System and method for detecting and storing file identity change information within a file system

• US 7,328,217 B2
• Filed: 11/26/2003
• Issued: 02/05/2008
• Est. Priority Date: 11/26/2003
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (Gen Digital Inc.)
• Inventors: Premo, Nur, Borthakur, Dhrubajyoti
• Primary Examiner(s): Rones; Charles
• Assistant Examiner(s): CAO, PHUONG THAO
• Application Number:
  US10/723,704
• Publication Number:
  US 20050114363A1
• Time in Patent Office: 1,532 Days
• Field of Search: 707/100, 707/101, 707/3
• US Class Current: 707/823
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation

Abstract

A system and method for detecting and storing file identity change information within a file system. In one embodiment, the system may include a storage device configured to store a plurality of files and a file system configured to manage access to the storage device. The file system may be configured to detect an operation to modify an identity of a first file stored on the storage device and, subsequent to detecting the operation, store a record of the operation associated with the first file, where the record includes a signature corresponding to the first file.

Claims

1. A system, comprising:

a storage device configured to provide a storage space for data storage; and

a file system configured to map a plurality of files and a plurality of named streams corresponding respectively to said files to said storage space for storage and to manage access to said storage device, wherein said named streams are configured to store metadata corresponding respectively to said files, and wherein said file system is configured to;

detect an operation to modify an identity of a first one of said files;

in response to detecting said operation, store a record of said operation within a respective one of said named streams corresponding to said first file, wherein said record includes a signature corresponding to said first file;

detect an identity-modifying file operation specifying one or more source ones of said plurality of files and a destination one of said plurality of files; and

in response to detecting said identity-modifying file operation, for existing records of operations previously detected by said file system and responsively stored within said respective named streams corresponding to said one or more source files, store at least some of said existing records within said respective named stream corresponding to said destination file.

2. The system as recited in claim 1, wherein said operation corresponds to a file create operation, a file delete operation, a file rename operation, or a file copy operation.

3. The system as recited in claim 1, wherein said file system comprises a history stream, and wherein said file system is further configured to store an indication of said operation in said history stream in response to storing said record in said respective named stream corresponding to said first file.

4. The system as recited in claim 3, wherein said file system is further configured to scan said history stream independently of detecting operations to modify identities of ones of said plurality of files, and in response to detecting said indication of said operation in said history stream, to store said record of said operation in a database configured to store a plurality of entries, wherein said database is further configured to respond to a query of said plurality of entries.

5. The system as recited in claim 1, wherein said record is stored in extensible markup language (XML) format.

6. The system as recited in claim 1, wherein said signature is computed according to the Message Digest 5 (MD5) algorithm.

7. The system as recited in claim 1, wherein subsequent to storing said record, said file system is further configured to associate said record with a second one of said files in response to detecting a second operation to modify the identity of said first file, wherein said second operation corresponds to a file copy operation specifying said first file as a copy source and said second file as a copy destination.

8. A method, comprising:

storing a plurality of files;

a file system mapping a plurality of files and a plurality of named streams corresponding respectively to said files to a storage space for data storage provided by a storage device, wherein said file system is configured to manage access to said storage device, and wherein said named streams are configured to store metadata corresponding respectively to said files;

said file system detecting an operation to modify an identity of a first one of said files;

in response to detecting said operation, said file system storing a record of said operation within a respective one of said named streams corresponding to said first file, wherein said record includes a signature corresponding to said first file;

said file system detecting an identity-modifying file operation specifying one or more source ones of said plurality of files and a destination one of said plurality of files; and

in response to detecting said identity-modifying file operation, for existing records of operations previously detected by said file system and responsively stored within said respective named streams corresponding to said one or more source files, said file system storing at least some of said existing records within said respective named stream corresponding to said destination file.

9. The method as recited in claim 8, wherein said operation corresponds to a file create operation, a file delete operation, a file rename operation, or a file copy operation.

10. The method as recited in claim 8, wherein the method further comprises storing an indication of said operation in a history stream in response to storing said record in said respective named stream corresponding to said first file.

11. The method as recited in claim 10, further comprising:

said file system scanning said history stream independently of detecting operations to modify identities of ones of said plurality of files, and

in response to detecting said indication of said operation in said history stream, said file system storing said record in a database configured to store a plurality of entries, wherein said database is further configured to respond to a query of said plurality of entries.

12. The method as recited in claim 8, wherein said record is stored in extensible markup language (XML) format.

13. The method as recited in claim 8, wherein said signature is computed according to the Message Digest 5 (MD5) algorithm.

14. The method as recited in claim 8, further comprising associating said record with a second one of said files in response to detecting a second operation to modify the identity of said first file, wherein said second operation corresponds to a file copy operation specifying said first file as a copy source and said second file as a copy destination.

15. A computer-accessible storage medium comprising program instructions, wherein the program instructions are computer-executable to implement:

a file system mapping a plurality of files and a plurality of named streams corresponding respectively to said files to a storage space for data storage provided by a storage device, wherein said file system is configured to manage access to said storage device, and wherein said named streams are configured to store metadata corresponding respectively to said files;

said file system detecting an operation to modify an identity of a first one of said files;

in response to detecting said operation, said file system storing a record of said operation within a respective one of said named streams corresponding to said first file, wherein said record includes a signature corresponding to said first file;

said file system detecting an identity-modifying file operation specifying one or more source ones of said plurality of files and a destination one of said plurality of files; and

in response to detecting said identity-modifying file operation, for existing records of operations previously detected by said file system and responsively stored within said respective named streams corresponding to said one or more source files, said file system storing at least some of said existing records within said respective named stream corresponding to said destination file.

16. The computer-accessible storage medium as recited in claim 15, wherein said operation corresponds to a file create operation, a file delete operation, a file rename operation, or a file copy operation.

17. The computer-accessible storage medium as recited in claim 15 wherein said program instructions are further computer-executable to store an indication of said operation in a history stream in response to storing said record in said respective named stream corresponding to said first file.

18. The computer-accessible storage medium as recited in claim 17, wherein said program instructions are further computer-executable to implement:

said file system scanning said history stream independently of detecting operations to modify identities of ones of said plurality of files, and

in response to detecting said indication of said operation in said history stream, said file system storing said record in a database configured to store a plurality of entries, wherein said database is further configured to respond to a query of said plurality of entries.

19. The computer-accessible storage medium as recited in claim 15, wherein said record is stored in extensible markup language (XML) format.

20. The computer-accessible storage medium as recited in claim 15, wherein said program instructions are further computer-executable to associate said record with a second one of said files in response to detecting a second operation to modify the identity of said first file, wherein said second operation corresponds to a file copy operation specifying said first file as a copy source and said second file as a copy destination.

21. A system, comprising:

a storage device configured to provide a storage space for data storage; and

a file system configured to map a plurality of files and a plurality of named streams corresponding respectively to said files to said storage space for storage and to manage access to said storage device, wherein said named streams are configured to store metadata corresponding respectively to said files, and wherein said file system is further configured to;

detect an identity-modifying file operation specifying one or more source ones of said plurality of files and a destination one of said plurality of files; and

in response to detecting said identity-modifying file operation, store a record of said identity-modifying file operation within said respective named stream corresponding to said destination file, and for existing records of operations previously detected by said file system and responsively stored within said respective named streams corresponding to said one or more source files, store at least some of said existing records within said respective named stream corresponding to said destination file.

22. The system as recited in claim 21, wherein for each given one of said files, said file system is further configured to generate a respective signature dependent upon at least a portion of content of said given file, to store a record of said respective signature within said respective named stream corresponding to said given file, and to regenerate and store an additional record of said respective signature in response to detecting a change in content of said given file, and wherein for a first and a second one of said plurality of files, said file system is further configured to determine whether said first and said second files share a record indicating a common signature.