MANAGEMENT OF SYMBOLIC LINKS

• US 20100030739A1
• Filed: 07/30/2008
• Published: 02/04/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lanjewar, Ujjwal, Sethia, Chanda, Golwalkar, Yogesh
• Granted Patent: US 8,135,746 B2
• Time in Patent Office: Days
• US Class Current: N/A
• CPC Class Codes: G06F 16/16 File or folder operations, e.g. details of user interfaces specifically adapted to file systems

Abstract

Disclosed is a method of creating a symbolic link in a source file system to a target file in a target file system, the method including querying the target file system for an identifier of the target file; incrementing a reference counter of the target file, the reference counter indicating how many symbolic links the target file is a target of; and creating the symbolic link in the source file system, the symbolic link including the identifier received from the target file system in response to the query.

Claims

1. A method of creating a symbolic link in a source file system to a target file in a target file system, the method comprising:

querying a target file system for an identifier, the identifier being part of a target file in the target file system;

incrementing a reference counter associated with the target file in the target file system, the reference counter indicating a number of symbolic links the target file is a target of; and

creating the symbolic link in the source file system, said symbolic link including the identifier received from the target file system in response to the querying.

2. The method of claim 1, further comprising adding an entry to a table in the target file system corresponding to the target file.

3. The method of claim 1, wherein a symbolic link is not created if the target file is non-existent in the target file system.

4. A method of deleting a symbolic link in a source file system to a target file in a target file system, the method comprising:

decrementing a reference counter associated with a target file in the target file system, the reference counter indicating a number of symbolic links the target file is a target of; and

deleting the symbolic link from the source file system.

5. The method of claim 4, further comprising:

removing, if the reference counter is zero, an entry corresponding to the target file from a table in the target file system.

6. A method of accessing a target file in a target file system through a symbolic link in a source file system, the method comprising:

querying the target file system utilizing an identifier of the target file, the target file belonging to the target file system;

determining whether the target file has been replaced by a new file;

updating, upon the target file being replaced with a new file, the symbolic link with an identifier for the new file; and

accessing the target file using the identifier for the new file.

7. The method of claim 6, further comprising:

upon the target file having been replaced with a new file,

decrementing, upon the target file not being deleted, a reference counter associated with the target file, the reference counter indicating a number of symbolic links the target file is a target of; and

incrementing a reference counter associated with the new file.

8. The method of claim 7, further comprising:

(a) performing at least one of;

adding an entry in a table of the target file system wherein the entry corresponds to the new file, and (b) removing, upon the reference counter for the target file being zero, an entry from the table in the target file system wherein the entry corresponds to the target file.

9. The method of claim 6, further comprising:

upon the target file having been moved to a new file system,

updating the symbolic link with the new file system; and

accessing the target file in the new file system utilizing the identifier.

10. The method of claim 6, further comprising:

updating the symbolic link with a new path, upon the target file being moved to a new path and not replaced with a new file.

11. The method of claim 6, further comprising:

deleting the symbolic link from the source file system, upon the target file being deleted and not replaced with a new file.

12. The method of claim 6, wherein said determining whether the target file in the target file system has been replaced, further comprises:

comparing a time difference associated with the target file with a delay parameter associated with the symbolic link.

13. The method of claim 12, wherein said time difference is a difference between a time at which the target file was moved or deleted and a time at which a new file appeared at a path of the target file.

14. A method of performing an operation on a target file that is a target of a symbolic link, the method comprising:

storing, in association with the target file, a timestamp at which the operation was invoked;

performing the operation on the target file; and

storing, in association with the target file, upon a new file appearing at the path of the target file, a time difference between the stored timestamp and a timestamp at which a new file appears at a path of the target file.