This patch implements volume information queries for device files, which allows NtQueryVolumeInformationFile to issue IRP_MJ_QUERY_VOLUME_INFORMATION to return volume information from a driver. The patch also now includes a simple test that issues FileFsVolumeInformation (for systems that support unsigned drivers).
v5: No change v4: Split out content from server/device.c and dlls/ntoskrnl.exe/ntoskrnl.c, fixed copy-paste error identified by Zeb, and added tests
Best, Erich