Re: NFSv4.x export options to mark export as case-insensitive, case-preserving? Re: LInux NFSv4.1 client and server- case insensitive filesystems supported?

Roland Mainz
2025-09-10T10:45:30Z

On Tue, Sep 9, 2025 at 9:32 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>
> On 9/9/25 12:33 PM, Cedric Blancher wrote:
> > On Tue, 9 Sept 2025 at 18:12, Chuck Lever <chuck.lever@oracle.com> wrote:
> >>
> >> On 9/9/25 12:06 PM, Cedric Blancher wrote:
> >>> Due lack of a VFS interface and the urgend use case of needing to
> >>> export a case-insensitive filesystem via NFSv4.x, could we please get
> >>> two /etc/exports options, one setting the case-insensitive boolean
> >>> (true, false, get-default-from-fs) and one for case-preserving (true,
> >>> false, get-default-from-fs)?
> >>>
> >>> So far LInux nfsd does the WRONG thing here, and exports even
> >>> case-insensitive filesystems as case-sensitive. The Windows NFSv4.1
> >>> server does it correctly.
>
> As always, I encourage you to, first, prototype in NFSD the hard-coding
> of these settings as returned to NFS clients to see if that does what
> you really need with Linux-native file systems.

If Cedric wants just case-insensitive mounts for a Windows NFSv4
(Exceed, OpenText, ms-nfs41-client, ms-nfs42-client, ...), then the
only thing needed is ext4fs or NTFS in case-insensitive mode, and that
the Linux NFSv4.1 server sets FATTR4_WORD0_CASE_INSENSITIVE==true and
FATTR4_WORD0_CASE_PRESERVING==true (for FAT
FATTR4_WORD0_CASE_PRESERVING==false). Only applications using ADS
(Alternate Data Streams) will not work, because the Linux NFS server
does not support "OPENATTR"&co ops.

If Cedric wants Windows home dirs:
This is not working with the Linux NFSv4.1 server, because it must support:
- FATTR4_WORD1_SYSTEM
- FATTR4_WORD0_ARCHIVE
- FATTR4_WORD0_HIDDEN
- Full ACL support, the current draft POSIX-ACLs in Linux NFSv4.1
server&&{ ext4fs, btrfs, xfs etc. } causes malfunctions in the Windows
"New User" profile setup (and gets you a temporary profile in
C:\Users\*.temp+lots of warnings and a note to log out immediately
because your user profile dir has been "corrupted")

Windows home dirs with NFSv4 only work so far with the
Solaris&&Illumos NFS servers, and maybe the FreeBSD >= 14 NFS server
(not tested yet).

----

Bye,
Roland
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