looking for mentor for creation of a new filesystem

[santi at gmx.eu]

Hello,

I'm pretty new to kernel-development, but I would like to write a filesystem like UnionFS, but much much smaller.
With the current kernel most existing tutorials like rkfs are broken and I did not succeed in trying to clone ramfs as a starting point - so I don't know, where to start.
I hope it's right to post here.

I wanted to start with a lightweight fs, that forwards all calls to an existing fs and only prints some logging messages from the wrapper-functions. The configuration should work with fstab.

Can anybody shine me a light, on where and how to start?
I already read lots of the kernel docs, as well as other fs-sources, but the existing fs are to complex to serve as a starting point and from docs I did not find answers for my questions:
- how can I find the superblock of the device, when I only have a mountpoint-path from fstab?
- or how can I do a path resolution of an absolute path-string from inside of a module/fs ?
- how can I mount another fs from a module (may be separate thread), when I only have the /dev/xxx, fstype and an optionstring from fstab?
- what is the prefferable way to communicate with userspace: /proc, /config or building a new virtual fs?

Any hint is appreciated.

kind regards

Santiago