Re: linux-next: manual merge of the akpm tree with Linus' tree

Al Viro
2013-09-13T20:31:55Z

On Fri, Sep 13, 2013 at 04:25:48PM -0400, Linus Torvalds wrote:
> On Fri, Sep 13, 2013 at 4:00 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> \>
> > It is right - for one thing, we are holding the lock on that LRU list,
> > so list_lru_del() would deadlock right there. For another, the same
> > list_lru_walk (OK, list_lru_walk_node()) will do ->nr_items decrement
> > when we return LRU_REMOVED to it, so we don't want to do it twice.
> > Plain list_del_init() is correct here.
>
> Yes. And I found the opposite bug in one place: when we are collecting
> dentries by walking the parents etc, we do *not* hold the global RCU
> lock,

??? LRU list lock, presumably?

so we cannot use the "d_lru_shrink_list()" thing after all. It's
> correct as far as the internal logic of fs/dcache.c goes, but it
> violates the global LRU list rules. So I replaced that with a
> dentry_lru_del() followed by a d_shrink_add() instead.