Description

This project aims to create a Linux equivalent to the git/fs concept from git9. Now, I'm aware that git provides worktrees, but they are not enough for many use cases. Having a read-only representation of the whole repository simplifies scripting by quite a bit and, most importantly, reduces disk space usage. For instance, during kernel livepatching development, we need to process and analyze the source code of hundreds of kernel versions simultaneously.This is rather painful with git-worktrees, as each kernel branch requires no less than 1G of disk space.

As for the technical details, I'll implement the file system using FUSE. The project itself should not take much time to complete, but let's see where it takes me.

I'll try to keep the same design as git9, so the file system will look something like:

/mnt/git
      +-- ctl
      +-- HEAD
      |    +-- tree
      |    |    +--files
      |    |    +--in
      |    |    +--head
      |    |
      |    +-- hash
      |    +-- msg
      |    +-- parent
      |
      +-- branch
      |      |
      |      +-- heads
      |      |      +-- master
      |      |            +-- [commit files, see HEAD]
      |      +-- remotes
      |             +-- origin
      |                     +-- master
      |                            +-- [commit files, see HEAD]
      +-- object
            +-- 00051fd3f066e8c05ae7d3cf61ee363073b9535f # blob contents
            +-- 00051fd3f066e8c05ae7d3cf61ee363073b9535c
                  +-- [tree contents, see HEAD/tree]
            +-- 3f5dbc97ae6caba9928843ec65fb3089b96c9283
                  +-- [commit files, see HEAD]

So, if you wanted to look at the commit message of the current branch, you could simply do:

cat /mnt/git/HEAD/msg 

No collaboration needed. This is a solo project.

Goals

• Implement a working prototype.

• Measure and improve the performance if possible. This step will be the most crucial one. User space filesystems are slower by nature.

Resources

https://orib.dev/git9.html

https://docs.kernel.org/filesystems/fuse/fuse.html