pNFS server code merge into head/current

Hi,

There is a source tree in svn at projects/pnfs-planb-server which adds support
for configuring a single Metadata Server (MDS) and multiple Data Servers (DS)
to create a simple pNFS service. (In a pNFS server the Read/Write operations
are separated from the rest of the metadata operations and go directly from the
NFSv4.1 client to the DS, since that is where the fils's data resides.)
The service does support mirrored DSs, but the recovery code for handling
a failed DS is not done yet. I plan on working on that during Winter 2018.

The current implementation seems to be working ok for my testing. Any third
party testing would be appreciated. The basic information on how it works and
how to set up a pNFS service is at
http://people.freebsd.org/~rmacklem/pnfs-planb-setup.txt
(John Hixon is working on porting/testing it in FreeNAS, but hasn't quite had
 to time get all set up yet.)

The big question is???
If/when this code should go into head/current?
I cannot do commits during Winter 2018, so if it is going to happen before
April 2018, I need to do it in December. I know a release schedule has not been
worked out for FreeBSD12, but is April 2018 early enough or should it be done
this December?

The merge is large, but should not affect non-pNFS NFS service, rick