Filter Device Object Attached to a Volume

Note

For optimal reliability and performance, use file system minifilter drivers with Filter Manager support instead of legacy file system filter drivers. To port your legacy driver to a minifilter driver, see Guidelines for Porting Legacy Filter Drivers.

To filter a volume, a filter driver creates a filter device object and attaches it above the volume device object for the volume.

Types of I/O Requests That Are Sent to a Volume

A filter device object that is attached above a volume can generally expect to receive the following types of I/O requests:

• IRP_MJ_CLEANUP
• IRP_MJ_CLOSE
• IRP_MJ_CREATE
• IRP_MJ_DEVICE_CONTROL
• IRP_MJ_DIRECTORY_CONTROL
• IRP_MJ_FILE_SYSTEM_CONTROL
• IRP_MJ_FLUSH_BUFFERS
• IRP_MJ_INTERNAL_DEVICE_CONTROL
• IRP_MJ_LOCK_CONTROL
• IRP_MJ_PNP
• IRP_MJ_QUERY_EA
• IRP_MJ_QUERY_INFORMATION
• IRP_MJ_QUERY_QUOTA
• IRP_MJ_QUERY_SECURITY
• IRP_MJ_QUERY_VOLUME_INFORMATION
• IRP_MJ_READ
• IRP_MJ_SET_EA
• IRP_MJ_SET_INFORMATION
• IRP_MJ_SET_QUOTA
• IRP_MJ_SET_SECURITY
• IRP_MJ_SET_VOLUME_INFORMATION
• IRP_MJ_SHUTDOWN
• IRP_MJ_WRITE
• Any of the following FAST_IO_DISPATCH callback routines:
  • FastIoCheckIfPossible
  • FastIoRead
  • FastIoWrite
  • FastIoQueryBasicInfo
  • FastIoQueryStandardInfo
  • FastIoLock
  • FastIoUnlockSingle
  • FastIoUnlockAll
  • FastIoUnlockAllByKey
  • FastIoDeviceControl
  • FastIoDetachDevice
  • FastIoQueryNetworkOpenInfo
  • MdlRead
  • MdlReadComplete
  • PrepareMdlWrite
  • MdlWriteComplete
  • FastIoReadCompressed
  • FastIoWriteCompressed
  • MdlReadCompleteCompressed
  • MdlWriteCompleteCompressed
  • FastIoQueryOpen

File system filter device objects attached to volumes must pass all unrecognized or unwanted IRPs to the next-lower driver on the driver stack by default. In addition, they must implement FastIoDetachDevice.

On Windows XP and later, file system filter drivers shouldn't use any of the following fast I/O callback routines because they're obsolete.

• AcquireForCcFlush
• AcquireFileForNtCreateSection
• AcquireForModWrite
• ReleaseForCcFlush
• ReleaseFileForNtCreateSection
• ReleaseForModWrite

For more information, see the reference entry for FsRtlRegisterFileSystemFilterCallbacks.