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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 73885C0044D for ; Thu, 12 Mar 2020 00:49:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84E872075F for ; Thu, 12 Mar 2020 00:49:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731620AbgCLAtj (ORCPT ); Wed, 11 Mar 2020 20:49:39 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:50920 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731423AbgCLAti (ORCPT ); Wed, 11 Mar 2020 20:49:38 -0400 Received: from dread.disaster.area (pa49-195-202-68.pa.nsw.optusnet.com.au [49.195.202.68]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 764693A2A95; Thu, 12 Mar 2020 11:49:33 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1jCC2W-0005cM-1s; Thu, 12 Mar 2020 11:49:32 +1100 Date: Thu, 12 Mar 2020 11:49:32 +1100 From: Dave Chinner To: Christoph Hellwig Cc: "Darrick J. Wong" , Ira Weiny , linux-kernel@vger.kernel.org, Alexander Viro , Dan Williams , "Theodore Y. Ts'o" , Jan Kara , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org Subject: Re: [PATCH V5 00/12] Enable per-file/per-directory DAX operations V5 Message-ID: <20200312004932.GH10776@dread.disaster.area> References: <20200227052442.22524-1-ira.weiny@intel.com> <20200305155144.GA5598@lst.de> <20200309170437.GA271052@iweiny-DESK2.sc.intel.com> <20200311033614.GQ1752567@magnolia> <20200311063942.GE10776@dread.disaster.area> <20200311064412.GA11819@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200311064412.GA11819@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=X6os11be c=1 sm=1 tr=0 a=mqTaRPt+QsUAtUurwE173Q==:117 a=mqTaRPt+QsUAtUurwE173Q==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=SS2py6AdgQ4A:10 a=7-415B0cAAAA:8 a=AbD9mO_pjJUxJnZMvogA:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 11, 2020 at 07:44:12AM +0100, Christoph Hellwig wrote: > On Wed, Mar 11, 2020 at 05:39:42PM +1100, Dave Chinner wrote: > > IOWs, the dax_associate_page() related functionality probably needs > > to be a filesystem callout - part of the aops vector, I think, so > > that device dax can still use it. That way XFS can go it's own way, > > while ext4 and device dax can continue to use the existing mechanism > > mechanisn that is currently implemented.... > > s/XFS/XFS with rmap/, as most XFS file systems currently don't have > that enabled we'll also need to keep the legacy path around. Sure, that's trivially easy to handle in the XFS code once the callouts are in place. But, quite frankly, we can enforce rmap to be enabled enabled because nobody is using a reflink enabled FS w/ DAX right now. Everyone will have to mkfs their filesystems anyway to enable reflink+dax, so we simply don't allow reflink+dax to be enabled unless rmap is also enabled. Simple, easy, trivial. Cheers, Dave. -- Dave Chinner david@fromorbit.com