[pve-devel] [PATCH v2 storage 07/10] iscsi direct plugin: support volume export

[Filip Schauer]

To test exporting a volume from the `iscsidirect` storage backend, I
installed `libiscsi-bin` and configured the storage in
`/etc/pve/storage.cfg` by using the same options as I used for the
`iscsi` storage.

```
$ pvesm export tgtdirectstorage:lun1 raw+size output
```

Then I imported the volume into a directory storage:

```
$ pvesm import local:117/vm-117-disk-0.raw raw+size output
Formatting '/var/lib/vz/images/117/vm-117-disk-0.raw', fmt=raw 
size=4290772992 preallocation=off
65472+0 records in
65472+0 records out
4290772992 bytes (4.3 GB, 4.0 GiB) copied, 3.62069 s, 1.2 GB/s
successfully imported 'local:117/vm-117-disk-0.raw'
```

Assigned the disk to a VM and it also booted up just fine.

Trying to import into a user mode iSCSI storage fails as expected:

```
$ pvesm import tgtdirectstorage raw+size output
cannot import into volume 'tgtdirectstorage'
```

Tested-by: Filip Schauer <f.schauer at proxmox.com>

On 17/12/2024 16:48, Fiona Ebner wrote:
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> ---
>
> New in v2.
>
>   src/PVE/Storage/ISCSIDirectPlugin.pm | 63 ++++++++++++++++++++++++++++
>   1 file changed, 63 insertions(+)
>
> diff --git a/src/PVE/Storage/ISCSIDirectPlugin.pm b/src/PVE/Storage/ISCSIDirectPlugin.pm
> index 6f02eee..e5f6808 100644
> --- a/src/PVE/Storage/ISCSIDirectPlugin.pm
> +++ b/src/PVE/Storage/ISCSIDirectPlugin.pm
> @@ -2,9 +2,12 @@ package PVE::Storage::ISCSIDirectPlugin;
>   
>   use strict;
>   use warnings;
> +
>   use IO::File;
> +use JSON qw(decode_json);
>   use HTTP::Request;
>   use LWP::UserAgent;
> +
>   use PVE::Tools qw(run_command file_read_firstline trim dir_glob_regex dir_glob_foreach);
>   use PVE::Storage::Plugin;
>   use PVE::JSONSchema qw(get_standard_option);
> @@ -252,4 +255,64 @@ sub volume_has_feature {
>       return undef;
>   }
>   
> +sub volume_export_formats {
> +    my ($class, $scfg, $storeid, $volname, $snapshot, $base_snapshot, $with_snapshots) = @_;
> +
> +    return () if defined($snapshot); # not supported
> +    return () if defined($base_snapshot); # not supported
> +    return () if $with_snapshots; # not supported
> +    return ('raw+size');
> +}
> +
> +sub volume_export {
> +    my (
> +	$class,
> +	$scfg,
> +	$storeid,
> +	$fh,
> +	$volname,
> +	$format,
> +	$snapshot,
> +	$base_snapshot,
> +	$with_snapshots,
> +    ) = @_;
> +
> +    die "volume export format $format not available for $class\n" if $format ne 'raw+size';
> +    die "cannot export volumes together with their snapshots in $class\n" if $with_snapshots;
> +    die "cannot export an incremental stream in $class\n" if defined($base_snapshot);
> +    die "cannot export a snapshot in $class\n" if defined($snapshot);
> +
> +    my $file = $class->path($scfg, $volname, $storeid, $snapshot);
> +
> +    my $json = '';
> +    run_command(
> +	['/usr/bin/qemu-img', 'info', '-f', 'raw', '--output=json', $file],
> +	outfunc => sub { $json .= shift },
> +    );
> +    die "failed to query size information for '$file' with qemu-img\n" if !$json;
> +    my $info = eval { decode_json($json) };
> +    die "could not parse qemu-img info command output for '$file' - $@\n" if $@;
> +
> +    my ($size) = ($info->{'virtual-size'} =~ /^(\d+)$/); # untaint
> +    die "size '$size' not an integer\n" if !defined($size);
> +    $size = int($size); # coerce back from string
> +
> +    PVE::Storage::Plugin::write_common_header($fh, $size);
> +    run_command(
> +	['qemu-img', 'dd', 'bs=64k', "if=$file", '-f', 'raw', '-O', 'raw'],
> +	output => '>&'.fileno($fh),
> +    );
> +    return;
> +}
> +
> +sub volume_import_formats {
> +    my ($class, $scfg, $storeid, $volname, $snapshot, $base_snapshot, $with_snapshots) = @_;
> +
> +    return ();
> +}
> +
> +sub volume_import {
> +    die "volume import is not possible on iscsi storage\n";
> +}
> +
>   1;