From e24471a722a6f23fb0051b4511f3fee2662d0e4e Mon Sep 17 00:00:00 2001 From: Chris Horn Date: Tue, 23 Jun 2020 13:02:51 -0500 Subject: [PATCH] LU-13708 lnet: lnet_notify sets route aliveness incorrectly lnet_notify() modifies route aliveness in two ways: 1. By setting lp_alive field of the lnet_peer struct. 2. By setting lr_alive field of the lnet_route struct (via call to lnet_set_route_aliveness()) In both cases, the aliveness value assigned is determined by a call to lnet_is_peer_ni_alive(), but that value only reflects the aliveness of a particular peer NI. A gateway may have multiple peer NIs, so the aliveness of a gateway peer (lp_alive) is not necessarily equivalent to the aliveness of one of its NIs. Furthermore, the lr_alive field is only used to determine route aliveness for path selection if discovery is disabled locally or on the gateway (see lnet_find_route_locked() and lnet_is_route_alive()). In general, we should not set lp_alive based on an lnet_notify() call, and we should only set lr_alive if discovery is disabled. For lr_alive specifically, we should only set it for those routes that have the peer NI as a next-hop. An exception to the above exists when the reset argument to lnet_notify() is set. The gnilnd uses this flag in its calls to lnet_notify() because gnilnd receives out-of-band notifications of node up and down events. Thus, when gnilnd calls lnet_notify() we actually know whether the gateway peer is up or down and we can set lp_alive appropriately. net lock/EX is held by other callers of lnet_set_route_aliveness, so we do the same in lnet_notify(). Fixes: e35be987da ("LU-12422 lnet: discovery off route state update") Fixes: ebc9835a97 ("LU-12941 lnet: Add peer level aliveness information") Test-Parameters: trivial HPE-bug-id: LUS-9034 Signed-off-by: Chris Horn Change-Id: I2927e5f5ef849e45c233c92d2a6deca765e496eb Reviewed-on: https://review.whamcloud.com/39160 Reviewed-by: Serguei Smirnov Reviewed-by: James Simmons Tested-by: jenkins Tested-by: Maloo Reviewed-by: Oleg Drokin --- lnet/lnet/router.c | 39 +++++++++++++++++++++++++++++++++------ 1 file changed, 33 insertions(+), 6 deletions(-) diff --git a/lnet/lnet/router.c b/lnet/lnet/router.c index acddc75..3d06b45 100644 --- a/lnet/lnet/router.c +++ b/lnet/lnet/router.c @@ -401,6 +401,7 @@ lnet_set_route_hop_type(struct lnet_peer *gw, struct lnet_route *route) lnet_check_route_inconsistency(route); } +/* Must hold net_lock/EX */ static inline void lnet_set_route_aliveness(struct lnet_route *route, bool alive) { @@ -415,6 +416,7 @@ lnet_set_route_aliveness(struct lnet_route *route, bool alive) } } +/* Must hold net_lock/EX */ void lnet_router_discovery_ping_reply(struct lnet_peer *lp) { @@ -1770,6 +1772,37 @@ lnet_notify(struct lnet_ni *ni, lnet_nid_t nid, bool alive, bool reset, /* recalculate aliveness */ alive = lnet_is_peer_ni_alive(lpni); + + lp = lpni->lpni_peer_net->lpn_peer; + /* If this is an LNet router then update route aliveness */ + if (lp->lp_rtr_refcount) { + if (reset) + /* reset flag indicates gateway peer went up or down */ + lp->lp_alive = alive; + + /* If discovery is disabled, locally or on the gateway, then + * any routes using lpni as next-hop need to be updated + * + * NB: We can get many notifications while a route is down, so + * we try and avoid the expensive net_lock/EX here for the + * common case of receiving duplicate lnet_notify() calls (i.e. + * only grab EX lock when we actually need to update the route + * aliveness). + */ + if (lnet_is_discovery_disabled(lp)) { + list_for_each_entry(route, &lp->lp_routes, lr_gwlist) { + if (route->lr_nid == lpni->lpni_nid && + route->lr_alive != alive) { + lnet_net_unlock(0); + lnet_net_lock(LNET_LOCK_EX); + lnet_set_route_aliveness(route, alive); + lnet_net_unlock(LNET_LOCK_EX); + lnet_net_lock(0); + } + } + } + } + lnet_net_unlock(0); if (ni != NULL && !alive) @@ -1778,12 +1811,6 @@ lnet_notify(struct lnet_ni *ni, lnet_nid_t nid, bool alive, bool reset, cpt = lpni->lpni_cpt; lnet_net_lock(cpt); lnet_peer_ni_decref_locked(lpni); - if (lpni && lpni->lpni_peer_net && lpni->lpni_peer_net->lpn_peer) { - lp = lpni->lpni_peer_net->lpn_peer; - lp->lp_alive = alive; - list_for_each_entry(route, &lp->lp_routes, lr_gwlist) - lnet_set_route_aliveness(route, alive); - } lnet_net_unlock(cpt); return 0; -- 1.8.3.1