HBASE-9645 Regionserver halt because of HLogs "Logic Error Snapshot seq id from earlier flush still present"

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1535288 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java

@@ -5610,4 +5610,21 @@ public class HRegion implements HeapSize { // , Writable{
       }
     }
   }
+
+  /**
+   * Lock the updates' readLock first, so that we could safely append logs in coprocessors.
+   * @throws RegionTooBusyException
+   * @throws InterruptedIOException
+   */
+  public void updatesLock() throws RegionTooBusyException, InterruptedIOException {
+    lock(updatesLock.readLock());
+  }
+
+  /**
+   * Unlock the updates' readLock after appending logs in coprocessors.
+   * @throws InterruptedIOException
+   */
+  public void updatesUnlock() throws InterruptedIOException {
+    updatesLock.readLock().unlock();
+  }
 }