How can I relate \Device\HarddiskVolumeX to \Device\HarddiskY\PartitionZ

I’m writing a volume filter driver that sits atop disk.sys. I create a
device object for each volume (e.g. \Device\HarddiskVolume1) on the system.
I need to figure out where this volume resides on the physical
drive/parition (e.g. \Device\Harddisk0\Partition1).

Any ideas on how I can find the physical-drive/partition from a volume?

Thanks!