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Date:   Wed, 15 Apr 2020 08:41:44 -0700
From:   "Darrick J. Wong" <darrick.wong@oracle.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc:     Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
        Jan Kara <jack@suse.com>, linux-ext4@vger.kernel.org,
        ira.weiny@intel.com
Subject: Re: [PATCH 12/34] docs: filesystems: convert dax.txt to ReST
Message-ID: <20200415154144.GA6733@magnolia>
References: <cover.1586960617.git.mchehab+huawei@kernel.org>
 <71b1f910b2c3569a9fdaa8778378dd734f4f0091.1586960617.git.mchehab+huawei@kernel.org>
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[add ira weiny to cc]

On Wed, Apr 15, 2020 at 04:32:25PM +0200, Mauro Carvalho Chehab wrote:
> - Add a SPDX header;
> - Adjust document title;
> - Some whitespace fixes and new line breaks;
> - Add it to filesystems/index.rst.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
>  Documentation/admin-guide/ext4.rst             | 2 +-
>  Documentation/filesystems/{dax.txt => dax.rst} | 9 +++++++--
>  Documentation/filesystems/ext2.rst             | 2 +-
>  Documentation/filesystems/index.rst            | 1 +
>  4 files changed, 10 insertions(+), 4 deletions(-)
>  rename Documentation/filesystems/{dax.txt => dax.rst} (97%)
> 
> diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst
> index 9443fcef1876..103bcc345bad 100644
> --- a/Documentation/admin-guide/ext4.rst
> +++ b/Documentation/admin-guide/ext4.rst
> @@ -392,7 +392,7 @@ When mounting an ext4 filesystem, the following option are accepted:
>  
>    dax
>          Use direct access (no page cache).  See
> -        Documentation/filesystems/dax.txt.  Note that this option is
> +        Documentation/filesystems/dax.rst.  Note that this option is
>          incompatible with data=journal.
>  
>  Data Mode
> diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.rst
> similarity index 97%
> rename from Documentation/filesystems/dax.txt
> rename to Documentation/filesystems/dax.rst
> index 735f3859b19f..5838144f80f0 100644
> --- a/Documentation/filesystems/dax.txt
> +++ b/Documentation/filesystems/dax.rst

Err, this will collide with the work that Ira's doing on DAX for 5.8[1].
Can the dax.txt conversion wait?

--D

[1] https://lore.kernel.org/linux-xfs/20200415152942.GS6742@magnolia/T/#m804562299416d865d8829caa82589a522b2080a5

> @@ -1,5 +1,8 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=======================
>  Direct Access for files
> ------------------------
> +=======================
>  
>  Motivation
>  ----------
> @@ -46,6 +49,7 @@ stall the CPU for an extended period, you should also not attempt to
>  implement direct_access.
>  
>  These block devices may be used for inspiration:
> +
>  - brd: RAM backed block device driver
>  - dcssblk: s390 dcss block device driver
>  - pmem: NVDIMM persistent memory driver
> @@ -55,6 +59,7 @@ Implementation Tips for Filesystem Writers
>  ------------------------------------------
>  
>  Filesystem support consists of
> +
>  - adding support to mark inodes as being DAX by setting the S_DAX flag in
>    i_flags
>  - implementing ->read_iter and ->write_iter operations which use dax_iomap_rw()
> @@ -127,6 +132,6 @@ by adding optional struct page support for pages under the control of
>  the driver (see CONFIG_NVDIMM_PFN in drivers/nvdimm for an example of
>  how to do this). In the non struct page cases O_DIRECT reads/writes to
>  those memory ranges from a non-DAX file will fail (note that O_DIRECT
> -reads/writes _of a DAX file_ do work, it is the memory that is being
> +reads/writes _of a DAX ``file_`` do work, it is the memory that is being
>  accessed that is key here).  Other things that will not work in the
>  non struct page case include RDMA, sendfile() and splice().
> diff --git a/Documentation/filesystems/ext2.rst b/Documentation/filesystems/ext2.rst
> index d83dbbb162e2..fa416b7a5802 100644
> --- a/Documentation/filesystems/ext2.rst
> +++ b/Documentation/filesystems/ext2.rst
> @@ -24,7 +24,7 @@ check=none, nocheck	(*)	Don't do extra checking of bitmaps on mount
>  				(check=normal and check=strict options removed)
>  
>  dax				Use direct access (no page cache).  See
> -				Documentation/filesystems/dax.txt.
> +				Documentation/filesystems/dax.rst.
>  
>  debug				Extra debugging information is sent to the
>  				kernel syslog.  Useful for developers.
> diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
> index c4f95f76ba6a..8e3ccb4ed483 100644
> --- a/Documentation/filesystems/index.rst
> +++ b/Documentation/filesystems/index.rst
> @@ -24,6 +24,7 @@ algorithms work.
>     splice
>     locking
>     directory-locking
> +   dax
>  
>     automount-support
>  
> -- 
> 2.25.2
>