From: Dave Chinner <david@fromorbit.com>
To: ira.weiny@intel.com
Cc: linux-kernel@vger.kernel.org,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Dan Williams <dan.j.williams@intel.com>,
Christoph Hellwig <hch@lst.de>,
"Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
Jeff Moyer <jmoyer@redhat.com>,
linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH V6 7/8] fs/xfs: Change xfs_ioctl_setattr_dax_invalidate() to xfs_ioctl_dax_check()
Date: Wed, 8 Apr 2020 12:23:18 +1000 [thread overview]
Message-ID: <20200408022318.GJ24067@dread.disaster.area> (raw)
In-Reply-To: <20200407182958.568475-8-ira.weiny@intel.com>
On Tue, Apr 07, 2020 at 11:29:57AM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> We only support changing FS_XFLAG_DAX on directories. Files get their
> flag from the parent directory on creation only. So no data
> invalidation needs to happen.
Which leads me to ask: how are users and/or admins supposed to
remove the flag from regular files once it is set in the filesystem?
Only being able to override the flag via the "dax=never" mount
option means that once the flag is set, nobody can ever remove it
and they can only globally turn off dax if it gets set incorrectly.
It also means a global interrupt because all apps on the filesystem
need to be stopped so the filesystem can be unmounted and mounted
again with dax=never. This is highly unfriendly to admins and users.
IOWs, we _must_ be able to clear this inode flag on regular inodes
in some way. I don't care if it doesn't change the current in-memory
state, but we must be able to clear the flags so that the next time
the inodes are instantiated DAX is not enabled for those files...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-04-08 2:23 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 18:29 [PATCH V6 0/8] Enable per-file/per-directory DAX operations V6 ira.weiny
2020-04-07 18:29 ` [PATCH V6 1/8] fs/xfs: Remove unnecessary initialization of i_rwsem ira.weiny
2020-04-07 23:46 ` Dave Chinner
2020-04-07 18:29 ` [PATCH V6 2/8] fs: Remove unneeded IS_DAX() check ira.weiny
2020-04-09 7:31 ` Christoph Hellwig
2020-04-09 14:57 ` Ira Weiny
2020-04-07 18:29 ` [PATCH V6 3/8] fs/stat: Define DAX statx attribute ira.weiny
2020-04-07 23:47 ` Dave Chinner
2020-04-07 18:29 ` [PATCH V6 4/8] fs/xfs: Make DAX mount option a tri-state ira.weiny
2020-04-07 23:59 ` Dave Chinner
2020-04-08 0:09 ` Ira Weiny
2020-04-08 0:48 ` Dave Chinner
2020-04-09 15:03 ` Ira Weiny
2020-04-07 18:29 ` [PATCH V6 5/8] fs/xfs: Create function xfs_inode_enable_dax() ira.weiny
2020-04-08 0:05 ` Dave Chinner
2020-04-08 0:13 ` Ira Weiny
2020-04-07 18:29 ` [PATCH V6 6/8] fs/xfs: Combine xfs_diflags_to_linux() and xfs_diflags_to_iflags() ira.weiny
2020-04-08 2:08 ` Dave Chinner
2020-04-08 17:09 ` Ira Weiny
2020-04-08 21:02 ` Dave Chinner
2020-04-08 21:28 ` Dan Williams
2020-04-08 22:10 ` Ira Weiny
2020-04-08 23:58 ` Dave Chinner
2020-04-09 0:22 ` Ira Weiny
2020-04-09 12:41 ` Christoph Hellwig
2020-04-09 20:49 ` Ira Weiny
2020-04-08 22:07 ` Ira Weiny
2020-04-08 23:21 ` Dave Chinner
2020-04-09 0:12 ` Ira Weiny
2020-04-09 0:30 ` Darrick J. Wong
2020-04-09 15:29 ` Ira Weiny
2020-04-09 16:59 ` Darrick J. Wong
2020-04-09 17:17 ` Jan Kara
2020-04-09 20:54 ` Ira Weiny
2020-04-09 0:49 ` Dave Chinner
2020-04-09 12:40 ` Christoph Hellwig
2020-04-10 0:27 ` Dave Chinner
2020-04-07 18:29 ` [PATCH V6 7/8] fs/xfs: Change xfs_ioctl_setattr_dax_invalidate() to xfs_ioctl_dax_check() ira.weiny
2020-04-08 2:23 ` Dave Chinner [this message]
2020-04-08 9:58 ` Jan Kara
2020-04-08 21:09 ` Dave Chinner
2020-04-08 22:26 ` Ira Weiny
2020-04-08 23:48 ` Dave Chinner
2020-04-09 12:28 ` Christoph Hellwig
2020-04-08 15:37 ` Darrick J. Wong
2020-04-08 18:13 ` Ira Weiny
2020-04-16 5:39 ` [fs/xfs] 857c9841f8: xfstests.xfs.046.fail kernel test robot
2020-04-07 18:29 ` [PATCH V6 8/8] Documentation/dax: Update Usage section ira.weiny
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