3 files changed, 17 insertions, 3 deletions

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 1c91391f4805..36358d435cb0 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -119,6 +119,9 @@ struct nfsd_net {
         u32 clverifier_counter;
 
         struct svc_serv *nfsd_serv;
+
+        wait_queue_head_t ntf_wq;
+        atomic_t ntf_refcnt;
 };
 
 /* Simple check to find out if a given net was properly initialized */
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 6493df6b1bd5..d107b4426f7e 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1241,6 +1241,9 @@ static __net_init int nfsd_init_net(struct net *net)
         nn->nfsd4_grace = 90;
         nn->clverifier_counter = prandom_u32();
         nn->clientid_counter = prandom_u32();
+
+        atomic_set(&nn->ntf_refcnt, 0);
+        init_waitqueue_head(&nn->ntf_wq);
         return 0;
 
 out_idmap_error:
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 33117d4ffce0..89cb484f1cfb 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -335,7 +335,8 @@ static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
         struct sockaddr_in sin;
 
-        if (event != NETDEV_DOWN)
+        if ((event != NETDEV_DOWN) ||
+            !atomic_inc_not_zero(&nn->ntf_refcnt))
                 goto out;
 
         if (nn->nfsd_serv) {
@@ -344,6 +345,8 @@ static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
                 sin.sin_addr.s_addr = ifa->ifa_local;
                 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin);
         }
+        atomic_dec(&nn->ntf_refcnt);
+        wake_up(&nn->ntf_wq);
 
 out:
         return NOTIFY_DONE;
@@ -363,7 +366,8 @@ static int nfsd_inet6addr_event(struct notifier_block *this,
         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
         struct sockaddr_in6 sin6;
 
-        if (event != NETDEV_DOWN)
+        if ((event != NETDEV_DOWN) ||
+            !atomic_inc_not_zero(&nn->ntf_refcnt))
                 goto out;
 
         if (nn->nfsd_serv) {
@@ -374,7 +378,8 @@ static int nfsd_inet6addr_event(struct notifier_block *this,
                         sin6.sin6_scope_id = ifa->idev->dev->ifindex;
                 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6);
         }
-
+        atomic_dec(&nn->ntf_refcnt);
+        wake_up(&nn->ntf_wq);
 out:
         return NOTIFY_DONE;
 }
@@ -391,6 +396,7 @@ static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
 {
         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
+        atomic_dec(&nn->ntf_refcnt);
         /* check if the notifier still has clients */
         if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
                 unregister_inetaddr_notifier(&nfsd_inetaddr_notifier);
@@ -398,6 +404,7 @@ static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
                 unregister_inet6addr_notifier(&nfsd_inet6addr_notifier);
 #endif
         }
+        wait_event(nn->ntf_wq, atomic_read(&nn->ntf_refcnt) == 0);
 
         /*
          * write_ports can create the server without actually starting
@@ -517,6 +524,7 @@ int nfsd_create_serv(struct net *net)
                 register_inet6addr_notifier(&nfsd_inet6addr_notifier);
 #endif
         }
+        atomic_inc(&nn->ntf_refcnt);
         ktime_get_real_ts64(&nn->nfssvc_boot); /* record boot time */
         return 0;
 }