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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 666C7C38A2B for ; Fri, 17 Apr 2020 16:04:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42B6B20771 for ; Fri, 17 Apr 2020 16:04:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729717AbgDQQEX (ORCPT ); Fri, 17 Apr 2020 12:04:23 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:54003 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729704AbgDQQEX (ORCPT ); Fri, 17 Apr 2020 12:04:23 -0400 Received: from callcc.thunk.org (pool-100-0-195-244.bstnma.fios.verizon.net [100.0.195.244]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 03HG3Q4N001660 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 Apr 2020 12:03:27 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 3F88342013D; Fri, 17 Apr 2020 12:03:26 -0400 (EDT) Date: Fri, 17 Apr 2020 12:03:26 -0400 From: "Theodore Y. Ts'o" To: Johannes Thumshirn Cc: Jens Axboe , Christoph Hellwig , linux-block , Damien Le Moal , Keith Busch , "linux-scsi @ vger . kernel . org" , "Martin K . Petersen" , "linux-fsdevel @ vger . kernel . org" , Daniel Wagner Subject: Re: [PATCH v7 00/11] Introduce Zone Append for writing to zoned block devices Message-ID: <20200417160326.GK5187@mit.edu> References: <20200417121536.5393-1-johannes.thumshirn@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200417121536.5393-1-johannes.thumshirn@wdc.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Apr 17, 2020 at 09:15:25PM +0900, Johannes Thumshirn wrote: > The upcoming NVMe ZNS Specification will define a new type of write > command for zoned block devices, zone append. > > When when writing to a zoned block device using zone append, the start > sector of the write is pointing at the start LBA of the zone to write to. > Upon completion the block device will respond with the position the data > has been placed in the zone. This from a high level perspective can be > seen like a file system's block allocator, where the user writes to a > file and the file-system takes care of the data placement on the device. What sort of reordering can take place due to I/O schedulers and or racing write appends from different CPU's? Is it purely the userspace's responsibility to avoid racings writes to a particular zone? - Ted