OpenAFS Workshop

Google Summer of Code 2026 Final Report

By: Junsouh Hong

Title: Adding Cell Creation Support to afsio

Link to GitHub: link

Link to Relevant Gerrit Topics (Used by OpenAFS for version control): ACL Refactor Commits, afsio Manpage Commits

Goals

The project aimed to improve the afsio CLI tool by adding support for mount point control and ACL manipulation. Previously, the fs CLI tool was the only way to perform these tasks, which was sometimes inconvenient both for testing and administrative purposes, as fs requires the kernel module to be loaded. As afsio directly performs the RPCs through the libafscp library, it does not require the kernel module to be loaded.

Overall, the goals of the project fell into three categories:

1. Refactoring of the ACL parsing code in fs so it can be used in the new afsio commands.
2. Adding the ACL commands to afsio (afsio listacl/fidlistacl, setacl/fidsetacl), as well as man pages for these commands.
3. Adding the mount point commands to afsio (afsio lsmount/fidlsmount, mkmount, rmmount), as well as man pages for these commands.

Organization: OpenAFS Project

Mentors: Michael Meffie, Marcio Barbosa, Kailas Zadbuke

Contributor: Junsouh Hong

Work Done

All of the work planned out in the initial goals was accomplished. The link to the GitHub branch above contains the build of afs with every command implemented, including two additional commands, afsio rmfile and afsio rmdir, since they made sense to implement alongside afsio rmmount.

Remaining Work

Despite all the initial goals being met, there are still potentially more commands that could be added relatively easily to expand functionality. Two would be the afsio cleanacl/fidcleanacl and afsio copyacl/fidcopyacl commands. There was not enough time to get to these, but they would be relatively easy additions building off the foundations already established in afsio listacl/fidlistacl and afsio setacl/fidsetacl.

Further, while all the commands are implemented in the GitHub branch, only some of them have been merged upstream; the rest are still pending review on Gerrit. Currently, the ACL refactoring is still in the process of being merged, whose commits can be seen under the topic “gsoc-afsio-phase1” linked above and also here.

Challenges

• Learning OpenAFS: OpenAFS is a large codebase with many intricacies, so one of the primary challenges was the amount of code I had to read, parse, and either refactor or add to. In particular, learning how mount points, symlinks, and ACLs function in AFS was one of the largest obstacles.
• Implementing Feedback: Staying on top of the feedback given in the code reviews and staying flexible was another challenge, as this was my first time working on an open source project.

Lessons Learned

• Code Collaboration: This was my first time contributing heavily to a large project with many other contributors, so I learned how to navigate such a codebase and get feedback on my code.
• File System Concepts: Working on the AFS system gave me insight into how file systems like AFS function in general.
• Git: Working on this project also gave me significantly more experience in Git; while I knew how to use Git on a basic level before, this project gave me a lot more experience in less common features of Git and also in actually using Git on a large project.

Acknowledgments

I would like to thank the mentors (listed at the top) for their awesome support and feedback during the development process! The project was very engaging, and I hope to contribute to AFS and other open source projects in the future.