ubifs_calc_dark
dark = ubifs_calc_dark(c, spc);
lst->total_dark += ubifs_calc_dark(c, c->leb_size);
lst->total_dark += ubifs_calc_dark(c, c->leb_size);
lst->total_dark += ubifs_calc_dark(c, spc);
c->lst.total_dark -= ubifs_calc_dark(c, old_spc);
c->lst.total_dark += ubifs_calc_dark(c, new_spc);
int ubifs_calc_dark(const struct ubifs_info *c, int spc);