NFS: Introduce new-style XDR encoding functions for NFSv3

We're interested in taking advantage of the safety benefits of
xdr_streams.  These data structures allow more careful checking for
buffer overflow while encoding.  More careful type checking is also
introduced in the new functions.

For efficiency, we also eventually want to be able to pass xdr_streams
from call_encode() to all XDR encoding functions, rather than building
an xdr_stream in every XDR encoding function in the kernel.  To do
this means all encoders must be ready to handle a passed-in
xdr_stream.

The new encoders follow the modern paradigm for XDR encoders: BUG on
error, and always return a zero status code.

Static helper functions are left without the "inline" directive.  This
allows the compiler to choose automatically how to optimize these for
size or speed.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

include/linux/nfs3.h

@@ -11,6 +11,8 @@
 #define NFS3_MAXGROUPS		16
 #define NFS3_FHSIZE		64
 #define NFS3_COOKIESIZE		4
+#define NFS3_CREATEVERFSIZE	8
+#define NFS3_COOKIEVERFSIZE	8
 #define NFS3_FIFO_DEV		(-1)
 #define NFS3MODE_FMT		0170000
 #define NFS3MODE_DIR		0040000