Re: [PATCH 1/3] f2fs: fix missing kmem_cache_free

From: Jaegeuk Kim
Date: Fri Dec 05 2014 - 13:18:48 EST


Hi Gu,

On Fri, Dec 05, 2014 at 11:34:49AM +0800, Gu Zheng wrote:
> Hi Jaegeuk,
> On 12/05/2014 08:49 AM, Jaegeuk Kim wrote:
>
> > This patch fixes missing kmem_cache_free when handling errors.
> >
> > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > ---
> > fs/f2fs/node.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> > index b1466cf..c59341d 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -158,7 +158,7 @@ retry:
> > head->entry_cnt = 0;
> >
> > if (radix_tree_insert(&nm_i->nat_set_root, set, head)) {
> > - cond_resched();
> > + kmem_cache_free(nat_entry_set_slab, head);
>
> Why not reuse the allocated entry?
> This routine is under nat_tree_lock, so the free_old->research->alloc_new
> is needless, because no other ones can race with us.

IMO, this issue is quite different one that you're mentioning.
This patch just fixes a missing kfree.

>
> > goto retry;
>
> And radix_tree_insert can only fail -ENOMEM here, IMO, the in-time retry step
> makes very little sense here. How about retaining the "cond_resched()" and retry
> insert later?

I think the following patches related to radix_tree_preload that I submitted
would address that.
But, still it seems that I need to review the retrial paths again.

Thanks,

>
> If I misread something, please correct me.:)
>
> Thanks,
> Gu
>
> > }
> > }
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