Re: confusion and case problems: utf8 <-> iocharset

Eduard Bloch <edi@xxxxxx> writes:

The trouble:

First, the terminology in vfat.txt is not consistent with what actually
happens. It says "iocharset" but in fact it is not a charset used for IO
operations, it does not stand for charset at all but for the mapping of
encodings. The better name should be "visible_encoding", IMO.
And in the kernel setup, why do I need a separate "VFAT_IOCHARSET"
option? Why should I not use the systemwide settings, AFAICS that change
is relevant for what the users see and this thing should be consistent
across all mounted filesystems. So why do I need a separate kernel
setting here? Questions over questions.

Probably, you want to use "utf8" systemwidely. But, you shouldn't use
utf8 for vfat, because it's breaking. The main reason is this.

Second:
there is the "utf8" option. How does that exactly differ from
iocharset=utf8? There is not clear explanation in vfat.txt. What happens
if you use both options, especially if iocharset!=utf8? Which one is
prefered?

iocharset=utf8 doesn't have a case conversion table.

utf8 option is similar to iocharset=utf8, but utf8 uses case
conversion table of iocharset=xxx. But, there is a known bug.

Third:
how can I disable all that funny letter case conversions? They are not
described anywhere properly, nor the way to disable them. IMO there are
two problems:

- what you write to the FS is not the same what "ls" shows you later.
Eg. ABW becomes "abw" but "ABWÖ" becomes "ABWÖ". Abcd becomes "Abcd"
but "ABC" becomes "abc". Does it make sense? NO.
I would like to stop the kernel playing such games, I had enough of
such trouble back in my Windows 98 times.

Probably, you want to use shortname=xxx option.

- this case conversion can actually break things. When iocharset=utf-8
and utf8 are used, then you cannot access the data with the same
name after storing it.

Yes, it's a known bug.
--
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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