HDFS-16817. Remove useless DataNode lock related configuration (#5072)

Reviewed-by: litao <tomleescut@gmail.com>
Signed-off-by: ZanderXu <zanderxu@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -636,14 +636,6 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String DFS_DATANODE_LOCK_FAIR_KEY =
       "dfs.datanode.lock.fair";
   public static final boolean DFS_DATANODE_LOCK_FAIR_DEFAULT = true;
-  public static final String DFS_DATANODE_LOCK_READ_WRITE_ENABLED_KEY =
-      "dfs.datanode.lock.read.write.enabled";
-  public static final Boolean DFS_DATANODE_LOCK_READ_WRITE_ENABLED_DEFAULT =
-      true;
-  public static final String  DFS_DATANODE_LOCK_REPORTING_THRESHOLD_MS_KEY =
-      "dfs.datanode.lock-reporting-threshold-ms";
-  public static final long
-      DFS_DATANODE_LOCK_REPORTING_THRESHOLD_MS_DEFAULT = 300L;
 
   public static final String  DFS_UPGRADE_DOMAIN_FACTOR = "dfs.namenode.upgrade.domain.factor";
   public static final int DFS_UPGRADE_DOMAIN_FACTOR_DEFAULT = DFS_REPLICATION_DEFAULT;

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -3465,30 +3465,6 @@
   </description>
 </property>
 
-<property>
-  <name>dfs.datanode.lock.read.write.enabled</name>
-  <value>true</value>
-  <description>If this is true, the FsDataset lock will be a read write lock. If
-    it is false, all locks will be a write lock.
-    Enabling this should give better datanode throughput, as many read only
-    functions can run concurrently under the read lock, when they would
-    previously have required the exclusive write lock. As the feature is
-    experimental, this switch can be used to disable the shared read lock, and
-    cause all lock acquisitions to use the exclusive write lock.
-  </description>
-</property>
-
-<property>
-  <name>dfs.datanode.lock-reporting-threshold-ms</name>
-  <value>300</value>
-  <description>When thread waits to obtain a lock, or a thread holds a lock for
-    more than the threshold, a log message will be written. Note that
-    dfs.lock.suppress.warning.interval ensures a single log message is
-    emitted per interval for waiting threads and a single message for holding
-    threads to avoid excessive logging.
-  </description>
-</property>
-
 <property>
   <name>dfs.namenode.startup.delay.block.deletion.sec</name>
   <value>0</value>