On Wed, 2013-06-19 at 17:29 +0400, Glauber Costa wrote:
> On Wed, Jun 19, 2013 at 05:12:28PM +0800, Li Zhong wrote:
> > On Wed, 2013-06-19 at 11:31 +0400, Glauber Costa wrote:
> > > On Tue, Jun 18, 2013 at 05:42:01PM +0800, Li Zhong wrote:
> > > > On Fri, 2013-06-07 at 00:34 +0400, Glauber Costa wrote:
> > > >
> > > > > diff --git a/fs/super.c b/fs/super.c
> > > > > index 85a6104..1b6ef7b 100644
> > > > > --- a/fs/super.c
> > > > > +++ b/fs/super.c
> > > > > @@ -199,8 +199,12 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
> > > > > INIT_HLIST_NODE(&s->s_instances);
> > > > > INIT_HLIST_BL_HEAD(&s->s_anon);
> > > > > INIT_LIST_HEAD(&s->s_inodes);
> > > > > - list_lru_init(&s->s_dentry_lru);
> > > > > - list_lru_init(&s->s_inode_lru);
> > > > > +
> > > > > + if (list_lru_init(&s->s_dentry_lru))
> > > > > + goto err_out;
> > > > > + if (list_lru_init(&s->s_inode_lru))
> > > > > + goto err_out_dentry_lru;
> > > > > +
> > > > > INIT_LIST_HEAD(&s->s_mounts);
> > > > > init_rwsem(&s->s_umount);
> > > > > lockdep_set_class(&s->s_umount, &type->s_umount_key);
> > > > > @@ -240,6 +244,9 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
> > > > > }
> > > > > out:
> > > > > return s;
> > > > > +
> > > > > +err_out_dentry_lru:
> > > > > + list_lru_destroy(&s->s_dentry_lru);
> > > > > err_out:
> > > > > security_sb_free(s);
> > > > > #ifdef CONFIG_SMP
> > > >
> > > > It seems we also need to call list_lru_destroy() in destroy_super()?
> > > > like below:
> > > >
> > > > -----------
> > > > diff --git a/fs/super.c b/fs/super.c
> > > > index b79e732..06ee3af 100644
> > > > --- a/fs/super.c
> > > > +++ b/fs/super.c
> > > > @@ -269,6 +269,8 @@ err_out:
> > > > */
> > > > static inline void destroy_super(struct super_block *s)
> > > > {
> > > > + list_lru_destroy(&s->s_inode_lru);
> > > > + list_lru_destroy(&s->s_dentry_lru);
> > > > #ifdef CONFIG_SMP
> > > > free_percpu(s->s_files);
> > > > #endif
> > >
> > > Hi
> > >
> > > Thanks for taking a look at this.
> > >
> > > list_lru_destroy is called by deactivate_lock_super, so we should be fine already.
> >
> > Sorry, I'm a little confused...
> >
> > I didn't see list_lru_destroy() called in deactivate_locked_super().
> > Maybe I missed something?
>
> Err... the code in my tree reads:
>
> unregister_shrinker(&s->s_shrink);
> list_lru_destroy(&s->s_dentry_lru);
> list_lru_destroy(&s->s_inode_lru);
> put_filesystem(fs);
> put_super(s);
>
> But then I have just checked Andrew's, and it is not there - thank you.
>
> Andrew, should I send a patch for you to fold it ?
>
>
> >
> > But it seems other memory allocated in alloc_super(), are freed in
> > destroy_super(), e.g. ->s_files, why don't we also free this one here?
> Because we want this close to unregister_shrinker, it is a more natural
> location for this.
OK, I see. However, in some rare cases, destroy_super() might be called
in a row with alloc_super(), e.g. in sget(), if !test and err when set()
the fs private info.
By the way, there is memory allocated in register_shrinker() based on
nr_node_ids, so maybe we need to free it in unregister_shrinker()? Maybe
that's already covered in the deferred part.
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