Edit

FSCTL_GET_RETRIEVAL_POINTER_BASE control code

  • Article

The FSCTL_GET_RETRIEVAL_POINTER_BASE returns the sector offset to the first logical cluster number (LCN) of the file system relative to the start of the volume.

To perform this operation, call the FltFsControlFile function or ZwFsControlFile function with the following parameters.

Parameters

  • FileObject [in]: FltFsControlFile only. A file object pointer for the volume for which FSCTL_GET_RETRIEVAL_POINTER_BASE is to retrieve the base. This parameter is required and cannot be NULL.

  • FileHandle [in]: ZwFsControlFile only. A file handle for the volume for which FSCTL_GET_RETRIEVAL_POINTER_BASE is to retrieve the base. This parameter is required and cannot be NULL.

This handle must be opened with the SE_MANAGE_VOLUME_NAME access rights. For more information, see File Security and Access Rights.

  • FsControlCode [in]: A control code for the operation. Use FSCTL_GET_RETRIEVAL_POINTER_BASE for this operation.

  • InputBuffer [in]: Not used with this operation. Set to NULL.

  • InputBufferLength [in]: Not used with this operation. Set to zero.

  • OutputBuffer [out]: A pointer to a LARGE_INTEGER, which receives the sector offset to the first LCN of the file system relative to the start of the volume.

  • OutputBufferLength [out]: The size of the output buffer, in bytes. This value must be 8.

Status block

FltFsControlFile or ZwFsControlFile returns STATUS_SUCCESS or an appropriate NTSTATUS value such as one of the following:

Code Meaning
STATUS_SUCCESS The operation was successful. OutputBuffer contains the sector offset to the first LCN of the file system relative to the start of the volume.
STATUS_ACCESS_DENIED The user does not have SE_MANAGE_VOLUME access.
STATUS_BUFFER_TOO_SMALL OutputBuffer is not large enough for the result. No information has been written to the buffer.
STATUS_INVALID_PARAMETER A parameter was not valid; for example, the handle used is not a valid volume handle.

Remarks

Adding the value retrieved by FSCTL_GET_RETRIEVAL_POINTER_BASE to the value retrieved by the FSCTL_GET_RETRIEVAL_POINTERS control code results in a volume-relative file extent offset.

The FSCTL_GET_RETRIEVAL_POINTER_BASE control code can be used on FastFAT and exFAT devices. This capability supports the use of BitLocker for devices such as flash drives.

Requirements

Requirement type Requirement
Minimum supported client Windows 7
Minimum supported server Windows Server 2008 R2
Header Ntifs.h (include Ntifs.h or Fltkernel.h)

See also

FltFsControlFile

ZwFsControlFile