nfs: Update server port after referral or migration

After traversing a referral or recovering from a migration event,
ensure that the server port reported in /proc/mounts is updated
to the correct port setting for the new submount.
Reported-by: Helen Chao <helen.chao@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4client.c

@@ -861,6 +861,7 @@ static int nfs4_set_client(struct nfs_server *server,
 		set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
 	if (test_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status))
 		set_bit(NFS_CS_TSM_POSSIBLE, &cl_init.init_flags);
+	server->port = rpc_get_port(addr);
 
 	/* Allocate or find a client reference we can use */
 	clp = nfs_get_client(&cl_init);