NFS: Clean up TEST_STATEID and FREE_STATEID error reporting

As a finishing touch, add appropriate documenting comments and some
debugging printk's.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -6625,13 +6625,27 @@ static int _nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid)
 		.rpc_resp = &res,
 	};
 
+	dprintk("NFS call  test_stateid %p\n", stateid);
 	nfs41_init_sequence(&args.seq_args, &res.seq_res, 0);
 	status = nfs4_call_sync_sequence(server->client, server, &msg, &args.seq_args, &res.seq_res, 1);
-	if (status != NFS_OK)
+	if (status != NFS_OK) {
+		dprintk("NFS reply test_stateid: failed, %d\n", status);
 		return status;
+	}
+	dprintk("NFS reply test_stateid: succeeded, %d\n", -res.status);
 	return -res.status;
 }
 
+/**
+ * nfs41_test_stateid - perform a TEST_STATEID operation
+ *
+ * @server: server / transport on which to perform the operation
+ * @stateid: state ID to test
+ *
+ * Returns NFS_OK if the server recognizes that "stateid" is valid.
+ * Otherwise a negative NFS4ERR value is returned if the operation
+ * failed or the state ID is not currently valid.
+ */
 static int nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid)
 {
 	struct nfs4_exception exception = { };
@@ -6656,12 +6670,25 @@ static int _nfs4_free_stateid(struct nfs_server *server, nfs4_stateid *stateid)
 		.rpc_argp = &args,
 		.rpc_resp = &res,
 	};
+	int status;
 
+	dprintk("NFS call  free_stateid %p\n", stateid);
 	nfs41_init_sequence(&args.seq_args, &res.seq_res, 0);
-	return nfs4_call_sync_sequence(server->client, server, &msg,
+	status = nfs4_call_sync_sequence(server->client, server, &msg,
 					 &args.seq_args, &res.seq_res, 1);
+	dprintk("NFS reply free_stateid: %d\n", status);
+	return status;
 }
 
+/**
+ * nfs41_free_stateid - perform a FREE_STATEID operation
+ *
+ * @server: server / transport on which to perform the operation
+ * @stateid: state ID to release
+ *
+ * Returns NFS_OK if the server freed "stateid".  Otherwise a
+ * negative NFS4ERR value is returned.
+ */
 static int nfs41_free_stateid(struct nfs_server *server, nfs4_stateid *stateid)
 {
 	struct nfs4_exception exception = { };