FltIsIoRedirectionAllowed function (fltkernel.h)
The FltIsIoRedirectionAllowed routine determines whether I/O can be redirected from the specified source filter instance to another specified filter instance.
Syntax
NTSTATUS FLTAPI FltIsIoRedirectionAllowed(
[in] PFLT_INSTANCE SourceInstance,
[in] PFLT_INSTANCE TargetInstance,
[out] PBOOLEAN RedirectionAllowed
);
Parameters
[in] SourceInstance
The filter instance on the source device stack.
[in] TargetInstance
The filter instance on the target device stack.
[out] RedirectionAllowed
A value of TRUE if all I/O to the source device stack can be redirected to the target device stack by changing the filter instance referenced, otherwise FALSE.
Return value
An NTSTATUS value of STATUS_SUCCESS for success or STATUS_NOT_SUPPORTED if redirection is not supported.
Remarks
An I/O operation is associated with a FLT_CALLBACK_DATA structure. That structure contains a reference to a PFLT_IO_PARAMETER_BLOCK object, which contains a reference to the FLT_INSTANCE of the minifilter associated with the I/O operation.
If RedirectionAllowed is TRUE, the minifilter can redirect I/O by changing that instance to a new target instance.
If RedirectionAllowed is FALSE, the minifilter needs to allocate a new callback data object to issue I/O on the target stack or call FltAdjustDeviceStackSizeForIoRedirection to increase the size of the source device stack.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available in Windows 7 and later versions of the Windows operating system. |
| Target Platform | Universal |
| Header | fltkernel.h (include FltKernel.h) |
| Library | FltMgr.lib |
| DLL | Fltmgr.sys |
| IRQL | <=DISPATCH_LEVEL |