include Mirage_block.S
The type for block errors.
The type for write errors.
val pp_write_error : write_error Fmt.tpp_write_error is the pretty-printer for write errors.
include Mirage_device.S
val get_info : t -> Mirage_block.info Lwt.tQuery the characteristics of a specific block device
val read : t -> int64 -> Cstruct.t list -> (unit, error) Stdlib.result Lwt.tread 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) Stdlib.result Lwt.twrite 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.
Low-level convenience functions
val really_read : Lwt_unix.file_descr -> Cstruct.t -> unit Lwt.tval really_write : Lwt_unix.file_descr -> Cstruct.t -> unit Lwt.tval blkgetsize : string -> Unix.file_descr -> (int64, error) Stdlib.resultblkgetsize path fd: returns the size of the open block device given by fd. path is only used to construct a human-readable error message.
val ftruncate : Lwt_unix.file_descr -> int64 -> unit Lwt.tftruncate fd size: changes the size of the file backed by fd to size. This function works on Unix and Windows.
module Config : sig ... endval connect : ?buffered:bool -> ?sync:Config.sync_behaviour option -> ?lock:bool -> string -> t Lwt.tconnect ?buffered ?sync ?lock path connects to a block device on the filesystem at path. By default I/O is buffered and asynchronous. By default the file is unlocked. These defaults can be changed by supplying the optional arguments ~buffered:false and ~sync:false ~lock:true
val resize : t -> int64 -> (unit, write_error) Stdlib.result Lwt.tresize t new_size_sectors attempts to resize the connected device to have the given number of sectors. If successful, subsequent calls to get_info will reflect the new size.
val flush : t -> (unit, write_error) Stdlib.result Lwt.tflush t flushes any buffers, if the file has been opened in buffered mode
val seek_unmapped : t -> int64 -> (int64, error) Stdlib.result Lwt.tseek_unmapped t start returns the sector offset of the next guaranteed zero-filled region (typically guaranteed because it is unmapped)
val seek_mapped : t -> int64 -> (int64, error) Stdlib.result Lwt.tseek_mapped t start returns the sector offset of the next regoin of the device which may have data in it (typically this is the next mapped region)
val discard : t -> int64 -> int64 -> (unit, write_error) Stdlib.result Lwt.tdiscard sector n signals that the n sectors starting at sector are no longer needed and the contents may be discarded. Reads following the discard will return zeroes. Note the contents may not actually be irrecoverable: this is not a "secure erase".