From f70f7e34470142437f2e4f2c7ef78fa7711858aa Mon Sep 17 00:00:00 2001
From: Oleg Zhurakousky <oleg@suitcase.io>
Date: Wed, 23 Dec 2015 15:41:54 -0500
Subject: [PATCH] NIFI-1333 fixed FlowController shutdown deadlock. put read
 lock back. This closes #148

Signed-off-by: Matt Gilman <matt.c.gilman@gmail.com>
---
 .../nifi/controller/FlowController.java       | 27 ++++++++++++-------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/FlowController.java b/nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/FlowController.java
index 0cab9ad90f..04b48dd1da 100644
--- a/nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/FlowController.java
+++ b/nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/FlowController.java
@@ -1086,7 +1086,7 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
         this.shutdown = true;
         stopAllProcessors();
 
-        writeLock.lock();
+        readLock.lock();
         try {
             if (isTerminated() || timerDrivenEngineRef.get().isTerminating()) {
                 throw new IllegalStateException("Controller already stopped or still stopping...");
@@ -1099,19 +1099,24 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
             } else {
                 this.timerDrivenEngineRef.get().shutdown();
                 this.eventDrivenEngineRef.get().shutdown();
-                LOG.info("Initiated graceful shutdown of flow controller...waiting up to " + gracefulShutdownSeconds + " seconds");
+                LOG.info("Initiated graceful shutdown of flow controller...waiting up to " + gracefulShutdownSeconds
+                        + " seconds");
             }
 
             clusterTaskExecutor.shutdown();
 
-            // Trigger any processors' methods marked with @OnShutdown to be called
+            // Trigger any processors' methods marked with @OnShutdown to be
+            // called
             rootGroup.shutdown();
 
-            // invoke any methods annotated with @OnShutdown on Controller Services
+            // invoke any methods annotated with @OnShutdown on Controller
+            // Services
             for (final ControllerServiceNode serviceNode : getAllControllerServices()) {
                 try (final NarCloseable narCloseable = NarCloseable.withNarLoader()) {
-                    final ConfigurationContext configContext = new StandardConfigurationContext(serviceNode, controllerServiceProvider, null);
-                    ReflectionUtils.quietlyInvokeMethodsWithAnnotation(OnShutdown.class, serviceNode.getControllerServiceImplementation(), configContext);
+                    final ConfigurationContext configContext = new StandardConfigurationContext(serviceNode,
+                            controllerServiceProvider, null);
+                    ReflectionUtils.quietlyInvokeMethodsWithAnnotation(OnShutdown.class,
+                            serviceNode.getControllerServiceImplementation(), configContext);
                 }
             }
 
@@ -1119,7 +1124,8 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
             for (final ReportingTaskNode taskNode : getAllReportingTasks()) {
                 final ConfigurationContext configContext = taskNode.getConfigurationContext();
                 try (final NarCloseable narCloseable = NarCloseable.withNarLoader()) {
-                    ReflectionUtils.quietlyInvokeMethodsWithAnnotation(OnShutdown.class, taskNode.getReportingTask(), configContext);
+                    ReflectionUtils.quietlyInvokeMethodsWithAnnotation(OnShutdown.class, taskNode.getReportingTask(),
+                            configContext);
                 }
             }
 
@@ -1133,14 +1139,14 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
             try {
                 flowFileRepository.close();
             } catch (final Throwable t) {
-                LOG.warn("Unable to shut down FlowFileRepository due to {}", new Object[] {t});
+                LOG.warn("Unable to shut down FlowFileRepository due to {}", new Object[] { t });
             }
 
             if (this.timerDrivenEngineRef.get().isTerminated() && eventDrivenEngineRef.get().isTerminated()) {
                 LOG.info("Controller has been terminated successfully.");
             } else {
                 LOG.warn("Controller hasn't terminated properly.  There exists an uninterruptable thread that "
-                    + "will take an indeterminate amount of time to stop.  Might need to kill the program manually.");
+                        + "will take an indeterminate amount of time to stop.  Might need to kill the program manually.");
             }
 
             if (externalSiteListener != null) {
@@ -1166,8 +1172,9 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
                 }
             }
         } finally {
-            writeLock.unlock();
+            readLock.unlock();
         }
+
     }
 
     /**