[root@csontos1 mnt]# mount -v -t nfs4 localhost:/mnt/xxx /tmp/xs      
mount: pinging: prog 100003 vers 4 prot tcp port 2049
mount: block device localhost:/mnt/xxx is write-protected, mounting read-only
mount: pinging: prog 100003 vers 4 prot tcp port 2049
mount: cannot mount block device localhost:/mnt/xxx read-only