Re: [RFC v2] Unicode/UTF-8 support for XFS

J. Bruce Fields
2014-09-29T20:17:19Z

On Fri, Sep 26, 2014 at 10:03:50PM +0200, Olaf Weber wrote:
> On 26-09-14 21:46, Jeremy Allison wrote:
> >On Fri, Sep 26, 2014 at 09:37:11PM +0200, Olaf Weber wrote:
> >>
> >>My argument against "mount time case-insensitivity" and for "mkfs
> >>time case-insensitivity" is related to switching from the
> >>case-sensitive domain to the case-insensitive one.
> >>
> >>For case-sensitive, from "README" to "readme" there are 64 different
> >>possible filenames. Let's say you create 63 out of these 64. Now
> >>remount the filesystem case-insensitive, and try to open by the 64th
> >>version of "readme". It is not an exact match for any of the 63
> >>candidate files, and a case-insensitive match to all 63 candidate
> >>files. Which of these 63 files should be opened, and why that one in
> >>particular?
> >
> >I'm ok with "mkfs time case-insensitivity" - really !
> >Most of my OEMs would set that and claim victory (few
> >of them care much about NFS semantics :-).
>
> I'd say you can have CIFS-style case-insensitive semantics or
> NFS-style case-sensitive semantics, but not both.

Note the NFSv4 specs do claim to allow case insensitivity. No idea how
well clients deal with it.

I think rfc3530bis has the most up to date language on NFSv4
internationalization issues:

http://tools.ietf.org/html/draft-ietf-nfsv4-rfc3530bis-33

(One nit in the current knfsd: the server doesn't correctly report the
case_insensitive attribute. If it had some flag it could check in the
filesystem's superblock then it could do that right instead of just
assuming 0 as it currently does (see FATTR4_WORD0_CASE_INSENSITIVE in
fs/nfsd/nfs4xdr.c:nfsd4_encode_fattr).)

--b.