Other than the name, if "reflink(..., REFLINK_ATTR_NONE)" does the equivalent
as a standard unprivileged file copy, I think this is a great addition.
I don't know why one would extend the "ln" command however, when the
semantics of all modes of operation are essentially variations on "cp".
"reflink" really ought to be renamed accordingly for the same reason - from a
user perspective there is no link of any kind - it is just a space and time
efficient file copy.