NtFsControlFile function (ntifs.h)

The NtFsControlFile routine sends a control code directly to a specified file system or file system filter driver, causing the corresponding driver to perform the specified action.

Syntax

__kernel_entry NTSYSCALLAPI NTSTATUS NtFsControlFile(
  HANDLE           FileHandle,
  HANDLE           Event,
  PIO_APC_ROUTINE  ApcRoutine,
  PVOID            ApcContext,
  PIO_STATUS_BLOCK IoStatusBlock,
  ULONG            FsControlCode,
  PVOID            InputBuffer,
  ULONG            InputBufferLength,
  PVOID            OutputBuffer,
  ULONG            OutputBufferLength
);

Parameters

FileHandle

[in] Handle returned by NtCreateFile or NtOpenFile for the file object representing the file or directory on which the specified action is to be performed. The file object must have been opened for asynchronous I/O if the caller specifies an Event, ApcRoutine, and an APC context (in ApcContext), or a completion context (in ApcContext).

Event

[in, optional] Handle for a caller-created event. If this parameter is supplied, the caller will be put into a wait state until the requested operation is completed and the given event is set to the Signaled state. This parameter is optional and can be NULL. It must be NULL if the caller will wait for the FileHandle to be set to the Signaled state.

ApcRoutine

[in, optional] Address of a caller-supplied APC routine to be called when the requested operation completes. This parameter is optional and can be NULL. It must be NULL if there is an I/O completion object associated with the file object.

ApcContext

[in, optional] Pointer to a caller-determined context area. This parameter value is used as the APC context if the caller supplies an APC, or is used as the completion context if an I/O completion object has been associated with the file object. When the operation completes, either the APC context is passed to the APC, if one was specified, or the completion context is included as part of the completion message that the I/O Manager posts to the associated I/O completion object.

This parameter is optional and can be NULL. It must be NULL if ApcRoutine is NULL and there is no I/O completion object associated with the file object.

IoStatusBlock

[out] Pointer to an IO_STATUS_BLOCK structure that receives the final completion status and information about the operation. For successful calls that return data, the number of bytes written to the OutputBuffer is returned in the Information member of this structure.

FsControlCode

[in] FSCTL_XXX code that indicates which file system control operation is to be carried out. The value of this parameter determines the formats and required lengths of the InputBuffer and OutputBuffer, as well as which of the following parameter pairs are required. For detailed information about the system-defined FSCTL_XXX codes, see the "Remarks" section of the reference entry for DeviceIoControl in the Microsoft Windows SDK documentation.

InputBuffer

[in, optional] Pointer to a caller-allocated input buffer that contains device-specific information to be given to the target driver. If FsControlCode specifies an operation that does not require input data, this pointer is optional and can be NULL.

InputBufferLength

[in] Size, in bytes, of the buffer at InputBuffer. This value is ignored if InputBuffer is NULL.

OutputBuffer

[out, optional] Pointer to a caller-allocated output buffer in which information is returned from the target driver. If FsControlCode specifies an operation that does not produce output data, this pointer is optional and can be NULL.

OutputBufferLength

[in] Size, in bytes, of the buffer at OutputBuffer. This value is ignored if OutputBuffer is NULL.

Return value

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

Remarks

NtFsControlFile provides a consistent view of the input and output data to the system and to kernel-mode drivers, while providing applications and underlying drivers with a driver-dependent method of specifying a communications interface.

If the caller opened the file for asynchronous I/O (with neither FILE_SYNCHRONOUS_XXX create/open option set), the specified event, if any, will be set to the signaled state when the device control operation completes. Otherwise, the file object specified by FileHandle will be set to the signaled state. If an ApcRoutine was specified, it is called with the ApcContext and IoStatusBlock pointers.

The following FSCTL codes are currently documented for kernel-mode drivers:

FSCTL_DELETE_REPARSE_POINT

FSCTL_GET_REPARSE_POINT

FSCTL_OPBATCH_ACK_CLOSE_PENDING

FSCTL_OPLOCK_BREAK_ACK_NO_2

FSCTL_OPLOCK_BREAK_ACKNOWLEDGE

FSCTL_OPLOCK_BREAK_NOTIFY

FSCTL_REQUEST_BATCH_OPLOCK

FSCTL_REQUEST_FILTER_OPLOCK

FSCTL_REQUEST_OPLOCK_LEVEL_1

FSCTL_REQUEST_OPLOCK_LEVEL_2

FSCTL_SET_REPARSE_POINT

For more information about system-defined FSCTL_XXX codes, see the "Remarks" section of the reference entry for DeviceIoControl in the Microsoft Windows SDK documentation.

For more information about system-defined IOCTL_XXX codes, and about defining driver-specific IOCTL_XXX or FSCTL_XXX values, see Using I/O Control Codes in the Kernel Mode Architecture Guide and Device Input and Output Control Codes in the Windows SDK documentation.

Minifilters should use FltFsControlFile instead of NtFsControlFile.

Callers of NtFsControlFile must be running at IRQL = PASSIVE_LEVEL and with special kernel APCs enabled.

Note  If the call to the NtFsControlFile function occurs in user mode, you should use the name "NtFsControlFile" instead of "ZwFsControlFile".
 
For calls from kernel-mode drivers, the NtXxx and ZwXxx versions of a Windows Native System Services routine can behave differently in the way that they handle and interpret input parameters. For more information about the relationship between the NtXxx and ZwXxx versions of a routine, see Using Nt and Zw Versions of the Native System Services Routines.

Requirements

   
Minimum supported client Available starting with Windows 2000.
Target Platform Universal
Header ntifs.h (include Ntifs.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL PASSIVE_LEVEL (see Remarks section)
DDI compliance rules PowerIrpDDis, HwStorPortProhibitedDDIs

See also

FltFsControlFile

IRP_MJ_FILE_SYSTEM_CONTROL

IoGetFunctionCodeFromCtlCode

IoIsOperationSynchronous

Using I/O Control Codes

Using Nt and Zw Versions of the Native System Services Routines

ZwClose

ZwCreateFile

ZwDeviceIoControlFile

ZwOpenFile