From 13c5881f3ec697f53ec44449c66df8f39323d513 Mon Sep 17 00:00:00 2001
From: Boaz Leskes <b.leskes@gmail.com>
Date: Thu, 22 Dec 2016 18:45:44 +0100
Subject: [PATCH] UnicastZenPing's PingingRound should prevent opening
 connections after being closed

This may cause them to leak. Provisioning for it was made in #22277 but sadly a crucial ensureOpen call was forgotten
---
 .../java/org/elasticsearch/discovery/zen/UnicastZenPing.java  | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/org/elasticsearch/discovery/zen/UnicastZenPing.java b/core/src/main/java/org/elasticsearch/discovery/zen/UnicastZenPing.java
index 8018c47b4e1..4e2ed19f422 100644
--- a/core/src/main/java/org/elasticsearch/discovery/zen/UnicastZenPing.java
+++ b/core/src/main/java/org/elasticsearch/discovery/zen/UnicastZenPing.java
@@ -385,12 +385,14 @@ public class UnicastZenPing extends AbstractComponent implements ZenPing {
             try (Releasable ignore = connectionLock.acquire(node.getAddress())) {
                 result = tempConnections.get(node.getAddress());
                 if (result == null) {
+                    ensureOpen();
                     boolean success = false;
                     result = transportService.openConnection(node, connectionProfile);
                     try {
                         transportService.handshake(result, connectionProfile.getHandshakeTimeout().millis());
                         synchronized (this) {
-                            // acquire lock to prevent concurrent closing
+                            // acquire lock and check if closed, to prevent leaving an open connection after closing
+                            ensureOpen();
                             Connection existing = tempConnections.put(node.getAddress(), result);
                             assert existing == null;
                             success = true;