Revert " HBASE-23055 Alter hbase:meta (#655)"

"Too radical for branch-2"

This reverts commit ff217d4269.

hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java

@@ -304,18 +304,11 @@ public class MetaTableAccessor {
    */
   public static HRegionLocation getRegionLocation(Connection connection, RegionInfo regionInfo)
       throws IOException {
-    return getRegionLocation(getCatalogFamilyRow(connection, regionInfo),
+    byte[] row = getMetaKeyForRegion(regionInfo);
-        regionInfo, regionInfo.getReplicaId());
+    Get get = new Get(row);
-  }
-
-  /**
-   * @return Return the {@link HConstants#CATALOG_FAMILY} row from hbase:meta.
-   */
-  public static Result getCatalogFamilyRow(Connection connection, RegionInfo ri)
-      throws IOException {
-    Get get = new Get(getMetaKeyForRegion(ri));
     get.addFamily(HConstants.CATALOG_FAMILY);
-    return get(getMetaHTable(connection), get);
+    Result r = get(getMetaHTable(connection), get);
+    return getRegionLocation(r, regionInfo, regionInfo.getReplicaId());
   }
 
   /** Returns the row key to use for this regionInfo */
@@ -1117,7 +1110,7 @@ public class MetaTableAccessor {
   public static TableState getTableState(Connection conn, TableName tableName)
       throws IOException {
     if (tableName.equals(TableName.META_TABLE_NAME)) {
-      throw new IllegalAccessError("Go to the Master to find hbase:meta table state, not here");
+      return new TableState(tableName, TableState.State.ENABLED);
     }
     Table metaHTable = getMetaHTable(conn);
     Get get = new Get(tableName.getName()).addColumn(getTableFamily(), getTableStateColumn());
@@ -1145,8 +1138,7 @@ public class MetaTableAccessor {
   }
 
   /**
-   * Updates state in META.
+   * Updates state in META
-   * Do not use. For internal use only.
    * @param conn connection to use
    * @param tableName table to look for
    */

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java

@@ -1,4 +1,4 @@
-/*
+/**
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
@@ -45,7 +45,6 @@ import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.ReentrantLock;
-
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.AuthUtil;
 import org.apache.hadoop.hbase.CallQueueTooBigException;
@@ -164,7 +163,6 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
   private final int metaReplicaCallTimeoutScanInMicroSecond;
   private final int numTries;
   final int rpcTimeout;
-  private final int operationTimeout;
 
   /**
    * Global nonceGenerator shared per client.Currently there's no reason to limit its scope.
@@ -332,8 +330,6 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
       close();
       throw e;
     }
-    this.operationTimeout = this.conf.getInt(HConstants.HBASE_CLIENT_OPERATION_TIMEOUT,
-        HConstants.DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT);
   }
 
   private void spawnRenewalChore(final UserGroupInformation user) {
@@ -2061,30 +2057,12 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
 
   @Override
   public TableState getTableState(TableName tableName) throws IOException {
-    // Go to the Master for Table State. It is the authority. It knows State for user-space
+    checkClosed();
-    // and for system-space tables. Previous we went direct to the hbase:meta table to find
+    TableState tableState = MetaTableAccessor.getTableState(this, tableName);
-    // table-state. hbase:meta does not have system-table states. This puts new load on Master.
+    if (tableState == null) {
-    // Now it proxies reads to the hbase:meta. Benefit is that we hide table state implementation.
-    // Downside is more load on Master. Master is host for hbase:meta table-state (and for that of
-    // other tables). Going to Master means one-stop-shop for all table states.
-    RpcControllerFactory factory = getRpcControllerFactory();
-    try (MasterCallable<TableState.State> c = new MasterCallable<TableState.State>(this, factory) {
-      @Override
-      protected TableState.State rpcCall() throws Exception {
-        setPriority(tableName);
-        MasterProtos.GetTableStateRequest req =
-          RequestConverter.buildGetTableStateRequest(tableName);
-        MasterProtos.GetTableStateResponse ret = master.getTableState(getRpcController(), req);
-        if (!ret.hasTableState() || ret.getTableState() == null) {
       throw new TableNotFoundException(tableName);
     }
-        return TableState.State.valueOf(ret.getTableState().getState().toString());
+    return tableState;
-      }
-    }) {
-      RpcRetryingCaller<TableState.State> caller = getRpcRetryingCallerFactory().
-          newCaller(this.rpcTimeout);
-      return new TableState(tableName, caller.callWithRetries(c, this.operationTimeout));
-    }
   }
 
   @Override

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -543,9 +543,7 @@ public class HBaseAdmin implements Admin {
   static TableDescriptor getTableDescriptor(final TableName tableName, Connection connection,
       RpcRetryingCallerFactory rpcCallerFactory, final RpcControllerFactory rpcControllerFactory,
       int operationTimeout, int rpcTimeout) throws IOException {
-    if (tableName == null) {
+    if (tableName == null) return null;
-      return null;
-    }
     TableDescriptor td =
         executeCallable(new MasterCallable<TableDescriptor>(connection, rpcControllerFactory) {
       @Override
@@ -950,13 +948,22 @@ public class HBaseAdmin implements Admin {
   @Override
   public boolean isTableEnabled(final TableName tableName) throws IOException {
     checkTableExists(tableName);
-    return this.connection.getTableState(tableName).isEnabled();
+    return executeCallable(new RpcRetryingCallable<Boolean>() {
+      @Override
+      protected Boolean rpcCall(int callTimeout) throws Exception {
+        TableState tableState = MetaTableAccessor.getTableState(getConnection(), tableName);
+        if (tableState == null) {
+          throw new TableNotFoundException(tableName);
+        }
+        return tableState.inStates(TableState.State.ENABLED);
+      }
+    });
   }
 
   @Override
   public boolean isTableDisabled(TableName tableName) throws IOException {
     checkTableExists(tableName);
-    return this.connection.getTableState(tableName).isDisabled();
+    return connection.isTableDisabled(tableName);
   }
 
   @Override
@@ -4350,4 +4357,5 @@ public class HBaseAdmin implements Admin {
     });
 
   }
+
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterKeepAliveConnection.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Copyright The Apache Software Foundation
  *
  * Licensed to the Apache Software Foundation (ASF) under one
@@ -20,12 +20,9 @@
 
 package org.apache.hadoop.hbase.client;
 
-import java.io.Closeable;
-
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos;
 import org.apache.yetus.audience.InterfaceAudience;
 
-
 /**
  * A KeepAlive connection is not physically closed immediately after the close,
  *  but rather kept alive for a few minutes. It makes sense only if it is shared.
@@ -38,8 +35,7 @@ import org.apache.yetus.audience.InterfaceAudience;
  * final user code. Hence it's package protected.
  */
 @InterfaceAudience.Private
-interface MasterKeepAliveConnection extends
+interface MasterKeepAliveConnection extends MasterProtos.MasterService.BlockingInterface {
-    MasterProtos.MasterService.BlockingInterface, Closeable {
   // Do this instead of implement Closeable because closeable returning IOE is PITA.
   void close();
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java

@@ -89,7 +89,6 @@ import org.apache.hadoop.hbase.security.access.GetUserPermissionsRequest;
 import org.apache.hadoop.hbase.security.access.Permission;
 import org.apache.hadoop.hbase.security.access.ShadedAccessControlUtil;
 import org.apache.hadoop.hbase.security.access.UserPermission;
-
 import org.apache.hadoop.hbase.snapshot.ClientSnapshotDescriptionUtils;
 import org.apache.hadoop.hbase.snapshot.RestoreSnapshotException;
 import org.apache.hadoop.hbase.snapshot.SnapshotCreationException;
@@ -192,8 +191,6 @@ import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableDe
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableDescriptorsResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableNamesRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableNamesResponse;
-import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableStateRequest;
-import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableStateResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.IsBalancerEnabledRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.IsBalancerEnabledResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.IsCatalogJanitorEnabledRequest;
@@ -666,25 +663,42 @@ class RawAsyncHBaseAdmin implements AsyncAdmin {
 
   @Override
   public CompletableFuture<Boolean> isTableEnabled(TableName tableName) {
-    return isTableState(tableName, TableState.State.ENABLED);
+    if (TableName.isMetaTableName(tableName)) {
+      return CompletableFuture.completedFuture(true);
+    }
+    CompletableFuture<Boolean> future = new CompletableFuture<>();
+    addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (state, error) -> {
+      if (error != null) {
+        future.completeExceptionally(error);
+        return;
+      }
+      if (state.isPresent()) {
+        future.complete(state.get().inStates(TableState.State.ENABLED));
+      } else {
+        future.completeExceptionally(new TableNotFoundException(tableName));
+      }
+    });
+    return future;
   }
 
   @Override
   public CompletableFuture<Boolean> isTableDisabled(TableName tableName) {
-    return isTableState(tableName, TableState.State.DISABLED);
+    if (TableName.isMetaTableName(tableName)) {
+      return CompletableFuture.completedFuture(false);
     }
-
+    CompletableFuture<Boolean> future = new CompletableFuture<>();
-  /**
+    addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (state, error) -> {
-   * @return Future that calls Master getTableState and compares to <code>state</code>
+      if (error != null) {
-   */
+        future.completeExceptionally(error);
-  private CompletableFuture<Boolean> isTableState(TableName tableName, TableState.State state) {
+        return;
-    return this.<Boolean> newMasterCaller().
+      }
-        action((controller, stub) ->
+      if (state.isPresent()) {
-      this.<GetTableStateRequest, GetTableStateResponse, Boolean> call(controller, stub,
+        future.complete(state.get().inStates(TableState.State.DISABLED));
-          GetTableStateRequest.newBuilder().
+      } else {
-              setTableName(ProtobufUtil.toProtoTableName(tableName)).build(),
+        future.completeExceptionally(new TableNotFoundException(tableName));
-        (s, c, req, done) -> s.getTableState(c, req, done),
+      }
-        resp -> resp.getTableState().getState().toString().equals(state.toString()))).call();
+    });
+    return future;
   }
 
   @Override

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZKAsyncRegistry.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -158,8 +158,7 @@ class ZKAsyncRegistry implements AsyncRegistry {
           }
           Pair<RegionState.State, ServerName> stateAndServerName = getStateAndServerName(proto);
           if (stateAndServerName.getFirst() != RegionState.State.OPEN) {
-            LOG.warn("hbase:meta region (replicaId={}) is in state {}", replicaId,
+            LOG.warn("Meta region is in state " + stateAndServerName.getFirst());
-                stateAndServerName.getFirst());
           }
           locs[DEFAULT_REPLICA_ID] = new HRegionLocation(
             getRegionInfoForDefaultReplica(FIRST_META_REGIONINFO), stateAndServerName.getSecond());
@@ -174,7 +173,7 @@ class ZKAsyncRegistry implements AsyncRegistry {
             LOG.warn("Failed to fetch " + path, error);
             locs[replicaId] = null;
           } else if (proto == null) {
-            LOG.warn("hbase:meta znode for replica " + replicaId + " is null");
+            LOG.warn("Meta znode for replica " + replicaId + " is null");
             locs[replicaId] = null;
           } else {
             Pair<RegionState.State, ServerName> stateAndServerName = getStateAndServerName(proto);
@@ -198,8 +197,9 @@ class ZKAsyncRegistry implements AsyncRegistry {
   public CompletableFuture<RegionLocations> getMetaRegionLocation() {
     CompletableFuture<RegionLocations> future = new CompletableFuture<>();
     addListener(
-      zk.list(znodePaths.baseZNode).thenApply(children -> children.stream().
+      zk.list(znodePaths.baseZNode)
-          filter(c -> znodePaths.isMetaZNodePrefix(c)).collect(Collectors.toList())),
+        .thenApply(children -> children.stream()
+          .filter(c -> c.startsWith(znodePaths.metaZNodePrefix)).collect(Collectors.toList())),
       (metaReplicaZNodes, error) -> {
         if (error != null) {
           future.completeExceptionally(error);

hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZNodePaths.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -24,7 +24,6 @@ import static org.apache.hadoop.hbase.HConstants.SPLIT_LOGDIR_NAME;
 import static org.apache.hadoop.hbase.HConstants.ZOOKEEPER_ZNODE_PARENT;
 import static org.apache.hadoop.hbase.client.RegionInfo.DEFAULT_REPLICA_ID;
 
-import java.util.Collection;
 import java.util.Optional;
 import java.util.stream.IntStream;
 import org.apache.hadoop.conf.Configuration;
@@ -41,24 +40,15 @@ public class ZNodePaths {
   // TODO: Replace this with ZooKeeper constant when ZOOKEEPER-277 is resolved.
   public static final char ZNODE_PATH_SEPARATOR = '/';
 
-  private static final String META_ZNODE_PREFIX = "meta-region-server";
+  public final static String META_ZNODE_PREFIX = "meta-region-server";
   private static final String DEFAULT_SNAPSHOT_CLEANUP_ZNODE = "snapshot-cleanup";
 
   // base znode for this cluster
   public final String baseZNode;
-
+  // the prefix of meta znode, does not include baseZNode.
-  /**
+  public final String metaZNodePrefix;
-   * The prefix of meta znode. Does not include baseZNode.
+  // znodes containing the locations of the servers hosting the meta replicas
-   * Its a 'prefix' because meta replica id integer can be tagged on the end (if
+  public final ImmutableMap<Integer, String> metaReplicaZNodes;
-   * no number present, it is 'default' replica).
-   */
-  private final String metaZNodePrefix;
-
-  /**
-   * znodes containing the locations of the servers hosting the meta replicas
-   */
-  private final ImmutableMap<Integer, String> metaReplicaZNodes;
-
   // znode containing ephemeral nodes of the regionservers
   public final String rsZNode;
   // znode containing ephemeral nodes of the draining regionservers
@@ -168,21 +158,21 @@ public class ZNodePaths {
   }
 
   /**
-   * @return true if the znode is a meta region replica
+   * Is the znode of any meta replica
+   * @param node
+   * @return true or false
    */
   public boolean isAnyMetaReplicaZNode(String node) {
-    return this.metaReplicaZNodes.containsValue(node);
+    if (metaReplicaZNodes.containsValue(node)) {
+      return true;
+    }
+    return false;
   }
 
   /**
-   * @return Meta Replica ZNodes
+   * Get the znode string corresponding to a replicaId
-   */
+   * @param replicaId
-  public Collection<String> getMetaReplicaZNodes() {
+   * @return znode
-    return this.metaReplicaZNodes.values();
-  }
-
-  /**
-   * @return the znode string corresponding to a replicaId
    */
   public String getZNodeForReplica(int replicaId) {
     // return a newly created path but don't update the cache of paths
@@ -193,21 +183,24 @@ public class ZNodePaths {
   }
 
   /**
-   * Parse the meta replicaId from the passed znode name.
+   * Parse the meta replicaId from the passed znode
    * @param znode the name of the znode, does not include baseZNode
    * @return replicaId
    */
   public int getMetaReplicaIdFromZnode(String znode) {
-    return znode.equals(metaZNodePrefix)?
+    if (znode.equals(metaZNodePrefix)) {
-        RegionInfo.DEFAULT_REPLICA_ID:
+      return RegionInfo.DEFAULT_REPLICA_ID;
-        Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
+    }
+    return Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
   }
 
   /**
-   * @return True if meta znode.
+   * Is it the default meta replica's znode
+   * @param znode the name of the znode, does not include baseZNode
+   * @return true or false
    */
-  public boolean isMetaZNodePrefix(String znode) {
+  public boolean isDefaultMetaReplicaZnode(String znode) {
-    return znode != null && znode.startsWith(this.metaZNodePrefix);
+    return metaReplicaZNodes.get(DEFAULT_REPLICA_ID).equals(znode);
   }
 
   /**

hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java

@@ -1211,6 +1211,7 @@ public final class HConstants {
   /** Directories that are not HBase user table directories */
   public static final List<String> HBASE_NON_USER_TABLE_DIRS =
     Collections.unmodifiableList(Arrays.asList((String[])ArrayUtils.addAll(
+      new String[] { TableName.META_TABLE_NAME.getNameAsString() },
       HBASE_NON_TABLE_DIRS.toArray())));
 
   /** Health script related settings. */

hbase-server/src/main/java/org/apache/hadoop/hbase/TableDescriptors.java

@@ -25,19 +25,25 @@ import org.apache.hadoop.hbase.client.TableDescriptor;
 
 /**
  * Get, remove and modify table descriptors.
+ * Used by servers to host descriptors.
  */
 @InterfaceAudience.Private
 public interface TableDescriptors {
   /**
+   * @param tableName
    * @return TableDescriptor for tablename
+   * @throws IOException
    */
-  TableDescriptor get(final TableName tableName) throws IOException;
+  TableDescriptor get(final TableName tableName)
+      throws IOException;
 
   /**
    * Get Map of all NamespaceDescriptors for a given namespace.
    * @return Map of all descriptors.
+   * @throws IOException
    */
-  Map<String, TableDescriptor> getByNamespace(String name) throws IOException;
+  Map<String, TableDescriptor> getByNamespace(String name)
+  throws IOException;
 
   /**
    * Get Map of all TableDescriptors. Populates the descriptor cache as a
@@ -45,19 +51,25 @@ public interface TableDescriptors {
    * Notice: the key of map is the table name which contains namespace. It was generated by
    * {@link TableName#getNameWithNamespaceInclAsString()}.
    * @return Map of all descriptors.
+   * @throws IOException
    */
   Map<String, TableDescriptor> getAll() throws IOException;
 
   /**
    * Add or update descriptor
    * @param htd Descriptor to set into TableDescriptors
+   * @throws IOException
    */
-  void add(final TableDescriptor htd) throws IOException;
+  void add(final TableDescriptor htd)
+  throws IOException;
 
   /**
+   * @param tablename
    * @return Instance of table descriptor or null if none found.
+   * @throws IOException
    */
-  TableDescriptor remove(final TableName tablename) throws IOException;
+  TableDescriptor remove(final TableName tablename)
+  throws IOException;
 
   /**
    * Enables the tabledescriptor cache

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

@@ -49,6 +49,7 @@ import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Function;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import javax.servlet.ServletException;
@@ -661,6 +662,10 @@ public class HMaster extends HRegionServer implements MasterServices {
     return connector.getLocalPort();
   }
 
+  @Override
+  protected Function<TableDescriptorBuilder, TableDescriptorBuilder> getMetaTableObserver() {
+    return builder -> builder.setRegionReplication(conf.getInt(HConstants.META_REPLICAS_NUM, HConstants.DEFAULT_META_REPLICA_NUM));
+  }
   /**
    * For compatibility, if failed with regionserver credentials, try the master one
    */
@@ -1012,7 +1017,7 @@ public class HMaster extends HRegionServer implements MasterServices {
     RegionState rs = this.assignmentManager.getRegionStates().
         getRegionState(RegionInfoBuilder.FIRST_META_REGIONINFO);
     LOG.info("hbase:meta {}", rs);
-    if (rs != null && rs.isOffline()) {
+    if (rs.isOffline()) {
       Optional<InitMetaProcedure> optProc = procedureExecutor.getProcedures().stream()
         .filter(p -> p instanceof InitMetaProcedure).map(o -> (InitMetaProcedure) o).findAny();
       initMetaProc = optProc.orElseGet(() -> {

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

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -34,6 +34,7 @@ import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.Result;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.TableState;
+import org.apache.hadoop.hbase.exceptions.IllegalArgumentIOException;
 import org.apache.hadoop.hbase.util.IdReadWriteLock;
 import org.apache.hadoop.hbase.util.ZKDataMigrator;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
@@ -52,20 +53,8 @@ import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
 // TODO: Make this a guava Service
 @InterfaceAudience.Private
 public class TableStateManager {
+
   private static final Logger LOG = LoggerFactory.getLogger(TableStateManager.class);
-
-  /**
-   * All table state is kept in hbase:meta except that of hbase:meta itself.
-   * hbase:meta state is kept here locally in this in-memory variable. State
-   * for hbase:meta is not persistent. If this process dies, the hbase:meta
-   * state reverts to enabled. State is used so we can edit hbase:meta as we
-   * would any other table by disabling, altering, and then re-enabling. If this
-   * process dies in the midst of an edit, the table reverts to enabled. Schema
-   * is read from the filesystem. It is changed atomically so if we die midway
-   * through an edit we should be good.
-   */
-  private TableState.State metaTableState = TableState.State.ENABLED;
-
   /**
    * Set this key to false in Configuration to disable migrating table state from zookeeper so
    * hbase:meta table.
@@ -79,7 +68,7 @@ public class TableStateManager {
   private final ConcurrentMap<TableName, TableState.State> tableName2State =
     new ConcurrentHashMap<>();
 
-  TableStateManager(MasterServices master) {
+  public TableStateManager(MasterServices master) {
     this.master = master;
   }
 
@@ -98,6 +87,61 @@ public class TableStateManager {
     }
   }
 
+  /**
+   * Set table state to provided but only if table in specified states Caller should lock table on
+   * write.
+   * @param tableName table to change state for
+   * @param newState new state
+   * @param states states to check against
+   * @return null if succeed or table state if failed
+   */
+  public TableState setTableStateIfInStates(TableName tableName, TableState.State newState,
+      TableState.State... states) throws IOException {
+    ReadWriteLock lock = tnLock.getLock(tableName);
+    lock.writeLock().lock();
+    try {
+      TableState currentState = readMetaState(tableName);
+      if (currentState == null) {
+        throw new TableNotFoundException(tableName);
+      }
+      if (currentState.inStates(states)) {
+        updateMetaState(tableName, newState);
+        return null;
+      } else {
+        return currentState;
+      }
+    } finally {
+      lock.writeLock().unlock();
+    }
+  }
+
+  /**
+   * Set table state to provided but only if table not in specified states Caller should lock table
+   * on write.
+   * @param tableName table to change state for
+   * @param newState new state
+   * @param states states to check against
+   */
+  public boolean setTableStateIfNotInStates(TableName tableName, TableState.State newState,
+      TableState.State... states) throws IOException {
+    ReadWriteLock lock = tnLock.getLock(tableName);
+    lock.writeLock().lock();
+    try {
+      TableState currentState = readMetaState(tableName);
+      if (currentState == null) {
+        throw new TableNotFoundException(tableName);
+      }
+      if (!currentState.inStates(states)) {
+        updateMetaState(tableName, newState);
+        return true;
+      } else {
+        return false;
+      }
+    } finally {
+      lock.writeLock().unlock();
+    }
+  }
+
   public boolean isTableState(TableName tableName, TableState.State... states) {
     try {
       TableState tableState = getTableState(tableName);
@@ -111,7 +155,6 @@ public class TableStateManager {
 
   public void setDeletedTable(TableName tableName) throws IOException {
     if (tableName.equals(TableName.META_TABLE_NAME)) {
-      // Can't delete the hbase:meta table.
       return;
     }
     ReadWriteLock lock = tnLock.getLock(tableName);
@@ -140,7 +183,7 @@ public class TableStateManager {
    * @param states filter by states
    * @return tables in given states
    */
-  Set<TableName> getTablesInStates(TableState.State... states) throws IOException {
+  public Set<TableName> getTablesInStates(TableState.State... states) throws IOException {
     // Only be called in region normalizer, will not use cache.
     final Set<TableName> rv = Sets.newHashSet();
     MetaTableAccessor.fullScanTables(master.getConnection(), new MetaTableAccessor.Visitor() {
@@ -156,6 +199,12 @@ public class TableStateManager {
     return rv;
   }
 
+  public static class TableStateNotFoundException extends TableNotFoundException {
+    TableStateNotFoundException(TableName tableName) {
+      super(tableName.getNameAsString());
+    }
+  }
+
   @NonNull
   public TableState getTableState(TableName tableName) throws IOException {
     ReadWriteLock lock = tnLock.getLock(tableName);
@@ -163,7 +212,7 @@ public class TableStateManager {
     try {
       TableState currentState = readMetaState(tableName);
       if (currentState == null) {
-        throw new TableNotFoundException("No state found for " + tableName);
+        throw new TableStateNotFoundException(tableName);
       }
       return currentState;
     } finally {
@@ -172,18 +221,22 @@ public class TableStateManager {
   }
 
   private void updateMetaState(TableName tableName, TableState.State newState) throws IOException {
+    if (tableName.equals(TableName.META_TABLE_NAME)) {
+      if (TableState.State.DISABLING.equals(newState) ||
+        TableState.State.DISABLED.equals(newState)) {
+        throw new IllegalArgumentIOException("Cannot disable the meta table; " + newState);
+      }
+      // Otherwise, just return; no need to set ENABLED on meta -- it is always ENABLED.
+      return;
+    }
     boolean succ = false;
     try {
-      if (tableName.equals(TableName.META_TABLE_NAME)) {
-        this.metaTableState = newState;
-      } else {
       MetaTableAccessor.updateTableState(master.getConnection(), tableName, newState);
-      }
+      tableName2State.put(tableName, newState);
-      this.tableName2State.put(tableName, newState);
       succ = true;
     } finally {
       if (!succ) {
-        this.tableName2State.remove(tableName);
+        tableName2State.remove(tableName);
       }
     }
     metaStateUpdated(tableName, newState);
@@ -202,9 +255,7 @@ public class TableStateManager {
     if (state != null) {
       return new TableState(tableName, state);
     }
-    TableState tableState = tableName.equals(TableName.META_TABLE_NAME)?
+    TableState tableState = MetaTableAccessor.getTableState(master.getConnection(), tableName);
-        new TableState(TableName.META_TABLE_NAME, this.metaTableState):
-        MetaTableAccessor.getTableState(master.getConnection(), tableName);
     if (tableState != null) {
       tableName2State.putIfAbsent(tableName, tableState.getState());
     }
@@ -212,8 +263,10 @@ public class TableStateManager {
   }
 
   public void start() throws IOException {
+    TableDescriptors tableDescriptors = master.getTableDescriptors();
     migrateZooKeeper();
-    fixTableStates(master.getTableDescriptors(), master.getConnection());
+    Connection connection = master.getConnection();
+    fixTableStates(tableDescriptors, connection);
   }
 
   private void fixTableStates(TableDescriptors tableDescriptors, Connection connection)
@@ -282,7 +335,7 @@ public class TableStateManager {
         TableState ts = null;
         try {
           ts = getTableState(entry.getKey());
-        } catch (TableNotFoundException e) {
+        } catch (TableStateNotFoundException e) {
           // This can happen; table exists but no TableState.
         }
         if (ts == null) {

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java

@@ -147,7 +147,8 @@ public class RegionStateStore {
     }
   }
 
-  void updateRegionLocation(RegionStateNode regionStateNode) throws IOException {
+  public void updateRegionLocation(RegionStateNode regionStateNode)
+      throws IOException {
     if (regionStateNode.getRegionInfo().isMetaRegion()) {
       updateMetaLocation(regionStateNode.getRegionInfo(), regionStateNode.getRegionLocation(),
         regionStateNode.getState());

hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/CreateTableProcedure.java

@@ -78,7 +78,9 @@ public class CreateTableProcedure
   @Override
   protected Flow executeFromState(final MasterProcedureEnv env, final CreateTableState state)
       throws InterruptedException {
-    LOG.info("{} execute state={}", this, state);
+    if (LOG.isTraceEnabled()) {
+      LOG.trace(this + " execute state=" + state);
+    }
     try {
       switch (state) {
         case CREATE_TABLE_PRE_OPERATION:

hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DisableTableProcedure.java

@@ -28,6 +28,7 @@ import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.BufferedMutator;
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.TableState;
+import org.apache.hadoop.hbase.constraint.ConstraintException;
 import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
 import org.apache.hadoop.hbase.master.MasterFileSystem;
 import org.apache.hadoop.hbase.master.TableStateManager;
@@ -108,8 +109,8 @@ public class DisableTableProcedure
           setNextState(DisableTableState.DISABLE_TABLE_ADD_REPLICATION_BARRIER);
           break;
         case DISABLE_TABLE_ADD_REPLICATION_BARRIER:
-          if (env.getMasterServices().getTableDescriptors().get(tableName).
+          if (env.getMasterServices().getTableDescriptors().get(tableName)
-              hasGlobalReplicationScope()) {
+            .hasGlobalReplicationScope()) {
             MasterFileSystem fs = env.getMasterFileSystem();
             try (BufferedMutator mutator = env.getMasterServices().getConnection()
               .getBufferedMutator(TableName.META_TABLE_NAME)) {
@@ -241,7 +242,10 @@ public class DisableTableProcedure
    */
   private boolean prepareDisable(final MasterProcedureEnv env) throws IOException {
     boolean canTableBeDisabled = true;
-    if (!MetaTableAccessor.tableExists(env.getMasterServices().getConnection(), tableName)) {
+    if (tableName.equals(TableName.META_TABLE_NAME)) {
+      setFailure("master-disable-table", new ConstraintException("Cannot disable catalog table"));
+      canTableBeDisabled = false;
+    } else if (!MetaTableAccessor.tableExists(env.getMasterServices().getConnection(), tableName)) {
       setFailure("master-disable-table", new TableNotFoundException(tableName));
       canTableBeDisabled = false;
     } else if (!skipTableStateCheck) {

hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/EnableTableProcedure.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -22,17 +22,16 @@ import java.util.ArrayList;
 import java.util.List;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.MetaTableAccessor;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotDisabledException;
 import org.apache.hadoop.hbase.TableNotFoundException;
-import org.apache.hadoop.hbase.client.ClusterConnection;
 import org.apache.hadoop.hbase.client.Connection;
+import org.apache.hadoop.hbase.client.Get;
 import org.apache.hadoop.hbase.client.RegionInfo;
-import org.apache.hadoop.hbase.client.RegionLocator;
 import org.apache.hadoop.hbase.client.RegionReplicaUtil;
 import org.apache.hadoop.hbase.client.Result;
+import org.apache.hadoop.hbase.client.Table;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.TableState;
 import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
@@ -58,7 +57,6 @@ public class EnableTableProcedure
 
   /**
    * Constructor
-   *
    * @param env MasterProcedureEnv
    * @param tableName the table to operate on
    */
@@ -68,7 +66,6 @@ public class EnableTableProcedure
 
   /**
    * Constructor
-   *
    * @param env MasterProcedureEnv
    * @param tableName the table to operate on
    */
@@ -102,55 +99,66 @@ public class EnableTableProcedure
           setNextState(EnableTableState.ENABLE_TABLE_MARK_REGIONS_ONLINE);
           break;
         case ENABLE_TABLE_MARK_REGIONS_ONLINE:
-          // Get the region replica count. If changed since disable, need to do
+          Connection connection = env.getMasterServices().getConnection();
-          // more work assigning.
+          // we will need to get the tableDescriptor here to see if there is a change in the replica
-          ClusterConnection connection = env.getMasterServices().getClusterConnection();
+          // count
-          TableDescriptor tableDescriptor =
+          TableDescriptor hTableDescriptor =
               env.getMasterServices().getTableDescriptors().get(tableName);
-          int configuredReplicaCount = tableDescriptor.getRegionReplication();
+
-          // Get regions for the table from memory; get both online and offline regions ('true').
+          // Get the replica count
+          int regionReplicaCount = hTableDescriptor.getRegionReplication();
+
+          // Get the regions for the table from memory; get both online and offline regions
+          // ('true').
           List<RegionInfo> regionsOfTable =
               env.getAssignmentManager().getRegionStates().getRegionsOfTable(tableName, true);
 
-          // How many replicas do we currently have? Check regions returned from
+          int currentMaxReplica = 0;
-          // in-memory state.
+          // Check if the regions in memory have replica regions as marked in META table
-          int currentMaxReplica = getMaxReplicaId(regionsOfTable);
+          for (RegionInfo regionInfo : regionsOfTable) {
-
+            if (regionInfo.getReplicaId() > currentMaxReplica) {
-          // Read the META table to know the number of replicas the table currently has.
+              // Iterating through all the list to identify the highest replicaID region.
-          // If there was a table modification on region replica count then need to
+              // We can stop after checking with the first set of regions??
-          // adjust replica counts here.
+              currentMaxReplica = regionInfo.getReplicaId();
-          int replicasFound = TableName.isMetaTableName(this.tableName)?
-              getReplicaCountForMetaTable(connection):
-              getReplicaCountInMetaTable(connection, configuredReplicaCount, regionsOfTable);
-          LOG.info("replicasFound={} (configuredReplicaCount={} for {}", replicasFound,
-              configuredReplicaCount, tableName.getNameAsString());
-          if (currentMaxReplica == (configuredReplicaCount - 1)) {
-            if (LOG.isDebugEnabled()) {
-              LOG.debug("No change in number of region replicas (configuredReplicaCount={});"
-                  + " assigning.", configuredReplicaCount);
             }
-          } else if (currentMaxReplica > (configuredReplicaCount - 1)) {
+          }
-            // We have additional regions as the replica count has been decreased. Delete
+
+          // read the META table to know the actual number of replicas for the table - if there
+          // was a table modification on region replica then this will reflect the new entries also
+          int replicasFound =
+              getNumberOfReplicasFromMeta(connection, regionReplicaCount, regionsOfTable);
+          assert regionReplicaCount - 1 == replicasFound;
+          LOG.info(replicasFound + " META entries added for the given regionReplicaCount "
+              + regionReplicaCount + " for the table " + tableName.getNameAsString());
+          if (currentMaxReplica == (regionReplicaCount - 1)) {
+            if (LOG.isDebugEnabled()) {
+              LOG.debug("There is no change to the number of region replicas."
+                  + " Assigning the available regions." + " Current and previous"
+                  + "replica count is " + regionReplicaCount);
+            }
+          } else if (currentMaxReplica > (regionReplicaCount - 1)) {
+            // we have additional regions as the replica count has been decreased. Delete
             // those regions because already the table is in the unassigned state
             LOG.info("The number of replicas " + (currentMaxReplica + 1)
-                + "  is more than the region replica count " + configuredReplicaCount);
+                + "  is more than the region replica count " + regionReplicaCount);
-            List<RegionInfo> copyOfRegions = new ArrayList<>(regionsOfTable);
+            List<RegionInfo> copyOfRegions = new ArrayList<RegionInfo>(regionsOfTable);
             for (RegionInfo regionInfo : copyOfRegions) {
-              if (regionInfo.getReplicaId() > (configuredReplicaCount - 1)) {
+              if (regionInfo.getReplicaId() > (regionReplicaCount - 1)) {
                 // delete the region from the regionStates
                 env.getAssignmentManager().getRegionStates().deleteRegion(regionInfo);
                 // remove it from the list of regions of the table
-                LOG.info("Removed replica={} of {}", regionInfo.getRegionId(), regionInfo);
+                LOG.info("The regioninfo being removed is " + regionInfo + " "
+                    + regionInfo.getReplicaId());
                 regionsOfTable.remove(regionInfo);
               }
             }
           } else {
             // the replicasFound is less than the regionReplication
-            LOG.info("Number of replicas has increased. Assigning new region replicas." +
+            LOG.info("The number of replicas has been changed(increased)."
-                    "The previous replica count was {}. The current replica count is {}.",
+                + " Lets assign the new region replicas. The previous replica count was "
-                (currentMaxReplica + 1), configuredReplicaCount);
+                + (currentMaxReplica + 1) + ". The current replica count is " + regionReplicaCount);
-            regionsOfTable = RegionReplicaUtil.addReplicas(tableDescriptor, regionsOfTable,
+            regionsOfTable = RegionReplicaUtil.addReplicas(hTableDescriptor, regionsOfTable,
-                currentMaxReplica + 1, configuredReplicaCount);
+              currentMaxReplica + 1, regionReplicaCount);
           }
           // Assign all the table regions. (including region replicas if added).
           // createAssignProcedure will try to retain old assignments if possible.
@@ -178,31 +186,9 @@ public class EnableTableProcedure
     return Flow.HAS_MORE_STATE;
   }
 
-  /**
+  private int getNumberOfReplicasFromMeta(Connection connection, int regionReplicaCount,
-   * @return Count of hbase:meta replicas.
-   */
-  private static int getReplicaCountForMetaTable(ClusterConnection connection) throws IOException {
-    // It is hard to get at the meta replicas. Do this ugly stuff for now.
-    // In getRegionLocator, when meta, it uses the Registry. Default implementation
-    // is zk-based registry. It reads znodes that host hbase:meta region replicas.
-    RegionLocator rl = connection.getRegionLocator(TableName.META_TABLE_NAME);
-    if (rl != null) {
-      // Look at first region only.
-      List<HRegionLocation> rls = rl.getRegionLocations(HConstants.EMPTY_START_ROW);
-      if (rls != null) {
-        return rls.size();
-      }
-    }
-    // If can't find count, return 0.
-    return 0;
-  }
-
-  /**
-   * @return Count of replicas found reading hbase:meta table row.
-   */
-  private int getReplicaCountInMetaTable(Connection connection, int regionReplicaCount,
       List<RegionInfo> regionsOfTable) throws IOException {
-    Result r = MetaTableAccessor.getCatalogFamilyRow(connection, regionsOfTable.get(0));
+    Result r = getRegionFromMeta(connection, regionsOfTable);
     int replicasFound = 0;
     for (int i = 1; i < regionReplicaCount; i++) {
       // Since we have already added the entries to the META we will be getting only that here
@@ -215,6 +201,16 @@ public class EnableTableProcedure
     return replicasFound;
   }
 
+  private Result getRegionFromMeta(Connection connection, List<RegionInfo> regionsOfTable)
+      throws IOException {
+    byte[] metaKeyForRegion = MetaTableAccessor.getMetaKeyForRegion(regionsOfTable.get(0));
+    Get get = new Get(metaKeyForRegion);
+    get.addFamily(HConstants.CATALOG_FAMILY);
+    Table metaTable = MetaTableAccessor.getMetaHTable(connection);
+    Result r = metaTable.get(get);
+    return r;
+  }
+
   @Override
   protected void rollbackState(final MasterProcedureEnv env, final EnableTableState state)
       throws IOException {
@@ -412,19 +408,4 @@ public class EnableTableProcedure
       }
     }
   }
-
-  /**
-   * @return Maximum region replica id found in passed list of regions.
-   */
-  private static int getMaxReplicaId(List<RegionInfo> regions) {
-    int max = 0;
-    for (RegionInfo regionInfo: regions) {
-      if (regionInfo.getReplicaId() > max) {
-        // Iterating through all the list to identify the highest replicaID region.
-        // We can stop after checking with the first set of regions??
-        max = regionInfo.getReplicaId();
-      }
-    }
-    return max;
-  }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/replication/ModifyPeerProcedure.java

@@ -25,11 +25,11 @@ import java.util.function.LongConsumer;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.MetaTableAccessor;
 import org.apache.hadoop.hbase.TableName;
-import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.TableState;
 import org.apache.hadoop.hbase.master.TableStateManager;
+import org.apache.hadoop.hbase.master.TableStateManager.TableStateNotFoundException;
 import org.apache.hadoop.hbase.master.procedure.MasterProcedureEnv;
 import org.apache.hadoop.hbase.master.procedure.ProcedurePrepareLatch;
 import org.apache.hadoop.hbase.master.procedure.ReopenTableRegionsProcedure;
@@ -149,7 +149,7 @@ public abstract class ModifyPeerProcedure extends AbstractPeerProcedure<PeerModi
           return false;
         }
         Thread.sleep(SLEEP_INTERVAL_MS);
-      } catch (TableNotFoundException e) {
+      } catch (TableStateNotFoundException e) {
         return false;
       } catch (InterruptedException e) {
         throw (IOException) new InterruptedIOException(e.getMessage()).initCause(e);
@@ -228,7 +228,7 @@ public abstract class ModifyPeerProcedure extends AbstractPeerProcedure<PeerModi
           return true;
         }
         Thread.sleep(SLEEP_INTERVAL_MS);
-      } catch (TableNotFoundException e) {
+      } catch (TableStateNotFoundException e) {
         return false;
       } catch (InterruptedException e) {
         throw (IOException) new InterruptedIOException(e.getMessage()).initCause(e);

hbase-server/src/main/java/org/apache/hadoop/hbase/master/zksyncer/MetaLocationSyncer.java

@@ -1,4 +1,4 @@
-/*
+/**
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
@@ -41,6 +41,6 @@ public class MetaLocationSyncer extends ClientZKSyncer {
 
   @Override
   Collection<String> getNodesToWatch() {
-    return watcher.getZNodePaths().getMetaReplicaZNodes();
+    return watcher.getZNodePaths().metaReplicaZNodes.values();
   }
 }

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

@@ -588,9 +588,7 @@ public class CompactingMemStore extends AbstractMemStore {
    * It takes the updatesLock exclusively, pushes active into the pipeline, releases updatesLock
    * and compacts the pipeline.
    */
-  // When this class private, saw ClassNotFoundException? Being loaded from another classloader?
+  private class InMemoryCompactionRunnable implements Runnable {
-  // Trying with class as public to see if makes a difference.
-  public class InMemoryCompactionRunnable implements Runnable {
     @Override
     public void run() {
       inMemoryCompaction();

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

@@ -747,14 +747,9 @@ public class HRegionServer extends HasThread implements
 
   protected TableDescriptors getFsTableDescriptors() throws IOException {
     return new FSTableDescriptors(this.conf,
-      this.fs, this.rootDir, !canUpdateTableDescriptor(), false);
+      this.fs, this.rootDir, !canUpdateTableDescriptor(), false, getMetaTableObserver());
   }
 
-  /**
-   * @deprecated Since 2.3.0. Not needed anymore. Was used by Master to pass in replication
-   *   setting on hbase:meta construction. To be removed in hbase4.
-   */
-  @Deprecated
   protected Function<TableDescriptorBuilder, TableDescriptorBuilder> getMetaTableObserver() {
     return null;
   }

hbase-server/src/main/java/org/apache/hadoop/hbase/util/FSTableDescriptors.java

@@ -24,6 +24,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -98,7 +99,10 @@ public class FSTableDescriptors implements TableDescriptors {
   // TODO.
   private final Map<TableName, TableDescriptor> cache = new ConcurrentHashMap<>();
 
-  private final Configuration configuration;
+  /**
+   * Table descriptor for <code>hbase:meta</code> catalog table
+   */
+  private final TableDescriptor metaTableDescriptor;
 
   /**
    * Construct a FSTableDescriptors instance using the hbase root dir of the given
@@ -120,21 +124,29 @@ public class FSTableDescriptors implements TableDescriptors {
    */
   public FSTableDescriptors(final Configuration conf, final FileSystem fs,
                             final Path rootdir, final boolean fsreadonly, final boolean usecache) throws IOException {
+    this(conf, fs, rootdir, fsreadonly, usecache, null);
+  }
+
+  /**
+   * @param fsreadonly True if we are read-only when it comes to filesystem
+   *                   operations; i.e. on remove, we do not do delete in fs.
+   * @param metaObserver Used by HMaster. It need to modify the META_REPLICAS_NUM for meta table descriptor.
+   *                     see HMaster#finishActiveMasterInitialization
+   *                     TODO: This is a workaround. Should remove this ugly code...
+   */
+  public FSTableDescriptors(final Configuration conf, final FileSystem fs,
+                            final Path rootdir, final boolean fsreadonly, final boolean usecache,
+                            Function<TableDescriptorBuilder, TableDescriptorBuilder> metaObserver) throws IOException {
     this.fs = fs;
     this.rootdir = rootdir;
     this.fsreadonly = fsreadonly;
     this.usecache = usecache;
-    this.configuration = conf;
+    this.metaTableDescriptor = metaObserver == null ? createMetaTableDescriptor(conf)
+          : metaObserver.apply(createMetaTableDescriptorBuilder(conf)).build();
   }
 
-  /**
-   * Should be private
-   * @deprecated Since 2.3.0. Should be for internal use only. Used by testing.
-   */
-  @Deprecated
   @VisibleForTesting
-  public static TableDescriptorBuilder createMetaTableDescriptorBuilder(final Configuration conf)
+  public static TableDescriptorBuilder createMetaTableDescriptorBuilder(final Configuration conf) throws IOException {
-      throws IOException {
     // TODO We used to set CacheDataInL1 for META table. When we have BucketCache in file mode, now
     // the META table data goes to File mode BC only. Test how that affect the system. If too much,
     // we have to rethink about adding back the setCacheDataInL1 for META table CFs.
@@ -169,9 +181,7 @@ public class FSTableDescriptors implements TableDescriptors {
       .setCoprocessor(CoprocessorDescriptorBuilder.newBuilder(
         MultiRowMutationEndpoint.class.getName())
         .setPriority(Coprocessor.PRIORITY_SYSTEM)
-        .build())
+        .build());
-        .setRegionReplication(conf.getInt(HConstants.META_REPLICAS_NUM,
-            HConstants.DEFAULT_META_REPLICA_NUM));
   }
 
   @VisibleForTesting
@@ -208,11 +218,16 @@ public class FSTableDescriptors implements TableDescriptors {
   public TableDescriptor get(final TableName tablename)
   throws IOException {
     invocations++;
-    // If some one tries to get the descriptor for
+    if (TableName.META_TABLE_NAME.equals(tablename)) {
+      cachehits++;
+      return metaTableDescriptor;
+    }
+    // hbase:meta is already handled. If some one tries to get the descriptor for
     // .logs, .oldlogs or .corrupt throw an exception.
     if (HConstants.HBASE_NON_USER_TABLE_DIRS.contains(tablename.getNameAsString())) {
        throw new IOException("No descriptor found for non table = " + tablename);
     }
+
     if (usecache) {
       // Look in cache of descriptors.
       TableDescriptor cachedtdm = this.cache.get(tablename);
@@ -221,27 +236,24 @@ public class FSTableDescriptors implements TableDescriptors {
         return cachedtdm;
       }
     }
-    TableDescriptor td = null;
+    TableDescriptor tdmt = null;
     try {
-      td = getTableDescriptorFromFs(fs, rootdir, tablename);
+      tdmt = getTableDescriptorFromFs(fs, rootdir, tablename);
     } catch (NullPointerException e) {
-      LOG.debug("Exception during readTableDecriptor; tableName={}", tablename, e);
+      LOG.debug("Exception during readTableDecriptor. Current table name = "
+          + tablename, e);
     } catch (TableInfoMissingException e) {
-      if (TableName.isMetaTableName(tablename)) {
+      // ignore. This is regular operation
-        // If we tried to access hbase:meta and it not there, create it.
-        td = createMetaTableDescriptor(this.configuration);
-        LOG.info("Creating new hbase:meta table default descriptor/schema {}", td);
-      }
     } catch (IOException ioe) {
       LOG.debug("Exception during readTableDecriptor. Current table name = "
           + tablename, ioe);
     }
     // last HTD written wins
-    if (usecache && td != null) {
+    if (usecache && tdmt != null) {
-      this.cache.put(tablename, td);
+      this.cache.put(tablename, tdmt);
     }
 
-    return td;
+    return tdmt;
   }
 
   /**
@@ -251,21 +263,16 @@ public class FSTableDescriptors implements TableDescriptors {
   public Map<String, TableDescriptor> getAll()
   throws IOException {
     Map<String, TableDescriptor> tds = new TreeMap<>();
+
     if (fsvisited && usecache) {
-      if (this.cache.get(TableName.META_TABLE_NAME) == null) {
-        // This get will create hbase:meta if it does not exist. Will also populate cache.
-        get(TableName.META_TABLE_NAME);
-      }
       for (Map.Entry<TableName, TableDescriptor> entry: this.cache.entrySet()) {
         tds.put(entry.getKey().getNameWithNamespaceInclAsString(), entry.getValue());
       }
+      // add hbase:meta to the response
+      tds.put(this.metaTableDescriptor.getTableName().getNameAsString(), metaTableDescriptor);
     } else {
       LOG.trace("Fetching table descriptors from the filesystem.");
       boolean allvisited = true;
-      // Add hbase:meta descriptor. The get will create hbase:meta in fs if doesn't
-      // exist. FSUtils listing table names in fs skip meta dirs. TODO: Fill out
-      // FSUtils with methods to get userspace tables and system tables.
-      tds.put(TableName.META_TABLE_NAME.toString(), get(TableName.META_TABLE_NAME));
       for (Path d : FSUtils.getTableDirs(fs, rootdir)) {
         TableDescriptor htd = null;
         try {
@@ -319,9 +326,14 @@ public class FSTableDescriptors implements TableDescriptors {
     if (fsreadonly) {
       throw new NotImplementedException("Cannot add a table descriptor - in read only mode");
     }
-    if (HConstants.HBASE_NON_USER_TABLE_DIRS.contains(htd.getTableName().getNameAsString())) {
+    TableName tableName = htd.getTableName();
-      throw new NotImplementedException("Cannot add Descriptor for reserved subdirectory name: " +
+    if (TableName.META_TABLE_NAME.equals(tableName)) {
-          htd.getTableName().getNameAsString());
+      throw new NotImplementedException(HConstants.NOT_IMPLEMENTED);
+    }
+    if (HConstants.HBASE_NON_USER_TABLE_DIRS.contains(tableName.getNameAsString())) {
+      throw new NotImplementedException(
+          "Cannot add a table descriptor for a reserved subdirectory name: "
+              + htd.getTableName().getNameAsString());
     }
     updateTableDescriptor(htd);
   }
@@ -347,6 +359,26 @@ public class FSTableDescriptors implements TableDescriptors {
     return descriptor;
   }
 
+  /**
+   * Checks if a current table info file exists for the given table
+   *
+   * @param tableName name of table
+   * @return true if exists
+   * @throws IOException
+   */
+  public boolean isTableInfoExists(TableName tableName) throws IOException {
+    return getTableInfoPath(tableName) != null;
+  }
+
+  /**
+   * Find the most current table info file for the given table in the hbase root directory.
+   * @return The file status of the current table info file or null if it does not exist
+   */
+  private FileStatus getTableInfoPath(final TableName tableName) throws IOException {
+    Path tableDir = getTableDir(tableName);
+    return getTableInfoPath(tableDir);
+  }
+
   private FileStatus getTableInfoPath(Path tableDir)
   throws IOException {
     return getTableInfoPath(fs, tableDir, !fsreadonly);
@@ -361,6 +393,7 @@ public class FSTableDescriptors implements TableDescriptors {
    * were sequence numbers).
    *
    * @return The file status of the current table info file or null if it does not exist
+   * @throws IOException
    */
   public static FileStatus getTableInfoPath(FileSystem fs, Path tableDir)
   throws IOException {
@@ -378,6 +411,7 @@ public class FSTableDescriptors implements TableDescriptors {
    * older files.
    *
    * @return The file status of the current table info file or null if none exist
+   * @throws IOException
    */
   private static FileStatus getTableInfoPath(FileSystem fs, Path tableDir, boolean removeOldFiles)
   throws IOException {
@@ -565,6 +599,21 @@ public class FSTableDescriptors implements TableDescriptors {
     return p;
   }
 
+  /**
+   * Deletes all the table descriptor files from the file system.
+   * Used in unit tests only.
+   * @throws NotImplementedException if in read only mode
+   */
+  public void deleteTableDescriptorIfExists(TableName tableName) throws IOException {
+    if (fsreadonly) {
+      throw new NotImplementedException("Cannot delete a table descriptor - in read only mode");
+    }
+
+    Path tableDir = getTableDir(tableName);
+    Path tableInfoDir = new Path(tableDir, TABLEINFO_DIR);
+    deleteTableDescriptorFiles(fs, tableInfoDir, Integer.MAX_VALUE);
+  }
+
   /**
    * Deletes files matching the table info file pattern within the given directory
    * whose sequenceId is at most the given max sequenceId.
@@ -701,27 +750,6 @@ public class FSTableDescriptors implements TableDescriptors {
     if (fsreadonly) {
       throw new NotImplementedException("Cannot create a table descriptor - in read only mode");
     }
-    return createTableDescriptorForTableDirectory(this.fs, tableDir, htd, forceCreation);
-  }
-
-  /**
-   * Create a new TableDescriptor in the specified table directory and filesystem. Happens when we
-   * create a new table or snapshot a table. This method doesn't require creationg of an
-   * {@link FSTableDescriptors} instance so it takes a bunch of arguments. Users of the method
-   * above used to create an FSTableDescriptors instance just to run the method. That was fine
-   * until construction started expecting to be able to read the hbase:meta schema. Snapshotting
-   * to some random dir would fail construction if no hbase:meta schema available.
-   * @param fs Filesystem to write to. Snapshot can set it to other than that of running system.
-   * @param tableDir table directory under which we should write the file
-   * @param htd description of the table to write
-   * @param forceCreation if <tt>true</tt>,then even if previous table descriptor is present it will
-   *          be overwritten
-   * @return <tt>true</tt> if the we successfully created the file, <tt>false</tt> if the file
-   *         already exists and we weren't forcing the descriptor creation.
-   * @throws IOException if a filesystem error occurs
-   */
-  public static boolean createTableDescriptorForTableDirectory(FileSystem fs, Path tableDir,
-      TableDescriptor htd, boolean forceCreation) throws IOException {
     FileStatus status = getTableInfoPath(fs, tableDir);
     if (status != null) {
       LOG.debug("Current path=" + status.getPath());
@@ -737,5 +765,6 @@ public class FSTableDescriptors implements TableDescriptors {
     Path p = writeTableDescriptor(fs, htd, tableDir, status);
     return p != null;
   }
+
 }
 

hbase-server/src/test/java/org/apache/hadoop/hbase/HBaseTestingUtility.java

@@ -154,11 +154,8 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.impl.Log4jLoggerAdapter;
 
-import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
-
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 
-
 /**
  * Facility for testing HBase. Replacement for
  * old HBaseTestCase and HBaseClusterTestCase functionality.
@@ -501,20 +498,17 @@ public class HBaseTestingUtility extends HBaseZKTestingUtility {
 
   /**
    * @return META table descriptor
-   * @deprecated since 2.0 version and will be removed in 3.0 version. Currently for test only.
+   * @deprecated since 2.0 version and will be removed in 3.0 version.
-   *             use {@link #getMetaTableDescriptorBuilder()}. Alter the hbase:meta table instead.
+   *             use {@link #getMetaTableDescriptorBuilder()}
    */
   @Deprecated
   public HTableDescriptor getMetaTableDescriptor() {
-    return new ImmutableHTableDescriptor(getMetaTableDescriptor());
+    return new ImmutableHTableDescriptor(getMetaTableDescriptorBuilder().build());
   }
 
   /**
    * @return META table descriptor
-   * @deprecated Since 2.3.0. No one should be using this internal. Used in testing only.
    */
-  @Deprecated
-  @VisibleForTesting
   public TableDescriptorBuilder getMetaTableDescriptorBuilder() {
     try {
       return FSTableDescriptors.createMetaTableDescriptorBuilder(conf);

hbase-server/src/test/java/org/apache/hadoop/hbase/TestHBaseMetaEdit.java

@@ -1,109 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.hbase;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
-import java.io.IOException;
-
-import org.apache.hadoop.hbase.client.Admin;
-import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
-import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
-import org.apache.hadoop.hbase.client.RegionInfoBuilder;
-import org.apache.hadoop.hbase.client.TableDescriptor;
-import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
-import org.apache.hadoop.hbase.regionserver.Region;
-import org.apache.hadoop.hbase.testclassification.LargeTests;
-import org.apache.hadoop.hbase.testclassification.MiscTests;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.ClassRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.experimental.categories.Category;
-import org.junit.rules.TestName;
-
-
-/**
- * Test being able to edit hbase:meta.
- */
-@Category({MiscTests.class, LargeTests.class})
-public class TestHBaseMetaEdit {
-  @ClassRule
-  public static final HBaseClassTestRule CLASS_RULE =
-      HBaseClassTestRule.forClass(TestHBaseMetaEdit.class);
-  @Rule
-  public TestName name = new TestName();
-  private final static HBaseTestingUtility UTIL = new HBaseTestingUtility();
-
-  @Before
-  public void before() throws Exception {
-    UTIL.startMiniCluster();
-  }
-
-  @After
-  public void after() throws Exception {
-    UTIL.shutdownMiniCluster();
-  }
-
-  /**
-   * Set versions, set HBASE-16213 indexed block encoding, and add a column family.
-   * Verify they are all in place by looking at TableDescriptor AND by checking
-   * what the RegionServer sees after opening Region.
-   */
-  @Test
-  public void testEditMeta() throws IOException {
-    Admin admin = UTIL.getAdmin();
-    admin.disableTable(TableName.META_TABLE_NAME);
-    TableDescriptor descriptor = admin.getDescriptor(TableName.META_TABLE_NAME);
-    ColumnFamilyDescriptor cfd = descriptor.getColumnFamily(HConstants.CATALOG_FAMILY);
-    byte [] extraColumnFamilyName = Bytes.toBytes("xtra");
-    ColumnFamilyDescriptor newCfd =
-        ColumnFamilyDescriptorBuilder.newBuilder(extraColumnFamilyName).build();
-    int oldVersions = cfd.getMaxVersions();
-    // Add '1' to current versions count.
-    cfd = ColumnFamilyDescriptorBuilder.newBuilder(cfd).setMaxVersions(oldVersions + 1).
-        setConfiguration(ColumnFamilyDescriptorBuilder.DATA_BLOCK_ENCODING,
-            DataBlockEncoding.ROW_INDEX_V1.toString()).build();
-    admin.modifyColumnFamily(TableName.META_TABLE_NAME, cfd);
-    admin.addColumnFamily(TableName.META_TABLE_NAME, newCfd);
-    descriptor = admin.getDescriptor(TableName.META_TABLE_NAME);
-    // Assert new max versions is == old versions plus 1.
-    assertEquals(oldVersions + 1,
-        descriptor.getColumnFamily(HConstants.CATALOG_FAMILY).getMaxVersions());
-    admin.enableTable(TableName.META_TABLE_NAME);
-    descriptor = admin.getDescriptor(TableName.META_TABLE_NAME);
-    // Assert new max versions is == old versions plus 1.
-    assertEquals(oldVersions + 1,
-        descriptor.getColumnFamily(HConstants.CATALOG_FAMILY).getMaxVersions());
-    assertTrue(descriptor.getColumnFamily(newCfd.getName()) != null);
-    String encoding = descriptor.getColumnFamily(HConstants.CATALOG_FAMILY).getConfiguration().
-        get(ColumnFamilyDescriptorBuilder.DATA_BLOCK_ENCODING);
-    assertEquals(encoding, DataBlockEncoding.ROW_INDEX_V1.toString());
-    Region r = UTIL.getHBaseCluster().getRegionServer(0).
-        getRegion(RegionInfoBuilder.FIRST_META_REGIONINFO.getEncodedName());
-    assertEquals(oldVersions + 1,
-        r.getStore(HConstants.CATALOG_FAMILY).getColumnFamilyDescriptor().getMaxVersions());
-    encoding = r.getStore(HConstants.CATALOG_FAMILY).getColumnFamilyDescriptor().
-        getConfigurationValue(ColumnFamilyDescriptorBuilder.DATA_BLOCK_ENCODING);
-    assertEquals(encoding, DataBlockEncoding.ROW_INDEX_V1.toString());
-    assertTrue(r.getStore(extraColumnFamilyName) != null);
-  }
-}

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAdmin2.java

@@ -47,6 +47,7 @@ import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.UnknownRegionException;
 import org.apache.hadoop.hbase.Waiter.Predicate;
 import org.apache.hadoop.hbase.ZooKeeperConnectionException;
+import org.apache.hadoop.hbase.constraint.ConstraintException;
 import org.apache.hadoop.hbase.ipc.HBaseRpcController;
 import org.apache.hadoop.hbase.master.HMaster;
 import org.apache.hadoop.hbase.master.assignment.AssignmentManager;
@@ -537,6 +538,22 @@ public class TestAdmin2 extends TestAdminBase {
       " HBase was not available");
   }
 
+  @Test
+  public void testDisableCatalogTable() throws Exception {
+    try {
+      ADMIN.disableTable(TableName.META_TABLE_NAME);
+      fail("Expected to throw ConstraintException");
+    } catch (ConstraintException e) {
+    }
+    // Before the fix for HBASE-6146, the below table creation was failing as the hbase:meta table
+    // actually getting disabled by the disableTable() call.
+    HTableDescriptor htd =
+        new HTableDescriptor(TableName.valueOf(Bytes.toBytes(name.getMethodName())));
+    HColumnDescriptor hcd = new HColumnDescriptor(Bytes.toBytes("cf1"));
+    htd.addFamily(hcd);
+    TEST_UTIL.getHBaseAdmin().createTable(htd);
+  }
+
   @Test
   public void testIsEnabledOrDisabledOnUnknownTable() throws Exception {
     try {

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncAccessControlAdminApi.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
  * agreements. See the NOTICE file distributed with this work for additional information regarding
  * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableAdminApi2.java

@@ -39,6 +39,7 @@ import java.util.Set;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /**
  * Class to test asynchronous table admin operations
@@ -53,6 +54,18 @@ public class TestAsyncTableAdminApi2 extends TestAsyncAdminBase {
   public static final HBaseClassTestRule CLASS_RULE =
       HBaseClassTestRule.forClass(TestAsyncTableAdminApi2.class);
 
+  @Test
+  public void testDisableCatalogTable() throws Exception {
+    try {
+      this.admin.disableTable(TableName.META_TABLE_NAME).join();
+      fail("Expected to throw ConstraintException");
+    } catch (Exception e) {
+    }
+    // Before the fix for HBASE-6146, the below table creation was failing as the hbase:meta table
+    // actually getting disabled by the disableTable() call.
+    createTableWithDefaultConf(tableName);
+  }
+
   @Test
   public void testAddColumnFamily() throws Exception {
     // Create a table with two families

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableAdminApi3.java

@@ -18,9 +18,12 @@
 package org.apache.hadoop.hbase.client;
 
 import static org.apache.hadoop.hbase.TableName.META_TABLE_NAME;
+import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -29,6 +32,7 @@ import java.util.Optional;
 import java.util.concurrent.ExecutionException;
 import java.util.regex.Pattern;
 import org.apache.hadoop.hbase.AsyncMetaTableAccessor;
+import org.apache.hadoop.hbase.DoNotRetryIOException;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.TableName;
@@ -197,6 +201,14 @@ public class TestAsyncTableAdminApi3 extends TestAsyncAdminBase {
       ok = false;
     }
     assertTrue(ok);
+    // meta table can not be disabled.
+    try {
+      admin.disableTable(TableName.META_TABLE_NAME).get();
+      fail("meta table can not be disabled");
+    } catch (ExecutionException e) {
+      Throwable cause = e.getCause();
+      assertThat(cause, instanceOf(DoNotRetryIOException.class));
+    }
   }
 
   @Test

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestClusterId.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestLogRollingNoCluster.java

@@ -161,7 +161,7 @@ public class TestLogRollingNoCluster {
           byte[] bytes = Bytes.toBytes(i);
           edit.add(new KeyValue(bytes, bytes, bytes, now, EMPTY_1K_ARRAY));
           RegionInfo hri = RegionInfoBuilder.FIRST_META_REGIONINFO;
-          TableDescriptor htd = TEST_UTIL.getMetaTableDescriptor();
+          TableDescriptor htd = TEST_UTIL.getMetaTableDescriptorBuilder().build();
           NavigableMap<byte[], Integer> scopes = new TreeMap<>(Bytes.BYTES_COMPARATOR);
           for(byte[] fam : htd.getColumnFamilyNames()) {
             scopes.put(fam, 0);

hbase-server/src/test/java/org/apache/hadoop/hbase/util/TestFSTableDescriptors.java

@@ -322,9 +322,7 @@ public class TestFSTableDescriptors {
     }
 
     Map<String, TableDescriptor> tables = tds.getAll();
-    assertEquals(5, tables.size());
+    assertEquals(4, tables.size());
-    // Remove because it messes up below order test.
-    tables.remove(TableName.META_TABLE_NAME.toString());
 
     String[] tableNamesOrdered =
         new String[] { "bar:foo", "default:bar", "default:foo", "foo:bar" };
@@ -370,9 +368,6 @@ public class TestFSTableDescriptors {
 
     for (Map.Entry<String, TableDescriptor> entry: nonchtds.getAll().entrySet()) {
       String t = (String) entry.getKey();
-      if (t.equals(TableName.META_TABLE_NAME.toString())) {
-        continue;
-      }
       TableDescriptor nchtd = entry.getValue();
       assertTrue("expected " + htd.toString() +
                    " got: " + chtds.get(TableName.valueOf(t)).toString(),

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/MetaTableLocator.java

@@ -1,4 +1,4 @@
-/*
+/**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -61,6 +61,14 @@ public final class MetaTableLocator {
   private MetaTableLocator() {
   }
 
+  /**
+   * Checks if the meta region location is available.
+   * @return true if meta region location is available, false if not
+   */
+  public static boolean isLocationAvailable(ZKWatcher zkw) {
+    return getMetaRegionLocation(zkw) != null;
+  }
+
   /**
    * @param zkw ZooKeeper watcher to be used
    * @return meta table regions and their locations.
@@ -258,7 +266,7 @@ public final class MetaTableLocator {
   }
 
   /**
-   * Load the meta region state from the meta region server ZNode.
+   * Load the meta region state from the meta server ZNode.
    *
    * @param zkw reference to the {@link ZKWatcher} which also contains configuration and operation
    * @param replicaId the ID of the replica
@@ -298,8 +306,10 @@ public final class MetaTableLocator {
     if (serverName == null) {
       state = RegionState.State.OFFLINE;
     }
-    return new RegionState(RegionReplicaUtil.getRegionInfoForReplica(
+    return new RegionState(
-        RegionInfoBuilder.FIRST_META_REGIONINFO, replicaId), state, serverName);
+        RegionReplicaUtil.getRegionInfoForReplica(
+            RegionInfoBuilder.FIRST_META_REGIONINFO, replicaId),
+        state, serverName);
   }
 
   /**

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java

@@ -2057,7 +2057,7 @@ public final class ZKUtil {
       " byte(s) of data from znode " + znode +
       (watcherSet? " and set watcher; ": "; data=") +
       (data == null? "null": data.length == 0? "empty": (
-          zkw.getZNodePaths().isMetaZNodePrefix(znode)?
+          znode.startsWith(zkw.getZNodePaths().metaZNodePrefix)?
             getServerNameOrEmptyString(data):
           znode.startsWith(zkw.getZNodePaths().backupMasterAddressesZNode)?
             getServerNameOrEmptyString(data):