FltGetVolumeContext function (fltkernel.h)

Article
02/22/2024

The FltGetVolumeContext routine retrieves a context that was set for a volume by a given minifilter driver.

Syntax

NTSTATUS FLTAPI FltGetVolumeContext(
  [in]  PFLT_FILTER  Filter,
  [in]  PFLT_VOLUME  Volume,
  [out] PFLT_CONTEXT *Context
);

Parameters

[in] Filter

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

[in] Volume

Opaque pointer for the volume whose context is being retrieved. This parameter is required and cannot be NULL.

[out] Context

Pointer to a caller-allocated variable that receives the address of the requested context. This parameter is required and can't be set to NULL.

Return value

FltGetVolumeContext returns STATUS_SUCCESS when it successfully returns the requested context. Otherwise, it returns an appropriate NTSTATUS value such as the following:

Return code	Description
STATUS_NOT_FOUND	No matching context was found on this file at this time, so FltMgr set Context to NULL_CONTEXT. This is an error code.

Remarks

For more information about contexts, see About minifilter contexts.

FltGetVolumeContext increments the reference count on the context that the Context parameter points to. When this context pointer is no longer needed, the caller must decrement its reference count by calling FltReleaseContext. Thus every successful call to FltGetVolumeContext must be matched by a subsequent call to FltReleaseContext.

To set a context for a volume, call FltSetVolumeContext.

To allocate a new context, call FltAllocateContext.

To delete a volume context, call FltDeleteVolumeContext or FltDeleteContext.

Requirements

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