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=-2.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B08DCC04AAF for ; Thu, 9 May 2019 03:31:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81EE22173E for ; Thu, 9 May 2019 03:31:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726281AbfEIDbc (ORCPT ); Wed, 8 May 2019 23:31:32 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:34381 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726109AbfEIDbc (ORCPT ); Wed, 8 May 2019 23:31:32 -0400 Received: from callcc.thunk.org ([66.31.38.53]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x493V03d014929 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 8 May 2019 23:31:01 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 2CA6F420024; Wed, 8 May 2019 23:31:00 -0400 (EDT) Date: Wed, 8 May 2019 23:31:00 -0400 From: "Theodore Ts'o" To: Dave Chinner Cc: Amir Goldstein , Vijay Chidambaram , lsf-pc@lists.linux-foundation.org, "Darrick J. Wong" , Jan Kara , linux-fsdevel , Jayashree Mohan , Filipe Manana , Chris Mason , lwn@lwn.net Subject: Re: [TOPIC] Extending the filesystem crash recovery guaranties contract Message-ID: <20190509033100.GB29703@mit.edu> References: <20190503023043.GB23724@mit.edu> <20190509014327.GT1454@dread.disaster.area> <20190509022013.GC7031@mit.edu> <20190509025845.GV1454@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190509025845.GV1454@dread.disaster.area> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, May 09, 2019 at 12:58:45PM +1000, Dave Chinner wrote: > > SOMC does not defining crash consistency rules - it defines change > dependecies and how ordering and atomicity impact the dependency > graph. How other people have interpreted that is out of my control. Fine; but it's a specific set of the crash consistency rules which I'm objecting to; it's not a promise that I think I want to make. (And before you blindly sign on the bottom line, I'd suggest that you read it very carefully before deciding whether you want to agree to those consistency rules as something that XFS will have honor forever. The way I read it, it's goes beyond what you've articulated as SOMC.) > A new syscall with essentially the same user interface doesn't > guarantee that these implementation problems will be solved. Well, it makes it easier to send all of the requests to the file system in a single bundle. I'd also argue that it's simpler and easier for an application to use a fsync2() interface as I sketched out than trying to use the whole AIO or io_uring machinery. > So it's essentially identical to the AIO_FSYNC interface, except > that it is synchronous. Pretty much, yes. > Sheesh! Did LSFMM include a free lobotomy for participants, or > something? Well, we missed your presence, alas. No doubt your attendance would have improved the discussion. Cheers, - Ted