[pnfs] Some small changes and a byte order bug fix

[iyer at netapp.com]

Hi All,
Please take a look at these patches. They contain some minor changes like a Kconfig entry for experimental nfsv4.1 support, shutting down the v4.0 callback server if we're not using v4.0 and Benny's suggested fix.

The bug fix is a byte order bug in the reading of the call/reply flag
Thanks
Rahul

Summary
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 fs/Kconfig            |   23 +++++++++++++++++++++++
 fs/nfs/super.c        |   11 ++++++++++-
 net/sunrpc/xprtsock.c |   14 +++++++++-----
 3 files changed, 42 insertions(+), 6 deletions(-)

Patch Description
-----------------

[PATCH 1/5] Fixed the record length check as per Benny's comment


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[PATCH 2/5] Added comment reminding me to add a an ifdef

Added a comment in xs_tcp_read_request to add an ifdef so that the v4.1
callback code is eliminated from earlier nfs versions

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[PATCH 3/5] Added v4.1 defines to the Kconfig

Added NFS_V4_1 and NFSD_V4_1 to fs/Kconfig

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[PATCH 4/5] Shut down the v4 style callback server for v4.1

This patch shuts down the v4.1 server in case the mount is a v4.1 mount. If
it's a v4 mount, nothing changes.

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[PATCH 5/5] Fix byte order bug in xs_tcp_read_request

Fixed a bug in xs_tcp_read_request. The call/reply flag is in network order and
not in host order. It needs to be converted to host order before comparisons
are made. The reason the earlier code worked is because the comparison was
against RPC_CALL which is defined as 0 (ntohl(0) == 0)

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