prepare storage for lvmthin gui

this patch adds an lvmthin scan to the api, so that we can get a list
of thinpools for a specific vg via an api call

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

PVE/API2/Storage/Scan.pm

@@ -238,6 +238,41 @@ __PACKAGE__->register_method ({
 	return PVE::RESTHandler::hash_to_array($res, 'vg');
     }});
 
+__PACKAGE__->register_method ({
+    name => 'thinlvmscan',
+    path => 'lvmthin',
+    method => 'GET',
+    description => "List local LVM Thin Pools.",
+    protected => 1,
+    proxyto => "node",
+    permissions => {
+	check => ['perm', '/storage', ['Datastore.Allocate']],
+    },
+    parameters => {
+	additionalProperties => 0,
+	properties => {
+	    node => get_standard_option('pve-node'),
+	    vg => {
+		type => 'string',
+		pattern => '[a-zA-Z0-9\.\+\_][a-zA-Z0-9\.\+\_\-]+', # see lvm(8) manpage
+		maxLength => 100,
+	    },
+	},
+    },
+    returns => {
+	type => 'array',
+	items => {
+	    type => "object",
+	    properties => {
+		lv => { type => 'string'},
+	    },
+	},
+    },
+    code => sub {
+	my ($param) = @_;
+	return PVE::Storage::LvmThinPlugin::list_thinpools($param->{vg});
+    }});
+
 __PACKAGE__->register_method ({
     name => 'usbscan', 
     path => 'usb', 

PVE/Storage/LvmThinPlugin.pm

@@ -163,6 +163,20 @@ sub list_images {
     return $res;
 }
 
+sub list_thinpools {
+    my ($vg) = @_;
+
+    my $lvs = PVE::Storage::LVMPlugin::lvm_list_volumes($vg);
+    my $thinpools = [];
+
+    foreach my $lvname (keys %{$lvs->{$vg}}) {
+	next if $lvs->{$vg}->{$lvname}->{lv_type} ne 't';
+	push @$thinpools, { lv => $lvname };
+    }
+
+    return $thinpools;
+}
+
 sub status {
     my ($class, $storeid, $scfg, $cache) = @_;