NFS_READDIR
case NFS_READDIR:
args->a_io = NFS_READDIR;
if (mi->mi_async_reqs[NFS_READDIR] == NULL) {
mi->mi_async_reqs[NFS_READDIR] = args;
mi->mi_async_tail[NFS_READDIR] = args;
mi->mi_async_tail[NFS_READDIR]->a_next = args;
mi->mi_async_tail[NFS_READDIR] = args;
} else if (args->a_io == NFS_READDIR) {