nfsd: give up on CB_LAYOUTRECALLs after two lease periods

Have the CB_LAYOUTRECALL code treat NFS4_OK and NFS4ERR_DELAY returns
equivalently. Change the code to periodically resend CB_LAYOUTRECALLS
until the ls_layouts list is empty or the client returns a different
error code.

If we go for two lease periods without the list being emptied or the
client sending a hard error, then we give up and clean out the list
anyway.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4layouts.c

@@ -623,24 +623,39 @@ nfsd4_cb_layout_done(struct nfsd4_callback *cb, struct rpc_task *task)
 {
 	struct nfs4_layout_stateid *ls =
 		container_of(cb, struct nfs4_layout_stateid, ls_recall);
+	struct nfsd_net *nn;
+	ktime_t now, cutoff;
 	LIST_HEAD(reaplist);
 
+
 	switch (task->tk_status) {
 	case 0:
-		return 1;
+	case -NFS4ERR_DELAY:
+		/*
+		 * Anything left? If not, then call it done. Note that we don't
+		 * take the spinlock since this is an optimization and nothing
+		 * should get added until the cb counter goes to zero.
+		 */
+		if (list_empty(&ls->ls_layouts))
+			return 1;
+
+		/* Poll the client until it's done with the layout */
+		now = ktime_get();
+		nn = net_generic(ls->ls_stid.sc_client->net, nfsd_net_id);
+
+		/* Client gets 2 lease periods to return it */
+		cutoff = ktime_add_ns(task->tk_start,
+					 nn->nfsd4_lease * NSEC_PER_SEC * 2);
+
+		if (ktime_before(now, cutoff)) {
+			rpc_delay(task, HZ/100); /* 10 mili-seconds */
+			return 0;
+		}
+		/* Fallthrough */
 	case -NFS4ERR_NOMATCHING_LAYOUT:
 		trace_layout_recall_done(&ls->ls_stid.sc_stateid);
 		task->tk_status = 0;
 		return 1;
-	case -NFS4ERR_DELAY:
-		/* Poll the client until it's done with the layout */
-		/* FIXME: cap number of retries.
-		 * The pnfs standard states that we need to only expire
-		 * the client after at-least "lease time" .eg lease-time * 2
-		 * when failing to communicate a recall
-		 */
-		rpc_delay(task, HZ/100); /* 10 mili-seconds */
-		return 0;
 	default:
 		/*
 		 * Unknown error or non-responding client, we'll need to fence.