Subject: Re: [RFC PATCH] 9p: case-insensitive host filesystems

From: Dominique Martinet <[email-masked]>
Date: Sat, 23 Apr 2022 04:57:40 +0900

Christian Schoenebeck wrote on Fri, Apr 22, 2022 at 08:02:46PM +0200:
> So maybe it's better to handle case-insensitivity entirely on client side? 
> I've read that some generic "case fold" code has landed in the Linux kernel 
> recently that might do the trick?

I haven't tried, but settings S_CASEFOLD on every inodes i_flags might do
what you want client-side.
That's easy enough to test and could be a mount option

Even with that it's possible to do a direct open without readdir first
if one knows the path and I that would only be case-insensitive if the
backing server is case insensitive though, so just setting the option
and expecting it to work all the time might be a little bit
optimistic... I believe guess that should be an optimization at best.

Ideally the server should tell the client they are casefolded somehow,
but 9p doesn't have any capability/mount time negotiation besides msize
so that's difficult with the current protocol.

-- 
Dominique | Asmadeus