Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC: r268115
Merge the NFSv4.1 server code in projects/nfsv4.1-server over
into head. The code is not believed to have any effect
on the semantics of non-NFSv4.1 server behaviour.
It is a rather large merge, but I am hoping that there will
not be any regressions for the NFS server.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Move the NFSv4.1 client patches over from projects/nfsv4.1-client
to head. I don't think the NFS client behaviour will change unless
the new "minorversion=1" mount option is used. It includes basic
NFSv4.1 support plus support for pNFS using the Files Layout only.
All problems detecting during an NFSv4.1 Bakeathon testing event
in June 2012 have been resolved in this code and it has been tested
against the NFSv4.1 server available to me.
Although not reviewed, I believe that kib@ has looked at it.

Fix the new NFSv4 client so that it doesn't fill the cached
mode attribute in as 0 when doing writes. The change adds
the Mode attribute plus the others except Owner and Owner_group
to the list requested by the NFSv4 Write Operation. This fixed
a problem where an executable file built by "cc" would get mode
0111 instead of 0755 for some NFSv4 servers.
Found at the recent NFSv4 interoperability Bakeathon.

Tested by: tdh at excfb.com
MFC after: 2 weeks

Add DTrace support to the new NFS client. This is essentially
cloned from the old NFS client, plus additions for NFSv4. A
review of this code is in progress, however it was felt by the
reviewer that it could go in now, before code slush. Any changes
required by the review can be committed as bug fixes later.

Add a comment noting that the NFS code assumes that the
values of error numbers in sys/errno.h will be the same
as the ones specified by the NFS RFCs and that the code
needs to be fixed if error numbers are changed in sys/errno.h.

Suggested by: Peter Jeremy
MFC after: 2 weeks

Move the nfsstat structure and proc/op number definitions on the
experimental nfs subsystem from sys/fs/nfs/nfs.h and sys/fs/nfs/nfsproto.h
to sys/fs/nfs/nfsport.h and rename nfsstat to ext_nfsstat. This was done
so that src/usr.bin/nfsstat.c could use it alongside the regular nfs
include files and struct nfsstat.

Approved by: kib (mentor)

Add the experimental nfs subtree to the kernel, that includes
support for NFSv4 as well as NFSv2 and 3.
It lives in 3 subdirs under sys/fs:
nfs - functions that are common to the client and server
nfsclient - a mutation of sys/nfsclient that call generic functions
to do RPCs and handle state. As such, it retains the
buffer cache handling characteristics and vnode semantics that
are found in sys/nfsclient, for the most part.
nfsserver - the server. It includes a DRC designed specifically for
NFSv4, that is used instead of the generic DRC in sys/rpc.
The build glue will be checked in later, so at this point, it
consists of 3 new subdirs that should not affect kernel building.

Approved by: kib (mentor)