Whamcloud - gitweb
LU-12739 lnet: Don't queue msg when discovery has completed
[fs/lustre-release.git] / lnet / lnet / peer.c
index 0159101..e9505fd 100644 (file)
@@ -162,17 +162,18 @@ lnet_peer_ni_alloc(lnet_nid_t nid)
                return NULL;
 
        INIT_LIST_HEAD(&lpni->lpni_txq);
-       INIT_LIST_HEAD(&lpni->lpni_rtrq);
-       INIT_LIST_HEAD(&lpni->lpni_routes);
        INIT_LIST_HEAD(&lpni->lpni_hashlist);
        INIT_LIST_HEAD(&lpni->lpni_peer_nis);
        INIT_LIST_HEAD(&lpni->lpni_recovery);
        INIT_LIST_HEAD(&lpni->lpni_on_remote_peer_ni_list);
+       LNetInvalidateMDHandle(&lpni->lpni_recovery_ping_mdh);
 
        spin_lock_init(&lpni->lpni_lock);
 
-       lpni->lpni_alive = !lnet_peers_start_down(); /* 1 bit!! */
-       lpni->lpni_last_alive = ktime_get_seconds(); /* assumes alive */
+       if (lnet_peers_start_down())
+               lpni->lpni_ns_status = LNET_NI_STATUS_DOWN;
+       else
+               lpni->lpni_ns_status = LNET_NI_STATUS_UP;
        lpni->lpni_ping_feats = LNET_PING_FEAT_INVAL;
        lpni->lpni_nid = nid;
        lpni->lpni_cpt = cpt;
@@ -247,13 +248,24 @@ lnet_peer_alloc(lnet_nid_t nid)
        if (!lp)
                return NULL;
 
+       INIT_LIST_HEAD(&lp->lp_rtrq);
+       INIT_LIST_HEAD(&lp->lp_routes);
        INIT_LIST_HEAD(&lp->lp_peer_list);
        INIT_LIST_HEAD(&lp->lp_peer_nets);
        INIT_LIST_HEAD(&lp->lp_dc_list);
        INIT_LIST_HEAD(&lp->lp_dc_pendq);
+       INIT_LIST_HEAD(&lp->lp_rtr_list);
        init_waitqueue_head(&lp->lp_dc_waitq);
        spin_lock_init(&lp->lp_lock);
        lp->lp_primary_nid = nid;
+
+       /*
+        * all peers created on a router should have health on
+        * if it's not already on.
+        */
+       if (the_lnet.ln_routing && !lnet_health_sensitivity)
+               lp->lp_health_sensitivity = 1;
+
        /*
         * Turn off discovery for loopback peer. If you're creating a peer
         * for the loopback interface then that was initiated when we
@@ -276,6 +288,7 @@ lnet_destroy_peer_locked(struct lnet_peer *lp)
        CDEBUG(D_NET, "%p nid %s\n", lp, libcfs_nid2str(lp->lp_primary_nid));
 
        LASSERT(atomic_read(&lp->lp_refcount) == 0);
+       LASSERT(lp->lp_rtr_refcount == 0);
        LASSERT(list_empty(&lp->lp_peer_nets));
        LASSERT(list_empty(&lp->lp_peer_list));
        LASSERT(list_empty(&lp->lp_dc_list));
@@ -296,7 +309,9 @@ lnet_destroy_peer_locked(struct lnet_peer *lp)
         * Releasing the lock can cause an inconsistent state
         */
        spin_lock(&the_lnet.ln_msg_resend_lock);
+       spin_lock(&lp->lp_lock);
        list_splice(&lp->lp_dc_pendq, &the_lnet.ln_msg_resend);
+       spin_unlock(&lp->lp_lock);
        spin_unlock(&the_lnet.ln_msg_resend_lock);
        wake_up(&the_lnet.ln_dc_waitq);
 
@@ -359,12 +374,12 @@ lnet_peer_detach_peer_ni_locked(struct lnet_peer_ni *lpni)
 
 /* called with lnet_net_lock LNET_LOCK_EX held */
 static int
-lnet_peer_ni_del_locked(struct lnet_peer_ni *lpni)
+lnet_peer_ni_del_locked(struct lnet_peer_ni *lpni, bool force)
 {
        struct lnet_peer_table *ptable = NULL;
 
        /* don't remove a peer_ni if it's also a gateway */
-       if (lpni->lpni_rtr_refcount > 0) {
+       if (lnet_isrouter(lpni) && !force) {
                CERROR("Peer NI %s is a gateway. Can not delete it\n",
                       libcfs_nid2str(lpni->lpni_nid));
                return -EBUSY;
@@ -421,7 +436,7 @@ void lnet_peer_uninit(void)
        /* remove all peer_nis from the remote peer and the hash list */
        list_for_each_entry_safe(lpni, tmp, &the_lnet.ln_remote_peer_ni_list,
                                 lpni_on_remote_peer_ni_list)
-               lnet_peer_ni_del_locked(lpni);
+               lnet_peer_ni_del_locked(lpni, false);
 
        lnet_peer_tables_destroy();
 
@@ -439,7 +454,7 @@ lnet_peer_del_locked(struct lnet_peer *peer)
        lpni = lnet_get_next_peer_ni_locked(peer, NULL, lpni);
        while (lpni != NULL) {
                lpni2 = lnet_get_next_peer_ni_locked(peer, NULL, lpni);
-               rc = lnet_peer_ni_del_locked(lpni);
+               rc = lnet_peer_ni_del_locked(lpni, false);
                if (rc != 0)
                        rc2 = rc;
                lpni = lpni2;
@@ -473,6 +488,7 @@ lnet_peer_del_nid(struct lnet_peer *lp, lnet_nid_t nid, unsigned flags)
        struct lnet_peer_ni *lpni;
        lnet_nid_t primary_nid = lp->lp_primary_nid;
        int rc = 0;
+       bool force = (flags & LNET_PEER_RTR_NI_FORCE_DEL) ? true : false;
 
        if (!(flags & LNET_PEER_CONFIGURED)) {
                if (lp->lp_state & LNET_PEER_CONFIGURED) {
@@ -495,13 +511,22 @@ lnet_peer_del_nid(struct lnet_peer *lp, lnet_nid_t nid, unsigned flags)
         * This function only allows deletion of the primary NID if it
         * is the only NID.
         */
-       if (nid == lp->lp_primary_nid && lp->lp_nnis != 1) {
+       if (nid == lp->lp_primary_nid && lp->lp_nnis != 1 && !force) {
                rc = -EBUSY;
                goto out;
        }
 
        lnet_net_lock(LNET_LOCK_EX);
-       lnet_peer_ni_del_locked(lpni);
+
+       if (nid == lp->lp_primary_nid && lp->lp_nnis != 1 && force) {
+               struct lnet_peer_ni *lpni2;
+               /* assign the next peer_ni to be the primary */
+               lpni2 = lnet_get_next_peer_ni_locked(lp, NULL, lpni);
+               LASSERT(lpni2);
+               lp->lp_primary_nid = lpni->lpni_nid;
+       }
+       rc = lnet_peer_ni_del_locked(lpni, force);
+
        lnet_net_unlock(LNET_LOCK_EX);
 
 out:
@@ -528,7 +553,7 @@ lnet_peer_table_cleanup_locked(struct lnet_net *net,
 
                        peer = lpni->lpni_peer_net->lpn_peer;
                        if (peer->lp_primary_nid != lpni->lpni_nid) {
-                               lnet_peer_ni_del_locked(lpni);
+                               lnet_peer_ni_del_locked(lpni, false);
                                continue;
                        }
                        /*
@@ -573,7 +598,7 @@ lnet_peer_table_del_rtrs_locked(struct lnet_net *net,
 {
        struct lnet_peer_ni     *lp;
        struct lnet_peer_ni     *tmp;
-       lnet_nid_t              lpni_nid;
+       lnet_nid_t              gw_nid;
        int                     i;
 
        for (i = 0; i < LNET_PEER_HASH_SIZE; i++) {
@@ -582,13 +607,13 @@ lnet_peer_table_del_rtrs_locked(struct lnet_net *net,
                        if (net != lp->lpni_net)
                                continue;
 
-                       if (lp->lpni_rtr_refcount == 0)
+                       if (!lnet_isrouter(lp))
                                continue;
 
-                       lpni_nid = lp->lpni_nid;
+                       gw_nid = lp->lpni_peer_net->lpn_peer->lp_primary_nid;
 
                        lnet_net_unlock(LNET_LOCK_EX);
-                       lnet_del_route(LNET_NIDNET(LNET_NID_ANY), lpni_nid);
+                       lnet_del_route(LNET_NIDNET(LNET_NID_ANY), gw_nid);
                        lnet_net_lock(LNET_LOCK_EX);
                }
        }
@@ -654,6 +679,24 @@ lnet_find_peer_ni_locked(lnet_nid_t nid)
        return lpni;
 }
 
+struct lnet_peer_ni *
+lnet_peer_get_ni_locked(struct lnet_peer *lp, lnet_nid_t nid)
+{
+       struct lnet_peer_net *lpn;
+       struct lnet_peer_ni *lpni;
+
+       lpn = lnet_peer_get_net_locked(lp, LNET_NIDNET(nid));
+       if (!lpn)
+               return NULL;
+
+       list_for_each_entry(lpni, &lpn->lpn_peer_nis, lpni_peer_nis) {
+               if (lpni->lpni_nid == nid)
+                       return lpni;
+       }
+
+       return NULL;
+}
+
 struct lnet_peer *
 lnet_find_peer(lnet_nid_t nid)
 {
@@ -673,6 +716,39 @@ lnet_find_peer(lnet_nid_t nid)
        return lp;
 }
 
+struct lnet_peer_net *
+lnet_get_next_peer_net_locked(struct lnet_peer *lp, __u32 prev_lpn_id)
+{
+       struct lnet_peer_net *net;
+
+       if (!prev_lpn_id) {
+               /* no net id provided return the first net */
+               net = list_first_entry_or_null(&lp->lp_peer_nets,
+                                              struct lnet_peer_net,
+                                              lpn_peer_nets);
+
+               return net;
+       }
+
+       /* find the net after the one provided */
+       list_for_each_entry(net, &lp->lp_peer_nets, lpn_peer_nets) {
+               if (net->lpn_net_id == prev_lpn_id) {
+                       /*
+                        * if we reached the end of the list loop to the
+                        * beginning.
+                        */
+                       if (net->lpn_peer_nets.next == &lp->lp_peer_nets)
+                               return list_first_entry_or_null(&lp->lp_peer_nets,
+                                                               struct lnet_peer_net,
+                                                               lpn_peer_nets);
+                       else
+                               return list_next_entry(net, lpn_peer_nets);
+               }
+       }
+
+       return NULL;
+}
+
 struct lnet_peer_ni *
 lnet_get_next_peer_ni_locked(struct lnet_peer *peer,
                             struct lnet_peer_net *peer_net,
@@ -806,6 +882,8 @@ lnet_push_update_to_peers(int force)
        int cpt;
 
        lnet_net_lock(LNET_LOCK_EX);
+       if (lnet_peer_discovery_disabled)
+               force = 0;
        lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
        for (cpt = 0; cpt < lncpt; cpt++) {
                ptable = the_lnet.ln_peer_tables[cpt];
@@ -1072,6 +1150,35 @@ lnet_peer_primary_nid_locked(lnet_nid_t nid)
        return primary_nid;
 }
 
+bool
+lnet_is_discovery_disabled_locked(struct lnet_peer *lp)
+{
+       if (lnet_peer_discovery_disabled)
+               return true;
+
+       if (!(lp->lp_state & LNET_PEER_MULTI_RAIL) ||
+           (lp->lp_state & LNET_PEER_NO_DISCOVERY)) {
+               return true;
+       }
+
+       return false;
+}
+
+/*
+ * Peer Discovery
+ */
+bool
+lnet_is_discovery_disabled(struct lnet_peer *lp)
+{
+       bool rc = false;
+
+       spin_lock(&lp->lp_lock);
+       rc = lnet_is_discovery_disabled_locked(lp);
+       spin_unlock(&lp->lp_lock);
+
+       return rc;
+}
+
 lnet_nid_t
 LNetPrimaryNID(lnet_nid_t nid)
 {
@@ -1088,11 +1195,16 @@ LNetPrimaryNID(lnet_nid_t nid)
                goto out_unlock;
        }
        lp = lpni->lpni_peer_net->lpn_peer;
+
        while (!lnet_peer_is_uptodate(lp)) {
                rc = lnet_discover_peer_locked(lpni, cpt, true);
                if (rc)
                        goto out_decref;
                lp = lpni->lpni_peer_net->lpn_peer;
+
+               /* Only try once if discovery is disabled */
+               if (lnet_is_discovery_disabled(lp))
+                       break;
        }
        primary_nid = lp->lp_primary_nid;
 out_decref:
@@ -1327,6 +1439,18 @@ lnet_peer_add_nid(struct lnet_peer *lp, lnet_nid_t nid, unsigned flags)
                }
                /* If this is the primary NID, destroy the peer. */
                if (lnet_peer_ni_is_primary(lpni)) {
+                       struct lnet_peer *rtr_lp =
+                         lpni->lpni_peer_net->lpn_peer;
+                       int rtr_refcount = rtr_lp->lp_rtr_refcount;
+                       /*
+                        * if we're trying to delete a router it means
+                        * we're moving this peer NI to a new peer so must
+                        * transfer router properties to the new peer
+                        */
+                       if (rtr_refcount > 0) {
+                               flags |= LNET_PEER_RTR_NI_FORCE_DEL;
+                               lnet_rtr_transfer_to_peer(rtr_lp, lp);
+                       }
                        lnet_peer_del(lpni->lpni_peer_net->lpn_peer);
                        lpni = lnet_peer_ni_alloc(nid);
                        if (!lpni) {
@@ -1403,7 +1527,11 @@ lnet_peer_ni_traffic_add(lnet_nid_t nid, lnet_nid_t pref)
        struct lnet_peer *lp;
        struct lnet_peer_net *lpn;
        struct lnet_peer_ni *lpni;
-       unsigned flags = 0;
+       /*
+        * Assume peer is Multi-Rail capable and let discovery find out
+        * otherwise.
+        */
+       unsigned flags = LNET_PEER_MULTI_RAIL;
        int rc = 0;
 
        if (nid == LNET_NID_ANY) {
@@ -1549,6 +1677,15 @@ lnet_del_peer_ni(lnet_nid_t prim_nid, lnet_nid_t nid)
                return -ENODEV;
        }
 
+       lnet_net_lock(LNET_LOCK_EX);
+       if (lp->lp_rtr_refcount > 0) {
+               lnet_net_unlock(LNET_LOCK_EX);
+               CERROR("%s is a router. Can not be deleted\n",
+                      libcfs_nid2str(prim_nid));
+               return -EBUSY;
+       }
+       lnet_net_unlock(LNET_LOCK_EX);
+
        if (nid == LNET_NID_ANY || nid == lp->lp_primary_nid)
                return lnet_peer_del(lp);
 
@@ -1568,7 +1705,6 @@ lnet_destroy_peer_ni_locked(struct lnet_peer_ni *lpni)
        CDEBUG(D_NET, "%p nid %s\n", lpni, libcfs_nid2str(lpni->lpni_nid));
 
        LASSERT(atomic_read(&lpni->lpni_refcount) == 0);
-       LASSERT(lpni->lpni_rtr_refcount == 0);
        LASSERT(list_empty(&lpni->lpni_txq));
        LASSERT(lpni->lpni_txqnob == 0);
        LASSERT(list_empty(&lpni->lpni_peer_nis));
@@ -1695,9 +1831,29 @@ out_mutex_unlock:
        return lpni;
 }
 
-/*
- * Peer Discovery
- */
+bool
+lnet_peer_gw_discovery(struct lnet_peer *lp)
+{
+       bool rc = false;
+
+       spin_lock(&lp->lp_lock);
+       if (lp->lp_state & LNET_PEER_RTR_DISCOVERY)
+               rc = true;
+       spin_unlock(&lp->lp_lock);
+
+       return rc;
+}
+
+bool
+lnet_peer_is_uptodate(struct lnet_peer *lp)
+{
+       bool rc;
+
+       spin_lock(&lp->lp_lock);
+       rc = lnet_peer_is_uptodate_locked(lp);
+       spin_unlock(&lp->lp_lock);
+       return rc;
+}
 
 /*
  * Is a peer uptodate from the point of view of discovery?
@@ -1708,22 +1864,17 @@ out_mutex_unlock:
  * Otherwise look at whether the peer needs rediscovering.
  */
 bool
-lnet_peer_is_uptodate(struct lnet_peer *lp)
+lnet_peer_is_uptodate_locked(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
 {
        bool rc;
 
-       spin_lock(&lp->lp_lock);
        if (lp->lp_state & (LNET_PEER_DISCOVERING |
                            LNET_PEER_FORCE_PING |
                            LNET_PEER_FORCE_PUSH)) {
                rc = false;
-       } else if (lp->lp_state & LNET_PEER_NO_DISCOVERY) {
-               rc = true;
        } else if (lp->lp_state & LNET_PEER_REDISCOVER) {
-               if (lnet_peer_discovery_disabled)
-                       rc = true;
-               else
-                       rc = false;
+               rc = false;
        } else if (lnet_peer_needs_push(lp)) {
                rc = false;
        } else if (lp->lp_state & LNET_PEER_DISCOVERED) {
@@ -1734,7 +1885,6 @@ lnet_peer_is_uptodate(struct lnet_peer *lp)
        } else {
                rc = false;
        }
-       spin_unlock(&lp->lp_lock);
 
        return rc;
 }
@@ -1783,9 +1933,14 @@ static void lnet_peer_discovery_complete(struct lnet_peer *lp)
               libcfs_nid2str(lp->lp_primary_nid));
 
        list_del_init(&lp->lp_dc_list);
+       spin_lock(&lp->lp_lock);
        list_splice_init(&lp->lp_dc_pendq, &pending_msgs);
+       spin_unlock(&lp->lp_lock);
        wake_up_all(&lp->lp_dc_waitq);
 
+       if (lp->lp_rtr_refcount > 0)
+               lnet_router_discovery_complete(lp);
+
        lnet_net_unlock(LNET_LOCK_EX);
 
        /* iterate through all pending messages and send them again */
@@ -1921,38 +2076,9 @@ void lnet_peer_push_event(struct lnet_event *ev)
                goto out;
        }
 
-       /*
-        * Check whether the Put data is stale. Stale data can just be
-        * dropped.
-        */
-       if (pbuf->pb_info.pi_nnis > 1 &&
-           lp->lp_primary_nid == pbuf->pb_info.pi_ni[1].ns_nid &&
-           LNET_PING_BUFFER_SEQNO(pbuf) < lp->lp_peer_seqno) {
-               CDEBUG(D_NET, "Stale Push from %s: got %u have %u\n",
-                      libcfs_nid2str(lp->lp_primary_nid),
-                      LNET_PING_BUFFER_SEQNO(pbuf),
-                      lp->lp_peer_seqno);
-               goto out;
-       }
-
-       /*
-        * Check whether the Put data is new, in which case we clear
-        * the UPTODATE flag and prepare to process it.
-        *
-        * If the Put data is current, and the peer is UPTODATE then
-        * we assome everything is all right and drop the data as
-        * stale.
-        */
-       if (LNET_PING_BUFFER_SEQNO(pbuf) > lp->lp_peer_seqno) {
-               lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
-               lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
-       } else if (lp->lp_state & LNET_PEER_NIDS_UPTODATE) {
-               CDEBUG(D_NET, "Stale Push from %s: got %u have %u\n",
-                      libcfs_nid2str(lp->lp_primary_nid),
-                      LNET_PING_BUFFER_SEQNO(pbuf),
-                      lp->lp_peer_seqno);
-               goto out;
-       }
+       /* always assume new data */
+       lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
+       lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
 
        /*
         * If there is data present that hasn't been processed yet,
@@ -2036,6 +2162,7 @@ lnet_discover_peer_locked(struct lnet_peer_ni *lpni, int cpt, bool block)
        DEFINE_WAIT(wait);
        struct lnet_peer *lp;
        int rc = 0;
+       int count = 0;
 
 again:
        lnet_net_unlock(cpt);
@@ -2048,26 +2175,38 @@ again:
         * zombie if we race with DLC, so we must check for that.
         */
        for (;;) {
+               /* Keep lp alive when the lnet_net_lock is unlocked */
+               lnet_peer_addref_locked(lp);
                prepare_to_wait(&lp->lp_dc_waitq, &wait, TASK_INTERRUPTIBLE);
                if (signal_pending(current))
                        break;
                if (the_lnet.ln_dc_state != LNET_DC_STATE_RUNNING)
                        break;
+               /*
+                * Don't repeat discovery if discovery is disabled. This is
+                * done to ensure we can use discovery as a standard ping as
+                * well for backwards compatibility with routers which do not
+                * have discovery or have discovery disabled
+                */
+               if (lnet_is_discovery_disabled(lp) && count > 0)
+                       break;
                if (lp->lp_dc_error)
                        break;
                if (lnet_peer_is_uptodate(lp))
                        break;
                lnet_peer_queue_for_discovery(lp);
+               count++;
+               CDEBUG(D_NET, "Discovery attempt # %d\n", count);
+
                /*
-                * if caller requested a non-blocking operation then
-                * return immediately. Once discovery is complete then the
-                * peer ref will be decremented and any pending messages
-                * that were stopped due to discovery will be transmitted.
+                * If caller requested a non-blocking operation then
+                * return immediately. Once discovery is complete any
+                * pending messages that were stopped due to discovery
+                * will be transmitted.
                 */
                if (!block)
                        break;
 
-               lnet_peer_addref_locked(lp);
                lnet_net_unlock(LNET_LOCK_EX);
                schedule();
                finish_wait(&lp->lp_dc_waitq, &wait);
@@ -2080,11 +2219,13 @@ again:
 
        lnet_net_unlock(LNET_LOCK_EX);
        lnet_net_lock(cpt);
-
+       lnet_peer_decref_locked(lp);
        /*
-        * If the peer has changed after we've discovered the older peer,
-        * then we need to discovery the new peer to make sure the
-        * interface information is up to date
+        * The peer may have changed, so re-check and rediscover if that turns
+        * out to have been the case. The reference count on lp ensured that
+        * even if it was unlinked from lpni the memory could not be recycled.
+        * Thus the check below is sufficient to determine whether the peer
+        * changed. If the peer changed, then lp must not be dereferenced.
         */
        if (lp != lpni->lpni_peer_net->lpn_peer)
                goto again;
@@ -2097,7 +2238,7 @@ again:
                rc = lp->lp_dc_error;
        else if (!block)
                CDEBUG(D_NET, "non-blocking discovery\n");
-       else if (!lnet_peer_is_uptodate(lp))
+       else if (!lnet_peer_is_uptodate(lp) && !lnet_is_discovery_disabled(lp))
                goto again;
 
        CDEBUG(D_NET, "peer %s NID %s: %d. %s\n",
@@ -2168,6 +2309,36 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
                goto out;
        }
 
+
+       /*
+        * Only enable the multi-rail feature on the peer if both sides of
+        * the connection have discovery on
+        */
+       if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL) {
+               CDEBUG(D_NET, "Peer %s has Multi-Rail feature enabled\n",
+                      libcfs_nid2str(lp->lp_primary_nid));
+               lp->lp_state |= LNET_PEER_MULTI_RAIL;
+       } else {
+               CDEBUG(D_NET, "Peer %s has Multi-Rail feature disabled\n",
+                      libcfs_nid2str(lp->lp_primary_nid));
+               lp->lp_state &= ~LNET_PEER_MULTI_RAIL;
+       }
+
+       /*
+        * The peer may have discovery disabled at its end. Set
+        * NO_DISCOVERY as appropriate.
+        */
+       if ((pbuf->pb_info.pi_features & LNET_PING_FEAT_DISCOVERY) &&
+           !lnet_peer_discovery_disabled) {
+               CDEBUG(D_NET, "Peer %s has discovery enabled\n",
+                      libcfs_nid2str(lp->lp_primary_nid));
+               lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
+       } else {
+               CDEBUG(D_NET, "Peer %s has discovery disabled\n",
+                      libcfs_nid2str(lp->lp_primary_nid));
+               lp->lp_state |= LNET_PEER_NO_DISCOVERY;
+       }
+
        /*
         * Update the MULTI_RAIL flag based on the reply. If the peer
         * was configured with DLC then the setting should match what
@@ -2180,8 +2351,17 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
                        CWARN("Reply says %s is Multi-Rail, DLC says not\n",
                              libcfs_nid2str(lp->lp_primary_nid));
                } else {
-                       lp->lp_state |= LNET_PEER_MULTI_RAIL;
-                       lnet_peer_clr_non_mr_pref_nids(lp);
+                       /*
+                        * if discovery is disabled then we don't want to
+                        * update the state of the peer. All we'll do is
+                        * update the peer_nis which were reported back in
+                        * the initial ping
+                        */
+
+                       if (!lnet_is_discovery_disabled_locked(lp)) {
+                               lp->lp_state |= LNET_PEER_MULTI_RAIL;
+                               lnet_peer_clr_non_mr_pref_nids(lp);
+                       }
                }
        } else if (lp->lp_state & LNET_PEER_MULTI_RAIL) {
                if (lp->lp_state & LNET_PEER_CONFIGURED) {
@@ -2202,20 +2382,6 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
                lp->lp_data_nnis = pbuf->pb_info.pi_nnis;
 
        /*
-        * The peer may have discovery disabled at its end. Set
-        * NO_DISCOVERY as appropriate.
-        */
-       if (!(pbuf->pb_info.pi_features & LNET_PING_FEAT_DISCOVERY)) {
-               CDEBUG(D_NET, "Peer %s has discovery disabled\n",
-                      libcfs_nid2str(lp->lp_primary_nid));
-               lp->lp_state |= LNET_PEER_NO_DISCOVERY;
-       } else if (lp->lp_state & LNET_PEER_NO_DISCOVERY) {
-               CDEBUG(D_NET, "Peer %s has discovery enabled\n",
-                      libcfs_nid2str(lp->lp_primary_nid));
-               lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
-       }
-
-       /*
         * Check for truncation of the Reply. Clear PING_SENT and set
         * PING_FAILED to trigger a retry.
         */
@@ -2237,21 +2403,18 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
        if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL &&
            pbuf->pb_info.pi_nnis > 1 &&
            lp->lp_primary_nid == pbuf->pb_info.pi_ni[1].ns_nid) {
-               if (LNET_PING_BUFFER_SEQNO(pbuf) < lp->lp_peer_seqno) {
-                       CDEBUG(D_NET, "Stale Reply from %s: got %u have %u\n",
+               if (LNET_PING_BUFFER_SEQNO(pbuf) < lp->lp_peer_seqno)
+                       CDEBUG(D_NET, "peer %s: seq# got %u have %u. peer rebooted?\n",
                                libcfs_nid2str(lp->lp_primary_nid),
                                LNET_PING_BUFFER_SEQNO(pbuf),
                                lp->lp_peer_seqno);
-                       goto out;
-               }
 
-               if (LNET_PING_BUFFER_SEQNO(pbuf) > lp->lp_peer_seqno)
-                       lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
+               lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
        }
 
        /* We're happy with the state of the data in the buffer. */
-       CDEBUG(D_NET, "peer %s data present %u\n",
-              libcfs_nid2str(lp->lp_primary_nid), lp->lp_peer_seqno);
+       CDEBUG(D_NET, "peer %s data present %u. state = 0x%x\n",
+              libcfs_nid2str(lp->lp_primary_nid), lp->lp_peer_seqno, lp->lp_state);
        if (lp->lp_state & LNET_PEER_DATA_PRESENT)
                lnet_ping_buffer_decref(lp->lp_data);
        else
@@ -2261,6 +2424,15 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
 out:
        lp->lp_state &= ~LNET_PEER_PING_SENT;
        spin_unlock(&lp->lp_lock);
+
+       lnet_net_lock(LNET_LOCK_EX);
+       /*
+        * If this peer is a gateway, call the routing callback to
+        * handle the ping reply
+        */
+       if (lp->lp_rtr_refcount > 0)
+               lnet_router_discovery_ping_reply(lp);
+       lnet_net_unlock(LNET_LOCK_EX);
 }
 
 /*
@@ -2400,7 +2572,7 @@ static int lnet_peer_merge_data(struct lnet_peer *lp,
 {
        struct lnet_peer_ni *lpni;
        lnet_nid_t *curnis = NULL;
-       lnet_nid_t *addnis = NULL;
+       struct lnet_ni_status *addnis = NULL;
        lnet_nid_t *delnis = NULL;
        unsigned flags;
        int ncurnis;
@@ -2415,10 +2587,21 @@ static int lnet_peer_merge_data(struct lnet_peer *lp,
        if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL)
                flags |= LNET_PEER_MULTI_RAIL;
 
+       /*
+        * Cache the routing feature for the peer; whether it is enabled
+        * for disabled as reported by the remote peer.
+        */
+       spin_lock(&lp->lp_lock);
+       if (!(pbuf->pb_info.pi_features & LNET_PING_FEAT_RTE_DISABLED))
+               lp->lp_state |= LNET_PEER_ROUTER_ENABLED;
+       else
+               lp->lp_state &= ~LNET_PEER_ROUTER_ENABLED;
+       spin_unlock(&lp->lp_lock);
+
        nnis = MAX(lp->lp_nnis, pbuf->pb_info.pi_nnis);
-       LIBCFS_ALLOC(curnis, nnis * sizeof(lnet_nid_t));
-       LIBCFS_ALLOC(addnis, nnis * sizeof(lnet_nid_t));
-       LIBCFS_ALLOC(delnis, nnis * sizeof(lnet_nid_t));
+       LIBCFS_ALLOC(curnis, nnis * sizeof(*curnis));
+       LIBCFS_ALLOC(addnis, nnis * sizeof(*addnis));
+       LIBCFS_ALLOC(delnis, nnis * sizeof(*delnis));
        if (!curnis || !addnis || !delnis) {
                rc = -ENOMEM;
                goto out;
@@ -2441,7 +2624,7 @@ static int lnet_peer_merge_data(struct lnet_peer *lp,
                        if (pbuf->pb_info.pi_ni[i].ns_nid == curnis[j])
                                break;
                if (j == ncurnis)
-                       addnis[naddnis++] = pbuf->pb_info.pi_ni[i].ns_nid;
+                       addnis[naddnis++] = pbuf->pb_info.pi_ni[i];
        }
        /*
         * Check for NIDs in curnis[] not present in pbuf.
@@ -2453,24 +2636,59 @@ static int lnet_peer_merge_data(struct lnet_peer *lp,
        for (i = 0; i < ncurnis; i++) {
                if (LNET_NETTYP(LNET_NIDNET(curnis[i])) == LOLND)
                        continue;
-               for (j = 1; j < pbuf->pb_info.pi_nnis; j++)
-                       if (curnis[i] == pbuf->pb_info.pi_ni[j].ns_nid)
+               for (j = 1; j < pbuf->pb_info.pi_nnis; j++) {
+                       if (curnis[i] == pbuf->pb_info.pi_ni[j].ns_nid) {
+                               /*
+                                * update the information we cache for the
+                                * peer with the latest information we
+                                * received
+                                */
+                               lpni = lnet_find_peer_ni_locked(curnis[i]);
+                               if (lpni) {
+                                       lpni->lpni_ns_status = pbuf->pb_info.pi_ni[j].ns_status;
+                                       lnet_peer_ni_decref_locked(lpni);
+                               }
                                break;
+                       }
+               }
                if (j == pbuf->pb_info.pi_nnis)
                        delnis[ndelnis++] = curnis[i];
        }
 
+       /*
+        * If we get here and the discovery is disabled then we don't want
+        * to add or delete any NIs. We just updated the ones we have some
+        * information on, and call it a day
+        */
+       rc = 0;
+       if (lnet_is_discovery_disabled(lp))
+               goto out;
+
        for (i = 0; i < naddnis; i++) {
-               rc = lnet_peer_add_nid(lp, addnis[i], flags);
+               rc = lnet_peer_add_nid(lp, addnis[i].ns_nid, flags);
                if (rc) {
                        CERROR("Error adding NID %s to peer %s: %d\n",
-                              libcfs_nid2str(addnis[i]),
+                              libcfs_nid2str(addnis[i].ns_nid),
                               libcfs_nid2str(lp->lp_primary_nid), rc);
                        if (rc == -ENOMEM)
                                goto out;
                }
+               lpni = lnet_find_peer_ni_locked(addnis[i].ns_nid);
+               if (lpni) {
+                       lpni->lpni_ns_status = addnis[i].ns_status;
+                       lnet_peer_ni_decref_locked(lpni);
+               }
        }
+
        for (i = 0; i < ndelnis; i++) {
+               /*
+                * for routers it's okay to delete the primary_nid because
+                * the upper layers don't really rely on it. So if we're
+                * being told that the router changed its primary_nid
+                * then it's okay to delete it.
+                */
+               if (lp->lp_rtr_refcount > 0)
+                       flags |= LNET_PEER_RTR_NI_FORCE_DEL;
                rc = lnet_peer_del_nid(lp, delnis[i], flags);
                if (rc) {
                        CERROR("Error deleting NID %s from peer %s: %d\n",
@@ -2487,11 +2705,11 @@ static int lnet_peer_merge_data(struct lnet_peer *lp,
         */
        rc = 0;
 out:
-       LIBCFS_FREE(curnis, nnis * sizeof(lnet_nid_t));
-       LIBCFS_FREE(addnis, nnis * sizeof(lnet_nid_t));
-       LIBCFS_FREE(delnis, nnis * sizeof(lnet_nid_t));
+       LIBCFS_FREE(curnis, nnis * sizeof(*curnis));
+       LIBCFS_FREE(addnis, nnis * sizeof(*addnis));
+       LIBCFS_FREE(delnis, nnis * sizeof(*delnis));
        lnet_ping_buffer_decref(pbuf);
-       CDEBUG(D_NET, "peer %s: %d\n", libcfs_nid2str(lp->lp_primary_nid), rc);
+       CDEBUG(D_NET, "peer %s (%p): %d\n", libcfs_nid2str(lp->lp_primary_nid), lp, rc);
 
        if (rc) {
                spin_lock(&lp->lp_lock);
@@ -2564,6 +2782,18 @@ lnet_peer_set_primary_data(struct lnet_peer *lp, struct lnet_ping_buffer *pbuf)
        return 0;
 }
 
+static bool lnet_is_nid_in_ping_info(lnet_nid_t nid, struct lnet_ping_info *pinfo)
+{
+       int i;
+
+       for (i = 0; i < pinfo->pi_nnis; i++) {
+               if (pinfo->pi_ni[i].ns_nid == nid)
+                       return true;
+       }
+
+       return false;
+}
+
 /*
  * Update a peer using the data received.
  */
@@ -2631,7 +2861,17 @@ __must_hold(&lp->lp_lock)
                rc = lnet_peer_set_primary_nid(lp, nid, flags);
                if (!rc)
                        rc = lnet_peer_merge_data(lp, pbuf);
-       } else if (lp->lp_primary_nid == nid) {
+       /*
+        * if the primary nid of the peer is present in the ping info returned
+        * from the peer, but it's not the local primary peer we have
+        * cached and discovery is disabled, then we don't want to update
+        * our local peer info, by adding or removing NIDs, we just want
+        * to update the status of the nids that we currently have
+        * recorded in that peer.
+        */
+       } else if (lp->lp_primary_nid == nid ||
+                  (lnet_is_nid_in_ping_info(lp->lp_primary_nid, &pbuf->pb_info) &&
+                   lnet_is_discovery_disabled(lp))) {
                rc = lnet_peer_merge_data(lp, pbuf);
        } else {
                lpni = lnet_find_peer_ni_locked(nid);
@@ -2645,13 +2885,26 @@ __must_hold(&lp->lp_lock)
                                rc = lnet_peer_merge_data(lp, pbuf);
                        }
                } else {
-                       rc = lnet_peer_set_primary_data(
-                               lpni->lpni_peer_net->lpn_peer, pbuf);
+                       struct lnet_peer *new_lp;
+                       new_lp = lpni->lpni_peer_net->lpn_peer;
+                       /*
+                        * if lp has discovery/MR enabled that means new_lp
+                        * should have discovery/MR enabled as well, since
+                        * it's the same peer, which we're about to merge
+                        */
+                       if (!(lp->lp_state & LNET_PEER_NO_DISCOVERY))
+                               new_lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
+                       if (lp->lp_state & LNET_PEER_MULTI_RAIL)
+                               new_lp->lp_state |= LNET_PEER_MULTI_RAIL;
+
+                       rc = lnet_peer_set_primary_data(new_lp, pbuf);
+                       lnet_consolidate_routes_locked(lp, new_lp);
                        lnet_peer_ni_decref_locked(lpni);
                }
        }
 out:
-       CDEBUG(D_NET, "peer %s: %d\n", libcfs_nid2str(lp->lp_primary_nid), rc);
+       CDEBUG(D_NET, "peer %s(%p): %d. state = 0x%x\n", libcfs_nid2str(lp->lp_primary_nid), lp, rc,
+              lp->lp_state);
        mutex_unlock(&the_lnet.ln_api_mutex);
 
        spin_lock(&lp->lp_lock);
@@ -2871,7 +3124,7 @@ fail_unlink:
        LNetMDUnlink(lp->lp_push_mdh);
        LNetInvalidateMDHandle(&lp->lp_push_mdh);
 fail_error:
-       CDEBUG(D_NET, "peer %s: %d\n", libcfs_nid2str(lp->lp_primary_nid), rc);
+       CDEBUG(D_NET, "peer %s(%p): %d\n", libcfs_nid2str(lp->lp_primary_nid), lp, rc);
        /*
         * The errors that get us here are considered hard errors and
         * cause Discovery to terminate. So we clear PUSH_SENT, but do
@@ -2915,19 +3168,6 @@ __must_hold(&lp->lp_lock)
        return 0;
 }
 
-/*
- * Mark the peer as to be rediscovered.
- */
-static int lnet_peer_rediscover(struct lnet_peer *lp)
-__must_hold(&lp->lp_lock)
-{
-       lp->lp_state |= LNET_PEER_REDISCOVER;
-       lp->lp_state &= ~LNET_PEER_DISCOVERING;
-
-       CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(lp->lp_primary_nid));
-
-       return 0;
-}
 
 /*
  * Discovering this peer is taking too long. Cancel any Ping or Push
@@ -3055,6 +3295,8 @@ static int lnet_peer_discovery(void *arg)
        struct lnet_peer *lp;
        int rc;
 
+       wait_for_completion(&the_lnet.ln_started);
+
        CDEBUG(D_NET, "started\n");
        cfs_block_allsigs();
 
@@ -3102,8 +3344,8 @@ static int lnet_peer_discovery(void *arg)
                         * forcing a Ping or Push.
                         */
                        spin_lock(&lp->lp_lock);
-                       CDEBUG(D_NET, "peer %s state %#x\n",
-                               libcfs_nid2str(lp->lp_primary_nid),
+                       CDEBUG(D_NET, "peer %s(%p) state %#x\n",
+                               libcfs_nid2str(lp->lp_primary_nid), lp,
                                lp->lp_state);
                        if (lp->lp_state & LNET_PEER_DATA_PRESENT)
                                rc = lnet_peer_data_present(lp);
@@ -3115,16 +3357,14 @@ static int lnet_peer_discovery(void *arg)
                                rc = lnet_peer_send_ping(lp);
                        else if (lp->lp_state & LNET_PEER_FORCE_PUSH)
                                rc = lnet_peer_send_push(lp);
-                       else if (lnet_peer_discovery_disabled)
-                               rc = lnet_peer_rediscover(lp);
                        else if (!(lp->lp_state & LNET_PEER_NIDS_UPTODATE))
                                rc = lnet_peer_send_ping(lp);
                        else if (lnet_peer_needs_push(lp))
                                rc = lnet_peer_send_push(lp);
                        else
                                rc = lnet_peer_discovered(lp);
-                       CDEBUG(D_NET, "peer %s state %#x rc %d\n",
-                               libcfs_nid2str(lp->lp_primary_nid),
+                       CDEBUG(D_NET, "peer %s(%p) state %#x rc %d\n",
+                               libcfs_nid2str(lp->lp_primary_nid), lp,
                                lp->lp_state, rc);
                        spin_unlock(&lp->lp_lock);
 
@@ -3151,8 +3391,6 @@ static int lnet_peer_discovery(void *arg)
         * size of the thundering herd if there are multiple threads
         * waiting on discovery of a single peer.
         */
-       LNetEQFree(the_lnet.ln_dc_eqh);
-       LNetInvalidateEQHandle(&the_lnet.ln_dc_eqh);
 
        /* Queue cleanup 1: stop all pending pings and pushes. */
        lnet_net_lock(LNET_LOCK_EX);
@@ -3180,6 +3418,9 @@ static int lnet_peer_discovery(void *arg)
        }
        lnet_net_unlock(LNET_LOCK_EX);
 
+       LNetEQFree(the_lnet.ln_dc_eqh);
+       LNetInvalidateEQHandle(&the_lnet.ln_dc_eqh);
+
        the_lnet.ln_dc_state = LNET_DC_STATE_SHUTDOWN;
        wake_up(&the_lnet.ln_dc_waitq);
 
@@ -3228,7 +3469,14 @@ void lnet_peer_discovery_stop(void)
 
        LASSERT(the_lnet.ln_dc_state == LNET_DC_STATE_RUNNING);
        the_lnet.ln_dc_state = LNET_DC_STATE_STOPPING;
-       wake_up(&the_lnet.ln_dc_waitq);
+
+       /* In the LNetNIInit() path we may be stopping discovery before it
+        * entered its work loop
+        */
+       if (!completion_done(&the_lnet.ln_started))
+               complete(&the_lnet.ln_started);
+       else
+               wake_up(&the_lnet.ln_dc_waitq);
 
        wait_event(the_lnet.ln_dc_waitq,
                   the_lnet.ln_dc_state == LNET_DC_STATE_SHUTDOWN);
@@ -3260,7 +3508,7 @@ lnet_debug_peer(lnet_nid_t nid)
        }
 
        if (lnet_isrouter(lp) || lnet_peer_aliveness_enabled(lp))
-               aliveness = lp->lpni_alive ? "up" : "down";
+               aliveness = (lnet_is_peer_ni_alive(lp)) ? "up" : "down";
 
        CDEBUG(D_WARNING, "%-24s %4d %5s %5d %5d %5d %5d %5d %ld\n",
               libcfs_nid2str(lp->lpni_nid), atomic_read(&lp->lpni_refcount),
@@ -3316,7 +3564,7 @@ int lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
                        if (lnet_isrouter(lp) ||
                                lnet_peer_aliveness_enabled(lp))
                                snprintf(aliveness, LNET_MAX_STR_LEN,
-                                        lp->lpni_alive ? "up" : "down");
+                                        lnet_is_peer_ni_alive(lp) ? "up" : "down");
 
                        *nid = lp->lpni_nid;
                        *refcount = atomic_read(&lp->lpni_refcount);
@@ -3403,7 +3651,7 @@ int lnet_get_peer_info(struct lnet_ioctl_peer_cfg *cfg, void __user *bulk)
                if (lnet_isrouter(lpni) ||
                        lnet_peer_aliveness_enabled(lpni))
                        snprintf(lpni_info->cr_aliveness, LNET_MAX_STR_LEN,
-                               lpni->lpni_alive ? "up" : "down");
+                               lnet_is_peer_ni_alive(lpni) ? "up" : "down");
 
                lpni_info->cr_refcount = atomic_read(&lpni->lpni_refcount);
                lpni_info->cr_ni_peer_tx_credits = (lpni->lpni_net != NULL) ?
@@ -3495,6 +3743,10 @@ lnet_peer_ni_set_healthv(lnet_nid_t nid, int value, bool all)
        if (!all) {
                lnet_net_lock(LNET_LOCK_EX);
                lpni = lnet_find_peer_ni_locked(nid);
+               if (!lpni) {
+                       lnet_net_unlock(LNET_LOCK_EX);
+                       return;
+               }
                atomic_set(&lpni->lpni_healthv, value);
                lnet_peer_ni_add_to_recoveryq_locked(lpni);
                lnet_peer_ni_decref_locked(lpni);