Re: [PATCH v6 1/9] fs: Create sb_encoding() helper

[Amir Goldstein]

On Mon, Aug 25, 2025 at 2:38 PM Gabriel Krisman Bertazi <krisman@xxxxxxx> wrote:
>
> André Almeida <andrealmeid@xxxxxxxxxx> writes:
>
> > Filesystems that need to deal with the super block encoding need to use
> > a if IS_ENABLED(CONFIG_UNICODE) around it because this struct member is
> > not declared otherwise. In order to move this if/endif guards outside of
> > the filesytem code and make it simpler, create a new function that
> > returns the s_encoding member of struct super_block if Unicode is
> > enabled, and return NULL otherwise.
> >
> > Suggested-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx>
> > ---
> >  include/linux/fs.h | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index e1d4fef5c181d291a7c685e5897b2c018df439ae..a4d353a871b094b562a87ddcffe8336a26c5a3e2 100644
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -3733,15 +3733,20 @@ static inline bool generic_ci_validate_strict_name(struct inode *dir, struct qst
> >  }
> >  #endif
> >
> > -static inline bool sb_has_encoding(const struct super_block *sb)
> > +static inline struct unicode_map *sb_encoding(const struct super_block *sb)
> >  {
> >  #if IS_ENABLED(CONFIG_UNICODE)
> > -     return !!sb->s_encoding;
> > +     return sb->s_encoding;
> >  #else
> > -     return false;
> > +     return NULL;
> >  #endif
> >  }
> >
> > +static inline bool sb_has_encoding(const struct super_block *sb)
> > +{
> > +     return !!sb_encoding(sb);
> > +}
> > +
>
> FWIW, sb_has_encoding is completely superfluous now.  It is also only
> used by overlayfs itself, so it should be easy to drop in favor of your
> new helper in the following patches.  It even has a smaller function
> name :)

Heh. ok maybe we should.
I'll wait for Christian to decide how he would like to funnel those helpers
and maybe he has an opinion.

Thanks,
Amir.