I want to write a filesystem. Where, code wise, do I start?

[CheetahPixie]

I have ideas for something to possibly later forward to Linux proper, but I thought this might be a nice testbed, since I intend it to be usable across the widest possible range of hardware.

But, question in the title remains.

[ghaerr]

The ELKS filesystem code is arranged in two parts, the upper level common code in elks/fs/, sometimes called VFS for Virtual File System, and then particular filesystem code for each filesystem type (MINIX, MSDOS and ROMFS) in subdirectories minix/, msdos/ and romfs/ respectively.

Filesystem code is pretty complex, I recommend studying elks/fs/minix/ first. ELKS supports MINIX v1 whose structure can be learned about online. The ELKS filesystem VFS and MINIX code is somewhat close to Linux v2.0's implementations, with later Linux implementations considerably more complicated.

[CheetahPixie]

Complex has never stopped any shows for me. In fact, it has so far only been extra motivation to learn and execute.

It is this exact attitude I have already taken to ARM hardware with great success. I know the boot process of Amlogic like the back of my hand, simply because I charged headfirst into the metaphorical danger.

So, doing that for filesystems is something I'm more than excited for.

Which I thank you for the pointers to.