diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index 61282d52..2df6d88c 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -662,6 +662,7 @@ my $delete_drive = sub {
 	my $volid = $drive->{file};
 	if (&$vm_is_volid_owner($storecfg, $vmid, $volid)) {
 	    if ($force || $key =~ m/^unused/) {
+		# fixme: aliases!!
 		eval { PVE::Storage::vdisk_free($storecfg, $volid); };
 		die $@ if $@;
 	    } else {
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 64c95f0d..db767d66 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -1696,6 +1696,7 @@ sub write_vm_config {
 
     my $used_volids = {};
 
+    # fixme: allow to add unused disk even if disk is used inside snapshot
     my $cleanup_config = sub {
 	my ($cref) = @_;
 
@@ -3643,8 +3644,11 @@ sub update_disksize {
 	    next if !$volid_hash->{$volid};
 
 	    $drive->{size} = $volid_hash->{$volid}->{size};
-	    $changes = 1;
-	    $conf->{$opt} = print_drive($vmid, $drive);
+	    my $new = print_drive($vmid, $drive);
+	    if ($new ne $conf->{$opt}) {
+		$changes = 1;
+		$conf->{$opt} = $new;
+	    }
 	}
     }