diff --git a/PVE/API2/Disks/Directory.pm b/PVE/API2/Disks/Directory.pm
index 27009f5..a1e1afe 100644
--- a/PVE/API2/Disks/Directory.pm
+++ b/PVE/API2/Disks/Directory.pm
@@ -201,7 +201,7 @@ __PACKAGE__->register_method ({
 	my $type = $param->{filesystem} // 'ext4';
 
 	$dev = PVE::Diskmanage::verify_blockdev_path($dev);
-	PVE::Diskmanage::check_unused($dev);
+	PVE::Diskmanage::assert_disk_unused($dev);
 	PVE::Storage::assert_sid_unused($name) if $param->{add_storage};
 
 	my $worker = sub {
diff --git a/PVE/API2/Disks/LVM.pm b/PVE/API2/Disks/LVM.pm
index 7f8c319..569e9d1 100644
--- a/PVE/API2/Disks/LVM.pm
+++ b/PVE/API2/Disks/LVM.pm
@@ -149,7 +149,7 @@ __PACKAGE__->register_method ({
 	my $node = $param->{node};
 
 	$dev = PVE::Diskmanage::verify_blockdev_path($dev);
-	PVE::Diskmanage::check_unused($dev);
+	PVE::Diskmanage::assert_disk_unused($dev);
 	PVE::Storage::assert_sid_unused($name) if $param->{add_storage};
 
 	my $worker = sub {
diff --git a/PVE/API2/Disks/LVMThin.pm b/PVE/API2/Disks/LVMThin.pm
index 596d393..23c0279 100644
--- a/PVE/API2/Disks/LVMThin.pm
+++ b/PVE/API2/Disks/LVMThin.pm
@@ -103,7 +103,7 @@ __PACKAGE__->register_method ({
 	my $node = $param->{node};
 
 	$dev = PVE::Diskmanage::verify_blockdev_path($dev);
-	PVE::Diskmanage::check_unused($dev);
+	PVE::Diskmanage::assert_disk_unused($dev);
 	PVE::Storage::assert_sid_unused($name) if $param->{add_storage};
 
 	my $worker = sub {
diff --git a/PVE/API2/Disks/ZFS.pm b/PVE/API2/Disks/ZFS.pm
index f187eb2..371cc5a 100644
--- a/PVE/API2/Disks/ZFS.pm
+++ b/PVE/API2/Disks/ZFS.pm
@@ -341,7 +341,7 @@ __PACKAGE__->register_method ({
 
 	foreach my $dev (@$devs) {
 	    $dev = PVE::Diskmanage::verify_blockdev_path($dev);
-	    PVE::Diskmanage::check_unused($dev);
+	    PVE::Diskmanage::assert_disk_unused($dev);
 	}
 
 	PVE::Storage::assert_sid_unused($name) if $param->{add_storage};
diff --git a/PVE/Diskmanage.pm b/PVE/Diskmanage.pm
index 5a5fc87..def0791 100644
--- a/PVE/Diskmanage.pm
+++ b/PVE/Diskmanage.pm
@@ -602,10 +602,10 @@ sub locked_disk_action {
     return $res;
 }
 
-sub check_unused {
+sub assert_disk_unused {
     my ($dev) = @_;
 
-    die "device $dev is already in use\n" if disk_is_used($dev);
+    die "device '$dev' is already in use\n" if disk_is_used($dev);
 
     return undef;
 }