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authorRichard W.M. Jones <rjones@redhat.com>2008-04-15 15:08:34 +0100
committerRichard W.M. Jones <rjones@redhat.com>2008-04-15 15:08:34 +0100
commitbf03017c3a390f75130d810bed403008abcbe7f4 (patch)
treee77719af7c2edd042770a2ad471fd0eb70767ec4
parent2f24ddc7c65beb0df82f208bf7410ea09102f7a8 (diff)
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Read out metadata offset & length from PV header.
-rw-r--r--virt-df/virt_df_lvm2.ml54
1 files changed, 42 insertions, 12 deletions
diff --git a/virt-df/virt_df_lvm2.ml b/virt-df/virt_df_lvm2.ml
index dc97656..abc247e 100644
--- a/virt-df/virt_df_lvm2.ml
+++ b/virt-df/virt_df_lvm2.ml
@@ -29,29 +29,58 @@ let plugin_name = "LVM2"
let sector_size = 512
let sector_size64 = 512L
-let pv_label_offset = sector_size64
-
(* Probe to see if it's an LVM2 PV. Look for the "LABELONE" label. *)
let rec probe_pv lvm_plugin_id dev =
try
- let uuid = read_pv_label dev in
+ let uuid, metadata_offset, metadata_length = read_pv_label dev in
+ if debug then
+ eprintf "LVM2 detected UUID %s md offset 0x%lx len %ld\n%!"
+ uuid metadata_offset metadata_length;
{ lvm_plugin_id = lvm_plugin_id; pv_uuid = uuid }
with _ -> raise Not_found
and read_pv_label dev =
- (* Load the second sector. *)
- let bits = dev#read_bitstring pv_label_offset sector_size in
+ (* Load the first 8 sectors. I found by experimentation that
+ * the second sector contains the header ("LABELONE" etc) and
+ * the nineth sector contains some additional information about
+ * the location of the current metadata.
+ *)
+ let bits = dev#read_bitstring 0L (9 * sector_size) in
- (*Bitmatch.hexdump_bitstring stdout bits;*)
+ Bitmatch.hexdump_bitstring stdout bits;
bitmatch bits with
- | labelone : 8*8 : bitstring; (* "LABELONE" *)
- padding : 16*8 : bitstring;
+ | sector0 : sector_size*8 : bitstring; (* sector 0 *)
+ labelone : 8*8 : bitstring; (* "LABELONE" *)
+ padding : 16*8 : bitstring; (* Seems to contain something. *)
lvm2_ver : 8*8 : bitstring; (* "LVM2 001" *)
- uuid : 32*8 : bitstring (* UUID *)
+ uuid : 32*8 : bitstring; (* UUID *)
+ padding2 : (sector_size-64)*8 : bitstring; (* to end of second sector *)
+ sector234567 : sector_size*8 * 6 : bitstring; (* sectors 2-6 *)
+ padding3 : 0x28*8 : bitstring; (* start of sector 8 *)
+ metadata_offset : 32 : littleendian;(* metadata offset *)
+ padding4 : 4*8 : bitstring;
+ metadata_length : 32 : littleendian (* length of metadata (bytes) *)
when Bitmatch.string_of_bitstring labelone = "LABELONE" &&
- Bitmatch.string_of_bitstring lvm2_ver = "LVM2 001" ->
- Bitmatch.string_of_bitstring uuid
+ Bitmatch.string_of_bitstring lvm2_ver = "LVM2 001" ->
+ let metadata_offset = metadata_offset +* 0x1000_l in
+
+ (* Check the metadata offset & length look reasonable for this
+ * device. Otherwise maybe it's a newer or older header which
+ * we don't really understand properly.
+ *)
+ let () =
+ let size =
+ if dev#size <= Int64.of_int32 Int32.max_int then Int64.to_int32 dev#size
+ else Int32.max_int in
+ if metadata_offset < 0x1200_l || metadata_offset >= size
+ || metadata_length < 0_l || metadata_offset+*metadata_length >= size
+ then
+ invalid_arg "read_pv_label: bad metadata offset or length" in
+
+ Bitmatch.string_of_bitstring uuid, metadata_offset, metadata_length
+
+
| _ ->
invalid_arg (sprintf "read_pv_label: %s: not an LVM2 physical volume"
dev#name)
@@ -61,7 +90,8 @@ and read_pv_label dev =
* (as devices) and return them. Note that we don't try to detect
* what is on these LVs - that will be done in the main code.
*)
-let list_lvs devs = []
+let list_lvs devs =
+ []
(* Register with main code. *)
let () =