Synchronizing for Directory Changes Performed While Offline

• US 20090193107A1
• Filed: 01/25/2008
• Published: 07/30/2009
• Est. Priority Date: 01/25/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Srinivasan, Sriram, Jolly, Thomas Ewan, Kruse, David Matthew, Aust, Brian Scott
• Granted Patent: US 8,065,381 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: G06F 16/172 Caching, prefetching or hoarding of files
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/289 Intermediate processing functionally located close to the data consumer application, e.g. in same machine, in same home or in same sub-network
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/59 Providing operational support to end devices by off-loading in the network or by emulation, e.g. when they are unavailable

Abstract

Aspects of the subject matter described herein relate to synchronizing for directory actions performed while offline. In aspects, file system objects that reside on a remote data store are made available for offline use. While offline, a client receives an indication that a directory is to be deleted or renamed. In response, the client modifies its local copy of the directory and its descendants if any and stores one or more tombstones that include information that the client can use when synchronizing the changes made to the directory when the client is reconnected to the remote data store. When the client reconnects to the remote data store, the client synchronizes changes made while offline with the remote data store. Resolution conflict mechanisms may be used during this synchronization.

Claims

1. A method implemented at least in part by a computer, the method comprising:

storing data regarding a directory on a local store, a copy of the directory being stored on a remote store associated with a server;

becoming disconnected from the server;

receiving an indication that the directory is to be deleted on the local store;

associating a tombstone with the directory, the tombstone indicating that the directory has been deleted on the local store, the tombstone including information usable to identify the directory on the remote store;

reconnecting with the server; and

using at least the tombstone in determining whether to delete the directory on the remote store.

2. The method of claim 1, wherein receiving an indication that the directory is to be deleted comprises receiving an indication from a user that the directory is to be deleted.

3. The method of claim 1, further comprising removing the directory locally such that locally the directory is unavailable to processes executing locally.

4. The method of claim 1, wherein the information included in the tombstone includes a name of the directory.

5. The method of claim 1, wherein in response to receiving an indication that the directory is to be deleted, each descendant of the directory is associated with a tombstone indicating that the descendant has been deleted locally, a tombstone associated with a descendant including information usable to identify the descendant on the remote store.

6. The method of claim 5, wherein the information comprises a timestamp of when an object was created or updated on the remote store.

7. The method of claim 5, further comprising after reconnecting with the server, for each tombstone associated with a descendant of the directory, attempting to find a corresponding descendant of the directory on the remote store, and if found and not changed, deleting the corresponding descendant on the remote store.

8. The method of claim 1, further comprising detecting a conflict when objects in the directory have been added, changed, or renamed on the remote store after becoming disconnected.

9. The method of claim 1, wherein the tombstone is associated with the directory by a process that is independent of all processes of the server, the method being implemented in an environment in which it is a client'"'"'s responsibility to synchronize changes made to the directory while the client is offline, the client having access to the local store but not the remote store while the client is offline.

10. A computer storage medium having computer-executable instructions, which when executed perform actions, comprising:

storing data regarding a first directory on a local store, a copy of the first directory being stored on a remote store associated with a server, the first directory having a first name;

going offline from the server;

receiving an indication that the first directory is to be renamed to a second directory on the local store, the second directory having a second name;

renaming the first directory on the local store to the second directory;

creating a data structure that indicates that the first directory and its descendants are deleted locally;

going online with the server; and

updating the remote store with rename changes associated with the first and second directories.

11. The computer storage medium of claim 10, wherein updating the remote store with changes associated with the first and second directories comprises:

adding a third directory on the remote store;

copying the descendants of the second directory from the local store to the third directory on the remote store; and

after the descendants have been copied, deleting, from the remote store, all descendants that were deleted locally that exist in the remote store and have not changed after going offline from the server.

12. The computer storage medium of claim 11, further comprising deleting, from the remote store, the first directory if the first directory on the remote store has no remaining descendants.

13. The computer storage medium of claim 11, wherein updating the remote store with rename changes associated with the first and second directories comprises:

determining that no changes have occurred to descendants of the first directory on the remote store after going offline from the server; and

renaming the first directory on the remote store to a third directory on the remote store, the third directory having the second name.

14. The computer storage medium of claim 10, further comprising:

determining that the second directory has been marked as deleted;

marking the second directory as not deleted; and

merging descendants of the first directory into the second directory.

15. The computer storage medium of claim 14, wherein merging descendants of the first directory into the second directory comprises maintaining information for each descendant that also existed in the remote store before going offline, the information indentifying a corresponding object that existed on the remote store before going offline.

16. The computer storage medium of claim 14, wherein merging descendants of the first directory into the second directory comprises deleting information for each descendant of the first directory that was created after going offline.

17. The computer storage medium of claim 10, wherein going offline from the server comprises being disconnected form the server and wherein going online with the server comprises reconnecting to the server.

18. In a computing environment, an apparatus, comprising:

a store selector operable to determine whether to access a local data store or a remote data store;

a deleter operable to engage in deletion activities for objects stored on the local data store;

a tombstone maintainer operable to maintain information about objects that have been deleted on the local store, the information identifying corresponding objects on the remote data store that existed before going offline from the remote data store, the information indicating that the objects have been deleted on the local store;

a merger operable to undelete objects that have been deleted on the local store and to merge information about renamed objects into data structures associated with the undelted objects; and

synchronization logic operable to synchronize changes that occurred after going offline from the remote data store, the synchronization logic not relying on synchronization logic hosted on a server associated with the remote data store to synchronize the changes.

19. The apparatus of claim 18, wherein the deleter is operable to engage in deletion activities for objects stored on the local data store by actions, comprising for each object deleted on the local data store, associating a tombstone with the object, the tombstone including information to identify a corresponding object on the remote store that existed before going offline with the remote store.

20. The apparatus of claim 18, wherein in merging information about renamed objects into data structures associated with the objects, the merger retains information that identifies a corresponding object on the remote store of an object that is undeleted on the local store.