HDDS-11280. Add Synchronize in AbstractCommitWatcher.addAckDataLength

[ashishkumar50]

What changes were proposed in this pull request?

TestBlockOutputStream.testWriteMoreThanFlushSize is flaky after HDDS-9844 fix.
It is due to addAckDataLength is not kept as thread safe which is causing wrong totalAckDataLength.
In this PR we are adding synchronized in AbstractCommitWatcher.addAckDataLength to make thread safe.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-11280

How was this patch tested?

Verified in 10X10 run and it is green after the fix
https://github.com/ashishkumar50/ozone/actions/runs/10244918136/workflow

[szetszwo]

@ashishkumar50 , thanks for working on this! Let's use AtomicLong as below.

+++ b/hadoop-hdds/client/src/main/java/org/apache/hadoop/hdds/scm/storage/AbstractCommitWatcher.java
@@ -38,6 +38,7 @@
 import java.util.concurrent.ConcurrentSkipListMap;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * This class executes watchForCommit on ratis pipeline and releases
@@ -62,7 +63,7 @@ abstract class AbstractCommitWatcher<BUFFER> {
 
   private final XceiverClientSpi client;
 
-  private long totalAckDataLength;
+  private final AtomicLong totalAckDataLength = new AtomicLong();
 
   AbstractCommitWatcher(XceiverClientSpi client) {
     this.client = client;
@@ -80,12 +81,11 @@ synchronized void updateCommitInfoMap(long index, List<BUFFER> buffers) {
 
   /** @return the total data which has been acknowledged. */
   long getTotalAckDataLength() {
-    return totalAckDataLength;
+    return totalAckDataLength.get();
   }
 
   long addAckDataLength(long acked) {
-    totalAckDataLength += acked;
-    return totalAckDataLength;
+    return totalAckDataLength.addAndGet(acked);
   }
 
   /**

[ashishkumar50]

@szetszwo Thanks for the review.
Updated with AtomicLong.
It looks like there is still flakiness and it failed in second 10X10 run while the first 10X10 run was all success.

[szetszwo]

+1 the change looks good.

[jojochuang]

+1 looks correct to me. Merging it now.