gistfile1.txt

commit 081e16ad9cfcba9cdb6d438845c2c60552589c18
Author: Todd Lipcon <todd@lipcon.org>
Date:   Tue May 18 19:06:17 2010 -0700

    HDFS-895. Tighten up assertions on sequence numbering, fix a small bug where the sequence would have "holes" in it

diff --git a/src/hdfs/org/apache/hadoop/hdfs/DFSClient.java b/src/hdfs/org/apache/hadoop/hdfs/DFSClient.java
index 2460f6a..5bcbaa8 100644
--- a/src/hdfs/org/apache/hadoop/hdfs/DFSClient.java
+++ b/src/hdfs/org/apache/hadoop/hdfs/DFSClient.java
@@ -2502,7 +2502,7 @@ public class DFSClient implements FSConstants, java.io.Closeable {
             }
 
             synchronized (ackQueue) {
-              assert ack.getSeqno()> lastAckedSeqno;
+              assert ack.getSeqno() == lastAckedSeqno + 1;
               lastAckedSeqno = ack.getSeqno();
               ackQueue.removeFirst();
               ackQueue.notifyAll();
@@ -3157,6 +3157,7 @@ public class DFSClient implements FSConstants, java.io.Closeable {
            * any partial checksum chunk will be sent now and in next packet.
            */
           long saveOffset = bytesCurBlock;
+          Packet oldCurrentPacket = currentPacket;
 
           // flush checksum buffer, but keep checksum buffer intact
           flushBuffer(true);
@@ -3176,6 +3177,12 @@ public class DFSClient implements FSConstants, java.io.Closeable {
             enqueueCurrentPacket();
           } else {
             // just discard the current packet since it is already been sent.
+            if (oldCurrentPacket == null && currentPacket != null) {
+              // If we didn't previously have a packet queued, and now we do,
+              // but we don't plan on sending it, then we should not
+              // skip a sequence number for it!
+              currentSeqno--;
+            }
             currentPacket = null;
           }
           // Restore state of stream. Record the last flush offset