let sector_size = 512
let sector_size64 = 512L
+(*----------------------------------------------------------------------*)
+(* Block device which can do linear maps, same as the kernel dm-linear.c *)
+class linear_map_device name extent_size segments =
+ (* The segments are passed containing (start_extent, extent_count, ...)
+ * but it's easier to deal with (start_extent, end_extent, ...) so
+ * rewrite them.
+ *)
+ let segments = List.map
+ (fun (start_extent, extent_count, dev, pvoffset) ->
+ (start_extent, start_extent +^ extent_count, dev, pvoffset)
+ ) segments in
+
+ (* Calculate the size of the device (in bytes). Note that because
+ * of the random nature of the mapping this doesn't imply that we can
+ * satisfy any read request up to the full size.
+ *)
+ let size_in_extents =
+ List.fold_left max 0L
+ (List.map (fun (_, end_extent, _, _) -> end_extent) segments) in
+ let size = size_in_extents *^ extent_size in
+object
+ inherit device
+ method name = name
+ method size = size
+
+ (* Read method checks which segment the request lies inside and
+ * maps it to the underlying device. If there is no mapping then
+ * we have to return an error.
+ *
+ * The request must lie inside a single extent, otherwise this is
+ * also an error (XXX - should lift this restriction, however default
+ * extent size is 4 MB so we probably won't hit this very often).
+ *)
+ method read offset len =
+ let offset_in_extents = offset /^ extent_size in
+
+ (* Check we don't cross an extent boundary. *)
+ if (offset +^ Int64.of_int (len-1)) /^ extent_size <> offset_in_extents
+ then invalid_arg "linear_map_device: request crosses extent boundary";
+
+ if offset_in_extents < 0L || offset_in_extents >= size_in_extents then
+ invalid_arg "linear_map_device: read outside device";
+
+ let rec loop = function
+ | [] ->
+ invalid_arg "linear_map_device: offset not mapped"
+ | (start_extent, end_extent, dev, pvoffset) :: rest ->
+ eprintf "pvoffset = %Ld\n" pvoffset;
+ if start_extent <= offset_in_extents &&
+ offset_in_extents < end_extent
+ then dev#read (offset +^ pvoffset *^ extent_size) len
+ else loop rest
+ in
+ loop segments
+end
+
+(*----------------------------------------------------------------------*)
(* Probe to see if it's an LVM2 PV. *)
let rec probe_pv lvm_plugin_id dev =
try
*)
dev#read offset64 (Int64.to_int len64)
+(*----------------------------------------------------------------------*)
(* We are passed a list of devices which we previously identified
* as PVs belonging to us. From these produce a list of all LVs
* (as devices) and return them. Note that we don't try to detect
dev)
) pvs in
- (* Print the parsed metadata.
- List.iter (
- fun (uuid, (metadata, dev)) ->
- eprintf "metadata for UUID %s:\n" uuid;
- output_metadata stderr metadata
- ) pvs;
- *)
+ (* Print the parsed metadata. *)
+ if !debug then
+ List.iter (
+ fun (uuid, (metadata, dev)) ->
+ eprintf "metadata for PV UUID %s on %s:\n" uuid dev#name;
+ output_metadata stderr metadata
+ ) pvs;
(* Scan for volume groups. The first entry in the metadata
* appears to be the volume group name. This gives us a
and get_meta field meta =
match List.assoc field meta with
| Metadata md -> md
- | _ -> raise Not_found in
+ | _ -> raise Not_found
+ and get_stripes field meta = (* List of (string,int) pairs. *)
+ match List.assoc field meta with
+ | List xs ->
+ let rec loop = function
+ | [] -> []
+ | String pvname :: Int offset :: xs ->
+ (pvname, offset) :: loop xs
+ | _ -> raise Not_found
+ in
+ loop xs
+ | _ -> raise Not_found
in
+ (* The volume groups refer to the physical volumes using their
+ * own naming system ("pv0", "pv1", etc.) instead of PV UUIDs.
+ *
+ * Each PV also has a start (in sectors) & count (in extents)
+ * of the writable area (the bit after the superblock and metadata)
+ * which normally starts at sector 384.
+ *
+ * Create a PV device (simple offset + size) and a map from PV
+ * names to these devices.
+ *)
+ let vgs = List.map (
+ fun (vgname, (pvuuids, vgmeta)) ->
+ let pvdevs, extent_size =
+ try
+ (* NB: extent_size is in sectors here - we convert to bytes. *)
+ let extent_size = get_int "extent_size" vgmeta 0 (1024*1024) in
+ let extent_size = Int64.of_int extent_size *^ sector_size64 in
+
+ (* Get the physical_volumes section of the metadata. *)
+ let pvdevs = get_meta "physical_volumes" vgmeta in
+
+ List.filter_map (
+ function
+ | (pvname, Metadata meta) ->
+ (* Get the UUID. *)
+ let pvuuid = get_string "id" meta in
+ let pvuuid = canonical_uuid pvuuid in
+
+ (* Get the underlying physical device. *)
+ let _, dev = List.assoc pvuuid pvs in
+
+ (* Construct a PV device. *)
+ let pe_start = get_int64 "pe_start" meta in
+ let pe_start = pe_start *^ sector_size64 in
+ let pe_count = get_int64 "pe_count" meta in
+ let pe_count = pe_count *^ extent_size in
+ let pvdev = new offset_device pvuuid pe_start pe_count dev in
+
+ Some (pvname, pvdev)
+ | _ ->
+ None
+ ) pvdevs, extent_size
+ with
+ (* Something went wrong - just return an empty map. *)
+ Not_found -> [], 0L in
+ (vgname, (pvuuids, vgmeta, pvdevs, extent_size))
+ ) vgs in
+
(* Scan for logical volumes. Each VG contains several LVs.
* This gives us a list of LVs within each VG (hence extends
* the vgs variable).
*)
let vgs = List.map (
- fun (vgname, (pvuuids, vgmeta)) ->
+ fun (vgname, (pvuuids, vgmeta, pvdevs, extent_size)) ->
let lvs =
try
- let extent_size = get_int "extent_size" vgmeta 0 (256*1024) in
let lvs = get_meta "logical_volumes" vgmeta in
let lvs = List.filter_map (
function
let extent_count =
get_int64 "extent_count" segmeta in
let segtype = get_string "type" segmeta in
+
+ (* Can only handle striped segments at the
+ * moment. XXX
+ *)
if segtype <> "striped" then raise Not_found;
+
let stripe_count =
get_int "stripe_count" segmeta 0 1024 in
- (* let stripes = in *)
+ let stripes = get_stripes "stripes" segmeta in
+
+ if List.length stripes <> stripe_count then
+ raise Not_found;
- (start_extent, extent_count, stripe_count)
+ (* Can only handle linear striped segments at
+ * the moment. XXX
+ *)
+ if stripe_count <> 1 then raise Not_found;
+ let pvname, pvoffset = List.hd stripes in
+
+ (start_extent, extent_count, pvname, pvoffset)
) segments in
- Some (lvname, (lvmeta, segments))
+ Some (lvname, segments)
with
(* Something went wrong with segments - omit this LV. *)
Not_found -> None)
Not_found ->
(* Something went wrong - assume no LVs found. *)
[] in
- (vgname, (pvuuids, vgmeta, lvs))
+ (vgname, (pvuuids, vgmeta, pvdevs, extent_size, lvs))
) vgs in
(* Print the LVs. *)
- if !debug then
+ if !debug then (
List.iter (
- fun (vgname, (pvuuids, vgmeta, lvs)) ->
- let lvnames = List.map fst lvs in
- eprintf "VG %s contains LVs: %s\n%!" vgname (String.concat ", " lvnames)
+ fun (vgname, (pvuuids, vgmeta, pvdevs, extent_size, lvs)) ->
+ eprintf "VG %s: (extent_size = %Ld bytes)\n" vgname extent_size;
+ List.iter (
+ fun (lvname, segments) ->
+ eprintf " %s/%s:\n" vgname lvname;
+ List.iter (
+ fun (start_extent, extent_count, pvname, pvoffset) ->
+ eprintf " start %Ld count %Ld at %s:%Ld\n"
+ start_extent extent_count pvname pvoffset
+ ) segments
+ ) lvs
) vgs;
+ flush stderr
+ );
+
+ (* Finally we can set up devices for the LVs. *)
+ let lvs =
+ List.map (
+ fun (vgname, (pvuuid, vgmeta, pvdevs, extent_size, lvs)) ->
+ try
+ List.map (
+ fun (lvname, segments) ->
+ let name = vgname ^ "/" ^ lvname in
+ let segments = List.map (
+ fun (start_extent, extent_count, pvname, pvoffset) ->
+ (* Get the PV device. *)
+ let pvdev = List.assoc pvname pvdevs in
+
+ (* Extents mapped to: *)
+ (start_extent, extent_count, pvdev, pvoffset)
+ ) segments in
+
+ (* Create a linear mapping device. *)
+ let lv_dev = new linear_map_device name extent_size segments in
+
+ { lv_dev = lv_dev }
+ ) lvs
+ with
+ Not_found -> []
+ ) vgs in
+ let lvs = List.concat lvs in
- []
+ (* Return the list of LV devices. *)
+ lvs
+(*----------------------------------------------------------------------*)
(* Register with main code. *)
let () =
lvm_type_register plugin_name probe_pv list_lvs
git.annexia.org / virt-top.git / commitdiff