An NBD client which allows you to connect to remote disks and perform I/O.

include S.CLIENT
include Mirage_block.S with type error = [ Mirage_block.error | `Protocol_error of Protocol.Error.t ] and type write_error = [ Mirage_block.write_error | `Protocol_error of Protocol.Error.t ]
type error = [
  1. | Mirage_block.error
  2. | `Protocol_error of Protocol.Error.t

The type for block errors.

val pp_error : error Fmt.t

pp_error is the pretty-printer for errors.

type write_error = [
  1. | Mirage_block.write_error
  2. | `Protocol_error of Protocol.Error.t

The type for write errors.

val pp_write_error : write_error Fmt.t

pp_write_error is the pretty-printer for write errors.

include Mirage_device.S
type t

The type representing the internal state of the device

val disconnect : t -> unit Lwt.t

Disconnect from the device. While this might take some time to complete, it can never result in an error.

val get_info : t -> Lwt.t

Query the characteristics of a specific block device

val read : t -> int64 -> Cstruct.t list -> (unit, error) result Lwt.t

read device sector_start buffers reads data starting at sector_start from the block device into buffers. Ok () means the buffers have been filled. Error _ indicates an I/O error has happened and some of the buffers may not be filled. Each of elements in the list buffers must be a whole number of sectors in length. The list of buffers can be of any length.

val write : t -> int64 -> Cstruct.t list -> (unit, write_error) result Lwt.t

write device sector_start buffers writes data from buffers onto the block device starting at sector_start. Ok () means the contents of the buffers have been written. Error _ indicates a partial failure in which some of the writes may not have happened.

Once submitted, it is not possible to cancel a request and there is no timeout.

The operation may fail with:

  • `Unimplemented: the operation has not been implemented, no data has been written.
  • `Is_read_only: the device is read-only, no data has been written.
  • `Disconnected: the device has been disconnected at application request, an unknown amount of data has been written.

Each of buffers must be a whole number of sectors in length. The list of buffers can be of any length.

The data will not be copied, so the supplied buffers must not be re-used until the IO operation completes.

type size = int64

The size of a remote disk

val list : -> (string list, [ `Policy | `Unsupported ]) result Lwt.t

list channel returns a list of exports known by the server. `Error `Policy means the server has this function disabled deliberately. `Error `Unsupported means the server is old and does not support the query function.

val negotiate : -> string -> (t * size * Protocol.PerExportFlag.t list) Lwt.t

negotiate channel export takes an already-connected channel, performs the initial protocol negotiation and connects to the named export. Returns disk * remote disk size * flags