HDFS-8546. Use try with resources in DataStorage and Storage.

(cherry picked from commit 1403b84b122fb76ef2b085a728b5402c32499c1f)

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

@@ -338,6 +338,8 @@ Release 2.8.0 - UNRELEASED
 
     HDFS-8665. Fix replication check in DFSTestUtils#waitForReplication. (wang)
 
+    HDFS-8546. Use try with resources in DataStorage and Storage. (wang)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/Storage.java

@@ -709,6 +709,7 @@ public abstract class Storage extends StorageInfo {
       try {
         res = file.getChannel().tryLock();
         if (null == res) {
+          LOG.error("Unable to acquire file lock on path " + lockF.toString());
           throw new OverlappingFileLockException();
         }
         file.write(jvmName.getBytes(Charsets.UTF_8));
@@ -971,35 +972,28 @@ public abstract class Storage extends StorageInfo {
   public void writeProperties(File to, StorageDirectory sd) throws IOException {
     Properties props = new Properties();
     setPropertiesFromFields(props, sd);
-    writeProperties(to, sd, props);
+    writeProperties(to, props);
   }
 
-  public static void writeProperties(File to, StorageDirectory sd,
-      Properties props) throws IOException {
-    RandomAccessFile file = new RandomAccessFile(to, "rws");
-    FileOutputStream out = null;
-    try {
+  public static void writeProperties(File to, Properties props)
+      throws IOException {
+    try (RandomAccessFile file = new RandomAccessFile(to, "rws");
+        FileOutputStream out = new FileOutputStream(file.getFD())) {
       file.seek(0);
-      out = new FileOutputStream(file.getFD());
       /*
-       * If server is interrupted before this line, 
+       * If server is interrupted before this line,
        * the version file will remain unchanged.
        */
       props.store(out, null);
       /*
-       * Now the new fields are flushed to the head of the file, but file 
-       * length can still be larger then required and therefore the file can 
+       * Now the new fields are flushed to the head of the file, but file
+       * length can still be larger then required and therefore the file can
        * contain whole or corrupted fields from its old contents in the end.
        * If server is interrupted here and restarted later these extra fields
        * either should not effect server behavior or should be handled
        * by the server correctly.
        */
       file.setLength(out.getChannel().position());
-    } finally {
-      if (out != null) {
-        out.close();
-      }
-      file.close();
     }
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataStorage.java

@@ -44,17 +44,15 @@ import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.common.StorageInfo;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
 import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
-import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.io.nativeio.NativeIO;
 import org.apache.hadoop.util.Daemon;
 import org.apache.hadoop.util.DiskChecker;
 
 import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -82,7 +80,6 @@ import java.util.concurrent.Future;
 public class DataStorage extends Storage {
 
   public final static String BLOCK_SUBDIR_PREFIX = "subdir";
-  final static String COPY_FILE_PREFIX = "dncp_";
   final static String STORAGE_DIR_DETACHED = "detach";
   public final static String STORAGE_DIR_RBW = "rbw";
   public final static String STORAGE_DIR_FINALIZED = "finalized";
@@ -614,20 +611,22 @@ public class DataStorage extends Storage {
   @Override
   public boolean isPreUpgradableLayout(StorageDirectory sd) throws IOException {
     File oldF = new File(sd.getRoot(), "storage");
-    if (!oldF.exists())
+    if (!oldF.exists()) {
       return false;
+    }
     // check the layout version inside the storage file
     // Lock and Read old storage file
-    RandomAccessFile oldFile = new RandomAccessFile(oldF, "rws");
-    FileLock oldLock = oldFile.getChannel().tryLock();
-    try {
+    try (RandomAccessFile oldFile = new RandomAccessFile(oldF, "rws");
+      FileLock oldLock = oldFile.getChannel().tryLock()) {
+      if (null == oldLock) {
+        LOG.error("Unable to acquire file lock on path " + oldF.toString());
+        throw new OverlappingFileLockException();
+      }
       oldFile.seek(0);
       int oldVersion = oldFile.readInt();
-      if (oldVersion < LAST_PRE_UPGRADE_LAYOUT_VERSION)
+      if (oldVersion < LAST_PRE_UPGRADE_LAYOUT_VERSION) {
         return false;
-    } finally {
-      oldLock.release();
-      oldFile.close();
+      }
     }
     return true;
   }
@@ -1218,23 +1217,8 @@ public class DataStorage extends Storage {
       return;
     }
     if (!from.isDirectory()) {
-      if (from.getName().startsWith(COPY_FILE_PREFIX)) {
-        FileInputStream in = new FileInputStream(from);
-        try {
-          FileOutputStream out = new FileOutputStream(to);
-          try {
-            IOUtils.copyBytes(in, out, 16*1024);
-            hl.linkStats.countPhysicalFileCopies++;
-          } finally {
-            out.close();
-          }
-        } finally {
-          in.close();
-        }
-      } else {
-        HardLink.createHardLink(from, to);
-        hl.linkStats.countSingleLinks++;
-      }
+      HardLink.createHardLink(from, to);
+      hl.linkStats.countSingleLinks++;
       return;
     }
     // from is a directory
@@ -1285,8 +1269,7 @@ public class DataStorage extends Storage {
     String[] otherNames = from.list(new java.io.FilenameFilter() {
         @Override
         public boolean accept(File dir, String name) {
-          return name.startsWith(BLOCK_SUBDIR_PREFIX) 
-            || name.startsWith(COPY_FILE_PREFIX);
+          return name.startsWith(BLOCK_SUBDIR_PREFIX);
         }
       });
     for(int i = 0; i < otherNames.length; i++)