let du fln_lst =
let du_aux (sz, lst) fln =
let st = stat fln
in
(size_add sz st.size, (fln, st.size) :: lst)
in
List.fold_left
(fun (accu : size * (filename * size) list) fln -> find True fln du_aux accu)
(B 0L, [])
fln_lst