Revert "HDFS-14111. hdfsOpenFile on HDFS causes unnecessary IO from file offset 0. Contributed by Sahil Takiar."

This reverts commit f5a4b43a49.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java

@@ -740,7 +740,6 @@ public class CryptoInputStream extends FilterInputStream implements
     case StreamCapabilities.READAHEAD:
     case StreamCapabilities.DROPBEHIND:
     case StreamCapabilities.UNBUFFER:
-    case StreamCapabilities.READBYTEBUFFER:
       return true;
     default:
       return false;

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

@@ -1,64 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.fs;
-
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.classification.InterfaceStability;
-
-import java.io.IOException;
-import java.nio.ByteBuffer;
-
-/**
- * Implementers of this interface provide a positioned read API that writes to a
- * {@link ByteBuffer} rather than a {@code byte[]}.
- *
- * @see PositionedReadable
- * @see ByteBufferReadable
- */
-@InterfaceAudience.Public
-@InterfaceStability.Evolving
-public interface ByteBufferPositionedReadable {
-  /**
-   * Reads up to {@code buf.remaining()} bytes into buf from a given position
-   * in the file and returns the number of bytes read. Callers should use
-   * {@code buf.limit(...)} to control the size of the desired read and
-   * {@code buf.position(...)} to control the offset into the buffer the data
-   * should be written to.
-   * <p>
-   * After a successful call, {@code buf.position()} will be advanced by the
-   * number of bytes read and {@code buf.limit()} should be unchanged.
-   * <p>
-   * In the case of an exception, the values of {@code buf.position()} and
-   * {@code buf.limit()} are undefined, and callers should be prepared to
-   * recover from this eventuality.
-   * <p>
-   * Many implementations will throw {@link UnsupportedOperationException}, so
-   * callers that are not confident in support for this method from the
-   * underlying filesystem should be prepared to handle that exception.
-   * <p>
-   * Implementations should treat 0-length requests as legitimate, and must not
-   * signal an error upon their receipt.
-   *
-   * @param position position within file
-   * @param buf the ByteBuffer to receive the results of the read operation.
-   * @return the number of bytes read, possibly zero, or -1 if reached
-   *         end-of-stream
-   * @throws IOException if there is some error performing the read
-   */
-  int read(long position, ByteBuffer buf) throws IOException;
-}

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

@@ -59,12 +59,6 @@ public interface StreamCapabilities {
    */
   String UNBUFFER = "in:unbuffer";
 
-  /**
-   * Stream read(ByteBuffer) capability implemented by
-   * {@link ByteBufferReadable#read(java.nio.ByteBuffer)}.
-   */
-  String READBYTEBUFFER = "in:readbytebuffer";
-
   /**
    * Capabilities that a stream can support and be queried for.
    */

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java

@@ -1779,7 +1779,6 @@ public class DFSInputStream extends FSInputStream
     case StreamCapabilities.READAHEAD:
     case StreamCapabilities.DROPBEHIND:
     case StreamCapabilities.UNBUFFER:
-    case StreamCapabilities.READBYTEBUFFER:
       return true;
     default:
       return false;

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/hdfs.c

@@ -1013,7 +1013,7 @@ static hdfsFile hdfsOpenFileImpl(hdfsFS fs, const char *path, int flags,
        return f{is|os};
     */
     int accmode = flags & O_ACCMODE;
-    jstring jStrBufferSize = NULL, jStrReplication = NULL, jCapabilityString = NULL;
+    jstring jStrBufferSize = NULL, jStrReplication = NULL;
     jobject jConfiguration = NULL, jPath = NULL, jFile = NULL;
     jobject jFS = (jobject)fs;
     jthrowable jthr;
@@ -1171,22 +1171,16 @@ static hdfsFile hdfsOpenFileImpl(hdfsFS fs, const char *path, int flags,
     file->flags = 0;
 
     if ((flags & O_WRONLY) == 0) {
-        // Check the StreamCapabilities of jFile to see if we can do direct reads
+        // Try a test read to see if we can do direct reads
-        jthr = newJavaStr(env, "in:readbytebuffer", &jCapabilityString);
+        char buf;
-        if (jthr) {
+        if (readDirect(fs, file, &buf, 0) == 0) {
-            ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+            // Success - 0-byte read should return 0
-                                        "hdfsOpenFile(%s): newJavaStr", path);
-            goto done;
-        }
-        jthr = invokeMethod(env, &jVal, INSTANCE, jFile, HADOOP_ISTRM,
-                            "hasCapability", "(Ljava/lang/String;)Z", jCapabilityString);
-        if (jthr) {
-            ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
-                                        "hdfsOpenFile(%s): FSDataInputStream#hasCapability", path);
-            goto done;
-        }
-        if (jVal.z) {
             file->flags |= HDFS_FILE_SUPPORTS_DIRECT_READ;
+        } else if (errno != ENOTSUP) {
+            // Unexpected error. Clear it, don't set the direct flag.
+            fprintf(stderr,
+                  "hdfsOpenFile(%s): WARN: Unexpected error %d when testing "
+                  "for direct read compatibility\n", path, errno);
         }
     }
     ret = 0;
@@ -1197,7 +1191,6 @@ done:
     destroyLocalReference(env, jConfiguration); 
     destroyLocalReference(env, jPath); 
     destroyLocalReference(env, jFile); 
-    destroyLocalReference(env, jCapabilityString);
     if (ret) {
         if (file) {
             if (file->file) {

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc

@@ -503,10 +503,7 @@ TEST_F(HdfsExtTest, TestReadStats) {
   hdfsFileFreeReadStatistics(stats);
 
   EXPECT_EQ(0, hdfsCloseFile(fs, file));
-  // Since libhdfs is not guaranteed to set errno to 0 on successful
+  EXPECT_EQ(0, errno);
-  // operations, we disable this check for now, see HDFS-14325 for a
-  // long term solution to this problem
-  // EXPECT_EQ(0, errno);
 }
 
 //Testing working directory

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/AddBlockPoolException.java

@@ -1,27 +0,0 @@
-package org.apache.hadoop.hdfs.server.datanode.fsdataset.impl;
-
-import java.io.IOException;
-import java.util.Map;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
-
-/**
- * This exception collects all IOExceptions thrown when adding block pools and
- * scanning volumes. It keeps the information about which volume is associated
- * with an exception.
- *
- */
-public class AddBlockPoolException extends IOException {
-  private Map<FsVolumeSpi, IOException> unhealthyDataDirs;
-  public AddBlockPoolException(Map<FsVolumeSpi, IOException>
-      unhealthyDataDirs) {
-    this.unhealthyDataDirs = unhealthyDataDirs;
-  }
-
-  public Map<FsVolumeSpi, IOException> getFailingVolumes() {
-    return unhealthyDataDirs;
-  }
-  @Override
-  public String toString() {
-    return getClass().getName() + ": " + unhealthyDataDirs.toString();
-  }
-}

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

@@ -1,269 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.hdfs;
-
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FSDataInputStream;
-import org.apache.hadoop.fs.FSDataOutputStream;
-import org.apache.hadoop.fs.FileSystem;
-import org.apache.hadoop.fs.Path;
-
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
-
-import java.io.IOException;
-import java.nio.ByteBuffer;
-import java.util.Arrays;
-import java.util.Random;
-
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-/**
- * This class tests the DFS positional read functionality on a single node
- * mini-cluster. These tests are inspired from {@link TestPread}. The tests
- * are much less comprehensive than other pread tests because pread already
- * internally uses {@link ByteBuffer}s.
- */
-public class TestByteBufferPread {
-
-  private static MiniDFSCluster cluster;
-  private static FileSystem fs;
-  private static byte[] fileContents;
-  private static Path testFile;
-  private static Random rand;
-
-  private static final long SEED = 0xDEADBEEFL;
-  private static final int BLOCK_SIZE = 4096;
-  private static final int FILE_SIZE = 12 * BLOCK_SIZE;
-
-  @BeforeClass
-  public static void setup() throws IOException {
-    // Setup the cluster with a small block size so we can create small files
-    // that span multiple blocks
-    Configuration conf = new Configuration();
-    conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
-    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(3).build();
-    fs = cluster.getFileSystem();
-
-    // Create a test file that spans 12 blocks, and contains a bunch of random
-    // bytes
-    fileContents = new byte[FILE_SIZE];
-    rand = new Random(SEED);
-    rand.nextBytes(fileContents);
-    testFile = new Path("/byte-buffer-pread-test.dat");
-    try (FSDataOutputStream out = fs.create(testFile, (short) 3)) {
-      out.write(fileContents);
-    }
-  }
-
-  /**
-   * Test preads with {@link java.nio.HeapByteBuffer}s.
-   */
-  @Test
-  public void testPreadWithHeapByteBuffer() throws IOException {
-    testPreadWithByteBuffer(ByteBuffer.allocate(FILE_SIZE));
-    testPreadWithFullByteBuffer(ByteBuffer.allocate(FILE_SIZE));
-    testPreadWithPositionedByteBuffer(ByteBuffer.allocate(FILE_SIZE));
-    testPreadWithLimitedByteBuffer(ByteBuffer.allocate(FILE_SIZE));
-    testPositionedPreadWithByteBuffer(ByteBuffer.allocate(FILE_SIZE));
-  }
-
-  /**
-   * Test preads with {@link java.nio.DirectByteBuffer}s.
-   */
-  @Test
-  public void testPreadWithDirectByteBuffer() throws IOException {
-    testPreadWithByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
-    testPreadWithFullByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
-    testPreadWithPositionedByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
-    testPreadWithLimitedByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
-    testPositionedPreadWithByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
-  }
-
-  /**
-   * Reads the entire testFile using the pread API and validates that its
-   * contents are properly loaded into the supplied {@link ByteBuffer}.
-   */
-  private void testPreadWithByteBuffer(ByteBuffer buffer) throws IOException {
-    int bytesRead;
-    int totalBytesRead = 0;
-    try (FSDataInputStream in = fs.open(testFile)) {
-      while ((bytesRead = in.read(totalBytesRead, buffer)) > 0) {
-        totalBytesRead += bytesRead;
-        // Check that each call to read changes the position of the ByteBuffer
-        // correctly
-        assertEquals(totalBytesRead, buffer.position());
-      }
-
-      // Make sure the buffer is full
-      assertFalse(buffer.hasRemaining());
-      // Make sure the contents of the read buffer equal the contents of the
-      // file
-      buffer.position(0);
-      byte[] bufferContents = new byte[FILE_SIZE];
-      buffer.get(bufferContents);
-      assertArrayEquals(bufferContents, fileContents);
-      buffer.position(buffer.limit());
-    }
-  }
-
-  /**
-   * Attempts to read the testFile into a {@link ByteBuffer} that is already
-   * full, and validates that doing so does not change the contents of the
-   * supplied {@link ByteBuffer}.
-   */
-  private void testPreadWithFullByteBuffer(ByteBuffer buffer)
-          throws IOException {
-    // Load some dummy data into the buffer
-    byte[] existingBufferBytes = new byte[FILE_SIZE];
-    rand.nextBytes(existingBufferBytes);
-    buffer.put(existingBufferBytes);
-    // Make sure the buffer is full
-    assertFalse(buffer.hasRemaining());
-
-    try (FSDataInputStream in = fs.open(testFile)) {
-      // Attempt to read into the buffer, 0 bytes should be read since the
-      // buffer is full
-      assertEquals(0, in.read(buffer));
-
-      // Double check the buffer is still full and its contents have not
-      // changed
-      assertFalse(buffer.hasRemaining());
-      buffer.position(0);
-      byte[] bufferContents = new byte[FILE_SIZE];
-      buffer.get(bufferContents);
-      assertArrayEquals(bufferContents, existingBufferBytes);
-    }
-  }
-
-  /**
-   * Reads half of the testFile into the {@link ByteBuffer} by setting a
-   * {@link ByteBuffer#limit} on the buffer. Validates that only half of the
-   * testFile is loaded into the buffer.
-   */
-  private void testPreadWithLimitedByteBuffer(
-          ByteBuffer buffer) throws IOException {
-    int bytesRead;
-    int totalBytesRead = 0;
-    // Set the buffer limit to half the size of the file
-    buffer.limit(FILE_SIZE / 2);
-
-    try (FSDataInputStream in = fs.open(testFile)) {
-      while ((bytesRead = in.read(totalBytesRead, buffer)) > 0) {
-        totalBytesRead += bytesRead;
-        // Check that each call to read changes the position of the ByteBuffer
-        // correctly
-        assertEquals(totalBytesRead, buffer.position());
-      }
-
-      // Since we set the buffer limit to half the size of the file, we should
-      // have only read half of the file into the buffer
-      assertEquals(totalBytesRead, FILE_SIZE / 2);
-      // Check that the buffer is full and the contents equal the first half of
-      // the file
-      assertFalse(buffer.hasRemaining());
-      buffer.position(0);
-      byte[] bufferContents = new byte[FILE_SIZE / 2];
-      buffer.get(bufferContents);
-      assertArrayEquals(bufferContents,
-              Arrays.copyOfRange(fileContents, 0, FILE_SIZE / 2));
-    }
-  }
-
-  /**
-   * Reads half of the testFile into the {@link ByteBuffer} by setting the
-   * {@link ByteBuffer#position} the half the size of the file. Validates that
-   * only half of the testFile is loaded into the buffer.
-   */
-  private void testPreadWithPositionedByteBuffer(
-          ByteBuffer buffer) throws IOException {
-    int bytesRead;
-    int totalBytesRead = 0;
-    // Set the buffer position to half the size of the file
-    buffer.position(FILE_SIZE / 2);
-
-    try (FSDataInputStream in = fs.open(testFile)) {
-      while ((bytesRead = in.read(totalBytesRead, buffer)) > 0) {
-        totalBytesRead += bytesRead;
-        // Check that each call to read changes the position of the ByteBuffer
-        // correctly
-        assertEquals(totalBytesRead + FILE_SIZE / 2, buffer.position());
-      }
-
-      // Since we set the buffer position to half the size of the file, we
-      // should have only read half of the file into the buffer
-      assertEquals(totalBytesRead, FILE_SIZE / 2);
-      // Check that the buffer is full and the contents equal the first half of
-      // the file
-      assertFalse(buffer.hasRemaining());
-      buffer.position(FILE_SIZE / 2);
-      byte[] bufferContents = new byte[FILE_SIZE / 2];
-      buffer.get(bufferContents);
-      assertArrayEquals(bufferContents,
-              Arrays.copyOfRange(fileContents, 0, FILE_SIZE / 2));
-    }
-  }
-
-  /**
-   * Reads half of the testFile into the {@link ByteBuffer} by specifying a
-   * position for the pread API that is half of the file size. Validates that
-   * only half of the testFile is loaded into the buffer.
-   */
-  private void testPositionedPreadWithByteBuffer(
-          ByteBuffer buffer) throws IOException {
-    int bytesRead;
-    int totalBytesRead = 0;
-
-    try (FSDataInputStream in = fs.open(testFile)) {
-      // Start reading from halfway through the file
-      while ((bytesRead = in.read(totalBytesRead + FILE_SIZE / 2,
-              buffer)) > 0) {
-        totalBytesRead += bytesRead;
-        // Check that each call to read changes the position of the ByteBuffer
-        // correctly
-        assertEquals(totalBytesRead, buffer.position());
-      }
-
-      // Since we starting reading halfway through the file, the buffer should
-      // only be half full
-      assertEquals(totalBytesRead, FILE_SIZE / 2);
-      assertEquals(buffer.position(), FILE_SIZE / 2);
-      assertTrue(buffer.hasRemaining());
-      // Check that the buffer contents equal the second half of the file
-      buffer.position(0);
-      byte[] bufferContents = new byte[FILE_SIZE / 2];
-      buffer.get(bufferContents);
-      assertArrayEquals(bufferContents,
-              Arrays.copyOfRange(fileContents, FILE_SIZE / 2, FILE_SIZE));
-    }
-  }
-
-  @AfterClass
-  public static void shutdown() throws IOException {
-    try {
-      fs.delete(testFile, false);
-      fs.close();
-    } finally {
-      cluster.shutdown(true);
-    }
-  }
-}