Re: [PATCH 0/5] Support case insensitive filesystems in NFSv4

[Trond Myklebust <trondmy@hammerspace.com>]

On Mon, 2022-01-03 at 16:46 -0500, bfields@fieldses.org wrote:
> On Mon, Jan 03, 2022 at 08:11:57PM +0000, Trond Myklebust wrote:
> > On Mon, 2022-01-03 at 15:08 -0500, J. Bruce Fields wrote:
> > > On Fri, Dec 17, 2021 at 03:36:53PM -0500,
> > > trondmy@kernel.org wrote:
> > > > From: Trond Myklebust <trond.myklebust@hammerspace.com>
> > > > 
> > > > Add support for detecting an export of a case insensitive
> > > > filesystem in
> > > > NFSv4. If that is the case, then we need to adjust the dentry
> > > > caching
> > > > and invalidation rules to ensure that we don't inadvertently
> > > > end up
> > > > caching other case folded aliases after an operation that
> > > > results
> > > > in a
> > > > directory entry name change.
> > > 
> > > What server and configuration are you testing this against?
> > 
> > Ours.
> 
> You mean, hammerspace?
> 
> > Why?
> 
> Partly just curiousity.  Partly I thought we'd previously been trying
> to
> add features on server and client side together when it makes sense,
> if
> only to make it possible to test without access to proprietary
> software.
> 
> I don't actually have a strong opinion on the policy, but if this
> *is* a
> change in policy then it's worth mentioning.
> 
> There should be other exportable filesystems supporting those
> attributes
> so the work to export them on the server side wouldn't be a whole
> lot.
> (But I can't volunteer.)
> 
> --b.
> 
> > > > 

I don't see how it can be considered a change in policy or why it
matters if it was. We already have plenty of features in the client
which are not supported by knfsd, including several pNFS features, pNFS
drivers, NFS ACL modes, filesystem migration support, to name but a
few... knfsd lags behind in all these areas for a variety of reasons.

As for these particular features, they are of interest for Linux, not
just for interoperability reasons. With recent changes, Linux has
several filesystems that either are case insensitive, or can be
configured that way, so there should be an interest in having knfsd
support it. However I'm not going to volunteer either, because it's not
something I can commit my employer's resources towards doing at this
time.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com