merge -r 1382408:1382409 for HDFS-2757

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1431506 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -33,6 +33,9 @@ Release 0.23.6 - UNRELEASED
     choose a source datanode that has reached its max replication limit 
     (Derek Dagit via tgraves)
 
+    HDFS-2757. Cannot read a local block that's being written to when
+    using the local read short circuit. (Jean-Daniel Cryans via eli)
+
 Release 0.23.5 - UNRELEASED
 
   INCOMPATIBLE CHANGES
@@ -121,6 +124,45 @@ Release 0.23.4
 
 Release 0.23.3
 
+<<<<<<< .working
+=======
+    HDFS-3469. start-dfs.sh will start zkfc, but stop-dfs.sh will not stop zkfc similarly.
+    (Vinay via umamahesh)
+
+    HDFS-1490. TransferFSImage should timeout (Dmytro Molkov and Vinay via todd)
+
+    HDFS-3828. Block Scanner rescans blocks too frequently.
+    (Andy Isaacson via eli)
+
+    HDFS-3809. Make BKJM use protobufs for all serialization with ZK.(Ivan Kelly via umamahesh)
+
+    HDFS-3895. hadoop-client must include commons-cli (tucu)
+
+    HDFS-2757. Cannot read a local block that's being written to when
+    using the local read short circuit. (Jean-Daniel Cryans via eli)
+    
+  BREAKDOWN OF HDFS-3042 SUBTASKS
+
+    HDFS-2185. HDFS portion of ZK-based FailoverController (todd)
+    
+    HDFS-3200. Scope all ZKFC configurations by nameservice (todd)
+    
+    HDFS-3223. add zkfc to hadoop-daemon.sh script (todd)
+    
+    HDFS-3261. TestHASafeMode fails on HDFS-3042 branch (todd)
+    
+    HDFS-3159. Document NN auto-failover setup and configuration (todd)
+    
+    HDFS-3412. Fix findbugs warnings in auto-HA branch (todd)
+    
+    HDFS-3432. TestDFSZKFailoverController tries to fail over too early (todd)
+
+    HDFS-3833. TestDFSShell fails on windows due to concurrent file 
+    read/write. (Brandon Li via suresh)
+
+Release 2.0.0-alpha - 05-23-2012
+
+>>>>>>> .merge-right.r1382409
   INCOMPATIBLE CHANGES
 
   NEW FEATURES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -1843,10 +1843,7 @@ public class DFSClient implements java.io.Closeable {
   
   boolean shouldTryShortCircuitRead(InetSocketAddress targetAddr)
       throws IOException {
-    if (shortCircuitLocalReads && isLocalAddress(targetAddr)) {
-      return true;
-    }
-    return false;
+    return shortCircuitLocalReads && isLocalAddress(targetAddr);
   }
 
   void reportChecksumFailure(String file, ExtendedBlock blk, DatanodeInfo dn) {

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

@@ -202,6 +202,10 @@ public class DFSInputStream extends FSInputStream {
         locatedBlocks.getFileLength() + lastBlockBeingWrittenLength;
   }
 
+  private synchronized boolean blockUnderConstruction() {
+    return locatedBlocks.isUnderConstruction();
+  }
+
   /**
    * Returns the datanode from which the stream is currently reading.
    */
@@ -750,7 +754,9 @@ public class DFSInputStream extends FSInputStream {
                                        String clientName)
       throws IOException {
     
-    if (dfsClient.shouldTryShortCircuitRead(dnAddr)) {
+    // Can't local read a block under construction, see HDFS-2757
+    if (dfsClient.shouldTryShortCircuitRead(dnAddr) &&
+        !blockUnderConstruction()) {
       return DFSClient.getLocalBlockReader(dfsClient.conf, src, block,
           blockToken, chosenNode, dfsClient.hdfsTimeout, startOffset);
     }