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sparsify: Add virt-sparsify --in-place mode.

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This commit is contained in:
Richard W.M. Jones
2014-03-11 18:28:49 +00:00
parent b48e885004
commit e3a32f95d0
6 changed files with 259 additions and 30 deletions
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1
po/POTFILES-ml
View File

@@ -35,6 +35,7 @@ mllib/urandom.ml
resize/resize.ml
sparsify/cmdline.ml
sparsify/copying.ml
sparsify/in_place.ml
sparsify/sparsify.ml
sysprep/main.ml
sysprep/sysprep_operation.ml

2
sparsify/Makefile.am
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@@ -28,6 +28,7 @@ CLEANFILES = *~ *.cmi *.cmo *.cmx *.cmxa *.o virt-sparsify
SOURCES = \
cmdline.ml \
copying.ml \
in_place.ml \
sparsify.ml \
statvfs-c.c
@@ -46,6 +47,7 @@ deps = \
statvfs-c.o \
cmdline.cmx \
copying.cmx \
in_place.cmx \
sparsify.cmx
if HAVE_OCAMLOPT

77
sparsify/cmdline.ml
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@@ -27,7 +27,8 @@ let prog = Filename.basename Sys.executable_name
let error fs = error ~prog fs
type mode_t =
Mode_copying of string * check_t * bool * string option * string option
| Mode_copying of string * check_t * bool * string option * string option
| Mode_in_place
and check_t = [`Ignore|`Continue|`Warn|`Fail]
let parse_cmdline () =
@@ -54,6 +55,7 @@ let parse_cmdline () =
let debug_gc = ref false in
let format = ref "" in
let ignores = ref [] in
let in_place = ref false in
let machine_readable = ref false in
let option = ref "" in
let quiet = ref false in
@@ -69,6 +71,8 @@ let parse_cmdline () =
"--debug-gc", Arg.Set debug_gc, " " ^ s_"Debug GC and memory allocations";
"--format", Arg.Set_string format, s_"format" ^ " " ^ s_"Format of input disk";
"--ignore", Arg.String (add ignores), s_"fs" ^ " " ^ s_"Ignore filesystem";
"--in-place", Arg.Set in_place, " " ^ s_"Modify the disk image in-place";
"--inplace", Arg.Set in_place, ditto;
"--long-options", Arg.Unit display_long_options, " " ^ s_"List long options";
"--machine-readable", Arg.Set machine_readable, " " ^ s_"Make output machine readable";
"-o", Arg.Set_string option, s_"option" ^ " " ^ s_"Add qemu-img options";
@@ -90,6 +94,8 @@ let parse_cmdline () =
virt-sparsify [--options] indisk outdisk
virt-sparsify [--options] --in-place disk
A short summary of the options is given below. For detailed help please
read the man page virt-sparsify(1).
")
@@ -103,6 +109,7 @@ read the man page virt-sparsify(1).
let debug_gc = !debug_gc in
let format = match !format with "" -> None | str -> Some str in
let ignores = List.rev !ignores in
let in_place = !in_place in
let machine_readable = !machine_readable in
let option = match !option with "" -> None | str -> Some str in
let quiet = !quiet in
@@ -118,6 +125,7 @@ read the man page virt-sparsify(1).
printf "linux-swap\n";
printf "zero\n";
printf "check-tmpdir\n";
printf "in-place\n";
let g = new G.guestfs () in
g#add_drive "/dev/null";
g#launch ();
@@ -128,12 +136,14 @@ read the man page virt-sparsify(1).
exit 0
);
(* Verify we got exactly 2 disks. *)
(* Verify we got exactly 1 or 2 disks, depending on the mode. *)
let indisk, outdisk =
match List.rev !disks with
| [indisk; outdisk] -> indisk, outdisk
match in_place, List.rev !disks with
| false, [indisk; outdisk] -> indisk, outdisk
| true, [disk] -> disk, ""
| _ ->
error "usage is: %s [--options] indisk outdisk" prog in
error "usage is: %s [--options] indisk outdisk OR %s --in-place disk"
prog prog in
(* Simple-minded check that the user isn't trying to use the
* same disk for input and output.
@@ -141,24 +151,49 @@ read the man page virt-sparsify(1).
if indisk = outdisk then
error (f_"you cannot use the same disk image for input and output");
(* The input disk must be an absolute path, so we can store the name
* in the overlay disk.
*)
let indisk =
if not (Filename.is_relative indisk) then
if not in_place then (
(* The input disk must be an absolute path, so we can store the name
* in the overlay disk.
*)
let indisk =
if not (Filename.is_relative indisk) then
indisk
else
Sys.getcwd () // indisk in
(* Check the output is not a block or char special (RHBZ#1056290). *)
if is_block_device outdisk then
error (f_"output '%s' cannot be a block device, it must be a regular file")
outdisk;
if is_char_device outdisk then
error (f_"output '%s' cannot be a character device, it must be a regular file")
outdisk;
indisk
)
else ( (* --in-place checks *)
if check_tmpdir <> `Warn then
error (f_"you cannot use --in-place and --check-tmpdir options together");
if compress then
error (f_"you cannot use --in-place and --compress options together");
if convert <> None then
error (f_"you cannot use --in-place and --convert options together");
if option <> None then
error (f_"you cannot use --in-place and -o options together");
indisk
) in
let mode =
if not in_place then
Mode_copying (outdisk, check_tmpdir, compress, convert, option)
else
Sys.getcwd () // indisk in
(* Check the output is not a block or char special (RHBZ#1056290). *)
if is_block_device outdisk then
error (f_"output '%s' cannot be a block device, it must be a regular file")
outdisk;
if is_char_device outdisk then
error (f_"output '%s' cannot be a character device, it must be a regular file")
outdisk;
Mode_in_place in
indisk, debug_gc, format, ignores, machine_readable,
quiet, verbose, trace, zeroes,
Mode_copying (outdisk, check_tmpdir, compress, convert, option)
quiet, verbose, trace, zeroes, mode

143
sparsify/in_place.ml Normal file
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@@ -0,0 +1,143 @@
(* virt-sparsify
* Copyright (C) 2011-2014 Red Hat Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*)
(* This is the virt-sparsify --in-place mode. *)
open Unix
open Printf
open Common_gettext.Gettext
module G = Guestfs
open Common_utils
open Cmdline
let run disk format ignores machine_readable quiet verbose trace zeroes =
(* Connect to libguestfs. *)
let g = new G.guestfs () in
if trace then g#set_trace true;
if verbose then g#set_verbose true;
(* XXX Current limitation of the API. Can remove this hunk in future. *)
let format =
match format with
| Some _ -> format
| None -> Some (g#disk_format disk) in
g#add_drive ?format ~discard:"enable" disk;
if not quiet then Progress.set_up_progress_bar ~machine_readable g;
g#launch ();
(* Discard non-ignored filesystems that we are able to mount, and
* selected swap partitions.
*)
let filesystems = g#list_filesystems () in
let filesystems = List.map fst filesystems in
let filesystems = List.sort compare filesystems in
let is_ignored fs =
let fs = g#canonical_device_name fs in
List.exists (fun fs' -> fs = g#canonical_device_name fs') ignores
in
List.iter (
fun fs ->
if not (is_ignored fs) then (
if List.mem fs zeroes then (
if not quiet then
printf (f_"Zeroing %s ...\n%!") fs;
if not (g#blkdiscardzeroes fs) then
g#zero_device fs;
g#blkdiscard fs
) else (
let mounted =
try g#mount_options "discard" fs "/"; true
with _ -> false in
if mounted then (
if not quiet then
printf (f_"Trimming %s ...\n%!") fs;
g#fstrim "/"
) else (
let is_linux_x86_swap =
(* Look for the signature for Linux swap on i386.
* Location depends on page size, so it definitely won't
* work on non-x86 architectures (eg. on PPC, page size is
* 64K). Also this avoids hibernated swap space: in those,
* the signature is moved to a different location.
*)
try g#pread_device fs 10 4086L = "SWAPSPACE2"
with _ -> false in
if is_linux_x86_swap then (
if not quiet then
printf (f_"Clearing Linux swap on %s ...\n%!") fs;
(* Don't use mkswap. Just preserve the header containing
* the label, UUID and swap format version (libguestfs
* mkswap may differ from guest's own).
*)
let header = g#pread_device fs 4096 0L in
g#blkdiscard fs;
if g#pwrite_device fs header 0L <> 4096 then
error (f_"pwrite: short write restoring swap partition header")
)
)
);
g#umount_all ()
)
) filesystems;
(* Discard unused space in volume groups. *)
let vgs = g#vgs () in
let vgs = Array.to_list vgs in
let vgs = List.sort compare vgs in
List.iter (
fun vg ->
if not (List.mem vg ignores) then (
let lvname = string_random8 () in
let lvdev = "/dev/" ^ vg ^ "/" ^ lvname in
let created =
try g#lvcreate_free lvname vg 100; true
with _ -> false in
if created then (
if not quiet then
printf (f_"Discard space in volgroup %s ...\n%!") vg;
g#blkdiscard lvdev;
g#sync ();
g#lvremove lvdev
)
)
) vgs;
g#shutdown ();
g#close ();
(* Finished. *)
if not quiet then (
print_newline ();
wrap (s_"Sparsify in-place operation completed with no errors.\n");
)

3
sparsify/sparsify.ml
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@@ -37,6 +37,9 @@ let rec main () =
| Mode_copying (outdisk, check_tmpdir, compress, convert, option) ->
Copying.run indisk outdisk check_tmpdir compress convert
format ignores machine_readable option quiet verbose trace zeroes
| Mode_in_place ->
In_place.run indisk format ignores machine_readable
quiet verbose trace zeroes
);
if debug_gc then

63
sparsify/virt-sparsify.pod
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@@ -8,6 +8,8 @@ virt-sparsify - Make a virtual machine disk sparse
virt-sparsify [--options] indisk outdisk
virt-sparsify [--options] --in-place disk
=head1 DESCRIPTION
Virt-sparsify is a tool which can make a virtual machine disk (or any
@@ -45,13 +47,6 @@ such as C<du -sh>. It can make a huge difference:
=item *
Virt-sparsify does not do in-place modifications. It copies from a
source image to a destination image, leaving the source unchanged.
I<Check that the sparsification was successful before deleting the
source image>.
=item *
The virtual machine I<must be shut down> before using this tool.
=item *
@@ -60,6 +55,9 @@ Virt-sparsify may require up to 2x the virtual size of the source disk
image (1 temporary copy + 1 destination image). This is in the worst
case and usually much less space is required.
If you are using the I<--in-place> option, then large amounts of
temporary space are B<not> required.
=item *
Virt-sparsify cannot resize disk images. To do that, use
@@ -105,6 +103,11 @@ to ignore (don't zero free space on) certain filesystems by doing:
See L<virt-filesystems(1)> to get a list of filesystems within a disk
image.
Since virt-sparsify E<ge> 1.26, you can now sparsify a disk image
in place by doing:
virt-sparsify --in-place disk.img
=head1 OPTIONS
=over 4
@@ -147,11 +150,15 @@ B<fail> and exit.
=back
You cannot use this option and I<--in-place> together.
=item B<--compress>
Compress the output file. This I<only> works if the output format is
C<qcow2>.
You cannot use this option and I<--in-place> together.
=item B<--convert> raw
=item B<--convert> qcow2
@@ -171,6 +178,8 @@ then virt-sparsify doesn't need to try to guess the input format.
For fine-tuning the output format, see: I<--compress>, I<-o>.
You cannot use this option and I<--in-place> together.
=item B<--debug-gc>
Debug garbage collection and memory allocation. This is only useful
@@ -191,14 +200,23 @@ ensure the format is always specified.
=item B<--ignore> volgroup
Ignore the named filesystem. Free space on the filesystem will not be
Ignore the named filesystem.
When not using I<--in-place>: Free space on the filesystem will not be
zeroed, but existing blocks of zeroes will still be sparsified.
When using I<--in-place>, the filesystem is ignored completely.
In the second form, this ignores the named volume group. Use the
volume group name without the C</dev/> prefix, eg. I<--ignore vg_foo>
You can give this option multiple times.
=item B<--in-place>
Do in-place sparsification instead of copying sparsification.
See L</IN-PLACE SPARSIFICATION> below.
=item B<--machine-readable>
This option is used to make the output more machine friendly
@@ -217,6 +235,8 @@ them with commas, eg:
virt-sparsify --convert qcow2 \
-o cluster_size=512,preallocation=metadata ...
You cannot use this option and I<--in-place> together.
=item B<-q>
=item B<--quiet>
@@ -249,6 +269,28 @@ excellent! You can give this option multiple times.
=back
=head1 IN-PLACE SPARSIFICATION
Since virt-sparsify E<ge> 1.26, the tool is able to do in-place
sparsification (instead of copying from an input disk to an output
disk). This is more efficient. However it requires special support
in libguestfs, the kernel and qemu, and it is not able to recover
quite as much space as copying sparsification. So in-place
sparsification is considered to be experimental at this time.
To use this mode, specify a disk image which will be modified in
place:
virt-sparsify --in-place disk.img
Some options are not compatible with this mode: I<--convert>,
I<--compress> and I<-o> because they require wholesale disk format
changes; I<--check-tmpdir> because large amounts of temporary space
are not required.
In-place sparsification works using discard (a.k.a trim or unmap)
support.
=head1 MACHINE READABLE OUTPUT
The I<--machine-readable> option can be used to make the output more
@@ -332,6 +374,9 @@ size of the tmpfs mountpoint, eg:
mount -o remount,size=10G /tmp
If you are using the I<--in-place> option, then large amounts of
temporary space are B<not> required.
=back
For other environment variables, see L<guestfs(3)/ENVIRONMENT VARIABLES>.
@@ -355,4 +400,4 @@ Richard W.M. Jones L<http://people.redhat.com/~rjones/>
=head1 COPYRIGHT
Copyright (C) 2011-2012 Red Hat Inc.
Copyright (C) 2011-2014 Red Hat Inc.