Add comments regarding keyName change.

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmMetadataManagerImpl.java

@@ -1846,6 +1846,9 @@ public ExpiredOpenKeys getExpiredOpenKeys(Duration expireThreshold,
               !openKeyInfo.getMetadata().containsKey(OzoneConsts.LEASE_RECOVERY)) {
             // add hsync'ed keys
             final OmKeyInfo info = kt.get(dbKeyName);
+            // Set keyName from openFileTable which contains keyName with full path like(/a/b/c/d/e/file1),
+            // which is required in commit key request.
+            // Whereas fileTable contains only leaf in keyName(like file1) and so cannot be used in commit request.
             final KeyArgs.Builder keyArgs = KeyArgs.newBuilder()
                 .setVolumeName(info.getVolumeName())
                 .setBucketName(info.getBucketName())

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/request/file/OMFileRequest.java

@@ -477,8 +477,12 @@ public static void addOpenFileTableCacheEntry(
     final Table<String, OmKeyInfo> table = omMetadataManager.getOpenKeyTable(
         BucketLayout.FILE_SYSTEM_OPTIMIZED);
     if (omFileInfo != null) {
-      // Set keyName as fileName along with path
+      // For example, the user given key path is '/a/b/c/d/e/file1', then in DB
+      // keyName field stores full path, which is '/a/b/c/d/e/file1'.
+      // This is required as in some cases like hsync, Keys inside openKeyTable is used for auto commit after expiry.
+      // (Full key path is required in commit key request)
       omFileInfo.setKeyName(keyName);
+      // fileName will contain only the leaf(file1) which is actual file name.
       omFileInfo.setFileName(fileName);
       table.addCacheEntry(dbOpenFileName, omFileInfo, trxnLogIndex);
     } else {