From: Jan Kara <jack@suse.cz>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@lst.de>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Dave Chinner <david@fromorbit.com>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Dan Williams <dan.j.williams@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH V5 00/12] Enable per-file/per-directory DAX operations V5
Date: Mon, 6 Apr 2020 12:00:05 +0200 [thread overview]
Message-ID: <20200406100005.GB1143@quack2.suse.cz> (raw)
In-Reply-To: <20200403181843.GK3952565@iweiny-DESK2.sc.intel.com>
On Fri 03-04-20 11:18:43, Ira Weiny wrote:
> Ok For 5.8 why don't we not allow FS_XFLAG_DAX to be changed on files _at_
> _all_...
>
> In summary:
>
> - Applications must call statx to discover the current S_DAX state.
>
> - There exists an advisory file inode flag FS_XFLAG_DAX that is set based on
> the parent directory FS_XFLAG_DAX inode flag. (There is no way to change
> this flag after file creation.)
>
> If FS_XFLAG_DAX is set and the fs is on pmem then it will enable S_DAX at
> inode load time; if FS_XFLAG_DAX is not set, it will not enable S_DAX.
> Unless overridden...
OK, after considering all the options we were hashing out here, I think
this is the best API. There isn't the confusing "S_DAX will magically
switch on inode eviction" and although the functionality is limited, I
think 90% of users would end up using the functionality like this anyway.
> - There exists a dax= mount option.
>
> "-o dax=off" means "never set S_DAX, ignore FS_XFLAG_DAX"
> "-o nodax" means "dax=off"
> "-o dax=always" means "always set S_DAX (at least on pmem), ignore FS_XFLAG_DAX"
> "-o dax" by itself means "dax=always"
> "-o dax=iflag" means "follow FS_XFLAG_DAX" and is the default
>
> - There exists an advisory directory inode flag FS_XFLAG_DAX that can be
> changed at any time. The flag state is copied into any files or
> subdirectories when they are created within that directory. If programs
> require file access runs in S_DAX mode, they'll have to create those files
> inside a directory with FS_XFLAG_DAX set, or mount the fs with an
> appropriate dax mount option.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-04-06 10:00 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-27 5:24 [PATCH V5 00/12] Enable per-file/per-directory DAX operations V5 ira.weiny
2020-02-27 5:24 ` [PATCH V5 01/12] fs/xfs: Remove unnecessary initialization of i_rwsem ira.weiny
2020-02-27 17:25 ` Ira Weiny
2020-02-27 5:24 ` [PATCH V5 02/12] fs: Remove unneeded IS_DAX() check ira.weiny
2020-02-27 5:24 ` [PATCH V5 03/12] fs/stat: Define DAX statx attribute ira.weiny
2020-02-27 5:24 ` [PATCH V5 04/12] fs/xfs: Isolate the physical DAX flag from enabled ira.weiny
2020-02-27 5:24 ` [PATCH V5 05/12] fs/xfs: Create function xfs_inode_enable_dax() ira.weiny
2020-03-01 22:37 ` Dave Chinner
2020-02-27 5:24 ` [PATCH V5 06/12] fs: Add locking for a dynamic address space operations state ira.weiny
2020-03-02 1:26 ` Dave Chinner
2020-03-02 1:36 ` Dave Chinner
2020-02-27 5:24 ` [PATCH V5 07/12] fs: Prevent DAX state change if file is mmap'ed ira.weiny
2020-02-27 5:24 ` [PATCH V5 08/12] fs/xfs: Hold off aops users while changing DAX state ira.weiny
2020-02-27 5:24 ` [PATCH V5 09/12] fs/xfs: Clean up locking in dax invalidate ira.weiny
2020-02-27 5:24 ` [PATCH V5 10/12] fs/xfs: Allow toggle of effective DAX flag ira.weiny
2020-02-27 5:24 ` [PATCH V5 11/12] fs/xfs: Remove xfs_diflags_to_linux() ira.weiny
2020-02-27 5:24 ` [PATCH V5 12/12] Documentation/dax: Update Usage section ira.weiny
2020-03-05 15:51 ` [PATCH V5 00/12] Enable per-file/per-directory DAX operations V5 Christoph Hellwig
2020-03-09 17:04 ` Ira Weiny
2020-03-11 3:36 ` Darrick J. Wong
2020-03-11 6:29 ` Christoph Hellwig
2020-03-11 17:07 ` Dan Williams
2020-03-16 9:52 ` Jan Kara
2020-03-16 9:55 ` Christoph Hellwig
2020-04-01 4:00 ` Darrick J. Wong
2020-04-01 10:25 ` Jan Kara
2020-04-02 8:53 ` Christoph Hellwig
2020-04-02 20:55 ` Ira Weiny
2020-04-03 7:27 ` Christoph Hellwig
2020-04-03 15:48 ` Ira Weiny
2020-04-03 17:03 ` Jan Kara
2020-04-03 18:18 ` Ira Weiny
2020-04-03 18:21 ` Ira Weiny
2020-04-03 18:37 ` Darrick J. Wong
2020-04-05 6:19 ` Ira Weiny
2020-04-06 10:00 ` Jan Kara [this message]
2020-04-03 18:29 ` Darrick J. Wong
2020-04-03 16:05 ` Darrick J. Wong
2020-04-03 4:39 ` Ira Weiny
2020-03-11 6:39 ` Dave Chinner
2020-03-11 6:44 ` Christoph Hellwig
2020-03-11 17:07 ` Dan Williams
2020-03-12 0:49 ` Dave Chinner
2020-03-12 3:00 ` Darrick J. Wong
2020-03-12 7:27 ` Christoph Hellwig
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