1 (* 'df' command for virtual domains.
3 (C) Copyright 2007 Richard W.M. Jones, Red Hat Inc.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 open Virt_df_gettext.Gettext
27 let plugin_name = "LVM2"
30 let sector_size64 = 512L
32 (* Probe to see if it's an LVM2 PV. Look for the "LABELONE" label. *)
33 let rec probe_pv lvm_plugin_id dev =
35 let uuid, metadata_offset, metadata_length = read_pv_label dev in
37 eprintf "LVM2 detected UUID %s md offset 0x%lx len %ld\n%!"
38 uuid metadata_offset metadata_length;
39 { lvm_plugin_id = lvm_plugin_id; pv_uuid = uuid }
40 with _ -> raise Not_found
42 and read_pv_label dev =
43 (* Load the first 8 sectors. I found by experimentation that
44 * the second sector contains the header ("LABELONE" etc) and
45 * the nineth sector contains some additional information about
46 * the location of the current metadata.
48 let bits = dev#read_bitstring 0L (9 * sector_size) in
50 Bitmatch.hexdump_bitstring stdout bits;
53 | sector0 : sector_size*8 : bitstring; (* sector 0 *)
54 labelone : 8*8 : bitstring; (* "LABELONE" *)
55 padding : 16*8 : bitstring; (* Seems to contain something. *)
56 lvm2_ver : 8*8 : bitstring; (* "LVM2 001" *)
57 uuid : 32*8 : bitstring; (* UUID *)
58 padding2 : (sector_size-64)*8 : bitstring; (* to end of second sector *)
59 sector234567 : sector_size*8 * 6 : bitstring; (* sectors 2-6 *)
60 padding3 : 0x28*8 : bitstring; (* start of sector 8 *)
61 metadata_offset : 32 : littleendian;(* metadata offset *)
62 padding4 : 4*8 : bitstring;
63 metadata_length : 32 : littleendian (* length of metadata (bytes) *)
64 when Bitmatch.string_of_bitstring labelone = "LABELONE" &&
65 Bitmatch.string_of_bitstring lvm2_ver = "LVM2 001" ->
66 let metadata_offset = metadata_offset +* 0x1000_l in
68 (* Check the metadata offset & length look reasonable for this
69 * device. Otherwise maybe it's a newer or older header which
70 * we don't really understand properly.
74 if dev#size <= Int64.of_int32 Int32.max_int then Int64.to_int32 dev#size
76 if metadata_offset < 0x1200_l || metadata_offset >= size
77 || metadata_length < 0_l || metadata_offset+*metadata_length >= size
79 invalid_arg "read_pv_label: bad metadata offset or length" in
81 Bitmatch.string_of_bitstring uuid, metadata_offset, metadata_length
85 invalid_arg (sprintf "read_pv_label: %s: not an LVM2 physical volume"
88 (* We are passed a list of devices which we previously identified
89 * as PVs belonging to us. From these produce a list of all LVs
90 * (as devices) and return them. Note that we don't try to detect
91 * what is on these LVs - that will be done in the main code.
96 (* Register with main code. *)
98 lvm_type_register plugin_name probe_pv list_lvs