#ifndef _NTIOAPI_H

#define IOCTL_MOUNTMGR_KEEP_LINKS_WHEN_OFFLINE      CTL_CODE(MOUNTMGRCONTROLTYPE, 9, METHOD_BUFFERED, FILE_READ_ACCESS | FILE_WRITE_ACCESS)

#endif
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// mountmgr.h

// CTL_CODE(0x006d, 0x009, METHOD_BUFFERED, FILE_READ_ACCESS | FILE_WRITE_ACCESS)
#define IOCTL_MOUNTMGR_KEEP_LINKS_WHEN_OFFLINE 0x006DC024
View the official Windows Driver Kit DDI reference

NtDoc

This IOCTL is documented in Windows Driver Kit.

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Windows Driver Kit DDI reference (ni-mountmgr-ioctl_mountmgr_keep_links_when_offline)

Description

This IOCTL directs the mount manager to keep a symbolic link active after the Plug and Play manager has given notification that its corresponding volume has gone offline. When the volume goes back online, the mount manager reassigns the symbolic link to the volume. No other volume is allowed to claim the symbolic link while its original owner is offline.

Clusters use this IOCTL to ensure that a node can continue to access a volume with the same drive letter, even if the volume is not continually present in the system.

Parameters

Major code

IRP_MJ_DEVICE_CONTROL

Input buffer

The mount manager client loads the following structure with the symbolic link that will persist even after its volume is removed from the system. The initialized structure MOUNTMGR_TARGET_NAME is inserted 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_TARGET_NAME).

Output buffer

None.

Output buffer length

None.

Input/output buffer

N/A

Input/output buffer length

N/A

Status block

If the operation is successful, the Status field is set to STATUS_SUCCESS.

The input buffer size, indicated by InputBufferLength, must be large enough to hold the structure MOUNTMGR_TARGET_NAME and the symbolic link name that follows it. If it is not large enough, the Status field is set to STATUS_INVALID_PARAMETER.

Remarks

For more information, see Supporting Mount Manager Requests in a Storage Class Driver.

IOCTL_MOUNTMGR_KEEP_LINKS_WHEN_OFFLINE - NtDoc