DYNAMIC SYMBOLIC LINKS FOR REFERENCING IN A FILE SYSTEM

• US 20180041418A1
• Filed: 10/19/2017
• Published: 02/08/2018
• Est. Priority Date: 10/09/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Abe, Atsushi, Pease, David A., Villa Real, Lucas C.
• Granted Patent: US 10,212,067 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 45/02 Topology update or discovery

Abstract

Various embodiments relate to providing dynamic absolute-path symbolic links. According to one embodiment, indication of a symbolic link is received, which references a target, the indication including an absolute path of the target that includes a target mount point and a name of the target. A current mount point of the target is identified, and a verification is made that the target mount point is identical to the current mount point. When the target mount point is identical to the current mount point, a string length of the current mount point is determined, and an in-memory record of the symbolic link is created. The in-memory record includes the string length of the current mount point associated with the symbolic link.

Claims

1. A computer program product for providing dynamic absolute-path symbolic links, the computer program product comprising a computer readable storage medium having computer program code embodied therewith, the program code readable/executable by a processor to:

receive indication of a symbolic link which references a target, the indication including an absolute path of the target, wherein the absolute path comprises a target mount point and a name of the target;

identify a current mount point of the target;

verify that the target mount point is identical to the current mount point;

in response to a determination that the target mount point is identical to the current mount point;

determine a string length of the current mount point, and create an in-memory record of the symbolic link, the in-memory record comprising the string length of the current mount point associated with the symbolic link;

receive a request to utilize the symbolic link, the symbolic link comprising a second absolute path with an outdated target mount point;

determine whether an in-memory record exists for the symbolic link; and

return the second absolute path in response to a determination that the in-memory record is empty or does not exist.

2. The computer program product as recited in claim 1, wherein the program code for verifying that the target mount point is identical to the current mount point comprises program code readable/executable by the processor to:

compare a string length of the target mount point to a string length of the current mount point;

determine that the target mount point is not identical to the current mount point in response to a determination that the string length is different; and

determine that the target mount point is not identical to the current mount point in response to a determination that the string length is the same and a content of the current mount point is different from a content of the target mount point.

3. The computer program product as recited in claim 1, wherein the program code is further readable/executable by the processor to update the in-memory record of the symbolic link in response to a change to the current mount point of the target by:

determining a string length of the current mount point, and

updating the in-memory record of the symbolic link with the string length of the current mount point.

4. The computer program product as recited in claim 1, wherein the program code is further readable/executable by the processor to:

in response to a determination that the in-memory record is non-empty after receiving the request to the symbolic link;

replace the outdated target mount point from the second absolute path with the current mount point to form a modified absolute path; and

return the modified absolute path.

5. The computer program product as recited in claim 1, wherein the program code is further readable/executable by the processor to store a length of a media identifier to the in-memory record in response to a determination that the symbolic link includes the media identifier.

6. The computer program product as recited in claim 5, wherein the program code is further readable/executable by the processor to:

in response to a determination that the in-memory record is non-empty;

replace the outdated target mount point from the second absolute path with the current mount point and the media identifier to form a modified absolute path; and

return the modified absolute path.

7. The computer program product as recited in claim 1, wherein a plurality of in-memory records are stored for a plurality of symbolic links, each updated in-memory record indicating a current mount point for its associated target, and wherein the target comprises at least one file and/or at least one directory stored on media of a storage system.

8. A computer program product for using dynamic absolute-path symbolic links, the computer program product comprising a computer readable storage medium having computer program code embodied therewith, the program code readable/executable by a processor to:

receive a request to utilize a symbolic link which references a target using an absolute path, the absolute path comprising a target mount point and a name of the target;

determine whether an in-memory record exists for the symbolic link;

return the absolute path in response to a determination that the in-memory record is empty or does not exist;

in response to a determination that the in-memory record is non-empty;

replace the target mount point from the absolute path with a current mount point to form a modified absolute path and return the modified absolute path;

receive a request to utilize the symbolic link, the symbolic link comprising a second absolute path with an outdated target mount point;

determine whether an in-memory record exists for the symbolic link; and

return the second absolute path in response to a determination that the in-memory record is empty or does not exist.

9. The computer program product as recited in claim 8, wherein the program code is further readable/executable by the processor to:

receive indication of the symbolic link, the indication including the absolute path of the target;

identify the current mount point of the target;

verify that the target mount point is identical to the current mount point; and

in response to a determination that the target mount point is identical to the current mount point;

determine a string length of the current mount point; and

create an in-memory record for the symbolic link, the in-memory record comprising the string length of the current mount point associated with the symbolic link.

10. The computer program product as recited in claim 9, wherein the program code for verifying that the target mount point is identical to the current mount point comprises program code readable/executable by the processor to:

compare a string length of the target mount point to a string length of the current mount point;

determine that the target mount point is not identical to the current mount point in response to a determination that the string length is different; and

determine that the target mount point is not identical to the current mount point in response to a determination that the string length is the same and a content of the current mount point is different from a content of the target mount point.

11. The computer program product as recited in claim 9, wherein the program code is further readable/executable by the processor to store a length of a media identifier to the in-memory record in response to a determination that the symbolic link includes the media identifier.

12. The computer program product as recited in claim 8, wherein the program code is further readable/executable by the processor to add a media identifier to the modified absolute path in response to a determination that the in-memory record comprises the media identifier.

13. The computer program product as recited in claim 8, wherein the program code is further readable/executable by the processor to update the in-memory record of the symbolic link in response to a change to the current mount point of the target by:

determining a string length of the current mount point, and

updating the in-memory record of the symbolic link with the string length of the current mount point.

14. The computer program product as recited in claim 8, wherein a plurality of in-memory records are stored for a plurality of symbolic links, each updated in-memory record indicating a current mount point for its associated target, and wherein the target comprises at least one file and/or at least one directory stored on media of a storage system.

15. A computer-implemented method for providing dynamic absolute-path symbolic links, the method comprising:

receiving a request to utilize a symbolic link which references a target using an absolute path with an outdated target mount point;

determining whether an in-memory record exists for the symbolic link; and

in response to determining that the in-memory record is non-empty;

replacing the outdated target mount point from the absolute path with a current mount point to form a modified absolute path, and returning the modified absolute path.

16. The computer-implemented method as recited in claim 15, comprising returning the absolute path from the symbolic link in response to a determination that the in-memory record is empty or does not exist.

17. The computer-implemented method as recited in claim 15, comprising:

comparing a string length of the outdated target mount point to a string length of the current mount point for determining whether the outdated target mount point is not identical to the current mount point.

18. The computer-implemented method as recited in claim 17, comprising storing a length of a media identifier to the in-memory record in response to a determination that the symbolic link includes the media identifier.

19. The computer-implemented method as recited in claim 15, comprising adding a media identifier to the modified absolute path in response to a determination that the in-memory record comprises the media identifier.