[pve-devel] [PATCH storage v3 05/13] rbd plugin: implement volume import/export

[Fiona Ebner]

For now, only 'raw+size' is supported and it's not possible to
export/import with snapshots. The volume or snapshot is exported or
imported via the corresponding 'rbd' commands.

Introducing an 'rbd' transport format might be feasible for more
complete (i.e. with snapshots, incremental) transfer between two RBD
storages.

Use the '--dest-pool' switch rather than '-p' for import, because the
latter is deprecated.

Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---

Changes in v3:
* use rbd export/import

 src/PVE/Storage/RBDPlugin.pm | 102 ++++++++++++++++++++++++++++++++++-
 1 file changed, 101 insertions(+), 1 deletion(-)

diff --git a/src/PVE/Storage/RBDPlugin.pm b/src/PVE/Storage/RBDPlugin.pm
index 301918c..44770b0 100644
--- a/src/PVE/Storage/RBDPlugin.pm
+++ b/src/PVE/Storage/RBDPlugin.pm
@@ -88,7 +88,13 @@ my $build_cmd = sub {
     my $cmd_option = PVE::CephConfig::ceph_connect_option($scfg, $storeid);
     my $pool =  $scfg->{pool} ? $scfg->{pool} : 'rbd';
 
-    my $cmd = [$binary, '-p', $pool];
+
+    my $cmd = [$binary];
+    if ($op eq 'import') {
+	push $cmd->@*, '--dest-pool', $pool;
+    } else {
+	push $cmd->@*, '-p', $pool;
+    }
 
     if (defined(my $namespace = $scfg->{namespace})) {
 	# some subcommands will fail if the --namespace parameter is present
@@ -864,6 +870,100 @@ sub volume_has_feature {
     return undef;
 }
 
+sub volume_export_formats {
+    my ($class, $scfg, $storeid, $volname, $snapshot, $base_snapshot, $with_snapshots) = @_;
+
+    return $class->volume_import_formats(
+	$scfg, $storeid, $volname, $snapshot, $base_snapshot, $with_snapshots);
+}
+
+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);
+
+    my ($size) = $class->volume_size_info($scfg, $storeid, $volname);
+    PVE::Storage::Plugin::write_common_header($fh, $size);
+    my $cmd = $rbd_cmd->($scfg, $storeid, 'export', '--export-format', '1', $volname, '-');
+    run_rbd_command(
+	$cmd,
+	errmsg => 'could not export image',
+	output => '>&'.fileno($fh),
+    );
+
+    return;
+}
+
+sub volume_import_formats {
+    my ($class, $scfg, $storeid, $volname, $snapshot, $base_snapshot, $with_snapshots) = @_;
+    return () if $with_snapshots; # not supported
+    return () if defined($base_snapshot); # not supported
+    return ('raw+size');
+}
+
+sub volume_import {
+    my (
+	$class,
+	$scfg,
+	$storeid,
+	$fh,
+	$volname,
+	$format,
+	$snapshot,
+	$base_snapshot,
+	$with_snapshots,
+	$allow_rename,
+    ) = @_;
+
+    die "volume import format $format not available for $class\n" if $format ne 'raw+size';
+    die "cannot import volumes together with their snapshots in $class\n" if $with_snapshots;
+    die "cannot import an incremental stream in $class\n" if defined($base_snapshot);
+
+    my (undef, $name, $vmid, undef, undef, undef, $file_format) = $class->parse_volname($volname);
+    die "cannot import format $format into a volume of format $file_format\n"
+	if $file_format ne 'raw';
+
+    if (rbd_volume_exists($scfg, $storeid, $name)) {
+	die "volume $name already exists\n" if !$allow_rename;
+	warn "volume $name already exists - importing with a different name\n";
+	$volname = $class->find_free_diskname($storeid, $scfg, $vmid, $file_format);
+    }
+
+    my ($size) = PVE::Storage::Plugin::read_common_header($fh);
+    $size = int($size/1024);
+
+    eval {
+	my $cmd = $rbd_cmd->($scfg, $storeid, 'import', '--export-format', '1', '-', $volname);
+	run_rbd_command(
+	    $cmd,
+	    errmsg => 'could not import image',
+	    input => '<&'.fileno($fh),
+	);
+    };
+    if (my $err = $@) {
+	# FIXME there is a slight race between finding the free disk name and removal here
+	# Does not only affect this plugin, see:
+	# https://lore.proxmox.com/pve-devel/20240403150712.262773-1-h.duerr@proxmox.com/
+	eval { $class->free_image($storeid, $scfg, $volname, 0, $file_format); };
+	warn $@ if $@;
+	die $err;
+    }
+
+    return "$storeid:$volname";
+}
+
 sub rename_volume {
     my ($class, $scfg, $storeid, $source_volname, $target_vmid, $target_volname) = @_;
 
-- 
2.39.5