From e4ae368ff7a5396194f8bdd5692429af5457998b Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Wed, 13 Feb 2019 07:29:45 -0600
Subject: [PATCH] message/MMonMgrReport: conditionally reencode PGMapDigest

The encoding changed between luminous and mimic.  Reencode the
structure if the target doesn't have all the features.

Fixes: http://tracker.ceph.com/issues/38295
Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/CMakeLists.txt           |  1 +
 src/messages/MMonMgrReport.h | 21 ++++++++++++++++++++-
 src/mon/CMakeLists.txt       |  1 -
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c677d4100c57f..3f7123f5451ea 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -313,6 +313,7 @@ set(libcommon_files
   mon/MonMap.cc
   mon/MonSub.cc
   mgr/MgrClient.cc
+  mon/PGMap.cc
   mgr/ServiceMap.cc
   osd/ECMsgTypes.cc
   osd/HitSet.cc
diff --git a/src/messages/MMonMgrReport.h b/src/messages/MMonMgrReport.h
index ec5ea7aafa649..818511a37baf8 100644
--- a/src/messages/MMonMgrReport.h
+++ b/src/messages/MMonMgrReport.h
@@ -19,8 +19,10 @@
 #include "include/types.h"
 #include "include/health.h"
 #include "mon/health_check.h"
+#include "mon/PGMap.h"
 
-class MMonMgrReport : public MessageInstance<MMonMgrReport, PaxosServiceMessage> {
+class MMonMgrReport
+  : public MessageInstance<MMonMgrReport, PaxosServiceMessage> {
 public:
   friend factory;
 private:
@@ -53,6 +55,23 @@ public:
     encode(health_checks, payload);
     encode(service_map_bl, payload);
     encode(progress_events, payload);
+
+    if (!HAVE_FEATURE(features, SERVER_NAUTILUS) ||
+	!HAVE_FEATURE(features, SERVER_MIMIC)) {
+      // PGMapDigest had a backwards-incompatible change between
+      // luminous and mimic, and conditionally encodes based on
+      // provided features, so reencode the one in our data payload.
+      // The mgr isn't able to do this at the time the encoded
+      // PGMapDigest is constructed because we don't know which mon we
+      // will target.  Note that this only triggers if the user
+      // upgrades ceph-mgr before ceph-mon (tsk tsk).
+      PGMapDigest digest;
+      auto p = data.cbegin();
+      decode(digest, p);
+      bufferlist bl;
+      encode(digest, bl, features);
+      data.swap(bl);
+    }
   }
   void decode_payload() override {
     auto p = payload.cbegin();
diff --git a/src/mon/CMakeLists.txt b/src/mon/CMakeLists.txt
index bcfd451de613d..02b459e214bfa 100644
--- a/src/mon/CMakeLists.txt
+++ b/src/mon/CMakeLists.txt
@@ -18,7 +18,6 @@ set(lib_mon_srcs
   ConfigMonitor.cc
   Elector.cc
   HealthMonitor.cc
-  PGMap.cc
   ConfigKeyService.cc
   ../mds/MDSAuthCaps.cc
   ../mgr/mgr_commands.cc
-- 
2.39.5