From 5cf13459813228a2b8d78bba2d28a10528490c1f Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@newdream.net>
Date: Sun, 31 Jan 2021 10:29:51 -0600
Subject: [PATCH] mgr/MetricTypes: condition encoding on feature bits

Do not encode new metric|config types for older peers.

The combination of boost::optional and boost::variant make this super
awkward to condition on the features. :(

Fixes: https://tracker.ceph.com/issues/49069
Signed-off-by: Sage Weil <sage@newdream.net>
---
 src/messages/MMgrConfigure.h |  7 ++++++-
 src/messages/MMgrReport.h    |  7 ++++++-
 src/mgr/MetricTypes.h        | 17 +++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/messages/MMgrConfigure.h b/src/messages/MMgrConfigure.h
index aaa36790a4c06..7b27c9064eb37 100644
--- a/src/messages/MMgrConfigure.h
+++ b/src/messages/MMgrConfigure.h
@@ -59,7 +59,12 @@ public:
     encode(stats_period, payload);
     encode(stats_threshold, payload);
     encode(osd_perf_metric_queries, payload);
-    encode(metric_config_message, payload);
+    if (metric_config_message && metric_config_message->should_encode(features)) {
+      encode(metric_config_message, payload);
+    } else {
+      boost::optional<MetricConfigMessage> empty;
+      encode(empty, payload);
+    }
   }
 
   std::string_view get_type_name() const override { return "mgrconfigure"; }
diff --git a/src/messages/MMgrReport.h b/src/messages/MMgrReport.h
index 767ee775d22a5..5cd5f3d5442a4 100644
--- a/src/messages/MMgrReport.h
+++ b/src/messages/MMgrReport.h
@@ -157,7 +157,12 @@ public:
     encode(config_bl, payload);
     encode(osd_perf_metric_reports, payload);
     encode(task_status, payload);
-    encode(metric_report_message, payload);
+    if (metric_report_message && metric_report_message->should_encode(features)) {
+      encode(metric_report_message, payload);
+    } else {
+      boost::optional<MetricReportMessage> empty;
+      encode(empty, payload);
+    }
   }
 
   std::string_view get_type_name() const override { return "mgrreport"; }
diff --git a/src/mgr/MetricTypes.h b/src/mgr/MetricTypes.h
index 5f1adc6cf19f9..586c470ca5697 100644
--- a/src/mgr/MetricTypes.h
+++ b/src/mgr/MetricTypes.h
@@ -6,6 +6,7 @@
 
 #include <boost/variant.hpp>
 #include "include/denc.h"
+#include "include/ceph_features.h"
 #include "mgr/OSDPerfMetricTypes.h"
 #include "mgr/MDSPerfMetricTypes.h"
 
@@ -104,6 +105,14 @@ struct MetricReportMessage {
     : payload(payload) {
   }
 
+  bool should_encode(uint64_t features) const {
+    if (!HAVE_FEATURE(features, SERVER_PACIFIC) &&
+	boost::get<MDSMetricPayload>(&payload)) {
+      return false;
+    }
+    return true;
+  }
+
   void encode(ceph::buffer::list &bl) const {
     boost::apply_visitor(EncodeMetricPayloadVisitor(bl), payload);
   }
@@ -229,6 +238,14 @@ struct MetricConfigMessage {
     : payload(payload) {
   }
 
+  bool should_encode(uint64_t features) const {
+    if (!HAVE_FEATURE(features, SERVER_PACIFIC) &&
+	boost::get<MDSConfigPayload>(&payload)) {
+      return false;
+    }
+    return true;
+  }
+
   void encode(ceph::buffer::list &bl) const {
     boost::apply_visitor(EncodeConfigPayloadVisitor(bl), payload);
   }
-- 
2.39.5