Re: [RFC PATCH] fs: Plumb case sensitivity bits into statx

[Gabriel Krisman Bertazi <gabriel@krisman.be>]

Christian Brauner <brauner@kernel.org> writes:

> On Fri, Oct 03, 2025 at 05:15:24PM -0400, Gabriel Krisman Bertazi wrote:
>> Chuck Lever <cel@kernel.org> writes:
>> 
>> > On 10/3/25 4:43 PM, Gabriel Krisman Bertazi wrote:
>> >> Chuck Lever <cel@kernel.org> writes:
>> >> 
>> >>> On 10/3/25 11:24 AM, Gabriel Krisman Bertazi wrote:
>> >
>> >>>> Does the protocol care about unicode version?  For userspace, it would
>> >>>> be very relevant to expose it, as well as other details such as
>> >>>> decomposition type.
>> >>>
>> >>> For the purposes of indicating case sensitivity and preservation, the
>> >>> NFS protocol does not currently care about unicode version.
>> >>>
>> >>> But this is a very flexible proposal right now. Please recommend what
>> >>> you'd like to see here. I hope I've given enough leeway that a unicode
>> >>> version could be provided for other API consumers.
>> >> 
>> >> But also, encoding version information is filesystem-wide, so it would
>> >> fit statfs.
>> >
>> > ext4 appears to have the ability to set the case folding behavior
>> > on each directory, that's why I started with statx.
>> 
>> Yes. casefold is set per directory, but the unicode version and
>> casefolding semantics used by those casefolded directories are defined
>> for the entire filesystem.
>
> I'm not too fond of wasting statx() space for this. Couldn't this be
> exposed via the new file_getattr() system call?:

Do you mean exposing of unicode version and flags to userspace? If so,
yes, for sure, it can be fit in file_get_attr. It was never exposed
before, so there is no user expectation about it!

Thanks,

-- 
Gabriel Krisman Bertazi