FltGetVolumeInformation function (fltkernel.h)

Article
10/21/2021

The FltGetVolumeInformation routine provides information about a given volume.

Syntax

NTSTATUS FLTAPI FltGetVolumeInformation(
  [in]  PFLT_VOLUME                     Volume,
  [in]  FILTER_VOLUME_INFORMATION_CLASS InformationClass,
  [out] PVOID                           Buffer,
  [in]  ULONG                           BufferSize,
  [out] PULONG                          BytesReturned
);

Parameters

[in] Volume

Opaque pointer for the volume. This parameter is required and cannot be NULL.

[in] InformationClass

Type of information requested. This parameter is required and must be one of the following values.

Value	Meaning
FilterVolumeBasicInformation	The Buffer parameter receives a FILTER_VOLUME_BASIC_INFORMATION structure for the volume.
FilterVolumeStandardInformation	The Buffer parameter receives a FILTER_VOLUME_STANDARD_INFORMATION structure for the volume. This structure is available starting with Windows Vista.

[out] Buffer

Pointer to a caller-allocated buffer that receives the requested information. The type of the information returned in the buffer is defined by the InformationClass parameter. This parameter is required and cannot be NULL.

[in] BufferSize

Size, in bytes, of the buffer that the Buffer parameter points to. The caller should set this parameter according to the given InformationClass value. This parameter is required.

[out] BytesReturned

Pointer to a caller-allocated variable that receives the number of bytes returned in the buffer that Buffer points to. If the input value of BufferSize is too small, FltGetVolumeInformation returns STATUS_BUFFER_TOO_SMALL and sets this variable to the number of bytes required to store the requested information. This parameter is required and cannot be NULL.

Return value

FltGetVolumeInformation returns STATUS_SUCCESS or an appropriate NTSTATUS status code, such as one of the following:

Return code	Description
STATUS_INVALID_PARAMETER	An invalid value was specified for the InformationClass parameter. For example, if FilterVolumeStandardInformation is specified on an operating system prior to Windows Vista, the routine will return STATUS_INVALID_PARAMETER. This is an error code.
STATUS_BUFFER_TOO_SMALL	The buffer that the Buffer parameter points to is not large enough to store the requested information. This is an error code.

Remarks

Given an opaque volume pointer, such as that returned by the FltEnumerateVolumes routine, the FltGetVolumeInformation routine provides information about the volume pointed to by the opaque volume pointer, passed through the Volume parameter. Note that the caller must eventually release the opaque volume pointer by calling the FltObjectDereference routine.

The FltGetVolumeInformation routine returns information for a single volume. However, given a list of opaque volume pointers, the routine can be iteratively used to create a list of corresponding volume information structures. In such a list, it is possible for two or more of the structures to contain identical volume names. For more information, see Understanding Volume Enumerations with Duplicate Volume Names.

To list volume information for all volumes that are known to the filter manager, call FltEnumerateVolumeInformation.

The following list contains related information, which may be of use:

To enumerate all registered minifilter drivers in the system, call the FltEnumerateFilters routine.
To obtain information about minifilter driver instances attached to a given volume, call the FltEnumerateInstanceInformationByVolume routine.
To enumerate minifilter driver instances for a given minifilter driver or volume, call the FltEnumerateInstances routine.
To enumerate all volumes in the system, call the FltEnumerateVolumes routine.
To obtain an opaque pointer for the volume represented by a given volume device object (VDO), call the FltGetVolumeFromDeviceObject routine.
To obtain an opaque pointer for the volume that a given file stream resides on, call the FltGetVolumeFromFileObject routine.
To obtain an opaque pointer for the volume that a given minifilter driver instance is attached to, call the FltGetVolumeFromInstance routine.
To obtain an opaque pointer for the volume whose name matches a given volume name, call the FltGetVolumeFromName routine.

Requirements

Requirement	Value
Minimum supported client	This routine is available starting with Windows Vista.
Target Platform	Universal
Header	fltkernel.h (include FltKernel.h)
Library	FltMgr.lib
DLL	Fltmgr.sys
IRQL	<= APC_LEVEL