From 5452e25942bc1601bf6a05937aafdc3a9b681ab6 Mon Sep 17 00:00:00 2001
From: Dhairya Parmar <dparmar@redhat.com>
Date: Thu, 2 Mar 2023 18:37:14 +0530
Subject: [PATCH] mds,messages: enable beacon to report clients lagginess using
 new MDS health metric

Fixes: https://tracker.ceph.com/issues/58023
Signed-off-by: Dhairya Parmar <dparmar@redhat.com>
(cherry picked from commit 5a0e8a7e703495e958ae7aac79bd9a40d86b19d0)
---
 src/mds/Beacon.cc         | 18 ++++++++++++++++++
 src/messages/MMDSBeacon.h |  4 ++++
 2 files changed, 22 insertions(+)

diff --git a/src/mds/Beacon.cc b/src/mds/Beacon.cc
index 36ed489a31509..76e71f2fe6e55 100644
--- a/src/mds/Beacon.cc
+++ b/src/mds/Beacon.cc
@@ -478,6 +478,24 @@ void Beacon::notify_health(MDSRank const *mds)
     MDSHealthMetric m(MDS_HEALTH_CACHE_OVERSIZED, HEALTH_WARN, css->strv());
     health.metrics.push_back(m);
   }
+
+  // Report laggy client(s) due to laggy OSDs
+  {
+    auto&& laggy_clients = mds->server->get_laggy_clients();
+    if (!laggy_clients.empty()) {
+      std::vector<MDSHealthMetric> laggy_clients_metrics;
+      for (const auto& laggy_client: laggy_clients) {
+        CachedStackStringStream css;
+        *css << "Client " << laggy_client << " is laggy; not evicted"
+            << " because some OSD(s) is/are laggy";
+        MDSHealthMetric m(MDS_HEALTH_CLIENTS_LAGGY, HEALTH_WARN, css->strv());
+        laggy_clients_metrics.emplace_back(std::move(m));
+      }
+      auto&& m = laggy_clients_metrics;
+      health.metrics.insert(std::end(health.metrics), std::cbegin(m),
+                            std::cend(m));
+    }
+  }
 }
 
 MDSMap::DaemonState Beacon::get_want_state() const
diff --git a/src/messages/MMDSBeacon.h b/src/messages/MMDSBeacon.h
index bd46926e485a1..1a60a129c1b17 100644
--- a/src/messages/MMDSBeacon.h
+++ b/src/messages/MMDSBeacon.h
@@ -45,6 +45,7 @@ enum mds_metric_t {
   MDS_HEALTH_SLOW_REQUEST,
   MDS_HEALTH_CACHE_OVERSIZED,
   MDS_HEALTH_SLOW_METADATA_IO,
+  MDS_HEALTH_CLIENTS_LAGGY,
   MDS_HEALTH_DUMMY, // not a real health warning, for testing
 };
 
@@ -63,6 +64,7 @@ inline const char *mds_metric_name(mds_metric_t m)
   case MDS_HEALTH_SLOW_REQUEST: return "MDS_SLOW_REQUEST";
   case MDS_HEALTH_CACHE_OVERSIZED: return "MDS_CACHE_OVERSIZED";
   case MDS_HEALTH_SLOW_METADATA_IO: return "MDS_SLOW_METADATA_IO";
+  case MDS_HEALTH_CLIENTS_LAGGY: return "MDS_CLIENTS_LAGGY";
   case MDS_HEALTH_DUMMY: return "MDS_DUMMY";
   default:
     return "???";
@@ -97,6 +99,8 @@ inline const char *mds_metric_summary(mds_metric_t m)
     return "%num% MDSs report oversized cache";
   case MDS_HEALTH_SLOW_METADATA_IO:
     return "%num% MDSs report slow metadata IOs";
+  case MDS_HEALTH_CLIENTS_LAGGY:
+    return "%num% client(s) laggy due to laggy OSDs";  
   default:
     return "???";
   }
-- 
2.39.5