2 files changed, 113 insertions, 74 deletions

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 7d3027f2c06e..18aeb85079f8 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -749,6 +749,8 @@ struct ip_vs_dest_dst {
 	struct rcu_head		rcu_head;
 };
 
+/* In grace period after removing */
+#define IP_VS_DEST_STATE_REMOVING	0x01
 /*
  *	The real server destination forwarding entry
  *	with ip address, port number, and so on.
@@ -766,6 +768,7 @@ struct ip_vs_dest {
 
 	atomic_t		refcnt;		/* reference counter */
 	struct ip_vs_stats      stats;          /* statistics */
+	unsigned long		state;		/* state flags */
 
 	/* connection counters and thresholds */
 	atomic_t		activeconns;	/* active connections */
@@ -785,6 +788,7 @@ struct ip_vs_dest {
 	union nf_inet_addr	vaddr;		/* virtual IP address */
 	__u32			vfwmark;	/* firewall mark of service */
 
+	struct list_head	t_list;		/* in dest_trash */
 	struct rcu_head		rcu_head;
 	unsigned int		in_rs_table:1;	/* we are in rs_table */
 };
@@ -912,6 +916,9 @@ struct ipvs_master_sync_state {
 	struct netns_ipvs	*ipvs;
 };
 
+/* How much time to keep dests in trash */
+#define IP_VS_DEST_TRASH_PERIOD		(120 * HZ)
+
 /* IPVS in network namespace */
 struct netns_ipvs {
 	int			gen;		/* Generation */
@@ -961,6 +968,8 @@ struct netns_ipvs {
 
 	/* Trash for destinations */
 	struct list_head	dest_trash;
+	spinlock_t		dest_trash_lock;
+	struct timer_list	dest_trash_timer; /* expiration timer */
 	/* Service counters */
 	atomic_t		ftpsvc_counter;
 	atomic_t		nullsvc_counter;
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index a4f638880470..80d366b7daab 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -71,7 +71,7 @@ int ip_vs_get_debug_level(void)
 
 
 /*  Protos */
-static void __ip_vs_del_service(struct ip_vs_service *svc);
+static void __ip_vs_del_service(struct ip_vs_service *svc, bool cleanup);
 
 
 #ifdef CONFIG_IP_VS_IPV6
@@ -657,19 +657,25 @@ static struct ip_vs_dest *
 ip_vs_trash_get_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr,
 		     __be16 dport)
 {
-	struct ip_vs_dest *dest, *nxt;
+	struct ip_vs_dest *dest;
 	struct netns_ipvs *ipvs = net_ipvs(svc->net);
 
 	/*
 	 * Find the destination in trash
 	 */
-	list_for_each_entry_safe(dest, nxt, &ipvs->dest_trash, n_list) {
+	spin_lock_bh(&ipvs->dest_trash_lock);
+	list_for_each_entry(dest, &ipvs->dest_trash, t_list) {
 		IP_VS_DBG_BUF(3, "Destination %u/%s:%u still in trash, "
 			      "dest->refcnt=%d\n",
 			      dest->vfwmark,
 			      IP_VS_DBG_ADDR(svc->af, &dest->addr),
 			      ntohs(dest->port),
 			      atomic_read(&dest->refcnt));
+		/* We can not reuse dest while in grace period
+		 * because conns still can use dest->svc
+		 */
+		if (test_bit(IP_VS_DEST_STATE_REMOVING, &dest->state))
+			continue;
 		if (dest->af == svc->af &&
 		    ip_vs_addr_equal(svc->af, &dest->addr, daddr) &&
 		    dest->port == dport &&
@@ -679,29 +685,27 @@ ip_vs_trash_get_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr,
 		     (ip_vs_addr_equal(svc->af, &dest->vaddr, &svc->addr) &&
 		      dest->vport == svc->port))) {
 			/* HIT */
-			return dest;
-		}
-
-		/*
-		 * Try to purge the destination from trash if not referenced
-		 */
-		if (atomic_read(&dest->refcnt) == 1) {
-			IP_VS_DBG_BUF(3, "Removing destination %u/%s:%u "
-				      "from trash\n",
-				      dest->vfwmark,
-				      IP_VS_DBG_ADDR(svc->af, &dest->addr),
-				      ntohs(dest->port));
-			list_del(&dest->n_list);
-			__ip_vs_dst_cache_reset(dest);
-			__ip_vs_unbind_svc(dest);
-			free_percpu(dest->stats.cpustats);
-			kfree_rcu(dest, rcu_head);
+			list_del(&dest->t_list);
+			ip_vs_dest_hold(dest);
+			goto out;
 		}
 	}
 
-	return NULL;
+	dest = NULL;
+
+out:
+	spin_unlock_bh(&ipvs->dest_trash_lock);
+
+	return dest;
 }
 
+static void ip_vs_dest_free(struct ip_vs_dest *dest)
+{
+	__ip_vs_dst_cache_reset(dest);
+	__ip_vs_unbind_svc(dest);
+	free_percpu(dest->stats.cpustats);
+	kfree(dest);
+}
 
 /*
  *  Clean up all the destinations in the trash
@@ -710,19 +714,18 @@ ip_vs_trash_get_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr,
  *  When the ip_vs_control_clearup is activated by ipvs module exit,
  *  the service tables must have been flushed and all the connections
  *  are expired, and the refcnt of each destination in the trash must
- *  be 1, so we simply release them here.
+ *  be 0, so we simply release them here.
  */
 static void ip_vs_trash_cleanup(struct net *net)
 {
 	struct ip_vs_dest *dest, *nxt;
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
-	list_for_each_entry_safe(dest, nxt, &ipvs->dest_trash, n_list) {
-		list_del(&dest->n_list);
-		__ip_vs_dst_cache_reset(dest);
-		__ip_vs_unbind_svc(dest);
-		free_percpu(dest->stats.cpustats);
-		kfree_rcu(dest, rcu_head);
+	del_timer_sync(&ipvs->dest_trash_timer);
+	/* No need to use dest_trash_lock */
+	list_for_each_entry_safe(dest, nxt, &ipvs->dest_trash, t_list) {
+		list_del(&dest->t_list);
+		ip_vs_dest_free(dest);
 	}
 }
 
@@ -955,11 +958,6 @@ ip_vs_add_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
 			      IP_VS_DBG_ADDR(svc->af, &dest->vaddr),
 			      ntohs(dest->vport));
 
-		/*
-		 * Get the destination from the trash
-		 */
-		list_del(&dest->n_list);
-
 		__ip_vs_update_dest(svc, dest, udest, 1);
 		ret = 0;
 	} else {
@@ -1015,11 +1013,21 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
 	return 0;
 }
 
+static void ip_vs_dest_wait_readers(struct rcu_head *head)
+{
+	struct ip_vs_dest *dest = container_of(head, struct ip_vs_dest,
+					       rcu_head);
+
+	/* End of grace period after unlinking */
+	clear_bit(IP_VS_DEST_STATE_REMOVING, &dest->state);
+}
+
 
 /*
  *	Delete a destination (must be already unlinked from the service)
  */
-static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest)
+static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest,
+			     bool cleanup)
 {
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
@@ -1030,34 +1038,22 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest)
 	 */
 	ip_vs_rs_unhash(dest);
 
-	/*
-	 *  Decrease the refcnt of the dest, and free the dest
-	 *  if nobody refers to it (refcnt=0). Otherwise, throw
-	 *  the destination into the trash.
-	 */
-	if (atomic_dec_and_test(&dest->refcnt)) {
-		IP_VS_DBG_BUF(3, "Removing destination %u/%s:%u\n",
-			      dest->vfwmark,
-			      IP_VS_DBG_ADDR(dest->af, &dest->addr),
-			      ntohs(dest->port));
-		__ip_vs_dst_cache_reset(dest);
-		/* simply decrease svc->refcnt here, let the caller check
-		   and release the service if nobody refers to it.
-		   Only user context can release destination and service,
-		   and only one user context can update virtual service at a
-		   time, so the operation here is OK */
-		atomic_dec(&dest->svc->refcnt);
-		free_percpu(dest->stats.cpustats);
-		kfree_rcu(dest, rcu_head);
-	} else {
-		IP_VS_DBG_BUF(3, "Moving dest %s:%u into trash, "
-			      "dest->refcnt=%d\n",
-			      IP_VS_DBG_ADDR(dest->af, &dest->addr),
-			      ntohs(dest->port),
-			      atomic_read(&dest->refcnt));
-		list_add(&dest->n_list, &ipvs->dest_trash);
-		ip_vs_dest_hold(dest);
+	if (!cleanup) {
+		set_bit(IP_VS_DEST_STATE_REMOVING, &dest->state);
+		call_rcu(&dest->rcu_head, ip_vs_dest_wait_readers);
 	}
+
+	spin_lock_bh(&ipvs->dest_trash_lock);
+	IP_VS_DBG_BUF(3, "Moving dest %s:%u into trash, dest->refcnt=%d\n",
+		      IP_VS_DBG_ADDR(dest->af, &dest->addr), ntohs(dest->port),
+		      atomic_read(&dest->refcnt));
+	if (list_empty(&ipvs->dest_trash) && !cleanup)
+		mod_timer(&ipvs->dest_trash_timer,
+			  jiffies + IP_VS_DEST_TRASH_PERIOD);
+	/* dest lives in trash without reference */
+	list_add(&dest->t_list, &ipvs->dest_trash);
+	spin_unlock_bh(&ipvs->dest_trash_lock);
+	ip_vs_dest_put(dest);
 }
 
 
@@ -1122,13 +1118,38 @@ ip_vs_del_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
 	/*
 	 *	Delete the destination
 	 */
-	__ip_vs_del_dest(svc->net, dest);
+	__ip_vs_del_dest(svc->net, dest, false);
 
 	LeaveFunction(2);
 
 	return 0;
 }
 
+static void ip_vs_dest_trash_expire(unsigned long data)
+{
+	struct net *net = (struct net *) data;
+	struct netns_ipvs *ipvs = net_ipvs(net);
+	struct ip_vs_dest *dest, *next;
+
+	spin_lock(&ipvs->dest_trash_lock);
+	list_for_each_entry_safe(dest, next, &ipvs->dest_trash, t_list) {
+		/* Skip if dest is in grace period */
+		if (test_bit(IP_VS_DEST_STATE_REMOVING, &dest->state))
+			continue;
+		if (atomic_read(&dest->refcnt) > 0)
+			continue;
+		IP_VS_DBG_BUF(3, "Removing destination %u/%s:%u from trash\n",
+			      dest->vfwmark,
+			      IP_VS_DBG_ADDR(dest->svc->af, &dest->addr),
+			      ntohs(dest->port));
+		list_del(&dest->t_list);
+		ip_vs_dest_free(dest);
+	}
+	if (!list_empty(&ipvs->dest_trash))
+		mod_timer(&ipvs->dest_trash_timer,
+			  jiffies + IP_VS_DEST_TRASH_PERIOD);
+	spin_unlock(&ipvs->dest_trash_lock);
+}
 
 /*
  *	Add a service into the service hash table
@@ -1358,7 +1379,7 @@ out:
  *	- The service must be unlinked, unlocked and not referenced!
  *	- We are called under _bh lock
  */
-static void __ip_vs_del_service(struct ip_vs_service *svc)
+static void __ip_vs_del_service(struct ip_vs_service *svc, bool cleanup)
 {
 	struct ip_vs_dest *dest, *nxt;
 	struct ip_vs_scheduler *old_sched;
@@ -1394,7 +1415,7 @@ static void __ip_vs_del_service(struct ip_vs_service *svc)
 	 */
 	list_for_each_entry_safe(dest, nxt, &svc->destinations, n_list) {
 		__ip_vs_unlink_dest(svc, dest, 0);
-		__ip_vs_del_dest(svc->net, dest);
+		__ip_vs_del_dest(svc->net, dest, cleanup);
 	}
 
 	/*
@@ -1424,7 +1445,7 @@ static void __ip_vs_del_service(struct ip_vs_service *svc)
 /*
  * Unlink a service from list and try to delete it if its refcnt reached 0
  */
-static void ip_vs_unlink_service(struct ip_vs_service *svc)
+static void ip_vs_unlink_service(struct ip_vs_service *svc, bool cleanup)
 {
 	/*
 	 * Unhash it from the service table
@@ -1438,7 +1459,7 @@ static void ip_vs_unlink_service(struct ip_vs_service *svc)
 	 */
 	IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
 
-	__ip_vs_del_service(svc);
+	__ip_vs_del_service(svc, cleanup);
 
 	write_unlock_bh(&__ip_vs_svc_lock);
 }
@@ -1450,7 +1471,7 @@ static int ip_vs_del_service(struct ip_vs_service *svc)
 {
 	if (svc == NULL)
 		return -EEXIST;
-	ip_vs_unlink_service(svc);
+	ip_vs_unlink_service(svc, false);
 
 	return 0;
 }
@@ -1459,7 +1480,7 @@ static int ip_vs_del_service(struct ip_vs_service *svc)
 /*
  *	Flush all the virtual services
  */
-static int ip_vs_flush(struct net *net)
+static int ip_vs_flush(struct net *net, bool cleanup)
 {
 	int idx;
 	struct ip_vs_service *svc, *nxt;
@@ -1471,7 +1492,7 @@ static int ip_vs_flush(struct net *net)
 		list_for_each_entry_safe(svc, nxt, &ip_vs_svc_table[idx],
 					 s_list) {
 			if (net_eq(svc->net, net))
-				ip_vs_unlink_service(svc);
+				ip_vs_unlink_service(svc, cleanup);
 		}
 	}
 
@@ -1482,7 +1503,7 @@ static int ip_vs_flush(struct net *net)
 		list_for_each_entry_safe(svc, nxt,
 					 &ip_vs_svc_fwm_table[idx], f_list) {
 			if (net_eq(svc->net, net))
-				ip_vs_unlink_service(svc);
+				ip_vs_unlink_service(svc, cleanup);
 		}
 	}
 
@@ -1498,7 +1519,7 @@ void ip_vs_service_net_cleanup(struct net *net)
 	EnterFunction(2);
 	/* Check for "full" addressed entries */
 	mutex_lock(&__ip_vs_mutex);
-	ip_vs_flush(net);
+	ip_vs_flush(net, true);
 	mutex_unlock(&__ip_vs_mutex);
 	LeaveFunction(2);
 }
@@ -1558,9 +1579,11 @@ static int ip_vs_dst_event(struct notifier_block *this, unsigned long event,
 		}
 	}
 
-	list_for_each_entry(dest, &ipvs->dest_trash, n_list) {
+	spin_lock_bh(&ipvs->dest_trash_lock);
+	list_for_each_entry(dest, &ipvs->dest_trash, t_list) {
 		ip_vs_forget_dev(dest, dev);
 	}
+	spin_unlock_bh(&ipvs->dest_trash_lock);
 	mutex_unlock(&__ip_vs_mutex);
 	LeaveFunction(2);
 	return NOTIFY_DONE;
@@ -2394,7 +2417,7 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 
 	if (cmd == IP_VS_SO_SET_FLUSH) {
 		/* Flush the virtual service */
-		ret = ip_vs_flush(net);
+		ret = ip_vs_flush(net, false);
 		goto out_unlock;
 	} else if (cmd == IP_VS_SO_SET_TIMEOUT) {
 		/* Set timeout values for (tcp tcpfin udp) */
@@ -3403,7 +3426,7 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
 	mutex_lock(&__ip_vs_mutex);
 
 	if (cmd == IPVS_CMD_FLUSH) {
-		ret = ip_vs_flush(net);
+		ret = ip_vs_flush(net, false);
 		goto out;
 	} else if (cmd == IPVS_CMD_SET_CONFIG) {
 		ret = ip_vs_genl_set_config(net, info->attrs);
@@ -3800,6 +3823,9 @@ int __net_init ip_vs_control_net_init(struct net *net)
 		INIT_HLIST_HEAD(&ipvs->rs_table[idx]);
 
 	INIT_LIST_HEAD(&ipvs->dest_trash);
+	spin_lock_init(&ipvs->dest_trash_lock);
+	setup_timer(&ipvs->dest_trash_timer, ip_vs_dest_trash_expire,
+		    (unsigned long) net);
 	atomic_set(&ipvs->ftpsvc_counter, 0);
 	atomic_set(&ipvs->nullsvc_counter, 0);
 
@@ -3829,6 +3855,10 @@ void __net_exit ip_vs_control_net_cleanup(struct net *net)
 {
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
+	/* Some dest can be in grace period even before cleanup, we have to
+	 * defer ip_vs_trash_cleanup until ip_vs_dest_wait_readers is called.
+	 */
+	rcu_barrier();
 	ip_vs_trash_cleanup(net);
 	ip_vs_stop_estimator(net, &ipvs->tot_stats);
 	ip_vs_control_net_cleanup_sysctl(net);