Extended attributes and their particular implementation in linux are
different from FreeBSD so in this case we have started diverging from
the UFS EA implementation, which would be the natural reference.
Depending on future progress implementing ACLs this approach may change
but for now bring to the tree an implementation that is consistent and
can be tested.
Submitted by: Fedor Uporov
Differential Revision: https://reviews.freebsd.org/D10460