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FSCTL_UNLOCK_VOLUME IOCTL (winioctl.h)

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Unlocks a volume.

To perform this operation, call the DeviceIoControl function with the following parameters.

BOOL DeviceIoControl(
  (HANDLE) hDevice,            // handle to a volume
  FSCTL_UNLOCK_VOLUME,         // dwIoControlCode
  NULL,                        // lpInBuffer
  0,                           // nInBufferSize
  NULL,                        // lpOutBuffer
  0,                           // nOutBufferSize
  (LPDWORD) lpBytesReturned,   // number of bytes returned
  (LPOVERLAPPED) lpOverlapped  // OVERLAPPED structure
);

Irp->IoStatus.Status is set to STATUS_SUCCESS if the request is successful.

Otherwise, Status to the appropriate error condition as a NTSTATUS code.

For more information, see NTSTATUS Values.

Remarks

To lock a volume, use the FSCTL_LOCK_VOLUME control code.

The hDevice handle passed to DeviceIoControl must be a handle to a volume, opened for direct access. To retrieve this handle, call CreateFile with the lpFileName parameter set to a string of the following form:

\.\X:

where X is a hard-drive partition letter, floppy disk drive, or CD-ROM drive. The application must also specify the FILE_SHARE_READ and FILE_SHARE_WRITE flags in the dwShareMode parameter of CreateFile.

IIn Windows 8 and Windows Server 2012, this code is supported by the following technologies.

Technology Supported
Server Message Block (SMB) 3.0 protocol No
SMB 3.0 Transparent Failover (TFO) No
SMB 3.0 with Scale-out File Shares (SO) No
Cluster Shared Volume File System (CsvFS) See comment
 

PNP notification is issued only on the node where the FSCTL was issued.

After acquiring a lock on a CSV volume, you must close the handle used to lock that volume before opening a handle to the volume. Unlocking the volume by using FSCTL_UNLOCK_VOLUME is not sufficient.

Requirements

Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Header winioctl.h (include Windows.h)

See also

CreateFile

DeviceIoControl

FSCTL_LOCK_VOLUME

Volume Management Control Codes