Tracking file system changes for backup

• US 7,974,952 B1
• Filed: 12/29/2005
• Issued: 07/05/2011
• Est. Priority Date: 04/18/2005
• Status: Expired due to Fees

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Reitmeyer, Richard, Pyle, Michael, Lyon, Robert
• Primary Examiner(s): Mofiz; Apu M
• Assistant Examiner(s): Jacob; Ajith
• Application Number:
  US11/324,017
• Time in Patent Office: 2,014 Days
• Field of Search: 704/204, 704/641
• US Class Current: 707/641
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

In some embodiments, a method for tracking changes comprises reviewing a file system, wherein an entry is associated with the file system; providing a first record file, wherein a record is associated with the first record file; comparing the file system entry with the record; providing a second record file; and merging the first record file with the second record file.

Claims

1. A method for tracking file system changes for backup comprising:

reviewing a file system in a canonical order, wherein an entry is associated with the file system;

providing a current record file, wherein a record includes a set of information associated with a particular file system entry for the file system and the record is associated with the current record file and a sibling offset, wherein the sibling offset indicates a relative offset to a next sibling entry in the record file, wherein the next sibling entry is associated with a directory or file on a same hierarchal level in a same parent directory as the particular file system entry, and the current record file is arranged in the canonical order;

comparing the file system entry with the record;

in the event that the file system entry does not correspond to the record;

including in a scratch file a new record corresponding to the file system entry in the event it is determined that the file system entry does not correspond to the record because the file system entry is new; and

not including the record in the scratch file in the event it is determined that the file system entry does not correspond to the record because the record corresponds to a deleted file system entry which is not currently associated with the file system; and

merging the current record file with the scratch file in the canonical order to create a new current record file using the sibling offset to copy the record and its children to the new current record file.

2. The method of claim 1, wherein merging includes copying the new record from the scratch file to the new current record file.

3. The method of claim 1, wherein merging includes copying the new record from the current record file to the new current record file.

4. The method of claim 1, wherein merging includes copying the record from the current record file to the new current record file.

5. The method of claim 1, wherein merging includes copying the record from the current record file to the scratch file.

6. The method of claim 1, wherein merging includes using the sibling offset to copy the record and its children to the scratch file.

7. The method of claim 1, wherein the file system entry and a second file system entry are reviewed in a canonical order.

8. The method of claim 1, further comprising adding a second record to the new current record file wherein the second record is not in the current record file.

9. The method of claim 1, wherein comparing includes determining whether the file system entry is a newly-found file;

and

inserting a new record into the scratch file if it is determined that this file system entry is a newly-found file.

10. The method of claim 1, wherein comparing includes determining whether the file system entry is a newly-found file;

and

backing up the file system entry if the file system entry is a newly-found file.

11. The method of claim 1, wherein comparing includes determining whether the record is not associated with any file system entry in the file system;

and

wherein the record is not copied to the scratch file if it is determined that the record is not associated with any file system entry.

12. The method of claim 1, further comprising determining whether the file system entry is associated with the record;

determining whether the file system entry is before the record in a canonical ordering, if it is determined that the file system entry is not associated with the record; and

backing up the file system entry if it is before the record.

13. The method of claim 1, further comprising:

determining whether a file discovery time is newer than a whence time, if the file system entry is associated with the record; and

backing up the file system entry if the discovery time is newer than the whence time.

14. The method of claim 1, further comprising determining whether a file discovery time is newer than a whence time, if the file system entry is associated with the record;

and

copying the record to the scratch file if the discovery time is not newer than the whence time.

15. The method of claim 1, wherein comparing includes determining whether the record is after the file system entry in a canonical order;

and

inserting a second record if the record is after the file system entry.

18. The method of claim 1, wherein the deleted file system entry is not included in a range with which the record is associated.

16. A system for tracking file system changes for backup comprising:

a processor configured to

review a file system in a canonical order, wherein an entry is associated with the file system;

provide a current record file, wherein a record includes a set of information associated with a particular file system entry for the file system and the record is associated with the current record file and a sibling offset, wherein the sibling offset indicates a relative offset to a next sibling entry in the record file, wherein the next sibling entry is associated with a directory or file on a same hierarchal level in a same parent directory as the particular file system entry, and the current record file is arranged in the canonical order;

compare the file system entry with the record;

in the event that the file system entry does not correspond to the record;

include in a scratch file a new record corresponding to the file system entry in the event it is determined that the file system entry does not correspond to the record because the file system entry is new; and

not include the record in the scratch file in the event it is determined that the file system entry does not correspond to the record because the record corresponds to a deleted file system entry which is not currently associated with the file system; and

merge the current record file with the scratch file in the canonical order to create a new current record file using the sibling offset to copy the record and its children to the new current record file; and

a memory coupled to the processor, wherein the memory is configured to provide the processor with instructions.

19. The system of claim 16, wherein merging includes using the sibling offset to copy the record and its children to the scratch file.

20. The system of claim 16, wherein the file system entry and a second file system entry are reviewed in a canonical order.

21. The system of claim 16, further comprising determining whether the file system entry is associated with the record;

determining whether the file system entry is before the record in a canonical ordering, if it is determined that the file system entry is not associated with the record; and

backing up the file system entry if it is before the record.

22. The system of claim 16, further comprising:

determining whether a file discovery time is newer than a whence time, if the file system entry is associated with the record; and

backing up the file system entry if the discovery time is newer than the whence time.

23. The system of claim 16, wherein comparing includes determining whether the record is after the file system entry in a canonical order;

and inserting a second record if the record is after the file system entry.

24. The system of claim 16, wherein the deleted file system entry is not included in a range with which the record is associated.

17. A computer program product for tracking file system changes for backup, the computer program product being embodied in a computer readable medium and comprising computer instructions for:

reviewing a file system in a canonical order, wherein an entry is associated with the file system;

providing a current record file, wherein a record includes a set of information associated with a particular file system entry for the file system and the record is associated with the current record file and a sibling offset, wherein the sibling offset indicates a relative offset to a next sibling entry in the record file, wherein the next sibling entry is associated with a directory or file on a same hierarchal level in a same parent directory as the particular file system entry, and the current record file is arranged in the canonical order;

comparing the file system entry with the record;

in the event that the file system entry does not correspond to the record;

including in a scratch file a new record corresponding to the file system entry in the event it is determined that the file system entry does not correspond to the record because the file system entry is new; and

not including the record in the scratch file in the event it is determined that the file system entry does not correspond to the record because the record corresponds to a deleted file system entry which is not currently associated with the file system; and

merging the current record file with the scratch file in the canonical order to create a new current record file using the sibling offset to copy the record and its children to the new current record file.

25. The computer program product of claim 17, wherein merging includes using the sibling offset to copy the record and its children to the scratch file.

26. The computer program product of claim 17, wherein the file system entry and a second file system entry are reviewed in a canonical order.

27. The computer program product of claim 17, further comprising determining whether the file system entry is associated with the record;

determining whether the file system entry is before the record in a canonical ordering, if it is determined that the file system entry is not associated with the record; and

backing up the file system entry if it is before the record.

28. The computer program product of claim 17, further comprising:

determining whether a file discovery time is newer than a whence time, if the file system entry is associated with the record; and

backing up the file system entry if the discovery time is newer than the whence time.

29. The computer program product of claim 17, wherein comparing includes determining whether the record is after the file system entry in a canonical order;

and inserting a second record if the record is after the file system entry.

30. The computer program product of claim 17, wherein the deleted file system entry is not included in a range with which the record is associated.