FltGetVolumeFromInstance function (fltkernel.h)

Article
02/22/2024

The FltGetVolumeFromInstance routine returns an opaque pointer for the volume that a given minifilter driver instance is attached to.

Syntax

NTSTATUS FLTAPI FltGetVolumeFromInstance(
  [in]  PFLT_INSTANCE Instance,
  [out] PFLT_VOLUME   *RetVolume
);

Parameters

[in] Instance

Opaque instance pointer for the instance.

[out] RetVolume

Pointer to a caller-allocated variable that receives an opaque pointer for the volume. This parameter is required and cannot be NULL.

Return value

FltGetVolumeFromInstance returns STATUS_SUCCESS or an appropriate NTSTATUS value, such as the following:

Return code	Description
STATUS_FLT_DELETING_OBJECT	The volume that the minifilter driver instance is attached to is being torn down. This is an error code.

Remarks

FltGetVolumeFromInstance adds a rundown reference to the opaque volume pointer returned in the RetVolume parameter. When this pointer is no longer needed, the caller must release it by calling FltObjectDereference. Thus every successful call to FltGetVolumeFromInstance must be matched by a subsequent call to FltObjectDereference.

To get an opaque filter pointer for the minifilter driver that created a given instance, call FltGetFilterFromInstance.

To get a pointer to the device object for a given volume, call FltGetDeviceObject.

To get detailed information about the volume that a given instance is attached to, call FltQueryVolumeInformation.

Requirements

Requirement	Value
Target Platform	Universal
Header	fltkernel.h (include Fltkernel.h)
Library	FltMgr.lib
DLL	Fltmgr.sys
IRQL	<= APC_LEVEL