No?
Matt
----- Original Message -----
> From: "Satya Prakash GS" <g.satyaprak...@gmail.com>
> To: nfs-ganesha-devel@lists.sourceforge.net, "Malahal Naineni"
> <mala...@gmail.com>
> Sent: Wednesday, May 3, 2017 3:34:31 PM
> Subject: [Nfs-ganesha-devel] reg. drc nested locks
>
> Hi,
>
> In nfs_dupreq_start and nfs_dupreq_finish when allocating/freeing a
> dupreq_entry we are trying hard to keep both dupreq_q and the rbtree
> in sync acquiring both the partition lock and the drc (t->mtx,
> drc->mtx). This requires dropping and reacquiring locks at certain
> places. Can these nested locks be changed to take locks one after the
> other.
>
> For example at the time of allocation, we could choose to do this -
>
> PTHREAD_MUTEX_lock(&t->mtx); /* partition lock */
> nv = rbtree_x_cached_lookup(&drc->xt, t, &dk->rbt_k, dk->hk);
> if (!nv) {
> dk->refcnt = 2;
> (void)rbtree_x_cached_insert(&drc->xt, t,
> &dk->rbt_k, dk->hk);
> PTHREAD_MUTEX_unlock(&t->mtx); /* partition lock */
>
> PTHREAD_MUTEX_lock(&drc->mtx);
> TAILQ_INSERT_TAIL(&drc->dupreq_q, dk, fifo_q);
> ++(drc->size);
> PTHREAD_MUTEX_unlock(&drc->mtx);
> }
>
> I am assuming this would simplify the lock code a lot.
> If there is a case where this would introduce a race please let me know.
>
> Thanks,
> Satya.
>
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--
Matt Benjamin
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