Abstract: Files on a computing device are defined to include data and metadata relating to the data. Data from each file has been removed therefrom and stored at an alternate location and the file is in a reduced, ghosted form. Each of at least some ghosted files has been fully or partially reconstituted for use by retrieving the data thereof from the alternate location and associating such retrieved data with such ghosted file to form the reconstituted file. Upon receiving a trigger based on a triggering event, files are selected from among the fully and partially reconstituted files and never-ghosted files based on first predetermined selection criteria, and each of at least some of the selected files are re-ghosted.

Abstract: Aspects of the subject matter described herein relate to tracking file system namespace changes during transactions. In aspects, a filter monitors operations that may affect a tracked portion of a transactional file system's namespace. When an operation that affects the tracked portion is received, a data structure is modified to track the changes. Nodes within the data structure are marked to indicate whether they can be seen inside or outside of the transaction. If the transaction commits or rolls back, nodes within the data structure are deleted and made visible as appropriate.

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: 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: 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: A computing device has a file stored on a storage volume by a file system and accessed through such file system. The file is defined to include data and metadata relating to the data, and at least a portion of the data of the file is removed from the file and stored at an alternate location such that the data does not occupy substantially any space on the volume and the file is in a reduced, ghosted form. The ghosted file is reconstituted for use by retrieving the data from the alternate location and associating such retrieved data with such ghosted file to form the reconstituted file.

Abstract: To reconstitute a ghosted file for use, a single ghosting filter on a computing device locates ghosting information in the metadata of the ghosted file and locates within the ghosting information an identification of a particular ghosting manager of the computing device, where the identified ghosting manager is responsible for the ghosted file. Thereafter, the ghosting filter communicates to the identified ghosting manager a request to obtain data of the ghosted file from a corresponding alternate location, and the identified ghosting manager does in fact obtain such requested data from such alternate location. Upon receiving the requested data of the ghosted file from the identified ghosting manager, then, the ghosting filter reconstitutes the received data to the ghosted file. The single ghosting filter is generic to all of the ghosting managers of the computing device.

Abstract: A computing device has a storage volume, a file system managing the storage volume, and a file stored on the storage volume and accessed by such file system. The file system receives an open command for the file from an application, notes that the file has been ghosted in that data of the file has been moved to an alternate location, and returns an error. The returned error is intercepted and the file system is commanded to retrieve ghosting information from the ghosted file. A handle corresponding to the ghosted file is delivered to the application, and a read command for the file is received from the application, including the handle, an offset, and a read length. Reconstituting of the ghosted file is initiated based on the data thereof at the alternate location, and after reconstituting the read command is responded to with the data requested.

Abstract: A ghosting filter on a computing device receives a read command for a requested range of data of a ghosted file. The requested range is categorized into first segments present in the ghosted file, second segments pending to be reconstituted from an alternate location to the ghosted file, and third segments that are not first or second segments. Reconstitution of any third segments is initiated to convert same to second, pending segments, and the read command is responded to with the requested range of the data once all second segments are in fact reconstituted from the alternate location to the ghosted file and thus converted to first, pending segments.

Abstract: A method and system for maintaining namespace consistency between selected objects maintained by a file system and a filter associated therewith. A filter monitors selected types of requests (or operations associated therewith) and determines whether the object is within a namespace associated with the filter. The namespace associated with the filter is updated based on a change to the object.

Abstract: File system metadata regarding states of a file system affected by transactions is tracked consistently even in the face of dirty shutdowns which might cause rollbacks in transactions which have already been reflected in the metadata. In order to only request time- and resource-heavy rebuilding of metadata for metadata which may have been affected by rollbacks, reliability information is tracked regarding metadata items. When a metadata item is affected by a transaction which may not complete properly in the case of a problematic shutdown or other event, that metadata item's reliability information indicates that it may not be reliable in case of such a problematic (“dirty” or “abnormal”) event. In addition to flag information indicating unreliability, timestamp information tracking a time of the command which has made a metadata item unreliable is also maintained.

Abstract: Aspects of the subject matter described herein relate to tracking file system namespace changes during transactions. In aspects, a filter monitors operations that may affect a tracked portion of a transactional file system's namespace. When an operation that affects the tracked portion is received, a data structure is modified to track the changes. Nodes within the data structure are marked to indicate whether they can be seen inside or outside of the transaction. If the transaction commits or rolls back, nodes within the data structure are deleted and made visible as appropriate.

Abstract: Aspects of the subject matter described herein relate enforcing quotas in transactional file systems. In aspects, a filter monitors operations that may affect quota usage/charge of a file system object having a quota allotment. In doing so, the filter determines a quota value outside of any transaction for the object and a quota value associated with at least one transaction affecting the object. The filter receives a request that involves the use of additional quota. The filter then determines whether to allow or fail the request depending on whether enough quota is available to satisfy the request.

Abstract: A ghosting filter on a computing device perceives that a file is in a ghosted form and commands a file system of the device to retrieve ghosting information from the ghosted file. The ghosting filter receives a read command from an application on the device with respect to a portion of the data of the ghosted file. The read command has parameters including an offset into the portion of the data and a read length with respect to such portion. The ghosting filter initiates reconstituting of the portion of the data of the ghosted file based on the received ghosting information and data of the ghosted file at an alternate location, and after the portion of the data of the ghosted file has been reconstituted responds to the read command with the portion of the data requested.

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.