svn merge -c 1344419 from trunk for HDFS-744. Support hsync in HDFS.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1346056 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/CreateFlag.java

@@ -44,6 +44,9 @@ import org.apache.hadoop.classification.InterfaceStability;
  * else append to an existing file.</li>
  * <li> CREATE|OVERWRITE - to create a file if it does not exist, 
  * else overwrite an existing file.</li>
+ * <li> SYNC_BLOCK - to force closed blocks to the disk device.
+ * In addition {@link Syncable#hsync()} should be called after each write,
+ * if true synchronous behavior is required.</li>
  * </ol>
  * 
  * Following combination is not valid and will result in 
@@ -71,7 +74,12 @@ public enum CreateFlag {
   /**
    * Append to a file. See javadoc for more description.
    */
-  APPEND((short) 0x04);
+  APPEND((short) 0x04),
+
+  /**
+   * Force closed blocks to disk. Similar to POSIX O_SYNC. See javadoc for description.
+   */
+  SYNC_BLOCK((short) 0x08);
 
   private final short mode;
 

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java

@@ -830,6 +830,30 @@ public abstract class FileSystem extends Configured implements Closeable {
       long blockSize,
       Progressable progress) throws IOException;
   
+  /**
+   * Create an FSDataOutputStream at the indicated Path with write-progress
+   * reporting.
+   * @param f the file name to open
+   * @param permission
+   * @param flags {@link CreateFlag}s to use for this stream.
+   * @param bufferSize the size of the buffer to be used.
+   * @param replication required block replication for the file.
+   * @param blockSize
+   * @param progress
+   * @throws IOException
+   * @see #setPermission(Path, FsPermission)
+   */
+  public FSDataOutputStream create(Path f,
+      FsPermission permission,
+      EnumSet<CreateFlag> flags,
+      int bufferSize,
+      short replication,
+      long blockSize,
+      Progressable progress) throws IOException {
+    // only DFS support this
+    return create(f, permission, flags.contains(CreateFlag.OVERWRITE), bufferSize, replication, blockSize, progress);
+  }
+  
   
   /*.
    * This create has been added to support the FileContext that processes
@@ -954,10 +978,35 @@ public abstract class FileSystem extends Configured implements Closeable {
    public FSDataOutputStream createNonRecursive(Path f, FsPermission permission,
        boolean overwrite, int bufferSize, short replication, long blockSize,
        Progressable progress) throws IOException {
-     throw new IOException("createNonRecursive unsupported for this filesystem "
+     return createNonRecursive(f, permission,
-         + this.getClass());
+         overwrite ? EnumSet.of(CreateFlag.CREATE, CreateFlag.OVERWRITE)
+             : EnumSet.of(CreateFlag.CREATE), bufferSize,
+             replication, blockSize, progress);
    }
 
+   /**
+    * Opens an FSDataOutputStream at the indicated Path with write-progress
+    * reporting. Same as create(), except fails if parent directory doesn't
+    * already exist.
+    * @param f the file name to open
+    * @param permission
+    * @param flags {@link CreateFlag}s to use for this stream.
+    * @param bufferSize the size of the buffer to be used.
+    * @param replication required block replication for the file.
+    * @param blockSize
+    * @param progress
+    * @throws IOException
+    * @see #setPermission(Path, FsPermission)
+    * @deprecated API only for 0.20-append
+    */
+    @Deprecated
+    public FSDataOutputStream createNonRecursive(Path f, FsPermission permission,
+        EnumSet<CreateFlag> flags, int bufferSize, short replication, long blockSize,
+        Progressable progress) throws IOException {
+      throw new IOException("createNonRecursive unsupported for this filesystem "
+          + this.getClass());
+    }
+
   /**
    * Creates the given Path as a brand-new zero-length file.  If
    * create fails, or if it already existed, return false.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/SequenceFile.java

@@ -807,7 +807,7 @@ public class SequenceFile {
   }
   
   /** Write key/value pairs to a sequence-format file. */
-  public static class Writer implements java.io.Closeable {
+  public static class Writer implements java.io.Closeable, Syncable {
     private Configuration conf;
     FSDataOutputStream out;
     boolean ownOutputStream = true;
@@ -1193,13 +1193,31 @@ public class SequenceFile {
       }
     }
 
-    /** flush all currently written data to the file system */
+    /**
+     * flush all currently written data to the file system
+     * @deprecated Use {@link #hsync()} or {@link #hflush()} instead
+     */
+    @Deprecated
     public void syncFs() throws IOException {
       if (out != null) {
         out.sync();                               // flush contents to file system
       }
     }
 
+    @Override
+    public void hsync() throws IOException {
+      if (out != null) {
+        out.hsync();
+      }
+    }
+
+    @Override
+    public void hflush() throws IOException {
+      if (out != null) {
+        out.hflush();
+      }
+    }
+    
     /** Returns the configuration of this file. */
     Configuration getConf() { return conf; }
     

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFilterFileSystem.java

@@ -74,6 +74,11 @@ public class TestFilterFileSystem {
         Progressable progress) throws IOException {
       return null;
     }
+    public FSDataOutputStream createNonRecursive(Path f, FsPermission permission,
+            EnumSet<CreateFlag> flags, int bufferSize, short replication, long blockSize,
+            Progressable progress) throws IOException {
+      return null;
+    }
     public boolean mkdirs(Path f) { return false; }
     public FSDataInputStream open(Path f) { return null; }
     public FSDataOutputStream create(Path f) { return null; }
@@ -123,6 +128,15 @@ public class TestFilterFileSystem {
         Progressable progress) {
       return null;
     }
+    public FSDataOutputStream create(Path f,
+        FsPermission permission,
+        EnumSet<CreateFlag> flags,
+        int bufferSize,
+        short replication,
+        long blockSize,
+        Progressable progress) throws IOException {
+      return null;
+    }
     public String getName() { return null; }
     public boolean delete(Path f) { return false; }
     public short getReplication(Path src) { return 0 ; }