Re: [Jfs-discussion] Problems with charset.

[John G. <jgo...@co...>]

On Mon, Jun 28, 2004 at 02:55:58PM -0500, Dave Kleikamp wrote:

[ snip ]

> The jfs filesystem was ported from OS/2.  I tried to explain how it
> worked in OS/2 and why.  Because it was ported, I tried to maintain
> portability between OS/2 and Linux, therefore pathnames are stored in
> 16-bit unicode.  If jfs had been written from scratch for linux, it
> wouldn't work this way.

I wonder, though, if there is at least some way to always generate
valid, unique filenames, no matter what?

> > I migrated from ext3 to JFS.  ext3 has no iocharset uption.
> > CONFIG_NLS_DEFAULT did not change.  The machine is a Samba server, and I
> > have no idea what people are using for characters in their filenames on
> > clients.
> 
> I don't know how you got inaccessible files.  Files created in a
> particular charset should be accessible in the same charset.

I've experienced this before (in 2.6, prior to that patch, when I used
rsync to copy some files with Japanese names from my Zaurus).  Files
created, but are undeletable 2 minutes later.

> > Could you at least add an option, such as iocharset=none, to disable
> > conversion in a 2.4 kernel?
> 
> Yes, that would be reasonable.

Sounds excellent.

> > > for each process.  I've fixed the default in 2.6 to do no translation,
> > > but I'm not willing to change 2.4 now.
> > 
> > It can't.  I still don't understand why it needs to.
> 
> If it was possible (as it is in OS/2), it's a great feature.  User A,
> using an iso8859-1 locale, can create files containing any characters in
> that charset.  User B, using a utf-8 locale, can see those files
> correctly, even though they are represented as a different stream of

Ahh.  So on OS/2, JFS would translate a stream of bytes in charset A
(whever that may be) to the charset in use on the filesystem, and back?

So on Linux, how does JFS know what charset it is coming *from*?  (Say
you have iocharset=utf8, where does that conversion get used, and how
does it know what to convert to/from?)

> Don't get the wrong impression.  I'm not an OS/2 advocate.  I like linux
> much better.  I am only trying to explain why jfs was written this way. 
> I wish it wasn't.  :^)

What about JFS on AIX?  How does it handle this situation?

(We do have an AIX machine here runninf JFS2, and I've never experienced
this problem there.  OTOH, it's possible that I've never used anything
but 7-bit filenames there.)

-- John