On Thu, Aug 14, 2025 at 12:37 AM André Almeida <andrealmeid@xxxxxxxxxx> wrote: > > For cases where a file lookup can look in different filesystems (like in > overlayfs), both super blocks must have the same encoding and the same > flags. To help with that, create a sb_same_encoding() function. > > Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx> > Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx> please reorder vfs patches before ovl patches > Changes from v3: > - Improve wording > > Changes from v2: > - Simplify the code. Instead of `if (cond) return true`, just do `return > cond`; > --- > include/linux/fs.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 20102d81e18a59d5daaed06855d1f168979b4fa7..64d24e89bc5593915158b40f0442e6d8ef3d968d 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -3753,6 +3753,24 @@ static inline bool sb_has_encoding(const struct super_block *sb) > return !!sb_encoding(sb); > } > > +/* > + * Compare if two super blocks have the same encoding and flags > + */ > +static inline bool sb_same_encoding(const struct super_block *sb1, > + const struct super_block *sb2) > +{ > +#if IS_ENABLED(CONFIG_UNICODE) > + if (sb1->s_encoding == sb2->s_encoding) > + return true; > + > + return (sb1->s_encoding && sb2->s_encoding && > + (sb1->s_encoding->version == sb2->s_encoding->version) && > + (sb1->s_encoding_flags == sb2->s_encoding_flags)); > +#else > + return true; > +#endif > +} > + > int may_setattr(struct mnt_idmap *idmap, struct inode *inode, > unsigned int ia_valid); > int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *); > > -- > 2.50.1 >