Method and system of managing conflicts for a set of synchronized folders

• US 7,941,410 B2
• Filed: 09/30/2008
• Issued: 05/10/2011
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Sagar, Akash, Chung, Richard Yiu-Sai, Moromisato, George
• Primary Examiner(s): Vy; Hung T
• Assistant Examiner(s): Cao; Phuong-Thao
• Application Number:
  US12/242,372
• Publication Number:
  US 20100082534A1
• Time in Patent Office: 952 Days
• Field of Search: 707/999.101, 707/691, 707/802, 707/829
• US Class Current: 707/691
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems

Abstract

Generally, the described system and process enables resolution of conflicts in a synchronized folder. Within the described mesh operating environment, each of the devices may be configured to do the same processing so that the file system view of the synchronized folder looks the same on all devices (pending local capabilities). Updates that cannot be immediately realized to the local store due to conflicts may be deferred for later attempts when, for example, additional updates at the system level or local level are made to resolve or eliminate the conflict for the update item. Generally, further changes may be propagated by a user in addressing a particular conflict that the user is notified about (e.g., via a selected winner that the user disagrees with). Alternatively, the conflict may resolve itself when a further update occurs that overrides or renders moot the previous update (e.g., a deleted item having a modified enclosure, where the enclosure had a previous concurrency conflict).

Depending on the local file system, the described system and process may perform additional fix ups for file name, attributes, etc. In this case, the described system and process may be configured not to update a main replication feed since the updates are local or node application specific. Resolution may primarily depend on the user. When the user does resolve a conflict, the feed may be updated and the resolution propagated to all nodes.

Claims

1. A method of resolving conflicts for a synchronized folder comprising:

creating a synchronized folder as a set of local folders, each local folder associated with one of a plurality of devices, and wherein each local folder is processed to contain a consistent set of items organized by a hierarchical tree structure including parent and child relationships, and wherein an item is a folder or a file;

creating a holding area store that is restricted from user access;

receiving at a first node a set of update items of the synchronized folder, wherein the update items each contain an attribute for designating a link to an enclosure of the item and contain metadata indicating a hierarchical position of the item in the hierarchical tree structure;

merging the set of update items with corresponding items of a local feed to form a set of deferred items, wherein the local feed is separate and distinct from a local folder;

creating a deferred items store that is restricted from user access and that holds the deferred items;

executing an orphan conflict resolution process sequentially on the deferred items in the deferred items store to move a set of orphan items to the holding area store;

executing a duplicate conflict resolution process sequentially on the deferred items in the deferred items store to sort a set of duplicate items and to move all but a duplicate item having a most recent update time to the holding area store; and

executing a cycle conflict resolution process sequentially on the deferred items in the deferred items store to select a folder item of a cycle having an earliest modification date and re-parenting that folder to a root folder; and

updating the local folder with a deferred item that is not moved to the holding area store based on one of the resolution processes.

2. The method of claim 1, further comprising sorting the deferred items, before moving the deferred items, such that for each deferred item that is a parent and is not marked as deleted, children are listed sequentially before the deferred item, and for each deferred item that is a parent and is marked as deleted, children are listed sequentially after the parent deferred item.

3. The method of claim 1, wherein executing an orphan conflict resolution process comprises:

determining if a deferred item is deleted and moving any child of the deleted deferred item in the hierarchy to the holding area store;

determining if a parent of the deferred item is deleted and moving the parent and deferred item to the holding area store if the parent is deleted.

4. The method of claim 1, wherein executing the duplicate conflict resolution process comprises retrieving a set of sibling items of a deferred item, wherein a sibling item is an item that shares a common parent as the deferred item.

5. The method of claim 1, wherein executing the cycle conflict resolution process comprises determining parent and child relationships of a deferred item and determining parent and child relationships of an item of the local folder corresponding to the deferred item, and determining if any parent-child relationship of the deferred item and local folder item are reversed with respect to one another.

6. The method of claim 1, wherein the holding area items are included in the deferred items store after a first sequential run of each of the resolution processes is completed.

7. The method of claim 1, further comprising executing a file enclosure conflict resolution by selecting one conflicting update item having a reference to an enclosure for update to the local folder and a remaining update item for transfer to the holding area store.

8. The method of claim 1, further comprising transmitting an update feed from a local device when a user resolves a conflict at the local device.

9. The method of claim 1, further comprising executing the orphan conflict, duplicate conflict, and cycle conflict resolution process consistently on each of the plurality of devices associated with the synchronized folder.

10. A system for resolving conflicts for a synchronized folder comprising:

a plurality of computing devices configured to communicate with each other over a network, wherein each computing device includes a memory for storing executable instructions and a processor configured to execute the instructions;

a synchronized folder defined as a set of local folders, each local folder associated with one of the plurality of computing devices, and wherein each local folder is processed to contain a consistent set of items organized by a hierarchical tree structure including parent and child relationships, and wherein an item is a folder or a file;

a holding area store that is configured to be restricted from user access;

an application executed on each of the plurality of computing devices, wherein the application is programmed to;

receive a set of item updates for the local folder of the computing device;

execute an orphan conflict resolution routine that moves orphan files and folders to the holding area store;

execute a duplicate conflict resolution routine that sorts a set of duplicate items and moves all but a duplicate file having a most recent update time to the holding area store;

and

execute a cycle conflict resolution routine that selects a folder of a cycle with an earliest creation date and re-parents that folder to a root folder; and

update the local folder with an item update that is not moved to the holding area store based on the orphan conflict, cycle conflict, and duplicate conflict resolution routines.

11. The system of claim 10, further comprising a storage service that provides an atom feed to the computing device, wherein the atom feed is used to provide the set of item updates to the local synchronized folder of the computing device.

12. The system of claim 11, wherein the application is further programmed to notify a storage service of an update to the synchronized folder when a user modifies the local folder to resolve a holding area item.

13. The system of claim 10, further comprising a deferred items collection that is restricted from user access and that holds a set of deferred items, wherein the set of deferred items are formed by merging each update item with a corresponding item of a local feed, the local Iced being separate and distinct from the local folder.

14. The system of claim 13, wherein the application is further programmed to execute the orphan conflict resolution routine, the duplicate conflict resolution routine, and the cycle conflict resolution routine recursively on each item of the deferred items collection.

15. The system of claim 10, wherein the application is further programmed to execute a file enclosure conflict resolution routine by selecting one update item having a reference to an enclosure for update to the local folder and a remaining update item for transfer to the holding area store.

16. A computer-storage medium coupled to a processor and containing computer-executable instructions for performing operations comprising:

creating a local copy of a synchronized folder at a first device, wherein the synchronized folder includes a plurality of folders each located on a different computing device;

creating a holding area store on the first device that is configured to be restricted from user access;

receiving a feed containing a set of update items, wherein each update item contains an attribute for designating a link to an enclosure and metadata indicating a hierarchical position of the update item in a tree structure;

merging each update item with an item of the local copy of the synchronized folder that corresponds with the update item to form a set of deferred items;

executing an orphan conflict resolution process sequentially on each deferred item to move a set of orphan items to the holding area store;

executing a duplicate conflict resolution process sequentially on each deferred item to determine a set of duplicate items and to move all but a duplicate item having a most recent update time to the holding area store; and

executing a cycle conflict resolution process sequentially on each deferred item to select a folder of a cycle having an earliest modification date and re-parenting that folder to a root folder; and

updating the local copy of the synchronized folder with a set of deferred items not moved to the holding area store.

17. The computer storage medium of claim 16, further containing instructions comprising transmitting an update feed from the first device when a user resolves a conflict at the first device.

18. The computer storage medium of claim 16, further containing instructions comprising notifying a storage service of an update to the synchronized folder when a user modifies the synchronized folder to resolve a holding area item.

19. The computer storage medium of claim 16, further containing instructions comprising executing a file enclosure conflict resolution process by selecting one update item having an enclosure for update to the local folder and a remaining update item for transfer to the holding area store.

20. The computer storage medium of claim 16, further containing instructions comprising executing the orphan, duplicate, and cycle conflict resolution processes a second time on the items moved to the holding area store.