RE: [RFC] Should we consider to re-write HFS/HFS+ in Rust?

[Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>]

On Wed, 2025-05-28 at 20:40 +0800, Yangtao Li wrote:
> +cc rust-for-linux
> 
> 在 2025/5/28 07:39, Viacheslav Dubeyko 写道:
> > Hi Adrian, Yangtao,
> > 
> > One idea crossed my mind recently. And this is about re-writing HFS/HFS+ in
> > Rust. It could be interesting direction but I am not sure how reasonable it
> > could be. From one point of view, HFS/HFS+ are not critical subsystems and we
> > can afford some experiments. From another point of view, we have enough issues
> > in the HFS/HFS+ code and, maybe, re-working HFS/HFS+ can make the code more
> > stable.
> > 
> > I don't think that it's a good idea to implement the complete re-writing of the
> > whole driver at once. However, we need a some unification and generalization of
> > HFS/HFS+ code patterns in the form of re-usable code by both drivers. This re-
> > usable code can be represented as by C code as by Rust code. And we can
> > introduce this generalized code in the form of C and Rust at the same time. So,
> > we can re-write HFS/HFS+ code gradually step by step. My point here that we
> > could have C code and Rust code for generalized functionality of HFS/HFS+ and
> > Kconfig would define which code will be compiled and used, finally.
> > 
> > How do you feel about this? And can we afford such implementation efforts?
> 
> It must be a crazy idea! Honestly, I'm a fan of new things.
> If there is a clear path, I don't mind moving in that direction.
> 

Why don't try even some crazy way. :)

> It seems that downstream already has rust implementations of puzzle and 
> ext2 file systems. If I understand correctly, there is currently a lack 
> of support for vfs and various infrastructure.
> 

Yes, Rust implementation in kernel is slightly complicated topic. And I don't
suggest to implement the whole HFS/HFS+ driver at once. My idea is to start from
introduction of small Rust module that can implement some subset of HFS/HFS+
functionality that can be called by C code. It could look like a library that
HFS/HFS+ drivers can re-use. And we can have C and Rust "library" and people can
select what they would like to compile (C or Rust implementation).

> I'm not an expert on Rust, so it would be great if some Rust people 
> could share their opinions.
> 
> 

I hope that Rust people would like the idea. :)

Thanks,
Slava.