They disappeared some time around 2.6.18.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
  */
 static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
 {
+       struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
+       struct rpc_clnt *rpc;
+
        shrink_submounts(vfsmnt, &nfs_automount_list);
+
+       if (!(flags & MNT_FORCE))
+               return;
+       /* -EIO all pending I/O */
+       rpc = server->client_acl;
+       if (!IS_ERR(rpc))
+               rpc_killall_tasks(rpc);
+       rpc = server->client;
+       if (!IS_ERR(rpc))
+               rpc_killall_tasks(rpc);
 }
 
 /*