Repository: hadoop Updated Branches: refs/heads/branch-2 2b1f066d2 -> 07b0abe0b
HDFS-10182. Hedged read might overwrite user's buf. Contributed by zhouyingchao. (cherry picked from commit d8383c687c95dbb37effa307ab2d41497da1cfc2) Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/07b0abe0 Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/07b0abe0 Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/07b0abe0 Branch: refs/heads/branch-2 Commit: 07b0abe0b31f0f113428fe095e83d953be7b7a8d Parents: 2b1f066 Author: Walter Su <waltersu4...@apache.org> Authored: Mon Mar 28 15:44:25 2016 +0800 Committer: Walter Su <waltersu4...@apache.org> Committed: Mon Mar 28 15:46:01 2016 +0800 ---------------------------------------------------------------------- .../java/org/apache/hadoop/hdfs/DFSInputStream.java | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/07b0abe0/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java index 5d0744e..040055e 100644 --- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java +++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java @@ -1329,7 +1329,7 @@ public class DFSInputStream extends FSInputStream // chooseDataNode is a commitment. If no node, we go to // the NN to reget block locations. Only go here on first read. chosenNode = chooseDataNode(block, ignored); - bb = ByteBuffer.wrap(buf, offset, len); + bb = ByteBuffer.allocate(len); Callable<ByteBuffer> getFromDataNodeCallable = getFromOneDataNode( chosenNode, block, start, end, bb, corruptedBlockMap, hedgedReadId++); @@ -1340,7 +1340,9 @@ public class DFSInputStream extends FSInputStream Future<ByteBuffer> future = hedgedService.poll( conf.getHedgedReadThresholdMillis(), TimeUnit.MILLISECONDS); if (future != null) { - future.get(); + ByteBuffer result = future.get(); + System.arraycopy(result.array(), result.position(), buf, offset, + len); return; } DFSClient.LOG.debug("Waited {}ms to read from {}; spawning hedged " @@ -1378,13 +1380,9 @@ public class DFSInputStream extends FSInputStream ByteBuffer result = getFirstToComplete(hedgedService, futures); // cancel the rest. cancelAll(futures); - if (result.array() != buf) { // compare the array pointers - dfsClient.getHedgedReadMetrics().incHedgedReadWins(); - System.arraycopy(result.array(), result.position(), buf, offset, - len); - } else { - dfsClient.getHedgedReadMetrics().incHedgedReadOps(); - } + dfsClient.getHedgedReadMetrics().incHedgedReadWins(); + System.arraycopy(result.array(), result.position(), buf, offset, + len); return; } catch (InterruptedException ie) { // Ignore and retry