4:42 a.m.
This option allows oVirt to pass a prebuilt qcow2 file to use as the
temporary overlay. The file must be qcow2, and must have indisk as a
backing file - the code does minimal checks to ensure this is correct.
Example usage:
qemu-img create -f qcow2 -b indisk overlay.qcow2
virt-sparsify indisk --tmp prebuilt:overlay.qcow2 outdisk
Note this only applies in copying mode.
---
sparsify/cmdline.ml | 2 +-
sparsify/copying.ml | 54 ++++++++++++++++++++++++++++++++--------------
sparsify/virt-sparsify.pod | 27 +++++++++++++++++++++++
3 files changed, 66 insertions(+), 17 deletions(-)
diff --git a/sparsify/cmdline.ml b/sparsify/cmdline.ml
index 11e5895..a99c851 100644
--- a/sparsify/cmdline.ml
+++ b/sparsify/cmdline.ml
@@ -80,7 +80,7 @@ let parse_cmdline () =
"-o", Arg.Set_string option, s_"option" ^ "
" ^ s_"Add qemu-img options";
"-q", Arg.Set quiet, " " ^ s_"Quiet
output";
"--quiet", Arg.Set quiet, ditto;
- "--tmp", Arg.Set_string tmp, s_"block|dir" ^ "
" ^ s_"Set temporary block device or directory";
+ "--tmp", Arg.Set_string tmp,
s_"block|dir|prebuilt:file" ^ " " ^ s_"Set temporary block
device, directory or prebuilt file";
"-v", Arg.Set verbose, " " ^ s_"Enable
debugging messages";
"--verbose", Arg.Set verbose, ditto;
"-V", Arg.Unit display_version, " " ^ s_"Display
version and exit";
diff --git a/sparsify/copying.ml b/sparsify/copying.ml
index 5afb22f..b167b0c 100644
--- a/sparsify/copying.ml
+++ b/sparsify/copying.ml
@@ -33,7 +33,8 @@ open Cmdline
external statvfs_free_space : string -> int64 =
"virt_sparsify_statvfs_free_space"
-type tmp_place = Directory of string | Block_device of string
+type tmp_place =
+| Directory of string | Block_device of string | Prebuilt_file of string
let run indisk outdisk check_tmpdir compress convert
format ignores machine_readable option tmp_param
@@ -74,12 +75,26 @@ let run indisk outdisk check_tmpdir compress convert
| None -> Directory Filename.temp_dir_name (* $TMPDIR or /tmp *)
| Some dir when is_directory dir -> Directory dir
| Some dev when is_block_device dev -> Block_device dev
+ | Some file when string_prefix file "prebuilt:" ->
+ let file = String.sub file 9 (String.length file - 9) in
+ if not (Sys.file_exists file) then
+ error (f_"--tmp prebuilt:file: %s: file does not exist") file;
+ let g = new G.guestfs () in
+ if trace then g#set_trace true;
+ if verbose then g#set_verbose true;
+ if g#disk_format file <> "qcow2" then
+ error (f_"--tmp prebuilt:file: %s: file format is not qcow2") file;
+ if not (g#disk_has_backing_file file) then
+ error (f_"--tmp prebuilt:file: %s: file does not have backing file")
+ file;
+ Prebuilt_file file
| Some path ->
- error (f_"--tmp parameter must point to a directory or a block device")
in
+ error (f_"--tmp parameter must point to a directory, block device or prebuilt
file") in
(* Check there is enough space in temporary directory. *)
(match tmp_place with
- | Block_device _ -> ()
+ | Block_device _
+ | Prebuilt_file _ -> ()
| Directory tmpdir ->
(* Get virtual size of the input disk. *)
let virtual_size = (new G.guestfs ())#disk_virtual_size indisk in
@@ -136,31 +151,38 @@ You can ignore this warning or change it to a hard failure using
the
| Block_device device ->
printf (f_"Create overlay device %s to protect source disk ...\n%!")
device
+ | Prebuilt_file file ->
+ printf (f_"Using prebuilt file %s as overlay ...\n%!") file
);
- let tmp =
- match tmp_place with
- | Directory temp_dir ->
- let tmp = Filename.temp_file ~temp_dir "sparsify" ".qcow2"
in
- unlink_on_exit tmp;
- tmp
-
- | Block_device device -> device in
-
- (* Create it with the indisk as the backing file. *)
+ (* Create 'tmp' with the indisk as the backing file. *)
(* XXX Old code used to:
* - detect if compat=1.1 was supported
* - add lazy_refcounts option
*)
- let () =
+ let create tmp =
let g = new G.guestfs () in
if trace then g#set_trace true;
if verbose then g#set_verbose true;
g#disk_create
~backingfile:indisk ?backingformat:format ~compat:"1.1"
- tmp "qcow2" Int64.minus_one in
+ tmp "qcow2" Int64.minus_one
+ in
- tmp in
+ match tmp_place with
+ | Directory temp_dir ->
+ let tmp = Filename.temp_file ~temp_dir "sparsify" ".qcow2" in
+ unlink_on_exit tmp;
+ create tmp;
+ tmp
+
+ | Block_device device ->
+ create device;
+ device
+
+ | Prebuilt_file file ->
+ (* Don't create anything, use the prebuilt file as overlay. *)
+ file in
if not quiet then
printf (f_"Examine source disk ...\n%!");
diff --git a/sparsify/virt-sparsify.pod b/sparsify/virt-sparsify.pod
index bb7dbae..3b6cebd 100644
--- a/sparsify/virt-sparsify.pod
+++ b/sparsify/virt-sparsify.pod
@@ -262,6 +262,33 @@ L</TMPDIR> environment variable.
You cannot use this option and I<--in-place> together.
+=item B<--tmp> prebuilt:file
+
+In copying mode only, the specialized option I<--tmp prebuilt:file>
+(where C<prebuilt:> is a literal string) causes virt-sparsify to use
+the qcow2 C<file> as temporary space.
+
+=over 4
+
+=item *
+
+The file B<must> be freshly formatted as qcow2, with indisk as the
+backing file.
+
+=item *
+
+If you rerun virt-sparsify, you B<must> recreate the file before
+each run.
+
+=item *
+
+Virt-sparsify does not delete the file.
+
+=back
+
+This option is used by oVirt which requires a specially formatted
+temporary file.
+
=item B<-v>
=item B<--verbose>
--
1.9.0