mon: mkfs compatset may be different from runtime compatset

When we create a monitor we set a given number of compat features on
disk to clearly state the features a given monitor supports -- mostly to
break backward compatibility when such compatibility cannot be
guaranteed.

However, we may wish to toggle some features during runtime; e.g., wait
for all the monitors in the quorum to support a given feature before
flipping a switch and state that all monitors now require feature X.

We are already flipping those switches during runtime, but we weren't
allowing the monitor to set a subset of those features during mkfs.
While the initial approach worked fine with clusters being upgraded and
fresh clusters, it could become weird in a mixed-version environment.

Backport: emperor,firefly,giant

Signed-off-by: Joao Eduardo Luis <joao@redhat.com>

diff --git a/src/mon/Monitor.cc b/src/mon/Monitor.cc
index 1c26350b74c4cfc9b23f7159c78b1298ac370fdf..5480c8579b3e9ec82541f603f13e9952fbb0d7b5 100644 (file)
--- a/src/mon/Monitor.cc
+++ b/src/mon/Monitor.cc
@@ -341,20 +341,26 @@ void Monitor::handle_signal(int signum)
   shutdown();
 }
 
-CompatSet Monitor::get_supported_features()
+CompatSet Monitor::get_initial_supported_features()
 {
   CompatSet::FeatureSet ceph_mon_feature_compat;
   CompatSet::FeatureSet ceph_mon_feature_ro_compat;
   CompatSet::FeatureSet ceph_mon_feature_incompat;
   ceph_mon_feature_incompat.insert(CEPH_MON_FEATURE_INCOMPAT_BASE);
   ceph_mon_feature_incompat.insert(CEPH_MON_FEATURE_INCOMPAT_SINGLE_PAXOS);
-  ceph_mon_feature_incompat.insert(CEPH_MON_FEATURE_INCOMPAT_OSD_ERASURE_CODES);
-  ceph_mon_feature_incompat.insert(CEPH_MON_FEATURE_INCOMPAT_OSDMAP_ENC);
-  ceph_mon_feature_incompat.insert(CEPH_MON_FEATURE_INCOMPAT_ERASURE_CODE_PLUGINS_V2);
   return CompatSet(ceph_mon_feature_compat, ceph_mon_feature_ro_compat,
                   ceph_mon_feature_incompat);
 }
 
+CompatSet Monitor::get_supported_features()
+{
+  CompatSet compat = get_initial_supported_features();
+  compat.incompat.insert(CEPH_MON_FEATURE_INCOMPAT_OSD_ERASURE_CODES);
+  compat.incompat.insert(CEPH_MON_FEATURE_INCOMPAT_OSDMAP_ENC);
+  compat.incompat.insert(CEPH_MON_FEATURE_INCOMPAT_ERASURE_CODE_PLUGINS_V2);
+  return compat;
+}
+
 CompatSet Monitor::get_legacy_features()
 {
   CompatSet::FeatureSet ceph_mon_feature_compat;
@@ -4237,7 +4243,7 @@ int Monitor::mkfs(bufferlist& osdmapbl)
   t->put(MONITOR_NAME, "magic", magicbl);
 
 
-  features = get_supported_features();
+  features = get_initial_supported_features();
   write_features(t);
 
   // save monmap, osdmap, keyring.

diff --git a/src/mon/Monitor.h b/src/mon/Monitor.h
index d60d46dfabb79264ff64a50fcdc3bba4036a2015..657aece3b34c3edb61750714f1334fa655461481 100644 (file)
--- a/src/mon/Monitor.h
+++ b/src/mon/Monitor.h
@@ -796,6 +796,7 @@ public:
   void extract_save_mon_key(KeyRing& keyring);
 
   // features
+  static CompatSet get_initial_supported_features();
   static CompatSet get_supported_features();
   static CompatSet get_legacy_features();
   /// read the ondisk features into the CompatSet pointed to by read_features