external set_e2uuid : t -> string -> string -> unit = "ocaml_guestfs_set_e2uuid"
external get_e2uuid : t -> string -> string = "ocaml_guestfs_get_e2uuid"
external fsck : t -> string -> string -> int = "ocaml_guestfs_fsck"
+external zero : t -> string -> unit = "ocaml_guestfs_zero"