The VDS_FILE_SYSTEM_NOTIFICATION structure provides information about a file system notification.

 typedef struct _VDS_FILE_SYSTEM_NOTIFICATION {
   unsigned long ulEvent;
   VDS_OBJECT_ID volumeId;
   DWORD dwPercentCompleted;
 } VDS_FILE_SYSTEM_NOTIFICATION;

ulEvent: Determines the file system event for which an application will be notified; it MUST be one of the following values.

Value	Meaning
VDS_NF_FILE_SYSTEM_MODIFY 0x000000CB	A volume received a new label, or a file system was extended or shrunk; does not include a change to the file system compression flags.
VDS_NF_FILE_SYSTEM_FORMAT_PROGRESS 0x000000CC	A file system is being formatted.

volumeId: The VDS object ID of the volume object containing the file system that triggered the event.

dwPercentCompleted: The completed format progress as a percentage of the whole.