Re: [RFC PATCH 00/19] Rust abstractions for VFS

[Al Viro <viro@zeniv.linux.org.uk>]

On Wed, Jan 03, 2024 at 02:14:34PM -0500, Kent Overstreet wrote:

> We don't need to copy the C interface as is; we can use this as an
> opportunity to incrementally design a new API that will obviously take
> lessons from the C API (since it's wrapping it), but it doesn't have to
> do things the same and it doesn't have to do everything all at once.
> 
> Anyways, like you alluded to the C side is a bit of a mess w.r.t. what's
> in a_ops vs. i_ops, and cleaning that up on the C side is a giant hassle
> because then you have to fix _everything_ that implements or consumes
> those interfaces at the same time.
> 
> So instead, it would seem easier to me to do the cleaner version on the
> Rust side, and then once we know what that looks like, maybe we update
> the C version to match - or maybe we light it all on fire and continue
> with rewriting everything in Rust... *shrug*

No.  This "cleaner version on the Rust side" is nothing of that sort;
this "readdir doesn't need any state that might be different for different
file instances beyond the current position, because none of our examples
have needed that so far" is a good example of the garbage we really do
not need to deal with.