From c143b9a3db4492e5a2ee7919b22581955fc2a119 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Mon, 1 Apr 2019 10:20:46 -0500
Subject: [PATCH] mon/MonMap: add min_quorum_size() helper

Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/mon/MonMap.h   | 7 +++++++
 src/mon/Monitor.cc | 8 ++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/mon/MonMap.h b/src/mon/MonMap.h
index 97db1e64c1c..e35a218cae0 100644
--- a/src/mon/MonMap.h
+++ b/src/mon/MonMap.h
@@ -166,6 +166,13 @@ public:
     return mon_info.size();
   }
 
+  unsigned min_quorum_size(unsigned total_mons=0) const {
+    if (total_mons == 0) {
+      total_mons = size();
+    }
+    return total_mons / 2 + 1;
+  }
+
   epoch_t get_epoch() const { return epoch; }
   void set_epoch(epoch_t e) { epoch = e; }
 
diff --git a/src/mon/Monitor.cc b/src/mon/Monitor.cc
index a670af6e456..328b42583ce 100644
--- a/src/mon/Monitor.cc
+++ b/src/mon/Monitor.cc
@@ -2046,7 +2046,7 @@ void Monitor::handle_probe_reply(MonOpRequestRef op)
       return;
     }
 
-    unsigned need = monmap->size() / 2 + 1;
+    unsigned need = monmap->min_quorum_size();
     dout(10) << " outside_quorum now " << outside_quorum << ", need " << need << dendl;
     if (outside_quorum.size() >= need) {
       if (outside_quorum.count(name)) {
@@ -3715,7 +3715,7 @@ void Monitor::handle_command(MonOpRequestRef op)
 	wouldbe.erase(n);
       }
     }
-    if (wouldbe.size() < monmap->size() / 2 + 1) {
+    if (wouldbe.size() < monmap->min_quorum_size()) {
       r = -EBUSY;
       rs = "not enough monitors would be available (" + stringify(wouldbe) +
 	") after stopping mons " + stringify(ids);
@@ -3725,7 +3725,7 @@ void Monitor::handle_command(MonOpRequestRef op)
     rs = "quorum should be preserved (" + stringify(wouldbe) +
       ") after stopping " + stringify(ids);
   } else if (prefix == "mon ok-to-add-offline") {
-    if (quorum.size() < (monmap->size() + 1) / 2 + 1) {
+    if (quorum.size() < monmap->min_quorum_size(monmap->size() + 1)) {
       rs = "adding a monitor may break quorum (until that monitor starts)";
       r = -EBUSY;
       goto out;
@@ -3746,7 +3746,7 @@ void Monitor::handle_command(MonOpRequestRef op)
     }
     int rank = monmap->get_rank(id);
     if (quorum.count(rank) &&
-	quorum.size() - 1 < (monmap->size() - 1) / 2 + 1) {
+	quorum.size() - 1 < monmap->min_quorum_size(monmap->size() - 1)) {
       r = -EBUSY;
       rs = "removing mon." + id + " would break quorum";
       goto out;
-- 
2.39.5