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IOCTL_MOUNTMGR_CHANGE_NOTIFY IOCTL (mountmgr.h)

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Clients send this IOCTL to the mount manager to be informed whenever there is a change in the mount manager's persistent symbolic link name database.

The mount manager maintains a counter called EpicNumber that records how many changes have occurred in its persistent name database since the last startup. Clients send a number to the mount manager with every change notification request IRP, and the mount manager responds in the following manner:

  • If the number supplied by the client is not equal to EpicNumber, the mount manager returns STATUS_SUCCESS, indicating that changes have occurred since the client last compared its number with the mount manager's EpicNumber.
  • If the number supplied by the client is equal to EpicNumber, the mount manager interprets this as a request to be informed of the next change to the persistent name database, and it queues the change notification IRP and returns STATUS_PENDING. Whenever a change occurs in the database, the mount manager completes all of the pending change notification IRPs, thereby informing clients of the change.
A client that only wants to be informed of the changes to a particular volume is advised to register for Plug and Play target device notification and watch for GUID_IO_VOLUME_NAME_CHANGE.

Major code

IRP_MJ_DEVICE_CONTROL

Input buffer

The mount manager client initializes the MOUNTMGR_CHANGE_NOTIFY_INFO structure, defined in Mountmgr.h, at the beginning of the buffer at Irp->AssociatedIrp.SystemBuffer.

Input buffer length

Parameters.DeviceIoControl.InputBufferLength in the I/O stack location of the IRP indicates the size, in bytes, of the input buffer, which must be greater than or equal to sizeof(MOUNTMGR_CHANGE_NOTIFY_INFO).

Output buffer

The mount manager returns the current EpicNumber in the MOUNTMGR_CHANGE_NOTIFY_INFO structure, defined in Mountmgr.h, at the beginning of the buffer at Irp->AssociatedIrp.SystemBuffer.

Status block

If the operation is successful, the Status field is set to STATUS_SUCCESS and the Information field is set to sizeof(MOUNTMGR_CHANGE_NOTIFY_INFO).

If InputBufferLength is less than sizeof(MOUNTMGR_CHANGE_NOTIFY_INFO) or OutputBufferLength is less than sizeof(MOUNTMGR_CHANGE_NOTIFY_INFO), the Status field is set to STATUS_INVALID_PARAMETER.

Requirements

Requirement Value
Header mountmgr.h (include Mountmgr.h)

See also

MOUNTMGR_CHANGE_NOTIFY_INFO