FSCTL_GET_RETRIEVAL_POINTERS IOCTL

Description

Given a file handle, retrieves a data structure that describes the allocation and location on disk of a specific file, or, given a volume handle, the locations of bad clusters on a volume.

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

DeviceIoControl(
  (HANDLE) hDevice,                 // handle to file, directory, or volume
  FSCTL_GET_RETRIEVAL_POINTERS,     // dwIoControlCode
  (LPVOID) lpInBuffer,              // input buffer
  (DWORD) nInBufferSize,            // size of input buffer
  (LPVOID) lpOutBuffer,             // output buffer
  (DWORD) nOutBufferSize,           // size of output buffer
  (LPDWORD) lpBytesReturned,        // number of bytes returned
  (LPOVERLAPPED) lpOverlapped       // OVERLAPPED structure
);

Parameters

Input buffer

Input buffer length

Output buffer

Output buffer length

Input/output buffer

Input/output buffer length

Status block

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

The FSCTL_GET_RETRIEVAL_POINTERS operation retrieves a variably sized data structure that describes the allocation and location on disk of a specific file. The structure describes the mapping between virtual cluster numbers (VCN offsets within the file or stream space) and logical cluster numbers (LCN offsets within the volume space).

The FSCTL_GET_RETRIEVAL_POINTERS control code is supported for file or directory operations on NTFS, FAT, exFAT, UDF, and ReFS file systems.

On supported file systems, the FSCTL_GET_RETRIEVAL_POINTERS operation returns the extent locations of nonresident data. Resident data never has extent locations.

The FSCTL_GET_RETRIEVAL_POINTERS control code also supports the alternate functionality of locating bad clusters. To query for the locations of bad clusters on a volume formatted with NTFS, FAT, or exFAT, use a volume handle as the hDevice parameter. This functionality is supported only on NTFS, FAT, and exFAT, and the caller must have MANAGE_VOLUME_ACCESS permission to the volume.

For the implications of overlapped I/O on this operation, see the Remarks section of the DeviceIoControl topic.

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

See also

• CreateFile
• Defragmentation
• DeviceIoControl
• Disk Management Control Codes
• FSCTL_GET_RETRIEVAL_POINTER_BASE
• GetLastError
• GetOverlappedResult
• GetQueuedCompletionStatus
• OVERLAPPED
• RETRIEVAL_POINTERS_BUFFER
• STARTING_VCN_INPUT_BUFFER