Directory leasing

• US 9,092,450 B2
• Filed: 09/24/2013
• Issued: 07/28/2015
• Est. Priority Date: 09/17/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Kruse, David Matthew, George, Mathew, Havewala, Sarosh Cyrus, Allred, Christian Gregory, Christiansen, Neal Robert
• Primary Examiner(s): Nguyen, Angela
• Application Number:
  US14/035,737
• Publication Number:
  US 20140040332A1
• Time in Patent Office: 672 Days
• Field of Search: 709/226
• US Class Current: 1/1
• CPC Class Codes: G06F 16/164 File meta data generation
• CPC Class Codes: G06F 16/172 Caching, prefetching or hoarding of files
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 16/24552 Database cache management
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 21/6227 where protection concerns the structure of data, e.g. records, types, queries

Abstract

Described are embodiments for allowing clients that access a distributed file system to locally cache directory metadata. The client may request a read lease which allows the client to cache the directory metadata locally and service requests received from the same application which originally requested the directory metadata using the cache. In addition, the client may also request a handle lease which allows a client to delay the closing of a directory handle and allow the handle to be reused to service subsequent directory metadata requests from the same or a different application. A client may also request a write lease which allows an application on the client to modify the directory metadata, such as by creating or deleting new files in the directory, or changing their attributes, and cache those changes.

Claims

1. A method comprising:

receiving, from a requesting device, a request for directory metadata, wherein the request comprises;

a request for a handle to a directory containing the directory metadata;

a request for a lease, wherein the lease allows local caching of directory metadata until revocation of the lease;

a key, wherein the key is associated with a first directory that includes the requested directory metadata; and

a directory key, wherein the directory key is associated with a second directory, wherein the first directory is included in the second directory; and

transmitting a response to the requesting device, wherein the response comprises the directory metadata and an indication of an approval of the request for the lease.

2. The method of claim 1, wherein the request for the lease comprises a flag indicating a request for one or more of:

read caching, write caching, and handle caching.

3. The method of claim 1, further comprising:

receiving a second request to modify director metadata; and

determining whether the second request is received from a second requesting device.

4. The method of claim 1, further comprising:

receiving a second request to modify a file stored in the second directory, wherein the second request comprises a file key associated with the file and a second directory key.

5. The method of claim 1, wherein the directory key and the key are stored in a look-up table.

6. The method of claim 1, further comprising:

transmitting a notice of revocation of the lease; and

in response to transmitting the notice of revocation of the lease, receiving an acknowledgement of receipt of the notice of revocation.

7. The method of claim 1, further comprising transmitting a notice that the directory metadata has changed.

8. The method of claim 3, wherein determining whether the second request is received from a second requesting comprises comparing a directory key from the second request with a previously stored directory key.

9. The method of claim 8, further comprising sending a revocation notification to the requesting device to revoke the lease in response to determining that the directory key from the second request is not the same as a previously received directory key.

10. The method of claim 5, wherein the look-up table stores an association of the key and the directory key.

11. The method of claim 5, wherein notice of revocation comprises a notification that the directory metadata has been removed from a local cache accessible by the requesting device.

12. A computer-readable storage device encoding computer executable instructions which, when executed by at least one processor, performs a method, the method comprising:

receiving, from a requesting device, a request for directory metadata, wherein the request comprises;

a request for a handle to a directory containing the directory metadata;

a request for a lease, wherein the lease allows local caching of directory metadata until revocation of the lease;

a key, wherein the key is associated with a first directory that includes the requested directory metadata; and

a directory key, wherein the directory key is associated with a second directory, wherein the first directory is included in the second directory; and

transmitting a response to the requesting device, wherein the response comprises the directory metadata and an indication of an approval of the request for the lease.

13. The computer-readable storage device of claim 12, wherein the request for the lease comprises a flag indicating a request for one or more of:

read caching, write caching, and handle caching.

14. The computer-readable storage device of claim 12, further comprising:

receiving a second request to modify director metadata; and

determining whether the second request is received from a second requesting device.

15. The computer-readable storage device of claim 12, further comprising instructions for:

transmitting a notice of revocation of the lease; and

in response to transmitting the notice of revocation of the lease, receiving an acknowledgement of receipt of the notice of revocation.

16. The computer-readable storage device of claim 14, wherein determining whether the second request is received from a second requesting comprises comparing a directory key from the second request with a previously stored directory key.

17. The computer-readable storage device of claim 16, further comprising instructions for sending a revocation notification to the requesting device to revoke the lease in response to determining that the directory key from the second request is not the same as a previously received directory key.

18. A system comprising:

a processor; and

a memory coupled to the processor, the memory for storing instructions which, when executed by the processor, performs a method, the method comprising;

receiving a request for directory metadata, wherein the request comprises;

a request for a handle to a directory containing the directory metadata;

a request for a lease for enabling local caching of directory metadata;

a key associated with a first directory that includes the requested directory metadata; and

a directory key associated with a second directory; and

transmitting an approval response to the requesting device, wherein the response comprises an indication of an approval of the request for the lease.

19. The system of claim 18, wherein the response further comprises the directory metadata.

20. The system of claim 18, wherein the request for the lease comprises a flag indicating a request for one or more of:

read caching, write caching, and handle caching.