FltGetVolumeFromDeviceObject function (fltkernel.h)
The FltGetVolumeFromDeviceObject routine returns an opaque pointer for the volume represented by a volume device object (VDO).
Syntax
NTSTATUS FLTAPI FltGetVolumeFromDeviceObject(
[in] PFLT_FILTER Filter,
[in] PDEVICE_OBJECT DeviceObject,
[out] PFLT_VOLUME *RetVolume
);
Parameters
[in] Filter
Opaque filter pointer for the caller. This parameter is required and cannot be NULL.
[in] DeviceObject
Pointer to the volume device object.
[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
FltGetVolumeFromDeviceObject returns STATUS_SUCCESS or an appropriate NTSTATUS value such as one of the following:
| Return code | Description |
|---|---|
| STATUS_FLT_DELETING_OBJECT | The volume is being torn down. This is an error code. |
| STATUS_INVALID_PARAMETER | Volume device object specified in the DeviceObject parameter was not a valid volume device object pointer, or no matching volume was found. This is an error code. |
Remarks
The DeviceObject parameter can be a pointer to a filter or a file system volume device object (VDO). If it points to a storage device object, FltGetVolumeFromDeviceObject returns STATUS_INVALID_PARAMETER.
For more information about volume device objects, see File System Stacks.
FltGetVolumeFromDeviceObject 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 FltGetVolumeFromDeviceObject must be matched by a subsequent call to FltObjectDereference.
To get a pointer to the device object for a given volume, call FltGetDeviceObject.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Universal |
| Header | fltkernel.h (include Fltkernel.h) |
| Library | FltMgr.lib |
| DLL | Fltmgr.sys |
| IRQL | <= APC_LEVEL |