Abstract: Described is a mechanism comprising a data screening filter and user mode service that applies (enforces) policies regarding allowing or blocking file content of a directory, based on matching the filename against patterns associated with that directory. An administrator configures a screening policy, such as the types of files to allow in a particular directory and the types of files to block. File groups of member patterns and non-member exclusion patterns are defined and selectively collected in directory screening objects (DSOs). A directory screening object (DSO) is associated with a directory. When an I/O create request specifying a filename and a target directory is received, the filename is evaluated against the member/non-member patterns in the file groups referenced by the DSO for that directory to make for an allow or block policy decision. If not matched, DSOs on parent directories are evaluated upwards seeking a policy decision.

Abstract: Method and system for maintaining namespace consistency between selected objects maintained by a file system and a filter associated therewith. Metadata regarding selected objects of a file system is maintained by a filter while the filter is attached to the file system and persisted in non-volatile storage. The namespace of the file system may be changed while the filter is unattached from the file system. Afterwards, when the filter is attached to the file system, the namespace of the filter is synchronized with the namespace of the file system for the selected objects.

Abstract: A method and system for updating a filter's data after the filter's metadata file is restored. The filter maintains an open handle to the metadata until the filter receives a request to have the metadata restored. The filter then closes the open handle and allows the metadata to be restored. After the metadata is restored, data associated with the filter is rebuilt based on the restored metadata.

Abstract: A method and system for verifying the integrity of a storage volume. When volume verification is desired, a shadow copy of the volume is created. A verification tool operates on the shadow copy and provides a report that indicates if any errors are found in the shadow copy. If errors are found on the shadow copy, this indicates that the same errors likely still exist on the live volume. In the event of errors, a system administrator or the like may take the live volume off-line and fix the errors found.