Fixes Invoke-IcingaCheckPartitionSpace to report unknown if no usage data was found

Author: LordHepipud

plugins/Invoke-IcingaCheckUsedPartitionSpace.psm1

@@ -181,6 +181,12 @@ function Invoke-IcingaCheckPartitionSpace()
             } else {
                 $IcingaCheck.SetOk('No disk size available', $TRUE) | Out-Null;
             }
+        } elseif ([string]::IsNullOrEmpty($partition.FreeSpace) -or [string]::IsNullOrEmpty($partition.UsedSpace)) {
+            if ($SkipUnknown -eq $FALSE) {
+                $IcingaCheck.SetUnknown('No disk usage size available', $TRUE) | Out-Null;
+            } else {
+                $IcingaCheck.SetOk('No disk usage available', $TRUE) | Out-Null;
+            }
         } else {
             $IcingaCheck.WarnOutOfRange($Warning).CritOutOfRange($Critical) | Out-Null;
         }

provider/disks/Get-IcingaPartitionSpace.psm1

@@ -36,12 +36,18 @@ function Get-IcingaPartitionSpace()
             break;
         }
 
+        $UsedSpace = $null;
+
+        if ($null -ne $disk.FreeSpace) {
+            $UsedSpace = $DiskSize - [decimal]$disk.FreeSpace;
+        }
+
         $DiskData.Add(
             $disk.Name,
             @{
                 'Size'        = $DiskSize;
                 'FreeSpace'   = $disk.FreeSpace;
-                'UsedSpace'   = ($DiskSize - $disk.FreeSpace);
+                'UsedSpace'   = $UsedSpace;
                 'DriveLetter' = $disk.DriveLetter;
                 'DriveName'   = $disk.Name;
                 'HasLetter'   = -not [string]::IsNullOrEmpty($disk.DriveLetter);