reflink support and Samba running over XFS

[Steve French]

I noticed that reflink (FSCTL_DUPLICATE_EXTENTS) is not supported on
Samba when run over XFS but is with the vfs_btrfs.

I can do reflink locally on the XFS mount point, but not remotely
unless it is BTRFS (or to Windows eg. when the share is on REFS).

Any idea if there is a way to enable reflink (FSCTL_DUPLICATE_EXTENT)
support for Samba when not running on btrfs (e.g. on xfs)?

duplicate extents is needed for various Linux client features
(especially various fallocate operations)

-- 
Thanks,

Steve