[PATCH 3/3] xfs: introduce per-inode DAX enablement

[Theodore Ts'o]

On Mon, Jan 04, 2016 at 04:54:52PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> Rather than just being able to turn DAX on and off via a mount
> option, some applications may only want to enable DAX for certain
> performance critical files in a filesystem.
> 
> This patch introduces a new inode flag to enable DAX in the v3 inode
> di_flags2 field. It adds support for setting and clearing flags in
> the di_flags2 field via the XFS_IOC_FSSETXATTR ioctl, and sets the
> S_DAX inode flag appropriately when it is seen.
> 
> When this flag is set on a directory, it acts as an "inherit flag".
> That is, inodes created in the directory will automatically inherit
> the on-disk inode DAX flag, enabling administrators to set up
> directory heirarchies that automatically use DAX. Setting this flag
> on an empty root directory will make the entire filesystem use DAX
> by default.
> 
> Signed-off-by: Dave Chinner <dchinner at redhat.com>

Looks good to me.

Reviewed-by: Theodore Ts'o <tytso at mit.edu>

							- Ted