On Wed, Jun 11, 2025 at 09:26:29AM -0700, Darrick J. Wong wrote:
> On Sat, Mar 29, 2025 at 09:42:14AM +0100, Christian Brauner wrote:
> > The locking guarantees that the superblock is alive and sb->s_root is
> > still set. Remove the pointless check.
> >
> > Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
> > ---
> > fs/super.c | 19 ++++++-------------
> > 1 file changed, 6 insertions(+), 13 deletions(-)
> >
> > diff --git a/fs/super.c b/fs/super.c
> > index 97a17f9d9023..dc14f4bf73a6 100644
> > --- a/fs/super.c
> > +++ b/fs/super.c
> > @@ -930,8 +930,7 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
> >
> > locked = super_lock_shared(sb);
> > if (locked) {
> > - if (sb->s_root)
> > - f(sb, arg);
> > + f(sb, arg);
> > super_unlock_shared(sb);
> > }
> >
> > @@ -967,11 +966,8 @@ void iterate_supers_type(struct file_system_type *type,
> > spin_unlock(&sb_lock);
> >
> > locked = super_lock_shared(sb);
> > - if (locked) {
> > - if (sb->s_root)
> > - f(sb, arg);
> > - super_unlock_shared(sb);
> > - }
> > + if (locked)
> > + f(sb, arg);
>
> Hey Christian,
>
> I might be trying to be the second(?) user of iterate_supers_type[1]. :)
>
> This change removes the call to super_unlock_shared, which means that
> iterate_supers_type returns with the super_lock(s) still held. I'm
> guessing that this is a bug and not an intentional change to require the
> callback to call super_unlock_shared, right?
>
> --D
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/commit/?h=health-monitoring&id=3ae9b1d43dcdeaa38e93dc400d1871872ba0e27f
Yes, that's a bug. Can you send me a fix, please?
