Re: [PATCH 2/3] nfsd: fix callback restarts

["J. Bruce Fields" <bfields@fieldses.org>]

Looks good to me, just a changelog nit:

On Thu, Apr 30, 2015 at 11:49:24AM +0200, Christoph Hellwig wrote:
> Checking the rpc_client pointer is not a reliable way to detect a backchannel
> connetion failure, as the likelyhood of reusing the same slab object is
> very high.

I don't think that's true, if it's this comparison you're talking about:

> @@ -907,16 +900,21 @@ static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
>  			clp->cl_cb_session->se_cb_seq_nr);
>  	}
>  
> -	if (clp->cl_cb_client != task->tk_client) {
> -		/* We're shutting down or changing cl_cb_client; leave
> -		 * it to nfsd4_process_cb_update to restart the call if
> -		 * necessary. */

This is an rpc callback, so tk_client better still be allocated.
cl_cb_client too, since as far as I can tell that's never changed
without shutting down the rpc client first (which will wait for all
tasks to exit).

So I agree that this is wrong, but I think the reason it's actually
wrong is that the condition is just never true....

--b.