ubifs_tnc_find_child
child = ubifs_tnc_find_child(znode, 0);
zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1);
return ubifs_tnc_find_child(zr, 0);
znode = ubifs_tnc_find_child(zr, 0);
zn = ubifs_tnc_find_child(znode->parent, iip + 1);
zn = ubifs_tnc_find_child(zn, 0);