nfs4: Make the v4 callback service hidden

To avoid hangs in the svc_unregister(), on version 4 mounts
(and unmounts), when rpcbind is not running, make the nfs4 callback
program an 'hidden' service by setting the 'vs_hidden' flag in the
nfs4_callback_version structure.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index db30c0b..a2b8b4d 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -782,6 +782,7 @@
 	.vs_proc = nfs4_callback_procedures1,
 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
 	.vs_dispatch = NULL,
+	.vs_hidden = 1,
 };
 
 struct svc_version nfs4_callback_version4 = {