Presenting differences in a file system

• US 7,904,466 B1
• Filed: 12/21/2007
• Issued: 03/08/2011
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Manley, Stephen, Valencia, Victor, Zheng, Ling
• Primary Examiner(s): Cottingham; John R.
• Assistant Examiner(s): Rayyan; Susan F
• Application Number:
  US11/963,665
• Time in Patent Office: 1,173 Days
• Field of Search: 707/609, 707638-639, 707/649, 707/758, 707/822, 707/999.2
• US Class Current: 707/758
• CPC Class Codes: G06F 16/1734 Details of monitoring file system events, e.g. by the use of hooks, filter drivers, logs

Abstract

An embodiment of the invention provides an apparatus and method for presenting differences in a file system. In an embodiment, an application programming interface receives a request from a host, where the request is for a listing of changes in the file system within a time interval. A comparison unit determines each metadata container that has changed in the file system within the time interval. The application programming interface buffers at least one identifier that corresponds to a metadata container that has changed in the file system within the time interval. The application programming interface packages and transmits the at least one identifier to the host. The at least one identifier is readable on the host.

Claims

1. A method of presenting differences in a file system, the method comprising:

receiving a request from a host, where wherein the request is for an identification of changes in the file system within a time interval;

determining a metadata container that has changed in the file system within the time interval by comparing a first record of the metadata container with a second record of the metadata container, wherein the comparing includes performing a comparison of nonpointer fields of the first record and of the second record;

buffering an identifier that corresponds to, the metadata container that has changed in the file system within the time interval; and

packaging and transmitting the identifier to the host, wherein the identifier is readable on the host, wherein packaging and transmitting the identifier to the host includes packaging and transmitting buffered identifiers when an amount of buffered identifiers reaches a threshold.

2. The method of claim 1, wherein the host includes a software application that sends the request for the identification of changes in the file system within the time interval.

3. The method of claim 1, wherein determining the metadata container that has changed in the file system within the time interval includes comparing a metadata container in a data subset during a starting time T1 and during a subsequent time T2.

4. The method of claim 1, further comprising:

generating the identification of buffered identifiers including the identifier, wherein the identification is readable on the host.

5. The method of claim 1, further comprising:

sending from a host a request for changes in a file system.

6. The method of claim 5, further comprising:

in response to the request, sending a response including the identifier that corresponds to the metadata container that has changed in the file system within the time interval.

7. The method of claim 1, wherein the metadata container is associated with a file or a directory that has changed in the file system within the time interval.

8. The method of claim 7, wherein the file or directory that has changed in the file system within the time interval includes a file or directory that has been modified, added, deleted, or accessed within the time interval.

9. The method of claim 1, further comprising:

using in the host the identifier to update a file system index.

10. A method of presenting differences in a file system, the method comprising:

receiving a request from a host, wherein the request is for a listing of changes in the file system within a time interval;

comparing metadata containers in a first persistent point-in-time image of the file system corresponding to a first time value with metadata containers in a second persistent point-in-time image of the file system corresponding to a second time value, wherein the comparing includes performing a comparison of nonpointer fields of the metadata containers in the first persistent point-in-time image with nonpointer fields of the metadata containers in the second persistent point-in-time image;

determining each metadata container that has changed in the file system within the first time value and second time value;

assigning an identifier for each metadata container that has changed in the file system within the first time value and the second time value;

buffering each identifier that corresponds to a metadata container that has changed in the file system within the first time value and second time value; and

packaging and transmitting each identifier to the host, where each identifier is readable on the host, wherein each identifier is transmitted and packaged when an amount of buffered identifiers reaches a threshold.

11. The method of claim 10, wherein the host includes a software application that sends the request for the listing of changes in the file system within the first and second time values.

12. The method of claim 10, further comprising:

generating a listing of the identifiers, wherein the listing is readable on the host.

13. The method of claim 10 further comprising:

sending from the host a request for changes in a file system.

14. The method of claim 13, further comprising:

sending to the host a response including an identifier that corresponds to a metadata container that has changed in the file system within the first time value and second time value, in response to the request.

15. The method of claim 10, wherein the metadata container is associated with a file or a directory that has changed in the file system within the first time value and second time value.

16. The method of claim 15, wherein a file or directory that has changed in the file system within the first time value and second time value comprises a file or directory that has been modified, added, deleted, or accessed within the time interval.

17. The method of claim 10, further comprising:

using in the host the identifier to update a file system index.

18. An apparatus for presenting differences in a file system, the apparatus comprising:

a processor;

a storage operating system that is executable by the processor; and

an application programming interface that operates with the processor and that is configured to receive a request from a host, wherein the request is for a listing of changes in the file system within a time interval, configured to compare a first record of nonpointer fields of a metadata container with a second record of the nonpointer fields of the metadata container, configured to buffer an identifier that corresponds to a metadata container that has changed in the file system within the time interval based on the comparing, and configured to package and transmit the identifier to the host, wherein the identifier is readable on the host, and wherein the application programming interface is configured to package and transmit buffered identifiers when an amount of buffered identifiers reaches a threshold.

19. The apparatus of claim 18, wherein the host includes a software application that sends the request for the listing of changes in the file system within the time interval to the apparatus.

20. The apparatus of claim 18, wherein each metadata container that has changed in the file system within the time interval is determined by comparing a metadata container in a data subset during a starting time T1 and during a subsequent time T2.

21. The apparatus of claim 18, wherein the application programming interface is configured to generate a listing of the identifiers, wherein the listing is readable on the host.