Optimize read write lock constructs during translog upload to remote store

server/src/main/java/org/opensearch/index/translog/RemoteFsTranslog.java

@@ -292,6 +292,17 @@ private boolean prepareForUpload(Long generation) throws IOException {
         }
     }
 
+    /**
+     * This method does the remote store upload by first acquiring the lock on the uploadMutex monitor. The synchronized
+     * is required to restrict multiple uploads happening concurrently. The read lock is required to ensure that the
+     * underlying translog readers are not deleted and the current writer is not converted to a reader at the time of
+     * upload.
+     *
+     * @param primaryTerm current primary term
+     * @param generation  current generation
+     * @return true if upload is successful
+     * @throws IOException if the upload fails due to any underlying exceptions.
+     */
     private boolean performUpload(Long primaryTerm, Long generation) throws IOException {
         synchronized (uploadMutex) {
             try (Releasable ignored = readLock.acquire()) {
@@ -362,10 +373,8 @@ private boolean syncToDisk() throws IOException {
     @Override
     public void sync() throws IOException {
         try {
-            if (syncToDisk() || syncNeeded()) {
-                if (prepareForUpload(null)) {
-                    performUpload(primaryTermSupplier.getAsLong(), null);
-                }
+            if (syncToDisk() || syncNeeded() || prepareForUpload(null)) {
+                performUpload(primaryTermSupplier.getAsLong(), null);
             }
         } catch (final Exception e) {
             tragedy.setTragicException(e);

server/src/main/java/org/opensearch/index/translog/transfer/listener/TranslogTransferListener.java

@@ -10,14 +10,15 @@
 
 import org.opensearch.index.translog.transfer.TransferSnapshot;
 
+import java.io.Closeable;
 import java.io.IOException;
 
 /**
  * The listener to be invoked on the completion or failure of a {@link TransferSnapshot}
  *
  * @opensearch.internal
  */
-public interface TranslogTransferListener {
+public interface TranslogTransferListener extends Closeable {
     /**
      * Invoked when the transfer of {@link TransferSnapshot} succeeds
      * @param transferSnapshot the transfer snapshot
@@ -32,8 +33,4 @@ public interface TranslogTransferListener {
      * @throws IOException the exception during the transfer of data
      */
     void onUploadFailed(TransferSnapshot transferSnapshot, Exception ex) throws IOException;
-
-    default void close() {
-
-    }
 }

server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferManagerTests.java

@@ -168,6 +168,9 @@ public void onUploadComplete(TransferSnapshot transferSnapshot) {
             public void onUploadFailed(TransferSnapshot transferSnapshot, Exception ex) {
                 translogTransferFailed.incrementAndGet();
             }
+
+            @Override
+            public void close() {}
         }));
         assertEquals(4, fileTransferSucceeded.get());
         assertEquals(0, fileTransferFailed.get());