FILE SYSTEM

• US 20110055184A1
• Filed: 09/09/2009
• Published: 03/03/2011
• Est. Priority Date: 09/02/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Buban, Garret J., Tipton, William R., Cargille, Jonathan M.
• Granted Patent: US 8,694,464 B2
• Time in Patent Office: Days
• US Class Current: 707/704
• CPC Class Codes: G06F 16/11 File system administration, e.g. details of archiving or snapshots file system backup G06F11/14
• CPC Class Codes: G06F 16/1774 Locking methods, e.g. locking methods for file systems allowing shared and concurrent access to files

Abstract

For each of one or more existing nodes in a file system, pending notifications of updates that have been performed on the node can be identified and sent to one or more other nodes. The file system can be opened for use, and one or more other nodes can be updated in response to the pending notifications while the file system is open for use. For example, this may be done in an operation for recovering from a crash of the file system. Also, a process for dealing with stale data in container nodes in a file system can include processing access requests according to a stale data scheme.

Claims

1. A computer-implemented method, comprising:

closing a file system to use;

for each of one or more existing nodes in the file system;

identifying pending notifications of updates that have been performed on the node; and

sending the one or more pending notifications to one or more other nodes;

opening the file system for use; and

updating the one or more other nodes in response to the pending notifications while the file system is open for use.

2. The method of claim 1, further comprising, for each of the one or more existing nodes, having the node ensure its own integrity.

3. The method of claim 2, wherein, for each of the one or more existing nodes, if one or more pending notifications were generated by the existing node in ensuring its own integrity, then identifying pending notifications for that existing node comprises identifying the one or more pending notifications that were generated by that existing node in ensuring its own integrity.

4. The method of claim 1, wherein all pending notifications of updates performed on the one or more existing nodes are sent before opening the file system for use.

5. The method of claim 1, wherein identifying and sending the pending notifications are performed while the file system is closed to use.

6. The method of claim 1, wherein identifying the pending notifications and sending the pending notifications for each of the one or more existing nodes are allowed to be done in parallel for different nodes.

7. The method of claim 1, wherein updating the one or more other nodes is allowed to be done in parallel for different nodes.

8. The method of claim 1, wherein the one or more existing nodes comprise a contained node, and for that contained node, sending the one or more pending notifications to one or more other nodes comprises sending the one or more pending notifications to one or more containing nodes that contain the contained node.

9. The method of claim 1, wherein updating the one or more other nodes comprises acquiring locks of the one or more other nodes.

10. The method of claim 1, wherein:

identifying the pending notifications, sending the pending notifications, opening the file system for use, and updating the one or more other nodes are included in a file system recovery operation;

the pending notifications are notifications that are scheduled to be sent, but have not yet been confirmed as having been received;

all the pending notifications are sent before opening the file system for use;

identifying and sending the pending notifications are performed while the file system is closed to use; and

updating the one or more other nodes comprises acquiring locks for each of the one or more other nodes.

11. A computer system comprising:

at least one processor; and

a memory comprising instructions stored thereon that when executed by the at least one processor cause the at least one processor to perform acts comprising;

performing a recovery operation in a file system after a crash of the file system, the recovery operation comprising;

for each of a plurality of nodes in the file system, determining whether the node has one or more pending notifications of that node'"'"'s updates, and if so, then sending the one or more pending notifications to one or more other nodes;

opening the file system for use after sending the pending notifications, if any; and

after opening the file system for use, in response to one or more of the pending notifications, updating one or more indexes in the one or more other nodes.

12. The computer system of claim 11, wherein:

the plurality of nodes comprise all nodes in the file system that may have pending notifications;

all nodes in the file system that may have pending notifications are contained nodes; and

the one or more other nodes are container nodes.

13. The computer system of claim 11, wherein updating the one or more indexes comprises updating the one or more indexes in the one or more other nodes to reflect one or more updates performed prior to the crash of the file system.

14. The computer system of claim 11, wherein updating the one or more indexes in the one or more other nodes comprises updating the one or more indexes to reflect updates to one or more previously-updated nodes, updating the one or more indexes being independent of locks of the previously-updated nodes.

15. One or more computer-readable storage media having computer-executable instructions embodied thereon that, when executed by at least one processor, cause the at least one processor to perform acts comprising:

receiving an update request at a file system;

in response to the request;

performing an update of a contained node without locking a container node that contains the contained node; and

sending a notification of the update of the contained node to the container node;

receiving a request for access to data at the container node before the container node has processed the notification; and

processing the request for access according to a pre-determined scheme, processing the request for access beginning after the container node has received the notification but before the container node has processed the notification.

16. The one or more computer-readable storage media of claim 15, wherein the scheme dictates allowing the second node to return the data in response to the request for access before processing the notification.

17. The one or more computer-readable storage media of claim 15, wherein the scheme dictates processing the notification at the second node before processing the request for access, regardless of characteristics of the notification.

18. The one or more computer-readable storage media of claim 15, wherein the scheme dictates processing notification before processing the request for access if processing the notification would add data to the second node.

19. The one or more computer-readable storage media of claim 15, wherein the acts comprise altering the scheme according to search options.

20. The one or more computer-readable storage media of claim 15, wherein the acts further comprise processing the notification, and wherein processing the notification comprises performing an update of the container node that reflects the update of the contained node.