FltDoCompletionProcessingWhenSafe function (fltkernel.h)
If it is safe to do so, the FltDoCompletionProcessingWhenSafe function executes a minifilter driver post-operation callback routine.
Syntax
BOOLEAN FLTAPI FltDoCompletionProcessingWhenSafe(
[in] PFLT_CALLBACK_DATA Data,
[in] PCFLT_RELATED_OBJECTS FltObjects,
[in, optional] PVOID CompletionContext,
[in] FLT_POST_OPERATION_FLAGS Flags,
[in] PFLT_POST_OPERATION_CALLBACK SafePostCallback,
[out] PFLT_POSTOP_CALLBACK_STATUS RetPostOperationStatus
);
Parameters
[in] Data
Pointer to the callback data structure (FLT_CALLBACK_DATA) for the I/O operation. Usually this is the same as the Data pointer that was passed to the postoperation callback routine (PFLT_POST_OPERATION_CALLBACK) that called FltDoCompletionProcessingWhenSafe.
[in] FltObjects
Pointer to the related objects structure (FLT_RELATED_OBJECTS) for the I/O operation. Usually this is the same as the FltObjects pointer that was passed to the postoperation callback routine that called FltDoCompletionProcessingWhenSafe.
[in, optional] CompletionContext
Pointer to a caller-supplied context information that will be passed in to the callback function that is specified in the SafePostCallback parameter.
[in] Flags
Bitmask of flags which specify how completion processing will be performed. Usually this is the same as the Flags value that was passed to the postoperation callback routine that called FltDoCompletionProcessingWhenSafe. For more information, see the following Remarks section.
[in] SafePostCallback
Pointer to a caller-supplied PFLT_POST_OPERATION_CALLBACK-typed callback routine that the operating system calls when it is safe to do so.
[out] RetPostOperationStatus
Caller-allocated variable that receives the final status value for the I/O operation. For more information on how this parameter is set, see the following Remarks section.
Return value
FltDoCompletionProcessingWhenSafe returns TRUE if completion processing for the I/O operation can be performed immediately or the I/O operation was successfully posted to a worker thread; otherwise, it returns FALSE.
Remarks
FltDoCompletionProcessingWhenSafe executes the SafePostCallback immediately if the caller is running at IRQL <= APC_LEVEL. Otherwise, if it is safe to post the operation to a worker thread, the SafePostCallback processing is deferred until it can be called in a thread context where IRQL <= APC_LEVEL.
If IRQL < DISPATCH_LEVEL:
- FltDoCompletionProcessingWhenSafe immediately calls the SafePostCallback callback routine.
- The RetPostOperationStatus parameter receives a FLT_POSTOP_CALLBACK_STATUS value returned by SafePostCallback.
- FltDoCompletionProcessingWhenSafe returns TRUE.
If IRQL >= DISPATCH_LEVEL:
- FltDoCompletionProcessingWhenSafe attempts to post the I/O operation to a worker thread, and then call the SafePostCallback routine from the worker thread.
- If the I/O operation could be safely posted:
- Filter manager sets RetPostOperationStatus to FLT_POSTOP_MORE_PROCESSING_REQUIRED.
- FltDoCompletionProcessingWhenSafe returns TRUE.
- If the I/O operation could not be safely posted:
- Filter manager sets RetPostOperationStatus to FLT_POSTOP_FINISHED_PROCESSING.
- FltDoCompletionProcessingWhenSafe returns FALSE.
FltDoCompletionProcessingWhenSafe can only be called for IRP-based operations. To determine whether the operation is an IRP-based operation, use the FLT_IS_IRP_OPERATION macro.
FltDoCompletionProcessingWhenSafe cannot be used to post completion of a paging I/O operation to a worker thread.
FltDoCompletionProcessingWhenSafe can only be called from a minifilter driver's postoperation callback routine (PFLT_POST_OPERATION_CALLBACK). Note that FltDoCompletionProcessingWhenSafe should never be called if the Flags parameter of the postoperation callback has the FLTFL_POST_OPERATION_DRAINING bit set.
If a minifilter calls FltDoCompletionProcessingWhenSafe and the SafePostCallback is invoked in a worker thread because it is not safe to invoke it in the current thread context, the filter manager will resume completion processing as long as the minifilter does not return FLT_POSTOP_MORE_PROCESSING_REQUIRED from the SafePostCallback.
If the minifilter does return FLT_POSTOP_MORE_PROCESSING_REQUIRED from the SafePostCallback, the minifilter must call FltCompletePendedPostOperation to resume completion processing.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available in Microsoft Windows 2000 Update Rollup 1 for SP4, Windows XP SP2, Windows Server 2003 SP1, and later operating systems. Not available in Windows 2000 SP4 and earlier operating systems. |
| Target Platform | Universal |
| Header | fltkernel.h (include Fltkernel.h) |
| Library | Fltmgr.lib |
| IRQL | Any. |