On Monday 16 August 2021 16:14:17 Kari Argillander wrote:
> > > + * Load nls table or if @nls is utf8 then return NULL because
> > > + * nls=utf8 is totally broken.
> > > + */
> > > +static struct nls_table *ntfs_load_nls(char *nls)
> > > +{
> > > + struct nls_table *ret;
> > > +
> > > + if (!nls)
> > > + return ERR_PTR(-EINVAL);
> > > + if (strcmp(nls, "utf8"))
> > > + return NULL;
> > > + if (strcmp(nls, CONFIG_NLS_DEFAULT))
> > > + return load_nls_default();
> > > +
> > > + ret = load_nls(nls);
> > > + if (!ret)
> > > + return ERR_PTR(-EINVAL);
> > > +
> > > + return ret;
> > > +}
> >
> > This looks like something quite generic and not file system specific.
> > But I haven't found time to look at the series from Pali how this all
> > fits together.
>
> It is quite generic I agree. Pali's series not implemeted any new way
> doing this thing. In many cases Pali uses just load_nls and not
> load_nls_default. This function basically use that if possible. It seems
> that load_nls_default does not need error path so that's why it is nicer
> to use.
Yes, I'm using what is currently available. But providing some helper
function should be a nice cleanup.
> One though is to implement api function load_nls_or_utf8(). Then we do not
> need to test this utf8 stuff in all places.
Beware that there are more cases which can happen:
- iocharset is not specified
--> then driver default behavior is used
--> it is either some fixed encoding (e.g. iso8859-1, utf8) or
CONFIG_NLS_DEFAULT (*); so it should behave like iocharset is
set to that fixed encoding or CONFIG_NLS_DEFAULT
- iocharset is set to utf8
--> then native utf8* functions should be used instead of nls
- iocharset is set to CONFIG_NLS_DEFAULT
--> then load_nls_default() should be used which is IIRC guaranteed to
not fail
- iocharset is not set to utf8, neither to CONFIG_NLS_DEFAULT
--> then load_nls(iocharset) should be used; this may fail
(*) - it is pity that not all fs drivers are using CONFIG_NLS_DEFAULT
and some are using some their own fixed encoding... it just
increase mess and "user surprise"
