Whamcloud - gitweb
LU-9679 modules: convert MIN/MAX to kernel style
[fs/lustre-release.git] / lnet / lnet / peer.c
index 69a9e93..4e6a3e5 100644 (file)
@@ -162,8 +162,6 @@ 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);
@@ -172,8 +170,10 @@ lnet_peer_ni_alloc(lnet_nid_t nid)
 
        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;
@@ -248,13 +248,28 @@ 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;
+       if (lnet_peers_start_down())
+               lp->lp_alive = false;
+       else
+               lp->lp_alive = true;
+
+       /*
+        * 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
@@ -277,6 +292,7 @@ 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));
@@ -297,7 +313,9 @@ 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);
 
@@ -360,12 +378,12 @@ 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;
@@ -386,8 +404,6 @@ lnet_peer_ni_del_locked(struct lnet_peer_ni *lpni)
 
        /* decrement the ref count on the peer table */
        ptable = the_lnet.ln_peer_tables[lpni->lpni_cpt];
-       LASSERT(ptable->pt_number > 0);
-       ptable->pt_number--;
 
        /*
         * The peer_ni can no longer be found with a lookup. But there
@@ -422,7 +438,7 @@ 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();
 
@@ -440,7 +456,7 @@ 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;
@@ -474,6 +490,7 @@ 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) {
@@ -496,14 +513,21 @@ 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);
 
-       rc = 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);
 
@@ -531,7 +555,7 @@ 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;
                        }
                        /*
@@ -576,7 +600,7 @@ 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++) {
@@ -585,13 +609,13 @@ 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);
                }
        }
@@ -629,7 +653,8 @@ lnet_get_peer_ni_locked(struct lnet_peer_table *ptable, lnet_nid_t nid)
        struct list_head        *peers;
        struct lnet_peer_ni     *lp;
 
-       LASSERT(the_lnet.ln_state == LNET_STATE_RUNNING);
+       if (the_lnet.ln_state != LNET_STATE_RUNNING)
+               return NULL;
 
        peers = &ptable->pt_hash[lnet_nid2peerhash(nid)];
        list_for_each_entry(lp, peers, lpni_hashlist) {
@@ -657,6 +682,24 @@ 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)
 {
@@ -676,6 +719,39 @@ 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,
@@ -809,6 +885,8 @@ 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];
@@ -1075,6 +1153,36 @@ lnet_peer_primary_nid_locked(lnet_nid_t nid)
        return primary_nid;
 }
 
+bool
+lnet_is_discovery_disabled_locked(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+       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)
 {
@@ -1091,11 +1199,16 @@ 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:
@@ -1147,7 +1260,6 @@ lnet_peer_attach_peer_ni(struct lnet_peer *lp,
                ptable = the_lnet.ln_peer_tables[lpni->lpni_cpt];
                list_add_tail(&lpni->lpni_hashlist, &ptable->pt_hash[hash]);
                ptable->pt_version++;
-               ptable->pt_number++;
                /* This is the 1st refcount on lpni. */
                atomic_inc(&lpni->lpni_refcount);
        }
@@ -1330,6 +1442,18 @@ 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) {
@@ -1552,6 +1676,15 @@ 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);
 
@@ -1571,7 +1704,6 @@ 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));
@@ -1698,9 +1830,29 @@ 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?
@@ -1711,22 +1863,17 @@ 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) {
@@ -1737,7 +1884,6 @@ lnet_peer_is_uptodate(struct lnet_peer *lp)
        } else {
                rc = false;
        }
-       spin_unlock(&lp->lp_lock);
 
        return rc;
 }
@@ -1778,17 +1924,20 @@ static void lnet_peer_discovery_complete(struct lnet_peer *lp)
 {
        struct lnet_msg *msg, *tmp;
        int rc = 0;
-       struct list_head pending_msgs;
-
-       INIT_LIST_HEAD(&pending_msgs);
+       LIST_HEAD(pending_msgs);
 
        CDEBUG(D_NET, "Discovery complete. Dequeue peer %s\n",
               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 */
@@ -1924,38 +2073,9 @@ 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,
@@ -2039,6 +2159,7 @@ 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);
@@ -2051,26 +2172,38 @@ 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);
@@ -2083,11 +2216,13 @@ 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;
@@ -2100,7 +2235,7 @@ 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",
@@ -2171,6 +2306,22 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
                goto out;
        }
 
+
+       /*
+        * 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
@@ -2178,11 +2329,22 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
         */
        if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL) {
                if (lp->lp_state & LNET_PEER_MULTI_RAIL) {
-                       /* Everything's fine */
+                       CDEBUG(D_NET, "peer %s(%p) is MR\n",
+                              libcfs_nid2str(lp->lp_primary_nid), lp);
                } else if (lp->lp_state & LNET_PEER_CONFIGURED) {
                        CWARN("Reply says %s is Multi-Rail, DLC says not\n",
                              libcfs_nid2str(lp->lp_primary_nid));
+               } else if (lnet_peer_discovery_disabled) {
+                       CDEBUG(D_NET,
+                              "peer %s(%p) not MR: DD disabled locally\n",
+                              libcfs_nid2str(lp->lp_primary_nid), lp);
+               } else if (lp->lp_state & LNET_PEER_NO_DISCOVERY) {
+                       CDEBUG(D_NET,
+                              "peer %s(%p) not MR: DD disabled remotely\n",
+                              libcfs_nid2str(lp->lp_primary_nid), lp);
                } else {
+                       CDEBUG(D_NET, "peer %s(%p) is MR capable\n",
+                              libcfs_nid2str(lp->lp_primary_nid), lp);
                        lp->lp_state |= LNET_PEER_MULTI_RAIL;
                        lnet_peer_clr_non_mr_pref_nids(lp);
                }
@@ -2205,20 +2367,6 @@ 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.
         */
@@ -2240,21 +2388,18 @@ 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
@@ -2264,6 +2409,15 @@ 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);
 }
 
 /*
@@ -2403,7 +2557,7 @@ 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;
@@ -2418,10 +2572,21 @@ 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;
 
-       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));
+       /*
+        * 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_t(int, lp->lp_nnis, pbuf->pb_info.pi_nnis);
+       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;
@@ -2444,7 +2609,7 @@ 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.
@@ -2456,24 +2621,59 @@ 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",
@@ -2490,11 +2690,11 @@ 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);
@@ -2567,6 +2767,18 @@ 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.
  */
@@ -2634,7 +2846,17 @@ __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);
@@ -2648,13 +2870,26 @@ __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);
@@ -2742,7 +2977,7 @@ __must_hold(&lp->lp_lock)
        pnid = lnet_peer_select_nid(lp);
        lnet_net_unlock(cpt);
 
-       nnis = MAX(lp->lp_data_nnis, LNET_INTERFACES_MIN);
+       nnis = max(lp->lp_data_nnis, LNET_INTERFACES_MIN);
 
        rc = lnet_send_ping(pnid, &lp->lp_ping_mdh, nnis, lp,
                            the_lnet.ln_dc_eqh, false);
@@ -2874,7 +3109,7 @@ 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
@@ -2918,19 +3153,6 @@ __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
@@ -3030,11 +3252,9 @@ static int lnet_peer_discovery_wait_for_work(void)
 static void lnet_resend_msgs(void)
 {
        struct lnet_msg *msg, *tmp;
-       struct list_head resend;
+       LIST_HEAD(resend);
        int rc;
 
-       INIT_LIST_HEAD(&resend);
-
        spin_lock(&the_lnet.ln_msg_resend_lock);
        list_splice(&the_lnet.ln_msg_resend, &resend);
        spin_unlock(&the_lnet.ln_msg_resend_lock);
@@ -3058,6 +3278,8 @@ 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();
 
@@ -3105,8 +3327,8 @@ 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);
@@ -3118,16 +3340,14 @@ 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);
 
@@ -3154,8 +3374,6 @@ 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);
@@ -3183,6 +3401,9 @@ 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);
 
@@ -3231,7 +3452,14 @@ 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);
@@ -3263,7 +3491,7 @@ 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),
@@ -3319,7 +3547,7 @@ 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);
@@ -3406,7 +3634,7 @@ 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) ?