HBASE-7504 -ROOT- may be offline forever after FullGC of RS (Chunhui)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1431208 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/master/handler/ServerShutdownHandler.java

@@ -107,6 +107,12 @@ public class ServerShutdownHandler extends EventHandler {
       getLong("hbase.catalog.verification.timeout", 1000);
     if (!this.server.getCatalogTracker().verifyRootRegionLocation(timeout)) {
       this.services.getAssignmentManager().assignRoot();
+    } else if (serverName.equals(server.getCatalogTracker().getRootLocation())) {
+      throw new IOException("-ROOT- is onlined on the dead server "
+          + serverName);
+    } else {
+      LOG.info("Skip assigning -ROOT-, because it is online on the "
+          + server.getCatalogTracker().getRootLocation());
     }
   }