The nfs_quick_reply() functionality relies on taking a copy of the

The nfs_quick_reply() functionality relies on taking a copy of the
current transport for later use.

The problem with this is the context of the RPC message is kept in
the transport and if any RPC message arrives before nfs_quick_reply()
is called that context will be corrupted.

So add a function get_nfs_xprt() to replace the current transport
with a new one returning the passed in transort so nfs_quick_reply()
can use it later.

A function put_nfs_xprt() is also added (although not really needed
since it just destroys the now unused transport) for completeness.

From: Ian Kent