FltNotifyFilterChangeDirectory function

Description

The FltNotifyFilterChangeDirectory routine creates a notify structure for an IRP_MN_NOTIFY_CHANGE_DIRECTORY operation and adds it to the specified notify list.

Parameters

NotifySync [in, out]

Pointer to an opaque synchronization object for the change directory notify list that the NotifyList parameter points to.

NotifyList [in, out]

Pointer to the head of the change directory notify list for the current volume. Each element in the list is an opaque notify structure.

FsContext [in]

Pointer to a unique value assigned by the caller to identify the notify structure to be created. If a callback routine is supplied in the TraverseCallback parameter, FsContext is passed as the NotifyContext parameter to that routine.

FullDirectoryName [in]

Pointer to an ANSI or Unicode string that contains the full name for the directory associated with this notify structure.

WatchTree [in]

Set to TRUE if all subdirectories of the directory that is specified by the FullDirectoryName parameter should also be watched. Set to FALSE if only the directory itself is to be watched.

IgnoreBuffer [in]

Set to TRUE to ignore any user buffers and force the directory to be reenumerated. This action speeds the operation.

CompletionFilter [in]

Bitmask of flags that specify the types of changes to files or directories that should cause the callback data structures in the notify list to be completed. The possible flag values are described in the following table.

NotifyCallbackData [in]

Pointer to the callback data structure for the operation to be added to the notify list. This parameter is required and cannot be NULL.

TraverseCallback [in, optional]

Optional pointer to a callback routine to be invoked when a change occurs in a subdirectory that is being watched in a directory tree. This pointer lets the file system check whether the watcher has traverse access to that directory. Such a caller-supplied routine is declared as follows:

NTSTATUS
(*PCHECK_FOR_TRAVERSE_ACCESS) (
    IN PVOID NotifyContext,                     // FsContext
    IN PVOID TargetContext,                     // Context pointer
    IN PSECURITY_SUBJECT_CONTEXT SubjectContext // SubjectContext
    );

For more information about the TargetContext parameter, see the TargetContext parameter of the FsRtlNotifyFullReportChange routine.

SubjectContext [in, optional]

Pointer to a context structure to be passed to TraverseCallback. FltNotifyFilterChangeDirectory releases the context and frees the structure after using it. If a TraverseCallback routine is supplied, SubjectContext is passed as the SubjectContext parameter to that routine.

FilterCallback [in, optional]

Optional pointer to a callback routine to be invoked when a change occurs to the directory. If this callback routine returns TRUE, FsRtlNotifyFilterReportChange completes the pending IRP_MN_NOTIFY_CHANGE_DIRECTORY operations in the notify list; otherwise, it does not. Such a caller-supplied routine is declared as follows:

BOOLEAN
(*PFILTER_REPORT_CHANGE) (
    IN PVOID NotifyContext,                     // FsContext
    IN PVOID FilterContext                      // Context pointer
    );

Return value

None

Remarks

A minifilter driver can call FltNotifyFilterChangeDirectory from the preoperation callback routine (PFLT_PRE_OPERATION_CALLBACK) that it registered to process notify change directory operations. These operations have a major function code of IRP_MJ_DIRECTORY_CONTROL and a minor function code of IRP_MN_NOTIFY_CHANGE_DIRECTORY.

The minifilter driver calls FltNotifyFilterChangeDirectory to create a notify structure to hold the callback data structure for the operation and add the notify structure to the notify list for the current volume.

FltNotifyFilterChangeDirectory does the following:

• Checks whether the operation's file object has been cleaned up. If so, FltNotifyFilterChangeDirectory completes the operation with status STATUS_NOTIFY_CLEANUP and does not add it to the notify list.
• If the operation's file object has not been cleaned up, FltNotifyFilterChangeDirectory checks whether the notify list already contains a notify structure for the given FsContext value. If such a notify structure is found, and there are pending changes to report, FltNotifyFilterChangeDirectory completes the callback data structure pointed to by the NotifyCallbackData parameter. If a notify structure is found, but there are no pending changes to report, FltNotifyFilterChangeDirectory adds the operation to the notify structure. If no such notify structure is found, FltNotifyFilterChangeDirectory creates a notify structure for the operation and inserts it into the list.

When a change occurs to the directory, the file system calls FsRtlNotifyFilterReportChange to complete the pending IRP_MN_NOTIFY_CHANGE_DIRECTORY operations in the notify list.

See also

FsRtlNotifyFilterReportChange

IRP_MJ_DIRECTORY_CONTROL

PFLT_PRE_OPERATION_CALLBACK