nautilus: core: lazy omap stat collection

qa/suites/rados/singleton-nomsgr/all/lazy_omap_stats_output.yaml

@@ -0,0 +1,16 @@
+openstack:
+  - volumes: # attached to each instance
+      count: 2
+      size: 10 # GB
+roles:
+- [mon.a, mgr.x, osd.0, osd.1, osd.2, client.0]
+overrides:
+  ceph:
+    log-whitelist:
+      - \(POOL_APP_NOT_ENABLED\)
+tasks:
+- install:
+- ceph:
+- exec:
+    client.0:
+      - ceph_test_lazy_omap_stats

src/osd/PGBackend.cc

@@ -1247,6 +1247,10 @@ void PGBackend::be_omap_checks(const map<pg_shard_t,ScrubMap*> &maps,
   // Iterate through objects and update omap stats
   for (const auto& k : master_set) {
     for (const auto& map : maps) {
+      if (map.first != get_parent()->primary_shard()) {
+        // Only set omap stats for the primary
+        continue;
+      }
       auto it = map.second->objects.find(k);
       if (it == map.second->objects.end())
         continue;

src/test/CMakeLists.txt

@@ -68,6 +68,7 @@ add_subdirectory(system)
 if(WITH_FIO OR WITH_SYSTEM_FIO)
   add_subdirectory(fio)
 endif()
+add_subdirectory(lazy-omap-stats)
 
 # test_timers
 add_executable(ceph_test_timers

src/test/lazy-omap-stats/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Lazy omap stat collection tests
+
+add_executable(ceph_test_lazy_omap_stats
+  main.cc
+  lazy_omap_stats_test.cc)
+target_link_libraries(ceph_test_lazy_omap_stats
+  librados ${UNITTEST_LIBS} Boost::system)
+install(TARGETS
+  ceph_test_lazy_omap_stats
+  DESTINATION ${CMAKE_INSTALL_BINDIR})