NFSv4: Replace ad-hoc xdr encode/decode helpers with xdr_stream_* generics

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 6104696..7b5f37f 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -1949,10 +1949,7 @@ static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
 static void
 encode_opaque_fixed(struct xdr_stream *xdr, const void *buf, size_t len)
 {
-	__be32 *p;
-
-	p = xdr_reserve_space(xdr, len);
-	xdr_encode_opaque_fixed(p, buf, len);
+	WARN_ON_ONCE(xdr_stream_encode_opaque_fixed(xdr, buf, len) < 0);
 }
 
 static void