Re: RFC: _PC_HAS_HIDDENSYSTEM rename

On Mon, Oct 20, 2025 at 04:20:21PM -0700, Rick Macklem wrote:
> Hi
> 
> There are three flags UF_HIDDEN, UF_SYSTEM and UF_ARCHIVE
> defined in sys/stat.h (their origin is in MS-DOS). If a file system implements
> any of these flags, they implement all three of them, afaik.
> 
> Commit afd5bc6309 (in main) defined _PC_HAS_HIDDENSYSTEM
> to allow pathconf to indicate if a file system supports the first two of
> these.
> I had ignored the third, since it is listed as "deprecated" in RFC-8881.
> It now turns out that the Windows NFSv4.1 client folk want support
> for UF_ARCHIVE and consider that it should not be deprecated.
> 
> I do not think adding a separate _PC_HAS_ARCHIVE pathconf
> name is useful, since it is supported when _PC_HAS_HIDDENSYSTEM
> is returned non-zero.
> 
> However, the name _PC_HAS_HIDDENSYSTEM is misleading,
> so what do others think I should do?
> - Add an alias for _PC_HAS_HIDDENSYSTEM called something
>  like _PC_HAS_HIDSYSARCH or _PC_HAS_HIDDENSYSTEMARCHIVE?
> (Since _PC_HAS_HIDDENSYSTEM is now in the OpenZFS code, it
> needs to remain in unistd.h, at least for now.)

> Or
> - Just leave the name as is and document it correctly in pathconf(2)?
IMO the 'just leave' action is good enough.