nfsd: register NFS_ACL with rpcbind

Modify the NFS server to register the NFS_ACL services with the rpcbind
daemon.  This allows the client to ping for the existence of the NFS_ACL
support via commands such as "rpcinfo -t <server> nfs_acl".

This patch also modifies the NFS_ACL support so that responses to
version 2 NULLPROC requests can be made.

The changelog for the patch which turned off this functionality
mentioned something about not registering the NFS_ACL as being part of
some tradition.  I can't find this tradition and the only other
implementation which supports NFS_ACL does register them with the
rpcbind daemon.
Signed-off-by: Peter Staubach <staubach@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/nfs2acl.c

@@ -217,6 +217,16 @@ static int nfsaclsvc_decode_accessargs(struct svc_rqst *rqstp, __be32 *p,
  * XDR encode functions
  */
 
+/*
+ * There must be an encoding function for void results so svc_process
+ * will work properly.
+ */
+int
+nfsaclsvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p, void *dummy)
+{
+	return xdr_ressize_check(rqstp, p);
+}
+
 /* GETACL */
 static int nfsaclsvc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p,
 		struct nfsd3_getaclres *resp)
@@ -308,7 +318,6 @@ static int nfsaclsvc_release_access(struct svc_rqst *rqstp, __be32 *p,
 }
 
 #define nfsaclsvc_decode_voidargs	NULL
-#define nfsaclsvc_encode_voidres	NULL
 #define nfsaclsvc_release_void		NULL
 #define nfsd3_fhandleargs	nfsd_fhandle
 #define nfsd3_attrstatres	nfsd_attrstat
@@ -346,5 +355,5 @@ struct svc_version	nfsd_acl_version2 = {
 		.vs_proc	= nfsd_acl_procedures2,
 		.vs_dispatch	= nfsd_dispatch,
 		.vs_xdrsize	= NFS3_SVC_XDRSIZE,
-		.vs_hidden	= 1,
+		.vs_hidden	= 0,
 };

fs/nfsd/nfs3acl.c

@@ -264,6 +264,6 @@ struct svc_version	nfsd_acl_version3 = {
 		.vs_proc	= nfsd_acl_procedures3,
 		.vs_dispatch	= nfsd_dispatch,
 		.vs_xdrsize	= NFS3_SVC_XDRSIZE,
-		.vs_hidden	= 1,
+		.vs_hidden	= 0,
 };