HDFS-12877. Add open(PathHandle) with default buffersize

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

@@ -951,6 +951,21 @@ public abstract class FileSystem extends Configured implements Closeable {
         IO_FILE_BUFFER_SIZE_DEFAULT));
   }
 
+  /**
+   * Open an FSDataInputStream matching the PathHandle instance. The
+   * implementation may encode metadata in PathHandle to address the
+   * resource directly and verify that the resource referenced
+   * satisfies constraints specified at its construciton.
+   * @param fd PathHandle object returned by the FS authority.
+   * @throws IOException IO failure
+   * @throws UnsupportedOperationException If {@link #open(PathHandle, int)}
+   *                                       not overridden by subclass
+   */
+  public FSDataInputStream open(PathHandle fd) throws IOException {
+    return open(fd, getConf().getInt(IO_FILE_BUFFER_SIZE_KEY,
+        IO_FILE_BUFFER_SIZE_DEFAULT));
+  }
+
   /**
    * Open an FSDataInputStream matching the PathHandle instance. The
    * implementation may encode metadata in PathHandle to address the

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

@@ -79,6 +79,7 @@ public class TestFilterFileSystem {
 
     public boolean mkdirs(Path f);
     public FSDataInputStream open(Path f);
+    public FSDataInputStream open(PathHandle f);
     public FSDataOutputStream create(Path f);
     public FSDataOutputStream create(Path f, boolean overwrite);
     public FSDataOutputStream create(Path f, Progressable progress);

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

@@ -80,6 +80,7 @@ public class TestHarFileSystem {
 
     public boolean mkdirs(Path f);
     public FSDataInputStream open(Path f);
+    public FSDataInputStream open(PathHandle f);
     public FSDataOutputStream create(Path f);
     public FSDataOutputStream create(Path f, boolean overwrite);
     public FSDataOutputStream create(Path f, Progressable progress);