Re: Msdos name alias patch for 2.1.48

Janos Farkas (Janos.Farkas-#tFle8EyHCgCga7DvQ6ctSNsoKve@shadow.banki.hu)
Fri, 8 Aug 1997 12:52:26 +0200


On Thu, Aug 07, 1997 at 04:16:49PM -0700, Linus Torvalds wrote:
> The thing that makes me think that having the VFS layer handle
> case-insenstitivity (but nothing else) is a good idea is that it can
> potentially be useful even for things like ext2fs. Imagine having not to
> worry about case in DOSEMU or Wine, but instead doing
>
> int fd = open("/dosc/windows/windows.ini", O_NOCASE | O_RDONLY);
>
> and it would work even if it was a ext2 filesystem?
>
> What sort of case-insensitivity do various filesystems currently support?
> Are we talking A-Z only, Latin1, or what? I guess we don't really need to
> worry about what could theoretically be the worst case, but what MS-DOS,
> NT, OS/2 etc actually do right now..

If that matters, the native Amiga filesystem, affs has different flavors,
or subtypes, to decide if the case independence is ASCII, or latin1.
They did it wrong for the first years, and could only correct it by
introducing an "international" subtype which is latin1 case independent.
This is all per-filesystem. And as people said, ntfs might be even worse
with per-fs translation tables... But if the lookup could respect an
kludgy, (and only usable by win/dosemu) bit like O_NOCASE, what's so
wrong with the fs internal lookup() checking for/creating alias dentries?
And that's what Andreas proposed, and fits the "requirements" much better.
It's probably the only way to retain the correct referenced name in
dentries for all types of aliases (hard links, and case independence ---
affs has both).

-- 
Janos - Don't worry, my address works.  I'm just bored of spam.