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|
open Debug
type lvcreate_t = {
lvc_id : string;
lvc_segments : Allocator.t
}
and lvrename_t = {
lvmv_new_name : string;
}
and lvreduce_t = {
lvrd_new_extent_count : int64;
}
and lvexpand_t = {
lvex_segments : Allocator.t;
}
(** First string corresponds to the name of the LV. *)
and operation =
| LvCreate of string * lvcreate_t
| LvReduce of string * lvreduce_t
| LvExpand of string * lvexpand_t
| LvRename of string * lvrename_t
| LvRemove of string
| LvAddTag of string * Tag.t
| LvRemoveTag of string * Tag.t
and sequenced_op = {
so_seqno : int;
so_op : operation
} with rpc
(** Marshal to and from a string *)
let redo_to_string (l : sequenced_op) =
let s = Marshal.to_string l [] in
let len = String.length s in
Printf.sprintf "%012d%s" len s
(** Return tuple of operation * int where int is total length of the marshalled operation *)
let redo_of_string s ofs =
let len = int_of_string (String.sub s ofs 12) in
let res = String.sub s (ofs+12) len in
((Marshal.from_string res 0 : sequenced_op),(12+len))
exception OutOfSize of int
(** The initial pos is the absolute position of the first unset byte in the LV *)
let read_initial_pos fd offset =
ignore(Unix.LargeFile.lseek fd offset Unix.SEEK_SET);
let pos = try Int64.of_string (Unixext.really_read_string fd 12) with _ -> (Int64.add offset 12L) in
pos
let write_initial_pos fd offset pos =
ignore(Unix.LargeFile.lseek fd offset Unix.SEEK_SET);
let pos_str = Printf.sprintf "%012Ld" pos in
ignore(Unix.write fd pos_str 0 12)
let write fd offset size ops =
let pos = read_initial_pos fd offset in
let rec write ofs ops =
match ops with
| op::ops ->
let str = redo_to_string op in
debug ("LVM REDO: " ^ str);
let len = String.length str in
if (Int64.add ofs (Int64.of_int len)) > (Int64.add offset size) then
raise (OutOfSize op.so_seqno)
else begin
ignore(Unix.LargeFile.lseek fd ofs Unix.SEEK_SET);
ignore(Unix.write fd str 0 len);
let new_pos = Int64.add ofs (Int64.of_int len) in
write_initial_pos fd offset new_pos;
write new_pos ops
end
| [] -> ()
in write pos (List.rev ops)
let read fd offset size =
debug "Redo.read";
let end_ofs = read_initial_pos fd offset in
let start_ofs = Int64.add offset 12L in
let size = Int64.sub end_ofs start_ofs in
debug (Printf.sprintf "start_ofs: %Ld end_ofs: %Ld size: %Ld" start_ofs end_ofs size);
ignore(Unix.LargeFile.lseek fd start_ofs Unix.SEEK_SET);
let string = Unixext.really_read_string fd (Int64.to_int size) in
let rec read_ops pos ops =
debug (Printf.sprintf "Reading from pos: %d" pos);
if pos>=String.length string
then ops
else
let (op,length)=redo_of_string string pos in
read_ops (pos+length) (op::ops)
in
let result = read_ops 0 [] in
debug "Redo.read finished";
result
let reset fd offset =
write_initial_pos fd offset (Int64.add offset 12L)
(** Converts the redo operation to a human-readable string. *)
let redo_to_human_readable op =
let lvcreate_t_to_string l =
Printf.sprintf "{id:'%s', segments:[%s]}" l.lvc_id (Allocator.to_string l.lvc_segments) in
let lvexpand_t_to_string l =
Printf.sprintf "[%s]" (Allocator.to_string l.lvex_segments) in
let opstr =
match op.so_op with
| LvCreate (name,lvc) -> Printf.sprintf "LvCreate(%s,%s)" name (lvcreate_t_to_string lvc)
| LvRemove name -> Printf.sprintf "LvRemove(%s)" name
| LvReduce (name,lvrd) -> Printf.sprintf "LvReduce(%s,%Ld)" name lvrd.lvrd_new_extent_count
| LvExpand (name,lvex) -> Printf.sprintf "LvExpand(%s,%s)" name (lvexpand_t_to_string lvex)
| LvRename (name,lvmv) -> Printf.sprintf "LvRename(%s,%s)" name lvmv.lvmv_new_name
| LvAddTag (name,tag) -> Printf.sprintf "LvAddTag(%s,%s)" name (Tag.string_of tag)
| LvRemoveTag (name,tag) -> Printf.sprintf "LvRemoveTag(%s,%s)" name (Tag.string_of tag) in
Printf.sprintf "{seqno=%d; op=%s}" op.so_seqno opstr
|
