mirage-block 0.2 · OCaml Package

Utility functions over Mirage BLOCK devices

module Error = Mirage_block_error

val compare : 
  (module V1_LWT.BLOCK with type t = 'a) ->
  'a ->
  (module V1_LWT.BLOCK with type t = 'b) ->
  'b ->
  [ `Ok of int | `Error of [> `Msg of string ] ] Lwt.t

Compare the contents of two block devices.

val fold_s : 
  f:('a -> int64 -> Cstruct.t -> 'a Lwt.t) ->
  'a ->
  (module V1_LWT.BLOCK with type t = 'b) ->
  'b ->
  [ `Ok of 'a | `Error of [> `Msg of string ] ] Lwt.t

Folds f across blocks read sequentially from a block device

val fold_mapped_s : 
  f:('a -> int64 -> Cstruct.t -> 'a Mirage_block_error.result Lwt.t) ->
  'a ->
  (module Mirage_block_s.SEEKABLE with type t = 'b) ->
  'b ->
  'a Mirage_block_error.result Lwt.t

Folds f across data blocks read sequentially from a block device. In contrast to fold_s, fold_mapped_s will use knowledge about the underlying disk structure and will skip blocks which it knows contain only zeroes. Note it may still read blocks containing zeroes. The function f receives an accumulator, the sector number and a data buffer.

val fold_unmapped_s : 
  f:('a -> int64 -> int64 -> 'a Mirage_block_error.result Lwt.t) ->
  'a ->
  (module Mirage_block_s.SEEKABLE with type t = 'b) ->
  'b ->
  'a Mirage_block_error.result Lwt.t

Folds f acc ofs len across offsets of unmapped data blocks read sequentially from the block device. fold_unmapped_s will use knowledge about the underlying disk structure and will only fold across those blocks which are guaranteed to be zero i.e. those which are unmapped somehow.

val copy : 
  (module V1_LWT.BLOCK with type t = 'a) ->
  'a ->
  (module V1_LWT.BLOCK with type t = 'b) ->
  'b ->
  [ `Ok of unit
  | `Error of [> `Msg of string | `Is_read_only | `Different_sizes ] ]
    Lwt.t

Copy all data from a source BLOCK device to a destination BLOCK device.

Fails with `Different_sizes if the source and destination are not exactly the same size.

Fails with `Is_read_only if the destination device is read-only.

val sparse_copy : 
  (module Mirage_block_s.SEEKABLE with type t = 'a) ->
  'a ->
  (module V1_LWT.BLOCK with type t = 'b) ->
  'b ->
  [ `Ok of unit
  | `Error of [> `Msg of string | `Is_read_only | `Different_sizes ] ]
    Lwt.t

Copy all mapped data from a source SEEKABLE device to a destination BLOCK device.

This function will preserve sparseness information in the source disk. The destination block device must be pre-zeroed, otherwise previous data will "leak through".

Fails with `Different_sizes if the source and destination are not exactly the same size.

Fails with `Is_read_only if the destination device is read-only.

val random : 
  (module V1_LWT.BLOCK with type t = 'a) ->
  'a ->
  [ `Ok of unit | `Error of [> `Msg of string ] ] Lwt.t

Fill a block device with pseudorandom data

package mirage-block