nfs4_client_recover_expired_lease
extern int nfs4_client_recover_expired_lease(struct nfs_client *clp);
status = nfs4_client_recover_expired_lease(server->nfs_client);
ret = nfs4_client_recover_expired_lease(clp);
lseg = ERR_PTR(nfs4_client_recover_expired_lease(clp));