HDFS-3359. DFSClient.close should close cached sockets. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1334049 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -40,6 +40,8 @@ Release 0.23.3 - UNRELEASED
     HDFS-3331. In namenode, check superuser privilege for setBalancerBandwidth
     and acquire the write lock for finalizeUpgrade.  (szetszwo)
 
+    HDFS-3359. DFSClient.close should close cached sockets. (todd)
+
 Release 0.23.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -454,6 +454,7 @@ public class DFSClient implements java.io.Closeable {
   void abort() {
     clientRunning = false;
     closeAllFilesBeingWritten(true);
+    socketCache.clear();
     RPC.stopProxy(rpcNamenode); // close connections to the namenode
   }
 
@@ -491,6 +492,7 @@ public class DFSClient implements java.io.Closeable {
   public synchronized void close() throws IOException {
     if(clientRunning) {
       closeAllFilesBeingWritten(false);
+      socketCache.clear();
       clientRunning = false;
       leaserenewer.closeClient(this);
       // close connections to the namenode

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDistributedFileSystem.java

@@ -84,6 +84,7 @@ public class TestDistributedFileSystem {
   /**
    * Tests DFSClient.close throws no ConcurrentModificationException if 
    * multiple files are open.
+   * Also tests that any cached sockets are closed. (HDFS-3359)
    */
   @Test
   public void testDFSClose() throws Exception {
@@ -92,13 +93,24 @@ public class TestDistributedFileSystem {
     FileSystem fileSys = cluster.getFileSystem();
 
     try {
-      // create two files
+      // create two files, leaving them open
       fileSys.create(new Path("/test/dfsclose/file-0"));
       fileSys.create(new Path("/test/dfsclose/file-1"));
+      
+      // create another file, close it, and read it, so
+      // the client gets a socket in its SocketCache
+      Path p = new Path("/non-empty-file");
+      DFSTestUtil.createFile(fileSys, p, 1L, (short)1, 0L);
+      DFSTestUtil.readFile(fileSys, p);
+      
+      DFSClient client = ((DistributedFileSystem)fileSys).dfs;
+      SocketCache cache = client.socketCache;
+      assertEquals(1, cache.size());
 
       fileSys.close();
-    }
-    finally {
+      
+      assertEquals(0, cache.size());
+    } finally {
       if (cluster != null) {cluster.shutdown();}
     }
   }