On Sun, 21 May 2023 at 10:28, Andrea Righi <andrea.righi@xxxxxxxxxxxxx> wrote: > > When CONFIG_OVERLAY_FS_DEBUG is enabled add an explicit check to make > sure that OVL_FS() is always used with a valid overlayfs superblock. > Otherwise trigger a WARN_ON_ONCE(). > > Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx> > Signed-off-by: Andrea Righi <andrea.righi@xxxxxxxxxxxxx> > --- > fs/overlayfs/ovl_entry.h | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h > index b32c38fdf3c7..e156649d9c71 100644 > --- a/fs/overlayfs/ovl_entry.h > +++ b/fs/overlayfs/ovl_entry.h > @@ -97,8 +97,20 @@ static inline struct mnt_idmap *ovl_upper_mnt_idmap(struct ovl_fs *ofs) > > extern struct file_system_type ovl_fs_type; > > +static inline bool is_ovl_fs_sb(struct super_block *sb) > +{ > + return sb->s_type == &ovl_fs_type; > +} > + > +#ifdef CONFIG_OVERLAY_FS_DEBUG > +#define OVL_VALIDATE_SB(__sb) WARN_ON_ONCE(!is_ovl_fs_sb(__sb)) > +#else > +#define OVL_VALIDATE_SB(__sb) > +#endif > + > static inline struct ovl_fs *OVL_FS(struct super_block *sb) > { > + OVL_VALIDATE_SB(sb); This could be written simply and naturally: if (IS_ENABLED(CONFIG_OVERLAY_FS_DEBUG)) WARN_ON_ONCE(sb->s_type != &ovl_fs_type) Thanks, Miklos