Re: [patch V2 6/7] fs/jbd2: Make state lock a spinlock

[Jan Kara]

On Thu 01-08-19 13:28:49, Peter Zijlstra wrote:
> On Thu, Aug 01, 2019 at 03:01:32AM +0200, Thomas Gleixner wrote:
> 
> > @@ -1931,7 +1932,7 @@ static void __jbd2_journal_temp_unlink_b
> >  	transaction_t *transaction;
> >  	struct buffer_head *bh = jh2bh(jh);
> >  
> > -	J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
> > +	assert_spin_locked(&jh->state_lock);
> >  	transaction = jh->b_transaction;
> >  	if (transaction)
> >  		assert_spin_locked(&transaction->t_journal->j_list_lock);
> 
> > @@ -2415,7 +2416,7 @@ void __jbd2_journal_file_buffer(struct j
> >  	int was_dirty = 0;
> >  	struct buffer_head *bh = jh2bh(jh);
> >  
> > -	J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
> > +	assert_spin_locked(&jh->state_lock);
> >  	assert_spin_locked(&transaction->t_journal->j_list_lock);
> >  
> >  	J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
> 
> > @@ -2500,7 +2501,7 @@ void __jbd2_journal_refile_buffer(struct
> >  	int was_dirty, jlist;
> >  	struct buffer_head *bh = jh2bh(jh);
> >  
> > -	J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
> > +	assert_spin_locked(&jh->state_lock);
> >  	if (jh->b_transaction)
> >  		assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
> >  
> 
> Do those want to be:
> 
>   lockdep_assert_held(&jh->state_lock);
> 
> instead? The difference is of course that lockdep_assert_held() requires
> the current context to hold the lock, where assert_*_locked() merely
> checks _someone_ holds it.

Yeah, jbd2 doesn't play any weird locking tricks so lockdep_assert_held()
is fine. I'll replace those when I'm updating the patch.

								Honza

-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR