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sparsify: Implement --zero option.

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This unconditionally zeroes the named partition or filesystem.
This commit is contained in:
Richard W.M. Jones
2012-03-15 16:07:08 +00:00
parent 1c1ecb2c41
commit 98f066e274
2 changed files with 46 additions and 27 deletions
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65
sparsify/sparsify.ml
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@@ -30,7 +30,7 @@ let prog = Filename.basename Sys.executable_name
let indisk, outdisk, compress, convert, debug_gc,
format, ignores, machine_readable,
option, quiet, verbose, trace =
option, quiet, verbose, trace, zeroes =
let display_version () =
let g = new G.guestfs () in
let version = g#version () in
@@ -51,6 +51,7 @@ let indisk, outdisk, compress, convert, debug_gc,
let quiet = ref false in
let verbose = ref false in
let trace = ref false in
let zeroes = ref [] in
let argspec = Arg.align [
"--compress", Arg.Set compress, " Compressed output format";
@@ -67,6 +68,7 @@ let indisk, outdisk, compress, convert, debug_gc,
"-V", Arg.Unit display_version, " Display version and exit";
"--version", Arg.Unit display_version, " -\"-";
"-x", Arg.Set trace, " Enable tracing of libguestfs calls";
"--zero", Arg.String (add zeroes), "fs Zero filesystem";
] in
let disks = ref [] in
let anon_fun s = disks := s :: !disks in
@@ -93,6 +95,7 @@ read the man page virt-sparsify(1).
let quiet = !quiet in
let verbose = !verbose in
let trace = !trace in
let zeroes = List.rev !zeroes in
(* No arguments and machine-readable mode? Print out some facts
* about what this binary supports.
@@ -100,6 +103,7 @@ read the man page virt-sparsify(1).
if !disks = [] && machine_readable then (
printf "virt-sparsify\n";
printf "linux-swap\n";
printf "zero\n";
let g = new G.guestfs () in
g#add_drive_opts "/dev/null";
g#launch ();
@@ -135,7 +139,7 @@ read the man page virt-sparsify(1).
indisk, outdisk, compress, convert,
debug_gc, format, ignores, machine_readable,
option, quiet, verbose, trace
option, quiet, verbose, trace, zeroes
let () =
if not quiet then
@@ -204,38 +208,45 @@ let () =
List.iter (
fun fs ->
if not (is_ignored fs) then (
let mounted =
try g#mount_options "" fs "/"; true
with _ -> false in
if mounted then (
if List.mem fs zeroes then (
if not quiet then
printf "Fill free space in %s with zero ...\n%!" fs;
printf "Zeroing %s ...\n%!" fs;
g#zero_free_space "/"
g#zero_device fs
) 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"
let mounted =
try g#mount_options "" fs "/"; true
with _ -> false in
if is_linux_x86_swap then (
if mounted then (
if not quiet then
printf "Clearing Linux swap on %s ...\n%!" fs;
printf "Fill free space in %s with zero ...\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#zero_device fs;
if g#pwrite_device fs header 0L <> 4096 then
error "pwrite: short write restoring swap partition header"
g#zero_free_space "/"
) 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 "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#zero_device fs;
if g#pwrite_device fs header 0L <> 4096 then
error "pwrite: short write restoring swap partition header"
)
)
);

8
sparsify/virt-sparsify.pod
View File

@@ -191,6 +191,14 @@ Display version number and exit.
Enable tracing of libguestfs API calls.
=item B<--zero> partition
=item B<--zero> logvol
Zero the contents of the named partition or logical volume in the
guest. All data on the device is lost, but sparsification is
excellent! You can give this option multiple times.
=back
=head1 MACHINE READABLE OUTPUT