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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 56981C2BB1D for ; Tue, 14 Apr 2020 05:12:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F18120678 for ; Tue, 14 Apr 2020 05:12:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="wDyM6KBF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405421AbgDNFMm (ORCPT ); Tue, 14 Apr 2020 01:12:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2405411AbgDNFMf (ORCPT ); Tue, 14 Apr 2020 01:12:35 -0400 Received: from mail-ed1-x544.google.com (mail-ed1-x544.google.com [IPv6:2a00:1450:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CCCEC008749 for ; Mon, 13 Apr 2020 22:12:34 -0700 (PDT) Received: by mail-ed1-x544.google.com with SMTP id m12so15305366edl.12 for ; Mon, 13 Apr 2020 22:12:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lCKH9//GDUVyra9MYbJtXuz/rft75HC1YdEpud3oR/w=; b=wDyM6KBFKLlwwTmGUBwUr0f9mEfcZL3MHRC2qD1g8Ri5hzXZNb/yzQj6Pr/ZKsOXDZ i8o1+jiGMZA6uHKUntfBZb+bIsOtO7+1LBUceyEI8O/0tAVI4147/8qj5VnTkwYpzp8p OQwtvf3E1orMQsMGR1mGI4iaBrR52m55wkk2YuddOwJVzEJip2u4dKD8u1dHNHC44qyf 0p6BxMnrbJM4Vt58Ih9rpAxyb+KxIbYh8GXtZEX5seabEA+alTbGBBCsUbEbv7tMGQbY 5acT+NDRcEvCOXYhXjXmABnXdzSRCoer0XRx9DXEbsWcR75NMcPPUrLZjCNRkAkFZcJR U5gQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lCKH9//GDUVyra9MYbJtXuz/rft75HC1YdEpud3oR/w=; b=ZiPoox7LsAwiZDJ3S4r6jDZ7RHhZvkl5InJkhnTb3iCJGcsLp7502ZQdAPU17MkvrV IUQrPjRhEKxGodPPAzeKSrSYm9oDwzL7C+2K4NCvYkPsnc/BIsWtvsjAxOtaUHPEmo1D kJ9PEhoGYbaQ4Ndj5/e/lnvOFNYl35/F8X4QXe6GAiTV5AsIxWhSvGON39s5F97bfI0M WKVj/LlGNH8yHVtK2f+xgJLjDTCLEn00DHwuCVczcjjfyuhWJkx61fl8SLwNuToAZhHK EW/dcRnVNnbOzdM9TaaVi0UwBmKPRYIq90hnxWCve8pejBPyoFSVPFeuEi1XgypdXehF 6wOA== X-Gm-Message-State: AGi0PuYlXQW2mnXYlR6zxtdwc2ae4v96YckK/5ZXO1kK4gQmp/Zil5Nf Q44YFxKyl/uxBwKO7dAc37xPhNbtPdY7wLKwk+PasA== X-Google-Smtp-Source: APiQypKjvu1zmWD35TkvQGGIPcBAQQsVLki0XXXLdYacZXLIP+W15lBvsYFcPXTdJ4zV8Nr44sratkgYZ4gJIezi0ik= X-Received: by 2002:a17:906:1e42:: with SMTP id i2mr18225259ejj.317.1586841153456; Mon, 13 Apr 2020 22:12:33 -0700 (PDT) MIME-Version: 1.0 References: <20200413054046.1560106-1-ira.weiny@intel.com> <20200413054046.1560106-10-ira.weiny@intel.com> <20200413161912.GZ6742@magnolia> <20200414043821.GG1649878@iweiny-DESK2.sc.intel.com> In-Reply-To: <20200414043821.GG1649878@iweiny-DESK2.sc.intel.com> From: Dan Williams Date: Mon, 13 Apr 2020 22:12:22 -0700 Message-ID: Subject: Re: [PATCH V7 9/9] Documentation/dax: Update Usage section To: Ira Weiny Cc: "Darrick J. Wong" , Linux Kernel Mailing List , Dave Chinner , Christoph Hellwig , "Theodore Y. Ts'o" , Jan Kara , Jeff Moyer , linux-ext4 , linux-xfs , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 13, 2020 at 9:38 PM Ira Weiny wrote: > > On Mon, Apr 13, 2020 at 09:19:12AM -0700, Darrick J. Wong wrote: > > On Sun, Apr 12, 2020 at 10:40:46PM -0700, ira.weiny@intel.com wrote: > > > From: Ira Weiny > > > > > > Update the Usage section to reflect the new individual dax selection > > > functionality. > > > > Yum. :) > > > > > Signed-off-by: Ira Weiny > > > > > > --- > > > Changes from V6: > > > Update to allow setting FS_XFLAG_DAX any time. > > > Update with list of behaviors from Darrick > > > https://lore.kernel.org/lkml/20200409165927.GD6741@magnolia/ > > > > > > Changes from V5: > > > Update to reflect the agreed upon semantics > > > https://lore.kernel.org/lkml/20200405061945.GA94792@iweiny-DESK2.sc.intel.com/ > > > --- > > > Documentation/filesystems/dax.txt | 166 +++++++++++++++++++++++++++++- > > > 1 file changed, 163 insertions(+), 3 deletions(-) > > > > > > diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt > > > index 679729442fd2..af14c1b330a9 100644 > > > --- a/Documentation/filesystems/dax.txt > > > +++ b/Documentation/filesystems/dax.txt > > > @@ -17,11 +17,171 @@ For file mappings, the storage device is mapped directly into userspace. > > > Usage > > > ----- > > > > > > -If you have a block device which supports DAX, you can make a filesystem > > > +If you have a block device which supports DAX, you can make a file system > > > on it as usual. The DAX code currently only supports files with a block > > > size equal to your kernel's PAGE_SIZE, so you may need to specify a block > > > -size when creating the filesystem. When mounting it, use the "-o dax" > > > -option on the command line or add 'dax' to the options in /etc/fstab. > > > +size when creating the file system. > > > + > > > +Currently 2 filesystems support DAX, ext4 and xfs. Enabling DAX on them is > > > +different at this time. > > > > I thought ext2 supports DAX? > > Not that I know of? Does it? Yes. Seemed like a good idea at the time, but in retrospect... In fairness I believe this was also an olive branch to XIP users that were transitioned to DAX, so they did not also need to transition filesystems.