HDFS-12528. Add an option to not disable short-circuit reads on failures. Contributed by Xiao Chen.

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

@@ -127,6 +127,9 @@ public interface HdfsClientConfigKeys {
   boolean DFS_CLIENT_DOMAIN_SOCKET_DATA_TRAFFIC_DEFAULT = false;
   String  DFS_DOMAIN_SOCKET_PATH_KEY = "dfs.domain.socket.path";
   String  DFS_DOMAIN_SOCKET_PATH_DEFAULT = "";
+  String DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY =
+      "dfs.domain.socket.disable.interval.seconds";
+  long DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_DEFAULT = 600;
   String  DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS =
       "dfs.short.circuit.shared.memory.watcher.interrupt.check.ms";
   int     DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS_DEFAULT =

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

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hdfs.client.impl;
 
+import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY;
 import static org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.ShortCircuitFdResponse.USE_RECEIPT_VERIFICATION;
 
 import java.io.BufferedOutputStream;
@@ -644,10 +645,17 @@ public class BlockReaderFactory implements ShortCircuitReplicaCreator {
       LOG.debug("{}:{}", this, msg);
       return new ShortCircuitReplicaInfo(new InvalidToken(msg));
     default:
-      LOG.warn(this + ": unknown response code " + resp.getStatus() +
-          " while attempting to set up short-circuit access. " +
-          resp.getMessage() + ". Disabling short-circuit read for DataNode "
-          + datanode + " temporarily.");
+      final long expiration =
+          clientContext.getDomainSocketFactory().getPathExpireSeconds();
+      String disableMsg = "disabled temporarily for " + expiration + " seconds";
+      if (expiration == 0) {
+        disableMsg = "not disabled";
+      }
+      LOG.warn("{}: unknown response code {} while attempting to set up "
+              + "short-circuit access. {}. Short-circuit read for "
+              + "DataNode {} is {} based on {}.",
+          this, resp.getStatus(), resp.getMessage(), datanode,
+          disableMsg, DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY);
       clientContext.getDomainSocketFactory()
           .disableShortCircuitForPath(pathInfo.getPath());
       return null;

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

@@ -68,6 +68,8 @@ import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_CLIENT_USE_
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_CLIENT_WRITE_PACKET_SIZE_DEFAULT;
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_CLIENT_WRITE_PACKET_SIZE_KEY;
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DATANODE_SOCKET_WRITE_TIMEOUT_KEY;
+import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_DEFAULT;
+import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY;
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_PATH_DEFAULT;
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY;
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_REPLICATION_DEFAULT;
@@ -602,6 +604,7 @@ public class DfsClientConf {
     private final long shortCircuitMmapCacheExpiryMs;
     private final long shortCircuitMmapCacheRetryTimeout;
     private final long shortCircuitCacheStaleThresholdMs;
+    private final long domainSocketDisableIntervalSeconds;
 
     private final long keyProviderCacheExpiryMs;
 
@@ -679,6 +682,11 @@ public class DfsClientConf {
       shortCircuitSharedMemoryWatcherInterruptCheckMs = conf.getInt(
           DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS,
           DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS_DEFAULT);
+      domainSocketDisableIntervalSeconds = conf.getLong(
+          DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY,
+          DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_DEFAULT);
+      Preconditions.checkArgument(domainSocketDisableIntervalSeconds >= 0,
+          DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY + "can't be negative.");
 
       keyProviderCacheExpiryMs = conf.getLong(
           DFS_CLIENT_KEY_PROVIDER_CACHE_EXPIRY_MS,
@@ -793,6 +801,13 @@ public class DfsClientConf {
       return shortCircuitCacheStaleThresholdMs;
     }
 
+    /**
+     * @return the domainSocketDisableIntervalSeconds
+     */
+    public long getDomainSocketDisableIntervalSeconds() {
+      return domainSocketDisableIntervalSeconds;
+    }
+
     /**
      * @return the keyProviderCacheExpiryMs
      */
@@ -827,7 +842,9 @@ public class DfsClientConf {
           + ", shortCircuitSharedMemoryWatcherInterruptCheckMs = "
           + shortCircuitSharedMemoryWatcherInterruptCheckMs
           + ", keyProviderCacheExpiryMs = "
-          + keyProviderCacheExpiryMs;
+          + keyProviderCacheExpiryMs
+          + ", domainSocketDisableIntervalSeconds = "
+          + domainSocketDisableIntervalSeconds;
     }
   }
 }

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

@@ -92,10 +92,8 @@ public class DomainSocketFactory {
   /**
    * Information about domain socket paths.
    */
-  final Cache<String, PathState> pathMap =
-      CacheBuilder.newBuilder()
-      .expireAfterWrite(10, TimeUnit.MINUTES)
-      .build();
+  private final long pathExpireSeconds;
+  private final Cache<String, PathState> pathMap;
 
   public DomainSocketFactory(ShortCircuitConf conf) {
     final String feature;
@@ -121,6 +119,10 @@ public class DomainSocketFactory {
         LOG.debug(feature + " is enabled.");
       }
     }
+
+    pathExpireSeconds = conf.getDomainSocketDisableIntervalSeconds();
+    pathMap = CacheBuilder.newBuilder()
+        .expireAfterWrite(pathExpireSeconds, TimeUnit.SECONDS).build();
   }
 
   /**
@@ -192,4 +194,8 @@ public class DomainSocketFactory {
   public void clearPathMap() {
     pathMap.invalidateAll();
   }
+
+  public long getPathExpireSeconds() {
+    return pathExpireSeconds;
+  }
 }

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

@@ -278,7 +278,7 @@ public class ShortCircuitCache implements Closeable {
    * Maximum total size of the cache, including both mmapped and
    * no$-mmapped elements.
    */
-  private final int maxTotalSize;
+  private int maxTotalSize;
 
   /**
    * Non-mmaped elements older than this will be closed.
@@ -369,6 +369,11 @@ public class ShortCircuitCache implements Closeable {
     return staleThresholdMs;
   }
 
+  @VisibleForTesting
+  public void setMaxTotalSize(int maxTotalSize) {
+    this.maxTotalSize = maxTotalSize;
+  }
+
   /**
    * Increment the reference count of a replica, and remove it from any free
    * list it may be in.
@@ -1025,4 +1030,13 @@ public class ShortCircuitCache implements Closeable {
   public DfsClientShmManager getDfsClientShmManager() {
     return shmManager;
   }
+
+  /**
+   * Can be used in testing to verify whether a read went through SCR, after
+   * the read is done and before the stream is closed.
+   */
+  @VisibleForTesting
+  public int getReplicaInfoMapSize() {
+    return replicaInfoMap.size();
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -2603,6 +2603,17 @@
   </description>
 </property>
 
+<property>
+  <name>dfs.domain.socket.disable.interval.seconds</name>
+  <value>600</value>
+  <description>
+    The interval that a DataNode is disabled for future Short-Circuit Reads,
+    after an error happens during a Short-Circuit Read. Setting this to 0 will
+    not disable Short-Circuit Reads at all after errors happen. Negative values
+    are invalid.
+  </description>
+</property>
+
 <property>
   <name>dfs.client.read.shortcircuit.skip.checksum</name>
   <value>false</value>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/client/impl/TestBlockReaderFactory.java

@@ -22,6 +22,8 @@ import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_CLIENT_CONT
 import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_CLIENT_DOMAIN_SOCKET_DATA_TRAFFIC;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS;
+import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_DEFAULT;
+import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY;
 import static org.hamcrest.CoreMatchers.equalTo;
 
 import java.io.File;
@@ -36,9 +38,8 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.BlockReader;
@@ -54,18 +55,29 @@ import org.apache.hadoop.hdfs.shortcircuit.DfsClientShmManager.PerDatanodeVisito
 import org.apache.hadoop.hdfs.shortcircuit.DfsClientShmManager.Visitor;
 import org.apache.hadoop.hdfs.shortcircuit.ShortCircuitCache;
 import org.apache.hadoop.hdfs.shortcircuit.ShortCircuitReplicaInfo;
+import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.net.unix.DomainSocket;
 import org.apache.hadoop.net.unix.TemporarySocketDirectory;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.hamcrest.CoreMatchers;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Assume;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 
 import com.google.common.util.concurrent.Uninterruptibles;
+import org.junit.rules.Timeout;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class TestBlockReaderFactory {
-  static final Log LOG = LogFactory.getLog(TestBlockReaderFactory.class);
+  static final Logger LOG =
+      LoggerFactory.getLogger(TestBlockReaderFactory.class);
+
+  @Rule
+  public final Timeout globalTimeout = new Timeout(180000);
 
   @Before
   public void init() {
@@ -209,7 +221,7 @@ public class TestBlockReaderFactory {
    * occurs);  however, the failure result should not be cached.  We want
    * to be able to retry later and succeed.
    */
-  @Test(timeout=60000)
+  @Test
   public void testShortCircuitCacheTemporaryFailure()
       throws Exception {
     BlockReaderTestUtil.enableBlockReaderFactoryTracing();
@@ -302,7 +314,96 @@ public class TestBlockReaderFactory {
     Assert.assertFalse(testFailed.get());
   }
 
-   /**
+  /**
+   * Test that by default, reads after a failure does not go through SCR.
+   */
+  @Test
+  public void testShortCircuitCacheUnbufferDefault() throws Exception {
+    testShortCircuitCacheUnbufferWithDisableInterval(
+        DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_DEFAULT, true);
+  }
+  /**
+   * Test the case where if we disable the cache in
+   * {@link org.apache.hadoop.hdfs.shortcircuit.DomainSocketFactory}, reads
+   * after a failure still goes through SCR.
+   */
+  @Test
+  public void testShortCircuitCacheUnbufferDisabled() throws Exception {
+    testShortCircuitCacheUnbufferWithDisableInterval(0, false);
+  }
+
+  private void testShortCircuitCacheUnbufferWithDisableInterval(
+      final long interval, final boolean disabled) throws Exception {
+    final String testName = GenericTestUtils.getMethodName();
+    BlockReaderTestUtil.enableBlockReaderFactoryTracing();
+    try (TemporarySocketDirectory sockDir = new TemporarySocketDirectory()) {
+      Configuration conf = createShortCircuitConf(testName, sockDir);
+      conf.set(DFS_CLIENT_CONTEXT, testName + interval + disabled);
+      conf.setLong(DFS_DOMAIN_SOCKET_DISABLE_INTERVAL_SECOND_KEY, interval);
+      Configuration serverConf = new Configuration(conf);
+      MiniDFSCluster.Builder builder =
+          new MiniDFSCluster.Builder(serverConf).numDataNodes(1);
+      try (MiniDFSCluster cluster = builder.build();
+          DistributedFileSystem dfs = (DistributedFileSystem) FileSystem
+              .get(cluster.getURI(0), conf)) {
+        cluster.waitActive();
+        final Path testFile = new Path("/test_file");
+        final int testFileLen = 4000;
+        final int seed = 0xFADED;
+        DFSTestUtil.createFile(dfs, testFile, testFileLen, (short) 1, seed);
+        final byte[] expected = DFSTestUtil.
+            calculateFileContentsFromSeed(seed, testFileLen);
+
+        try (FSDataInputStream in = dfs.open(testFile)) {
+          Assert.assertEquals(0,
+              dfs.getClient().getClientContext().getShortCircuitCache()
+                  .getReplicaInfoMapSize());
+
+          final byte[] buf = new byte[testFileLen];
+          IOUtils.readFully(in, buf, 0, testFileLen);
+          validateReadResult(dfs, expected, buf, 1);
+
+          // Set cache size to 0 so the replica marked evictable by unbuffer
+          // will be purged immediately.
+          dfs.getClient().getClientContext().getShortCircuitCache()
+              .setMaxTotalSize(0);
+          LOG.info("Unbuffering");
+          in.unbuffer();
+          Assert.assertEquals(0,
+              dfs.getClient().getClientContext().getShortCircuitCache()
+                  .getReplicaInfoMapSize());
+
+          DFSTestUtil.appendFile(dfs, testFile, "append more data");
+
+          // This read will force a new replica read via TCP.
+          Arrays.fill(buf, (byte) 0);
+          in.seek(0);
+          IOUtils.readFully(in, buf, 0, testFileLen);
+          validateReadResult(dfs, expected, buf, 0);
+        }
+
+        LOG.info("Reading {} again.", testFile);
+        try (FSDataInputStream in = dfs.open(testFile)) {
+          final byte[] buf = new byte[testFileLen];
+          Arrays.fill(buf, (byte) 0);
+          IOUtils.readFully(in, buf, 0, testFileLen);
+          final int expectedMapSize = disabled ? 0 : 1;
+          validateReadResult(dfs, expected, buf, expectedMapSize);
+        }
+      }
+    }
+  }
+
+  private void validateReadResult(final DistributedFileSystem dfs,
+      final byte[] expected, final byte[] actual,
+      final int expectedScrRepMapSize) {
+    Assert.assertThat(expected, CoreMatchers.is(actual));
+    Assert.assertEquals(expectedScrRepMapSize,
+        dfs.getClient().getClientContext().getShortCircuitCache()
+            .getReplicaInfoMapSize());
+  }
+
+  /**
    * Test that a client which supports short-circuit reads using
    * shared memory can fall back to not using shared memory when
    * the server doesn't support it.