (ORCPT ); Fri, 11 Dec 2020 13:04:19 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C087DAE4A; Fri, 11 Dec 2020 18:03:37 +0000 (UTC) Subject: Re: [PATCH 0/3] block: blk_interposer - Block Layer Interposer To: Jens Axboe , Mike Snitzer , Sergei Shtepa , hch@lst.de Cc: "johannes.thumshirn@wdc.com" , "koct9i@gmail.com" , "ming.lei@redhat.com" , "josef@toxicpanda.com" , "steve@sk2.org" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Pavel Tide , dm-devel@redhat.com References: <1607518911-30692-1-git-send-email-sergei.shtepa@veeam.com> <20201209135148.GA32720@redhat.com> <20201210145814.GA31521@veeam.com> <20201210163222.GB10239@redhat.com> <20201211163049.GC16168@redhat.com> <1ee7652e-b77f-6fa4-634c-ff6639037321@kernel.dk> <208edf35-ecdc-2d73-4c48-0424943a78c0@suse.de> <06b4a10d-5ea5-27e1-af0d-83d5c714996f@kernel.dk> From: Hannes Reinecke Message-ID: Date: Fri, 11 Dec 2020 19:03:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <06b4a10d-5ea5-27e1-af0d-83d5c714996f@kernel.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/11/20 6:04 PM, Jens Axboe wrote: > On 12/11/20 9:56 AM, Hannes Reinecke wrote: >> On 12/11/20 5:33 PM, Jens Axboe wrote: >>> On 12/11/20 9:30 AM, Mike Snitzer wrote: >>>> While I still think there needs to be a proper _upstream_ consumer of >>>> blk_interposer as a condition of it going in.. I'll let others make the >>>> call. >>> >>> That's an unequivocal rule. >>> >>>> As such, I'll defer to Jens, Christoph and others on whether your >>>> minimalist blk_interposer hook is acceptable in the near-term. >>> >>> I don't think so, we don't do short term bandaids just to plan on >>> ripping that out when the real functionality is there. IMHO, the dm >>> approach is the way to go - it provides exactly the functionality that >>> is needed in an appropriate way, instead of hacking some "interposer" >>> into the core block layer. >>> >> Which is my plan, too. >> >> I'll be working with the Veeam folks to present a joint patchset >> (including the DM bits) for the next round. > > Just to be clear, core block additions for something that dm will > consume is obviously fine. Adding this as block layer functionality than > then exposes an application API for setting it up, tearing down, etc - > that is definitely NOT > That was never my intention. Any consumers of this thing would need to be in-kernel. If that was your concern. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer