[LU-14206] Router ping timeouts don't mark routes down if DD is disabled

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Severity: 3
• Assignee: Chris Horn
• Reporter: Chris Horn

Description

Discovery pings are used to determine the health of gateways and
associated routes. Ping replies from gateways with dynamic discovery
(DD) disabled (or if DD is disabled locally) are handled in
a special routine, lnet_router_discovery_ping_reply(), but this
function and related code doesn't handle the case where a discovery
ping hits the response tracker timeout and is unlinked by the
monitor thread. In this case, an UNLINK event is generated and we
do not call the lnet_router_discovery_ping_reply(). For gateways
with DD enabled (and DD enabled locally), we handle this case
in lnet_router_discovery_copmlete(). If discovery failed then
lp_dc_error is set and we mark all routes down for the gateway. We
can simply extend this logic to the case of gateways w/DD disabled
(or DD disabled locally).