Xv6 is usually a good source to learn about OS primitives: https://pdos.csail.mit.edu/6.828/2016/xv6.html https://pdos.csail.mit.edu/6.828/2016/xv6.html I have

Xv6 is usually a good source to learn about OS primitives: https://pdos.csail.mit.edu/6.828/2016/xv6.html https://pdos.csail.mit.edu/6.828/2016/xv6.html I have not looked at the filesystem implementation, but since it is designed as a teaching OS, my guess is that it should be a good entry point. https://github.com/mit-pdos/xv6-public/blob/master/fs.c https://github.com/mit-pdos/xv6-public/blob/master/fs.c