[21/50] [abbrv] hadoop git commit: HADOOP-11333. Fix deadlock in DomainSocketWatcher when the notification pipe is full (zhaoyunjiong via cmccabe)

[vi...@apache.org]

HADOOP-11333. Fix deadlock in DomainSocketWatcher when the notification pipe is full (zhaoyunjiong via cmccabe)


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/86e3993d
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/86e3993d
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/86e3993d

Branch: refs/heads/HDFS-EC
Commit: 86e3993def01223f92b8d1dd35f6c1f8ab6033f5
Parents: c732ed7
Author: Colin Patrick Mccabe <cm...@cloudera.com>
Authored: Mon Dec 1 11:42:10 2014 -0800
Committer: Colin Patrick Mccabe <cm...@cloudera.com>
Committed: Mon Dec 1 11:42:10 2014 -0800

----------------------------------------------------------------------
 hadoop-common-project/hadoop-common/CHANGES.txt      |  3 +++
 .../apache/hadoop/net/unix/DomainSocketWatcher.java  | 15 +++++++++++++++
 2 files changed, 18 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hadoop/blob/86e3993d/hadoop-common-project/hadoop-common/CHANGES.txt
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diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 3fe9219..59ccba0 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -473,6 +473,9 @@ Release 2.7.0 - UNRELEASED
     HADOOP-11300. KMS startup scripts must not display the keystore /
     truststore passwords. (Arun Suresh via wang)
 
+    HADOOP-11333. Fix deadlock in DomainSocketWatcher when the notification
+    pipe is full (zhaoyunjiong via cmccabe)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES

http://git-wip-us.apache.org/repos/asf/hadoop/blob/86e3993d/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
----------------------------------------------------------------------
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
index 95ef30d..0172f6b 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
@@ -103,6 +103,7 @@ public final class DomainSocketWatcher implements Closeable {
     public boolean handle(DomainSocket sock) {
       assert(lock.isHeldByCurrentThread());
       try {
+        kicked = false;
         if (LOG.isTraceEnabled()) {
           LOG.trace(this + ": NotificationHandler: doing a read on " +
             sock.fd);
@@ -228,6 +229,14 @@ public final class DomainSocketWatcher implements Closeable {
    * Whether or not this DomainSocketWatcher is closed.
    */
   private boolean closed = false;
+  
+  /**
+   * True if we have written a byte to the notification socket. We should not
+   * write anything else to the socket until the notification handler has had a
+   * chance to run. Otherwise, our thread might block, causing deadlock. 
+   * See HADOOP-11333 for details.
+   */
+  private boolean kicked = false;
 
   public DomainSocketWatcher(int interruptCheckPeriodMs) throws IOException {
     if (loadingFailureReason != null) {
@@ -348,8 +357,14 @@ public final class DomainSocketWatcher implements Closeable {
    */
   private void kick() {
     assert(lock.isHeldByCurrentThread());
+    
+    if (kicked) {
+      return;
+    }
+    
     try {
       notificationSockets[0].getOutputStream().write(0);
+      kicked = true;
     } catch (IOException e) {
       if (!closed) {
         LOG.error(this + ": error writing to notificationSockets[0]", e);