Re: LInux NFSv4.1 client and server- case insensitive filesystems supported?

Christoph Hellwig
2025-06-10T05:34:21Z

On Mon, Jun 09, 2025 at 10:16:24AM -0400, Chuck Lever wrote:
> > Date: Wed May 21 16:50:46 2008 +1000
> >
> > dcache: Add case-insensitive support d_ci_add() routine
>
> My memory must be quite faulty then. I remember there being significant
> controversy at the Park City LSF around some patches adding support for
> case insensitivity. But so be it -- I must not have paid terribly close
> attention due to lack of oxygen.

Well, that is when the ext4 CI code landed, which added the unicode
normalization, and with that another whole bunch of issues.

> > That being said no one ever intended any of these to be exported over
> > NFS, and I also question the sanity of anyone wanting to use case
> > insensitive file systems over NFS.
>
> My sense is that case insensitivity for NFS exports is for Windows-based
> clients

I still question the sanity of anyone using a Windows NFS client in
general, but even more so on a case insensitive file system :)

> Does it, for example, make sense for NFSD to query the file system
> on its case sensitivity when it prepares an NFSv3 PATHCONF response?
> Or perhaps only for NFSv4, since NFSv4 pretends to have some recognition
> of internationalized file names?

Linus hates pathconf any anything like it with passion. Altough we
basically got it now with statx by tacking it onto a fast path
interface instead, which he now obviously also hates. But yes, nfsd
not beeing able to query lots of attributes, including actual important
ones is largely due to the lack of proper VFS interfaces.