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

Theodore Ts'o
2025-06-08T20:53:02Z

On Sun, Jun 08, 2025 at 12:29:30PM -0400, Chuck Lever wrote:
>
> For some reason I thought case-insensitivity support was merged more
> recently than that. I recall it first appearing as a session at LSF in
> Park City, but maybe that one was in 2018.

commit b886ee3e778ec2ad43e276fd378ab492cf6819b7
Author: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Date: Thu Apr 25 14:12:08 2019 -0400

ext4: Support case-insensitive file name lookups

> nfs(5) describes the lookupcache= mount option. It controls how the
> Linux NFS client caches positive and negative lookup results.

Has anyone just tried it? It might just work. To create a
case-folded directory:

# mke2fs -Fq -t ext4 -O casefold /dev/vdc
# mount /dev/vdc /vdc
# mkdir /vdc/casefold
# chattr +F /vdc/casefold
# cp /etc/issue /vdc/casefold/MaDNeSS
# cat /vdc/casefold/madness

Then export the directory and mount it via NFS, and let us know how it
goes. I'm currently on a cruise ship so it's a bit harder for me to
do the experiment myself. :-)

- Ted