Re: FreeBSD NFSv4.1 *CLIENT* - case insensitive filesystems supported? Re: FreeBSD NFSv4.1 client and server - case insensitive filesystems supported?

From: Rick Macklem <rick.macklem_at_gmail.com>
Date: Fri, 16 Jan 2026 23:24:38 UTC 
On Fri, Jan 16, 2026 at 6:18 AM Konstantin Belousov <kostikbel@gmail.com> wrote:
>
> On Fri, Jan 16, 2026 at 05:53:56AM -0800, Rick Macklem wrote:
> > On Thu, Jan 15, 2026 at 11:55 PM Cedric Blancher
> > <cedric.blancher@gmail.com> wrote:
> > >
> > > On Mon, 12 Jan 2026 at 23:04, Rick Macklem <rick.macklem@gmail.com> wrote:
> > > >
> > > > On Mon, Jan 12, 2026 at 1:56 PM Rick Macklem <rick.macklem@gmail.com> wrote:
> > > > >
> > > > > On Mon, Jan 12, 2026 at 11:52 AM Cedric Blancher
> > > > > <cedric.blancher@gmail.com> wrote:
> > > > > >
> > > > > > Good evening!
> > > > > >
> > > > > > Does the FreeBSD >= 14.3 NFSv4.1 client and server support case
> > > > > > insensitive filesystems, e.g. exported ZFS or FAT?
> > > > > Greater than, as in 15.0.
> > > > Oops, that's 15.1->
> > > > (I looked and it is in stable/15, but not releng/15.0.)
> > > > (I work with main and the stable branches and don't keep track of when the
> > > > releases branch off.)
> > >
> > > What about the FreeBSD 15.x NFSv4.2 client - does it support
> > > case-insensitive filesystems?
> > I suppose. It doesn't care. If an application cares (I don't know of
> > one, offhand), it can check via pathconf(2) to see if the fs is
> > case-insensitive (the _PC_CASE_INSENSITIVE pathconf name
> > was added recently and will be in 15.1).
>
> If the client uses namecache, then I suppose it cares, esp. about caching
> the negative lookups.  Also for renames and deletes, the whole set of
> cached entries for the directory must be expunged.
Good point. I did have looking at this on my "to do" list, but forgot
about it. So, I suppose that the current answer is "the NFS client
does not handle case-insensitive file names correctly" until handling
of negative name caching is fixed.

Initially, I might just disable name caching for case-insensitive file
systems.

It sounds like the name caching code should have an option for
case-insensitive name comparison?
(For plain ASCII, that should be straightforward, but for non-ASCII
character sets?? I am not conversant with how case insensitivity is
handled for non-ASCII character sets. I know that ZFS has some
"form" options, but that's all I know?)

rick

>