Topic: Comparison FDO and it PDO
There are two USB flash.
Questions concerning Storage Device FDO and Logical Unit PDO, created usbstor.sys.
In current case FDO turn out from lower filter USBSTOR, and PDO undertake from FS the filter, and accordingly it is necessary to learn what volume is on what flash...
FDO1-Storage Device FDO, Created usbstor.sys
FDO2-Storage Device FDO, Created usbstor.sys
How knowing DEVICE_OBJECT FDO1, FDO2 and PDO1, PDO2 to learn, what PDO1 over FDO1 and PDO2 over FDO2?
Correctly I understand:
1. What it is impossible to receive DEVICE_OBJECT FDO, knowing PDO?
2. What it is impossible to interrogate (c the help irp requests or functions) FDO and to learn PDO which are under it?
3. It is theoretically possible to take NextDevice from DEVICE_OBJECT PDO and recursively to walk on all DEVICE_OBJECT created usbstor.sys and the first DEVICE_OBJECT with type FILE_DEVICE_BUS_EXTENDER and is underlaying FDO. But in this case, while we sort out NextDevice, somebody can be deleted or added and then actions are unpredictable.
Generally really to resolve this task?