noon
Iterating over source disks and creating temporary overlays for easy
rollback fits nicely into a separate function. In addition, determining
their size doesn't need to wait until the guestfs is launched: the size
can be obtained via disk_virtual_size() method.
Signed-off-by: Roman Kagan <rkagan(a)virtuozzo.com>
---
v2v/v2v.ml | 91 +++++++++++++++++++++++++++++---------------------------------
1 file changed, 42 insertions(+), 49 deletions(-)
diff --git a/v2v/v2v.ml b/v2v/v2v.ml
index a2cf249..b3dfa07 100644
--- a/v2v/v2v.ml
+++ b/v2v/v2v.ml
@@ -105,6 +105,45 @@ let amend_source source output_name network_map =
{ source with s_nics = nics }
+let create_overlays src_disks =
+ (* Create a qcow2 v3 overlay to protect the source image(s). There
+ * is a specific reason to use the newer qcow2 variant: Because the
+ * L2 table can store zero clusters efficiently, and because
+ * discarded blocks are stored as zero clusters, this should allow us
+ * to fstrim/blkdiscard and avoid copying significant parts of the
+ * data over the wire.
+ *)
+ message (f_"Creating overlays to protect the sources from being modified");
+ let overlay_dir = (new Guestfs.guestfs ())#get_cachedir () in
+ List.mapi (
+ fun i ({ s_qemu_uri = qemu_uri; s_format = format } as source) ->
+ let overlay_file =
+ Filename.temp_file ~temp_dir:overlay_dir "v2vovl" ".qcow2"
in
+ unlink_on_exit overlay_file;
+
+ let options =
+ "compat=1.1" ^
+ (match format with None -> ""
+ | Some fmt -> ",backing_fmt=" ^ fmt) in
+ let cmd =
+ sprintf "qemu-img create -q -f qcow2 -b %s -o %s %s"
+ (quote qemu_uri) (quote options) overlay_file in
+ if verbose () then printf "%s\n%!" cmd;
+ if Sys.command cmd <> 0 then
+ error (f_"qemu-img command failed, see earlier errors");
+
+ (* Sanity check created overlay (see below). *)
+ if not ((new G.guestfs ())#disk_has_backing_file overlay_file) then
+ error (f_"internal error: qemu-img did not create overlay with backing
file");
+
+ let sd = "sd" ^ drive_name i in
+
+ let vsize = (new G.guestfs ())#disk_virtual_size overlay_file in
+
+ { ov_overlay_file = overlay_file; ov_sd = sd;
+ ov_virtual_size = vsize; ov_source = source }
+ ) src_disks
+
let rec main () =
(* Handle the command line. *)
let input, output,
@@ -122,40 +161,7 @@ let rec main () =
let source = open_source input print_source in
let source = amend_source source output_name network_map in
-
- (* Create a qcow2 v3 overlay to protect the source image(s). There
- * is a specific reason to use the newer qcow2 variant: Because the
- * L2 table can store zero clusters efficiently, and because
- * discarded blocks are stored as zero clusters, this should allow us
- * to fstrim/blkdiscard and avoid copying significant parts of the
- * data over the wire.
- *)
- message (f_"Creating an overlay to protect the source from being modified");
- let overlay_dir = (new Guestfs.guestfs ())#get_cachedir () in
- let overlays =
- List.map (
- fun ({ s_qemu_uri = qemu_uri; s_format = format } as source) ->
- let overlay_file =
- Filename.temp_file ~temp_dir:overlay_dir "v2vovl" ".qcow2"
in
- unlink_on_exit overlay_file;
-
- let options =
- "compat=1.1" ^
- (match format with None -> ""
- | Some fmt -> ",backing_fmt=" ^ fmt) in
- let cmd =
- sprintf "qemu-img create -q -f qcow2 -b %s -o %s %s"
- (quote qemu_uri) (quote options) overlay_file in
- if verbose () then printf "%s\n%!" cmd;
- if Sys.command cmd <> 0 then
- error (f_"qemu-img command failed, see earlier errors");
-
- (* Sanity check created overlay (see below). *)
- if not ((new G.guestfs ())#disk_has_backing_file overlay_file) then
- error (f_"internal error: qemu-img did not create overlay with backing
file");
-
- overlay_file, source
- ) source.s_disks in
+ let overlays = create_overlays source.s_disks in
(* Open the guestfs handle. *)
message (f_"Opening the overlay");
@@ -164,7 +170,7 @@ let rec main () =
if verbose () then g#set_verbose true;
g#set_network true;
List.iter (
- fun (overlay_file, _) ->
+ fun ({ov_overlay_file = overlay_file}) ->
g#add_drive_opts overlay_file
~format:"qcow2" ~cachemode:"unsafe"
~discard:"besteffort"
~copyonread:true
@@ -172,20 +178,6 @@ let rec main () =
g#launch ();
- (* Create the list of overlays structs. Query each disk for its
- * virtual size, and fill in a few other fields.
- *)
- let overlays =
- mapi (
- fun i (overlay_file, source) ->
- let sd = "sd" ^ drive_name i in
- let dev = "/dev/" ^ sd in
- let vsize = g#blockdev_getsize64 dev in
-
- { ov_overlay_file = overlay_file; ov_sd = sd;
- ov_virtual_size = vsize; ov_source = source }
- ) overlays in
-
(* Work out where we will write the final output. Do this early
* just so we can display errors to the user before doing too much
* work.
@@ -451,6 +443,7 @@ let rec main () =
(* Save overlays if --debug-overlays option was used. *)
if debug_overlays then (
+ let overlay_dir = (new Guestfs.guestfs ())#get_cachedir () in
List.iter (
fun ov ->
let saved_filename =
--
2.4.3