HBASE-23055 Alter hbase:meta

Make it so hbase:meta can be altered. TableState for hbase:meta
    was hardcoded ENABLED. Make it dynamic. State is now kept in
    current active Master. It is transient so falls back to default
    if Master crashes. Add to registry a getMetaTableState
    which reads mirrored state from zookeeper (NOT from Master and
    defaults ENABLED if no implementation or error fetching state).
    hbase:meta schema will be bootstrapped from the filesystem.
    Changes to filesystem schema are atomic so we should be ok if
    Master fails mid-edit (TBD). Undoes a bunch of guards that
    prevented our being able to edit hbase:meta.

    TODO: Tests, more clarity around hbase:meta table state, and undoing
    references to hard-coded hbase:meta regioninfo.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java
     Throw illegal access exception if you try to use MetaTableAccessor
     getting state of the hbase:meta table.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java
     Add fetching of hbase:meta table state from registry. Adds cache of
     tablestates w/ a ttl of 1 second (adjustable).

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java
    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
      Add querying registry for hbase:meta table state.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZKAsyncRegistry.java
      Add querying of mirrored table state for hbase:meta table.

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

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

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/TableStateManager.java
     Add state holder for hbase:meta. Removed unused methods.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java
     Shut down access.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DisableTableProcedure.java
     Allow hbase:meta to be disabled.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/EnableTableProcedure.java
     Allow hbase:meta to be enabled.

Signed-off-by: Bharath Vissapragada <bharathv@apache.org>

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

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hbase;
 
+
 import edu.umd.cs.findbugs.annotations.NonNull;
 import edu.umd.cs.findbugs.annotations.Nullable;
 import java.io.ByteArrayOutputStream;
@@ -80,6 +81,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
+import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
 import org.apache.hbase.thirdparty.com.google.common.base.Throwables;
 
 /**
@@ -304,11 +306,18 @@ public class MetaTableAccessor {
    */
   public static HRegionLocation getRegionLocation(Connection connection, RegionInfo regionInfo)
       throws IOException {
-    byte[] row = getMetaKeyForRegion(regionInfo);
+    return getRegionLocation(getCatalogFamilyRow(connection, regionInfo),
-    Get get = new Get(row);
+        regionInfo, regionInfo.getReplicaId());
+  }
+
+  /**
+   * @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);
-    Result r = get(getMetaHTable(connection), get);
+    return get(getMetaHTable(connection), get);
-    return getRegionLocation(r, regionInfo, regionInfo.getReplicaId());
   }
 
   /** Returns the row key to use for this regionInfo */
@@ -972,7 +981,8 @@ public class MetaTableAccessor {
    * @return A ServerName instance or null if necessary fields not found or empty.
    */
   @Nullable
-  @InterfaceAudience.Private // for use by HMaster#getTableRegionRow which is used for testing only
+  // for use by HMaster#getTableRegionRow which is used for testing only
+  @InterfaceAudience.Private
   public static ServerName getServerName(final Result r, final int replicaId) {
     byte[] serverColumn = getServerColumn(replicaId);
     Cell cell = r.getColumnLatestCell(getCatalogFamily(), serverColumn);
@@ -1111,9 +1121,8 @@ public class MetaTableAccessor {
   @Nullable
   public static TableState getTableState(Connection conn, TableName tableName)
       throws IOException {
-    if (tableName.equals(TableName.META_TABLE_NAME)) {
+    Preconditions.checkArgument(!tableName.equals(TableName.META_TABLE_NAME),
-      return new TableState(tableName, TableState.State.ENABLED);
+      "Not for hbase:meta state");
-    }
     Table metaHTable = getMetaHTable(conn);
     Get get = new Get(tableName.getName()).addColumn(getTableFamily(), getTableStateColumn());
     Result result = metaHTable.get(get);
@@ -1140,7 +1149,8 @@ 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/AsyncRegistry.java

@@ -21,6 +21,7 @@ import java.io.Closeable;
 import java.util.concurrent.CompletableFuture;
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.ServerName;
+import org.apache.hadoop.hbase.TableName;
 import org.apache.yetus.audience.InterfaceAudience;
 
 /**
@@ -29,12 +30,26 @@ import org.apache.yetus.audience.InterfaceAudience;
  */
 @InterfaceAudience.Private
 interface AsyncRegistry extends Closeable {
+  /**
+   * A completed CompletableFuture to host default hbase:meta table state (ENABLED).
+   */
+  TableState ENABLED_META_TABLE_STATE =
+    new TableState(TableName.META_TABLE_NAME, TableState.State.ENABLED);
+  CompletableFuture<TableState> COMPLETED_GET_META_TABLE_STATE =
+    CompletableFuture.completedFuture(ENABLED_META_TABLE_STATE);
 
   /**
    * Get the location of meta region.
    */
   CompletableFuture<RegionLocations> getMetaRegionLocation();
 
+  /**
+   * The hbase:meta table state.
+   */
+  default CompletableFuture<TableState> getMetaTableState() {
+    return COMPLETED_GET_META_TABLE_STATE;
+  }
+
   /**
    * Should only be called once.
    * <p>

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

@@ -1,5 +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
@@ -86,6 +85,9 @@ import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
 import org.apache.hbase.thirdparty.com.google.common.base.Throwables;
+import org.apache.hbase.thirdparty.com.google.common.cache.CacheBuilder;
+import org.apache.hbase.thirdparty.com.google.common.cache.CacheLoader;
+import org.apache.hbase.thirdparty.com.google.common.cache.LoadingCache;
 import org.apache.hbase.thirdparty.com.google.protobuf.BlockingRpcChannel;
 import org.apache.hbase.thirdparty.com.google.protobuf.RpcController;
 import org.apache.hbase.thirdparty.com.google.protobuf.ServiceException;
@@ -154,6 +156,21 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
   public static final String RETRIES_BY_SERVER_KEY = "hbase.client.retries.by.server";
   private static final Logger LOG = LoggerFactory.getLogger(ConnectionImplementation.class);
 
+  /**
+   * TableState cache.
+   * Table States change super rarely. In synchronous client, state can be queried a lot
+   * particularly when Regions are moving. It is ok if we are not super responsive noticing
+   * Table State change. So, cache the last look up for a period. Use
+   * {@link #TABLESTATE_CACHE_DURATION_MS} to change default of one second.
+   * NOT-private to allow external readers of generated cache stats.
+   */
+  final LoadingCache<TableName, TableState> tableStateCache;
+
+  /**
+   * Duration in milliseconds a tablestate endures in the cache of tablestates.
+   */
+  public static final String TABLESTATE_CACHE_DURATION_MS = "hbase.client.tablestate.cache.ttl.ms";
+
   private static final String RESOLVE_HOSTNAME_ON_FAIL_KEY = "hbase.resolve.hostnames.on.failure";
 
   private final boolean hostnamesCanChange;
@@ -330,6 +347,26 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
       close();
       throw e;
     }
+    // Create tablestate cache. Add a loader that know how to find table state.
+    int duration = this.conf.getInt(TABLESTATE_CACHE_DURATION_MS, 1000);
+    this.tableStateCache = CacheBuilder.newBuilder().
+      expireAfterWrite(duration, TimeUnit.MILLISECONDS).
+      recordStats().
+      build(new CacheLoader<TableName, TableState>() {
+        @Override
+        public TableState load(TableName tableName) throws Exception {
+          if (tableName.equals(TableName.META_TABLE_NAME)) {
+            // We cannot get hbase:meta state by reading hbase:meta table. Read registry.
+            return registry.getMetaTableState().get();
+          }
+          TableState ts =
+            MetaTableAccessor.getTableState(ConnectionImplementation.this, tableName);
+          if (ts == null) {
+            throw new TableNotFoundException(tableName);
+          }
+          return ts;
+        }
+      });
   }
 
   private void spawnRenewalChore(final UserGroupInformation user) {
@@ -429,7 +466,19 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
 
   @Override
   public Admin getAdmin() throws IOException {
-    return new HBaseAdmin(this);
+    return new HBaseAdmin(this) {
+      @Override
+      public void enableTable(TableName tableName) throws IOException {
+        super.enableTable(tableName);
+        ConnectionImplementation.this.tableStateCache.invalidate(tableName);
+      }
+
+      @Override
+      public void disableTable(TableName tableName) throws IOException {
+        super.disableTable(tableName);
+        ConnectionImplementation.this.tableStateCache.invalidate(tableName);
+      }
+    };
   }
 
   @Override
@@ -754,13 +803,9 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
   @Override
   public RegionLocations relocateRegion(final TableName tableName,
       final byte [] row, int replicaId) throws IOException{
-    // Since this is an explicit request not to use any caching, finding
+    if (isTableDisabled(tableName)) {
-    // disabled tables should not be desirable.  This will ensure that an exception is thrown when
-    // the first time a disabled table is interacted with.
-    if (!tableName.equals(TableName.META_TABLE_NAME) && isTableDisabled(tableName)) {
       throw new TableNotEnabledException(tableName.getNameAsString() + " is disabled.");
     }
-
     return locateRegion(tableName, row, false, true, replicaId);
   }
 
@@ -2057,11 +2102,15 @@ class ConnectionImplementation implements ClusterConnection, Closeable {
   @Override
   public TableState getTableState(TableName tableName) throws IOException {
     checkClosed();
-    TableState tableState = MetaTableAccessor.getTableState(this, tableName);
+    try {
-    if (tableState == null) {
+      return this.tableStateCache.get(tableName);
-      throw new TableNotFoundException(tableName);
+    } catch (ExecutionException e) {
+      // Throws ExecutionException for any exceptions fetching table state. Probably an IOE.
+      if (e.getCause() instanceof IOException) {
+        throw (IOException)e.getCause();
+      }
+      throw new IOException(e);
     }
-    return tableState;
   }
 
   @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
@@ -543,7 +543,9 @@ 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) return null;
+    if (tableName == null) {
+      return null;
+    }
     TableDescriptor td =
         executeCallable(new MasterCallable<TableDescriptor>(connection, rpcControllerFactory) {
       @Override
@@ -948,22 +950,13 @@ public class HBaseAdmin implements Admin {
   @Override
   public boolean isTableEnabled(final TableName tableName) throws IOException {
     checkTableExists(tableName);
-    return executeCallable(new RpcRetryingCallable<Boolean>() {
+    return this.connection.getTableState(tableName).isEnabled();
-      @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 connection.isTableDisabled(tableName);
+    return this.connection.getTableState(tableName).isDisabled();
   }
 
   @Override
@@ -4357,5 +4350,4 @@ 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
@@ -20,9 +20,12 @@
 
 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.
@@ -35,7 +38,7 @@ import org.apache.yetus.audience.InterfaceAudience;
  * final user code. Hence it's package protected.
  */
 @InterfaceAudience.Private
-interface MasterKeepAliveConnection extends MasterProtos.MasterService.BlockingInterface {
+interface MasterKeepAliveConnection extends
-  // Do this instead of implement Closeable because closeable returning IOE is PITA.
+    MasterProtos.MasterService.BlockingInterface, Closeable {
   void close();
 }

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

@@ -89,6 +89,7 @@ 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;
@@ -661,22 +662,38 @@ class RawAsyncHBaseAdmin implements AsyncAdmin {
       new DisableTableProcedureBiConsumer(tableName));
   }
 
-  @Override
+  /**
-  public CompletableFuture<Boolean> isTableEnabled(TableName tableName) {
+   * Utility for completing passed TableState {@link CompletableFuture} <code>future</code>
-    if (TableName.isMetaTableName(tableName)) {
+   * using passed parameters.
-      return CompletableFuture.completedFuture(true);
+   */
-    }
+  private static CompletableFuture<Boolean> completeCheckTableState(
-    CompletableFuture<Boolean> future = new CompletableFuture<>();
+      CompletableFuture<Boolean> future, TableState tableState, Throwable error,
-    addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (state, error) -> {
+      TableState.State targetState, TableName tableName) {
     if (error != null) {
       future.completeExceptionally(error);
-        return;
+    } else {
-      }
+      if (tableState != null) {
-      if (state.isPresent()) {
+        future.complete(tableState.inStates(targetState));
-        future.complete(state.get().inStates(TableState.State.ENABLED));
       } else {
         future.completeExceptionally(new TableNotFoundException(tableName));
       }
+    }
+    return future;
+  }
+
+  @Override
+  public CompletableFuture<Boolean> isTableEnabled(TableName tableName) {
+    if (TableName.isMetaTableName(tableName)) {
+      CompletableFuture<Boolean> future = new CompletableFuture<>();
+      addListener(this.connection.registry.getMetaTableState(), (tableState, error) -> {
+        completeCheckTableState(future, tableState, error, TableState.State.ENABLED, tableName);
+      });
+      return future;
+    }
+    CompletableFuture<Boolean> future = new CompletableFuture<>();
+    addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (tableState, error) -> {
+      completeCheckTableState(future, tableState.isPresent()? tableState.get(): null, error,
+        TableState.State.ENABLED, tableName);
     });
     return future;
   }
@@ -684,19 +701,16 @@ class RawAsyncHBaseAdmin implements AsyncAdmin {
   @Override
   public CompletableFuture<Boolean> isTableDisabled(TableName tableName) {
     if (TableName.isMetaTableName(tableName)) {
-      return CompletableFuture.completedFuture(false);
+      CompletableFuture<Boolean> future = new CompletableFuture<>();
+      addListener(this.connection.registry.getMetaTableState(), (tableState, error) -> {
+        completeCheckTableState(future, tableState, error, TableState.State.DISABLED, tableName);
+      });
+      return future;
     }
     CompletableFuture<Boolean> future = new CompletableFuture<>();
-    addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (state, error) -> {
+    addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (tableState, error) -> {
-      if (error != null) {
+      completeCheckTableState(future, tableState.isPresent()? tableState.get(): null, error,
-        future.completeExceptionally(error);
+        TableState.State.DISABLED, tableName);
-        return;
-      }
-      if (state.isPresent()) {
-        future.complete(state.get().inStates(TableState.State.DISABLED));
-      } else {
-        future.completeExceptionally(new TableNotFoundException(tableName));
-      }
     });
     return future;
   }

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

@@ -215,8 +215,7 @@ public abstract class RegionServerCallable<T, S> implements RetryingCallable<T>
   @Override
   public void prepare(final boolean reload) throws IOException {
     // check table state if this is a retry
-    if (reload && tableName != null && !tableName.equals(TableName.META_TABLE_NAME)
+    if (reload && tableName != null && getConnection().isTableDisabled(tableName)) {
-        && getConnection().isTableDisabled(tableName)) {
       throw new TableNotEnabledException(tableName.getNameAsString() + " is disabled.");
     }
     try (RegionLocator regionLocator = connection.getRegionLocator(tableName)) {

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

@@ -27,6 +27,7 @@ import static org.apache.hadoop.hbase.zookeeper.ZKMetadata.removeMetaData;
 import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
 import java.util.stream.Collectors;
 import org.apache.commons.lang3.mutable.MutableInt;
 import org.apache.hadoop.conf.Configuration;
@@ -34,15 +35,18 @@ import org.apache.hadoop.hbase.ClusterId;
 import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.ServerName;
+import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.exceptions.DeserializationException;
 import org.apache.hadoop.hbase.master.RegionState;
 import org.apache.hadoop.hbase.util.Pair;
 import org.apache.hadoop.hbase.zookeeper.ReadOnlyZKClient;
 import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
 import org.apache.yetus.audience.InterfaceAudience;
+import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
+import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ZooKeeperProtos;
 
@@ -58,8 +62,19 @@ class ZKAsyncRegistry implements AsyncRegistry {
 
   private final ZNodePaths znodePaths;
 
+  /**
+   * A znode maintained by MirroringTableStateManager.
+   * MirroringTableStateManager is deprecated to be removed in hbase3. It can also be disabled.
+   * Make sure it is enabled if you want to alter hbase:meta table in hbase2. In hbase3,
+   * TBD how metatable state will be hosted; likely on active hbase master.
+   */
+  private final String znodeMirroredMetaTableState;
+
+
   ZKAsyncRegistry(Configuration conf) {
     this.znodePaths = new ZNodePaths(conf);
+    this.znodeMirroredMetaTableState =
+      ZNodePaths.joinZNode(this.znodePaths.tableZNode, TableName.META_TABLE_NAME.getNameAsString());
     this.zk = new ReadOnlyZKClient(conf);
   }
 
@@ -155,7 +170,8 @@ class ZKAsyncRegistry implements AsyncRegistry {
           }
           Pair<RegionState.State, ServerName> stateAndServerName = getStateAndServerName(proto);
           if (stateAndServerName.getFirst() != RegionState.State.OPEN) {
-            LOG.warn("Meta region is in state " + stateAndServerName.getFirst());
+            LOG.warn("hbase:meta region (replicaId={}) is in state {}", replicaId,
+                stateAndServerName.getFirst());
           }
           locs[DEFAULT_REPLICA_ID] = new HRegionLocation(
             getRegionInfoForDefaultReplica(FIRST_META_REGIONINFO), stateAndServerName.getSecond());
@@ -170,7 +186,7 @@ class ZKAsyncRegistry implements AsyncRegistry {
             LOG.warn("Failed to fetch " + path, error);
             locs[replicaId] = null;
           } else if (proto == null) {
-            LOG.warn("Meta znode for replica " + replicaId + " is null");
+            LOG.warn("hbase:meta znode for replica " + replicaId + " is null");
             locs[replicaId] = null;
           } else {
             Pair<RegionState.State, ServerName> stateAndServerName = getStateAndServerName(proto);
@@ -194,9 +210,8 @@ class ZKAsyncRegistry implements AsyncRegistry {
   public CompletableFuture<RegionLocations> getMetaRegionLocation() {
     CompletableFuture<RegionLocations> future = new CompletableFuture<>();
     addListener(
-      zk.list(znodePaths.baseZNode)
+      zk.list(znodePaths.baseZNode).thenApply(children -> children.stream().
-        .thenApply(children -> children.stream()
+          filter(c -> znodePaths.isMetaZNodePrefix(c)).collect(Collectors.toList())),
-          .filter(c -> c.startsWith(znodePaths.metaZNodePrefix)).collect(Collectors.toList())),
       (metaReplicaZNodes, error) -> {
         if (error != null) {
           future.completeExceptionally(error);
@@ -229,6 +244,43 @@ class ZKAsyncRegistry implements AsyncRegistry {
         });
   }
 
+  @Override
+  public CompletableFuture<TableState> getMetaTableState() {
+    return getAndConvert(this.znodeMirroredMetaTableState, ZKAsyncRegistry::getTableState).
+      thenApply(state -> {
+        return state == null || state.equals(ENABLED_META_TABLE_STATE.getState())?
+          ENABLED_META_TABLE_STATE: new TableState(TableName.META_TABLE_NAME, state);
+      }).exceptionally(e -> {
+        // Handle this case where no znode... Return default ENABLED in this case:
+        // Caused by: java.io.IOException: java.util.concurrent.ExecutionException:
+        // java.util.concurrent.ExecutionException:
+        // org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = NoNode for
+        //  /hbase/table/hbase:meta
+        // If not case of above, then rethrow but may need to wrap. See
+        // https://stackoverflow.com/questions/55453961/
+        //  completablefutureexceptionally-rethrow-checked-exception
+        if (e.getCause() instanceof KeeperException.NoNodeException) {
+          return ENABLED_META_TABLE_STATE;
+        }
+        throw e instanceof CompletionException? (CompletionException)e:
+          new CompletionException(e);
+      });
+  }
+
+  /**
+   * Get tablestate from data byte array found in the mirroring znode of table state.
+   */
+  private static TableState.State getTableState(byte[] data) throws DeserializationException {
+    if (data == null || data.length == 0) {
+      return null;
+    }
+    try {
+      return ProtobufUtil.toTableState(ProtobufUtil.toTableState(removeMetaData(data)));
+    } catch (IOException ioe) {
+      throw new DeserializationException(ioe);
+    }
+  }
+
   @Override
   public void close() {
     zk.close();

hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java

@@ -87,6 +87,7 @@ import org.apache.hadoop.hbase.client.SnapshotDescription;
 import org.apache.hadoop.hbase.client.SnapshotType;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
+import org.apache.hadoop.hbase.client.TableState;
 import org.apache.hadoop.hbase.client.metrics.ScanMetrics;
 import org.apache.hadoop.hbase.client.security.SecurityCapability;
 import org.apache.hadoop.hbase.exceptions.DeserializationException;
@@ -3372,4 +3373,46 @@ public final class ProtobufUtil {
       .build();
   }
 
+
+  /**
+   * Parses pb TableState from <code>data</code>
+   */
+  public static ZooKeeperProtos.DeprecatedTableState.State toTableState(byte [] data)
+    throws DeserializationException, IOException {
+    if (data == null || data.length <= 0) {
+      return null;
+    }
+    ProtobufUtil.expectPBMagicPrefix(data);
+    ZooKeeperProtos.DeprecatedTableState.Builder builder =
+      ZooKeeperProtos.DeprecatedTableState.newBuilder();
+    int magicLen = ProtobufUtil.lengthOfPBMagic();
+    ProtobufUtil.mergeFrom(builder, data, magicLen, data.length - magicLen);
+    return builder.getState();
+  }
+
+
+  /**
+   * @return Convert from pb TableState to pojo TableState.
+   */
+  public static TableState.State toTableState(ZooKeeperProtos.DeprecatedTableState.State state) {
+    TableState.State newState = TableState.State.ENABLED;
+    if (state != null) {
+      switch (state) {
+        case ENABLED:
+          newState = TableState.State.ENABLED;
+          break;
+        case DISABLED:
+          newState = TableState.State.DISABLED;
+          break;
+        case DISABLING:
+          newState = TableState.State.DISABLING;
+          break;
+        case ENABLING:
+          newState = TableState.State.ENABLING;
+          break;
+        default:
+      }
+    }
+    return newState;
+  }
 }

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
@@ -24,6 +24,7 @@ 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;
@@ -40,15 +41,24 @@ public class ZNodePaths {
   // TODO: Replace this with ZooKeeper constant when ZOOKEEPER-277 is resolved.
   public static final char ZNODE_PATH_SEPARATOR = '/';
 
-  public final static String META_ZNODE_PREFIX = "meta-region-server";
+  private static final 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;
+  /**
-  // znodes containing the locations of the servers hosting the meta replicas
+   * The prefix of meta znode. Does not include baseZNode.
-  public final ImmutableMap<Integer, String> metaReplicaZNodes;
+   * Its a 'prefix' because meta replica id integer can be tagged on the end (if
+   * 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
@@ -154,21 +164,21 @@ public class ZNodePaths {
   }
 
   /**
-   * Is the znode of any meta replica
+   * @return true if the znode is a meta region replica
-   * @param node
-   * @return true or false
    */
   public boolean isAnyMetaReplicaZNode(String node) {
-    if (metaReplicaZNodes.containsValue(node)) {
+    return this.metaReplicaZNodes.containsValue(node);
-      return true;
-    }
-    return false;
   }
 
   /**
-   * Get the znode string corresponding to a replicaId
+   * @return Meta Replica ZNodes
-   * @param replicaId
+   */
-   * @return znode
+  public Collection<String> getMetaReplicaZNodes() {
+    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
@@ -179,24 +189,21 @@ public class ZNodePaths {
   }
 
   /**
-   * Parse the meta replicaId from the passed znode
+   * Parse the meta replicaId from the passed znode name.
    * @param znode the name of the znode, does not include baseZNode
    * @return replicaId
    */
   public int getMetaReplicaIdFromZnode(String znode) {
-    if (znode.equals(metaZNodePrefix)) {
+    return znode.equals(metaZNodePrefix)?
-      return RegionInfo.DEFAULT_REPLICA_ID;
+        RegionInfo.DEFAULT_REPLICA_ID:
-    }
+        Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
-    return Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
   }
 
   /**
-   * Is it the default meta replica's znode
+   * @return True if meta znode.
-   * @param znode the name of the znode, does not include baseZNode
-   * @return true or false
    */
-  public boolean isDefaultMetaReplicaZnode(String znode) {
+  public boolean isMetaZNodePrefix(String znode) {
-    return metaReplicaZNodes.get(DEFAULT_REPLICA_ID).equals(znode);
+    return znode != null && znode.startsWith(this.metaZNodePrefix);
   }
 
   /**

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

@@ -27,7 +27,6 @@ import java.util.List;
 import java.util.UUID;
 import java.util.regex.Pattern;
 
-import org.apache.commons.lang3.ArrayUtils;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.yetus.audience.InterfaceAudience;
 
@@ -1225,12 +1224,6 @@ public final class HConstants {
       HBCK_SIDELINEDIR_NAME, HBASE_TEMP_DIRECTORY, MIGRATION_NAME
     }));
 
-  /** 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. */
   public static final String HEALTH_SCRIPT_LOC = "hbase.node.health.script.location";
   public static final String HEALTH_SCRIPT_TIMEOUT = "hbase.node.health.script.timeout";

hbase-common/src/main/java/org/apache/hadoop/hbase/util/CommonFSUtils.java

@@ -703,6 +703,8 @@ public abstract class CommonFSUtils {
       if (LOG.isTraceEnabled()) {
         LOG.trace("{} doesn't exist", dir);
       }
+    } catch (IllegalArgumentException iae) {
+      int x = 0;
     }
     if (status == null || status.length < 1) {
       return null;

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

@@ -25,25 +25,19 @@ 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)
+  TableDescriptor get(final TableName tableName) throws IOException;
-      throws IOException;
 
   /**
    * Get Map of all NamespaceDescriptors for a given namespace.
    * @return Map of all descriptors.
-   * @throws IOException
    */
-  Map<String, TableDescriptor> getByNamespace(String name)
+  Map<String, TableDescriptor> getByNamespace(String name) throws IOException;
-  throws IOException;
 
   /**
    * Get Map of all TableDescriptors. Populates the descriptor cache as a
@@ -51,25 +45,19 @@ 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)
+  void add(final TableDescriptor htd) throws IOException;
-  throws IOException;
 
   /**
-   * @param tablename
    * @return Instance of table descriptor or null if none found.
-   * @throws IOException
    */
-  TableDescriptor remove(final TableName tablename)
+  TableDescriptor remove(final TableName tablename) throws IOException;
-  throws IOException;
 
   /**
    * Enables the tabledescriptor cache

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

@@ -1025,7 +1025,7 @@ public class HMaster extends HRegionServer implements MasterServices {
     RegionState rs = this.assignmentManager.getRegionStates().
         getRegionState(RegionInfoBuilder.FIRST_META_REGIONINFO);
     LOG.info("hbase:meta {}", rs);
-    if (rs.isOffline()) {
+    if (rs != null && 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/MirroringTableStateManager.java

@@ -38,7 +38,8 @@ import org.slf4j.LoggerFactory;
  * mirroring. See in HMaster where we make the choice. The below does zk updates on a best-effort
  * basis only. If we fail updating zk we keep going because only hbase1 clients suffer; we'll just
  * log at WARN level.
- * @deprecated Since 2.0.0. To be removed in 3.0.0.
+ * @deprecated Since 2.0.0. To be removed in 3.0.0. ZKRegistry#getMetaTableState reads
+ *   mirrored state so add alternative mechanism before purge else cannot disable hbase:meta table
  */
 @Deprecated
 @InterfaceAudience.Private
@@ -47,7 +48,7 @@ public class MirroringTableStateManager extends TableStateManager {
 
   /**
    * Set this key to true in Configuration to enable mirroring of table state out to zookeeper so
-   * hbase-1.x clients can pick-up table state.
+   * hbase-1.x clients can pick-up table state. Default value is 'true'.
    */
   static final String MIRROR_TABLE_STATE_TO_ZK_KEY = "hbase.mirror.table.state.to.zookeeper";
 

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
@@ -34,7 +34,6 @@ 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;
@@ -53,8 +52,20 @@ 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.
@@ -68,7 +79,7 @@ public class TableStateManager {
   private final ConcurrentMap<TableName, TableState.State> tableName2State =
     new ConcurrentHashMap<>();
 
-  public TableStateManager(MasterServices master) {
+  TableStateManager(MasterServices master) {
     this.master = master;
   }
 
@@ -87,61 +98,6 @@ 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);
@@ -155,6 +111,7 @@ 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);
@@ -183,7 +140,7 @@ public class TableStateManager {
    * @param states filter by states
    * @return tables in given states
    */
-  public Set<TableName> getTablesInStates(TableState.State... states) throws IOException {
+  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() {
@@ -199,12 +156,6 @@ 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);
@@ -212,7 +163,7 @@ public class TableStateManager {
     try {
       TableState currentState = readMetaState(tableName);
       if (currentState == null) {
-        throw new TableStateNotFoundException(tableName);
+        throw new TableNotFoundException("No state found for " + tableName);
       }
       return currentState;
     } finally {
@@ -221,22 +172,18 @@ 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) {
-        tableName2State.remove(tableName);
+        this.tableName2State.remove(tableName);
       }
     }
     metaStateUpdated(tableName, newState);
@@ -255,7 +202,9 @@ public class TableStateManager {
     if (state != null) {
       return new TableState(tableName, state);
     }
-    TableState tableState = MetaTableAccessor.getTableState(master.getConnection(), tableName);
+    TableState tableState = tableName.equals(TableName.META_TABLE_NAME)?
+        new TableState(TableName.META_TABLE_NAME, this.metaTableState):
+        MetaTableAccessor.getTableState(master.getConnection(), tableName);
     if (tableState != null) {
       tableName2State.putIfAbsent(tableName, tableState.getState());
     }
@@ -263,10 +212,8 @@ public class TableStateManager {
   }
 
   public void start() throws IOException {
-    TableDescriptors tableDescriptors = master.getTableDescriptors();
     migrateZooKeeper();
-    Connection connection = master.getConnection();
+    fixTableStates(master.getTableDescriptors(), master.getConnection());
-    fixTableStates(tableDescriptors, connection);
   }
 
   private void fixTableStates(TableDescriptors tableDescriptors, Connection connection)
@@ -335,7 +282,7 @@ public class TableStateManager {
         TableState ts = null;
         try {
           ts = getTableState(entry.getKey());
-        } catch (TableStateNotFoundException e) {
+        } catch (TableNotFoundException 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

@@ -146,8 +146,7 @@ public class RegionStateStore {
     }
   }
 
-  public void updateRegionLocation(RegionStateNode regionStateNode)
+  void updateRegionLocation(RegionStateNode regionStateNode) throws IOException {
-      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

@@ -78,9 +78,7 @@ public class CreateTableProcedure
   @Override
   protected Flow executeFromState(final MasterProcedureEnv env, final CreateTableState state)
       throws InterruptedException {
-    if (LOG.isTraceEnabled()) {
+    LOG.info("{} execute state={}", this, state);
-      LOG.trace(this + " execute state=" + state);
-    }
     try {
       switch (state) {
         case CREATE_TABLE_PRE_OPERATION:
@@ -320,8 +318,7 @@ public class CreateTableProcedure
     // using a copy of descriptor, table will be created enabling first
     final Path tempTableDir = FSUtils.getTableDir(tempdir, tableDescriptor.getTableName());
     ((FSTableDescriptors)(env.getMasterServices().getTableDescriptors()))
-        .createTableDescriptorForTableDirectory(
+        .createTableDescriptorForTableDirectory(tempTableDir, tableDescriptor, false);
-          tempTableDir, tableDescriptor, false);
 
     // 2. Create Regions
     newRegions = hdfsRegionHandler.createHdfsRegions(env, tempdir,

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

@@ -28,7 +28,6 @@ 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;
@@ -109,8 +108,8 @@ 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)) {
@@ -242,10 +241,7 @@ public class DisableTableProcedure
    */
   private boolean prepareDisable(final MasterProcedureEnv env) throws IOException {
     boolean canTableBeDisabled = true;
-    if (tableName.equals(TableName.META_TABLE_NAME)) {
+    if (!MetaTableAccessor.tableExists(env.getMasterServices().getConnection(), tableName)) {
-      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
@@ -27,11 +27,9 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotDisabledException;
 import org.apache.hadoop.hbase.TableNotFoundException;
 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.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;
@@ -99,66 +97,55 @@ 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
+          // more work assigning.
           Connection connection = env.getMasterServices().getConnection();
-          // we will need to get the tableDescriptor here to see if there is a change in the replica
+          TableDescriptor tableDescriptor =
-          // count
-          TableDescriptor hTableDescriptor =
               env.getMasterServices().getTableDescriptors().get(tableName);
-
+          int configuredReplicaCount = tableDescriptor.getRegionReplication();
-          // Get the replica count
+          // Get regions for the table from memory; get both online and offline regions ('true').
-          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);
 
-          int currentMaxReplica = 0;
+          // How many replicas do we currently have? Check regions returned from
-          // Check if the regions in memory have replica regions as marked in META table
+          // in-memory state.
-          for (RegionInfo regionInfo : regionsOfTable) {
+          int currentMaxReplica = getMaxReplicaId(regionsOfTable);
-            if (regionInfo.getReplicaId() > currentMaxReplica) {
-              // Iterating through all the list to identify the highest replicaID region.
-              // We can stop after checking with the first set of regions??
-              currentMaxReplica = regionInfo.getReplicaId();
-            }
-          }
 
-          // read the META table to know the actual number of replicas for the table - if there
+          // Read the META table to know the number of replicas the table currently has.
-          // was a table modification on region replica then this will reflect the new entries also
+          // If there was a table modification on region replica count then need to
-          int replicasFound =
+          // adjust replica counts here.
-              getNumberOfReplicasFromMeta(connection, regionReplicaCount, regionsOfTable);
+          int replicasFound = TableName.isMetaTableName(this.tableName)?
-          assert regionReplicaCount - 1 == replicasFound;
+              0: // TODO: Figure better what to do here for hbase:meta replica.
-          LOG.info(replicasFound + " META entries added for the given regionReplicaCount "
+              getReplicaCountInMeta(connection, configuredReplicaCount, regionsOfTable);
-              + regionReplicaCount + " for the table " + tableName.getNameAsString());
+          LOG.info("replicasFound={} (configuredReplicaCount={} for {}", replicasFound,
-          if (currentMaxReplica == (regionReplicaCount - 1)) {
+              configuredReplicaCount, tableName.getNameAsString());
+          if (currentMaxReplica == (configuredReplicaCount - 1)) {
             if (LOG.isDebugEnabled()) {
-              LOG.debug("There is no change to the number of region replicas."
+              LOG.debug("No change in number of region replicas (configuredReplicaCount={});"
-                  + " Assigning the available regions." + " Current and previous"
+                  + " assigning.", configuredReplicaCount);
-                  + "replica count is " + regionReplicaCount);
             }
-          } else if (currentMaxReplica > (regionReplicaCount - 1)) {
+          } else if (currentMaxReplica > (configuredReplicaCount - 1)) {
-            // we have additional regions as the replica count has been decreased. Delete
+            // 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 " + regionReplicaCount);
+                + "  is more than the region replica count " + configuredReplicaCount);
             List<RegionInfo> copyOfRegions = new ArrayList<RegionInfo>(regionsOfTable);
             for (RegionInfo regionInfo : copyOfRegions) {
-              if (regionInfo.getReplicaId() > (regionReplicaCount - 1)) {
+              if (regionInfo.getReplicaId() > (configuredReplicaCount - 1)) {
                 // delete the region from the regionStates
                 env.getAssignmentManager().getRegionStates().deleteRegion(regionInfo);
                 // remove it from the list of regions of the table
-                LOG.info("The regioninfo being removed is " + regionInfo + " "
+                LOG.info("Removed replica={} of {}", regionInfo.getRegionId(), regionInfo);
-                    + regionInfo.getReplicaId());
                 regionsOfTable.remove(regionInfo);
               }
             }
           } else {
             // the replicasFound is less than the regionReplication
-            LOG.info("The number of replicas has been changed(increased)."
+            LOG.info("Number of replicas has increased. Assigning new region replicas." +
-                + " Lets assign the new region replicas. The previous replica count was "
+                "The previous replica count was {}. The current replica count is {}.",
-                + (currentMaxReplica + 1) + ". The current replica count is " + regionReplicaCount);
+                (currentMaxReplica + 1), configuredReplicaCount);
-            regionsOfTable = RegionReplicaUtil.addReplicas(hTableDescriptor, regionsOfTable,
+            regionsOfTable = RegionReplicaUtil.addReplicas(tableDescriptor, regionsOfTable,
-              currentMaxReplica + 1, regionReplicaCount);
+              currentMaxReplica + 1, configuredReplicaCount);
           }
           // Assign all the table regions. (including region replicas if added).
           // createAssignProcedure will try to retain old assignments if possible.
@@ -186,9 +173,13 @@ public class EnableTableProcedure
     return Flow.HAS_MORE_STATE;
   }
 
-  private int getNumberOfReplicasFromMeta(Connection connection, int regionReplicaCount,
+  /**
+   * @return Count of replicas found reading hbase:meta Region row or zk if
+   *   asking about the hbase:meta table itself..
+   */
+  private int getReplicaCountInMeta(Connection connection, int regionReplicaCount,
       List<RegionInfo> regionsOfTable) throws IOException {
-    Result r = getRegionFromMeta(connection, regionsOfTable);
+    Result r = MetaTableAccessor.getCatalogFamilyRow(connection, regionsOfTable.get(0));
     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
@@ -201,16 +192,6 @@ 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 {
@@ -408,4 +389,20 @@ 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;
@@ -148,7 +148,7 @@ public abstract class ModifyPeerProcedure extends AbstractPeerProcedure<PeerModi
           return false;
         }
         Thread.sleep(SLEEP_INTERVAL_MS);
-      } catch (TableStateNotFoundException e) {
+      } catch (TableNotFoundException e) {
         return false;
       } catch (InterruptedException e) {
         throw (IOException) new InterruptedIOException(e.getMessage()).initCause(e);
@@ -227,7 +227,7 @@ public abstract class ModifyPeerProcedure extends AbstractPeerProcedure<PeerModi
           return true;
         }
         Thread.sleep(SLEEP_INTERVAL_MS);
-      } catch (TableStateNotFoundException e) {
+      } catch (TableNotFoundException 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().metaReplicaZNodes.values();
+    return watcher.getZNodePaths().getMetaReplicaZNodes();
   }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/snapshot/SnapshotManifest.java

@@ -472,11 +472,10 @@ public final class SnapshotManifest {
 
   public void consolidate() throws IOException {
     if (getSnapshotFormat(desc) == SnapshotManifestV1.DESCRIPTOR_VERSION) {
-      Path rootDir = FSUtils.getRootDir(conf);
       LOG.info("Using old Snapshot Format");
       // write a copy of descriptor to the snapshot directory
-      new FSTableDescriptors(conf, workingDirFs, rootDir)
+      FSTableDescriptors.createTableDescriptorForTableDirectory(workingDirFs, workingDir, htd,
-        .createTableDescriptorForTableDirectory(workingDir, htd, false);
+          false);
     } else {
       LOG.debug("Convert to Single Snapshot Manifest");
       convertToV2SingleManifest();

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

@@ -122,6 +122,7 @@ public class FSTableDescriptors implements TableDescriptors {
    * @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.
    */
+  @VisibleForTesting
   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);
@@ -141,10 +142,26 @@ public class FSTableDescriptors implements TableDescriptors {
     this.rootdir = rootdir;
     this.fsreadonly = fsreadonly;
     this.usecache = usecache;
-    this.metaTableDescriptor = metaObserver == null ? createMetaTableDescriptor(conf)
+    TableDescriptor td = null;
-          : metaObserver.apply(createMetaTableDescriptorBuilder(conf)).build();
+    try {
+      td = getTableDescriptorFromFs(fs, rootdir, TableName.META_TABLE_NAME);
+    } catch (TableInfoMissingException e) {
+      td = metaObserver == null? createMetaTableDescriptor(conf):
+        metaObserver.apply(createMetaTableDescriptorBuilder(conf)).build();
+      if (!fsreadonly) {
+        LOG.info("Creating new hbase:meta table default descriptor/schema {}", td);
+        updateTableDescriptor(td);
+      }
+    }
+    this.metaTableDescriptor = td;
   }
 
+  /**
+   *
+   * 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) throws IOException {
     // TODO We used to set CacheDataInL1 for META table. When we have BucketCache in file mode, now
@@ -218,16 +235,6 @@ public class FSTableDescriptors implements TableDescriptors {
   public TableDescriptor get(final TableName tablename)
   throws IOException {
     invocations++;
-    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);
@@ -263,7 +270,6 @@ public class FSTableDescriptors implements TableDescriptors {
   public Map<String, TableDescriptor> getAll()
   throws IOException {
     Map<String, TableDescriptor> tds = new TreeMap<>();
-
     if (fsvisited && usecache) {
       for (Map.Entry<TableName, TableDescriptor> entry: this.cache.entrySet()) {
         tds.put(entry.getKey().getNameWithNamespaceInclAsString(), entry.getValue());
@@ -326,15 +332,6 @@ public class FSTableDescriptors implements TableDescriptors {
     if (fsreadonly) {
       throw new NotImplementedException("Cannot add a table descriptor - in read only mode");
     }
-    TableName tableName = htd.getTableName();
-    if (TableName.META_TABLE_NAME.equals(tableName)) {
-      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);
   }
 
@@ -359,26 +356,6 @@ 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);
@@ -393,7 +370,6 @@ 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 {
@@ -411,7 +387,6 @@ 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 {
@@ -599,21 +574,6 @@ 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.
@@ -736,7 +696,8 @@ public class FSTableDescriptors implements TableDescriptors {
 
   /**
    * Create a new TableDescriptor in HDFS in the specified table directory. Happens when we create
-   * a new table or snapshot a table.
+   * a new table during cluster start or in Clone and Create Table Procedures. Checks readOnly flag
+   * passed on construction.
    * @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
@@ -745,11 +706,28 @@ public class FSTableDescriptors implements TableDescriptors {
    *         already exists and we weren't forcing the descriptor creation.
    * @throws IOException if a filesystem error occurs
    */
-  public boolean createTableDescriptorForTableDirectory(Path tableDir,
+  public boolean createTableDescriptorForTableDirectory(Path tableDir, TableDescriptor htd,
-      TableDescriptor htd, boolean forceCreation) throws IOException {
+      boolean forceCreation) throws IOException {
-    if (fsreadonly) {
+    if (this.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 HDFS in the specified table directory. Happens when we create
+   * a new table snapshoting. Does not enforce read-only. That is for caller to determine.
+   * @param fs Filesystem to use.
+   * @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());
@@ -762,9 +740,7 @@ public class FSTableDescriptors implements TableDescriptors {
         }
       }
     }
-    Path p = writeTableDescriptor(fs, htd, tableDir, status);
+    return writeTableDescriptor(fs, htd, tableDir, status) != null;
-    return p != null;
+  }
-  }
-
 }
 

hbase-server/src/main/java/org/apache/hadoop/hbase/util/ZKDataMigrator.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
@@ -37,6 +37,7 @@ import org.slf4j.LoggerFactory;
 
 /**
  * Utlity method to migrate zookeeper data across HBase versions.
+ * Used by Master mirroring table state to zk for hbase-1 clients.
  * @deprecated Since 2.0.0. To be removed in hbase-3.0.0.
  */
 @Deprecated
@@ -65,25 +66,7 @@ public class ZKDataMigrator {
       return rv;
     for (String child: children) {
       TableName tableName = TableName.valueOf(child);
-      ZooKeeperProtos.DeprecatedTableState.State state = getTableState(zkw, tableName);
+      TableState.State newState = ProtobufUtil.toTableState(getTableState(zkw, tableName));
-      TableState.State newState = TableState.State.ENABLED;
-      if (state != null) {
-        switch (state) {
-        case ENABLED:
-          newState = TableState.State.ENABLED;
-          break;
-        case DISABLED:
-          newState = TableState.State.DISABLED;
-          break;
-        case DISABLING:
-          newState = TableState.State.DISABLING;
-          break;
-        case ENABLING:
-          newState = TableState.State.ENABLING;
-          break;
-        default:
-        }
-      }
       rv.put(tableName, newState);
     }
     return rv;
@@ -105,15 +88,8 @@ public class ZKDataMigrator {
       throws KeeperException, InterruptedException {
     String znode = ZNodePaths.joinZNode(zkw.getZNodePaths().tableZNode,
             tableName.getNameAsString());
-    byte [] data = ZKUtil.getData(zkw, znode);
-    if (data == null || data.length <= 0) return null;
     try {
-      ProtobufUtil.expectPBMagicPrefix(data);
+      return ProtobufUtil.toTableState(ZKUtil.getData(zkw, znode));
-      ZooKeeperProtos.DeprecatedTableState.Builder builder =
-          ZooKeeperProtos.DeprecatedTableState.newBuilder();
-      int magicLen = ProtobufUtil.lengthOfPBMagic();
-      ProtobufUtil.mergeFrom(builder, data, magicLen, data.length - magicLen);
-      return builder.getState();
     } catch (IOException e) {
       KeeperException ke = new KeeperException.DataInconsistencyException();
       ke.initCause(e);

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

@@ -152,6 +152,7 @@ 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;
 
 /**
@@ -496,7 +497,7 @@ public class HBaseTestingUtility extends HBaseZKTestingUtility {
 
   /**
    * @return META table descriptor
-   * @deprecated since 2.0 version and will be removed in 3.0 version.
+   * @deprecated since 2.0 version and will be removed in 3.0 version. Currently for test only.
    *             use {@link #getMetaTableDescriptorBuilder()}
    */
   @Deprecated
@@ -506,7 +507,10 @@ public class HBaseTestingUtility extends HBaseZKTestingUtility {
 
   /**
    * @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

@@ -0,0 +1,110 @@
+/*
+ * 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.tableExists(TableName.META_TABLE_NAME);
+    admin.disableTable(TableName.META_TABLE_NAME);
+    assertTrue(admin.isTableDisabled(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

@@ -47,7 +47,6 @@ 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;
@@ -538,22 +537,6 @@ 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

@@ -39,7 +39,6 @@ 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
@@ -54,18 +53,6 @@ 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

@@ -18,12 +18,9 @@
 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;
@@ -31,7 +28,6 @@ import java.util.List;
 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;
@@ -200,14 +196,6 @@ 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/client/TestConnectionImplementation.java

@@ -192,6 +192,16 @@ public class TestConnectionImplementation {
       table.close();
     }
 
+    // See if stats change.
+    LOG.info(((ConnectionImplementation)con1).tableStateCache.stats().toString());
+    assertEquals(0, ((ConnectionImplementation)con1).tableStateCache.stats().missCount());
+    try (Admin a = con1.getAdmin()) {
+      a.isTableDisabled(TableName.META_TABLE_NAME);
+    }
+    LOG.info(((ConnectionImplementation)con1).tableStateCache.stats().toString());
+    assertEquals(1, ((ConnectionImplementation)con1).tableStateCache.stats().missCount());
+    assertEquals(1,
+      ((ConnectionImplementation)con1).tableStateCache.stats().loadSuccessCount());
     con1.close();
 
     // if the pool was created on demand it should be closed upon connection close

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

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hbase.client;
 
+import static junit.framework.TestCase.assertTrue;
 import static org.apache.hadoop.hbase.HConstants.META_REPLICAS_NUM;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.junit.Assert.assertEquals;
@@ -128,4 +129,31 @@ public class TestZKAsyncRegistry {
       }
     }
   }
+
+  /**
+   * Test meta tablestate implementation.
+   * Test is a bit involved because meta has replicas... Replica assign lags so check
+   * between steps all assigned.
+   */
+  @Test
+  public void testMetaTableState() throws IOException, ExecutionException, InterruptedException {
+    assertTrue(TEST_UTIL.getMiniHBaseCluster().getMaster().isActiveMaster());
+    int ritTimeout = 10000;
+    TEST_UTIL.waitUntilNoRegionsInTransition(ritTimeout);
+    LOG.info("MASTER INITIALIZED");
+    try (ZKAsyncRegistry registry = new ZKAsyncRegistry(TEST_UTIL.getConfiguration())) {
+      assertEquals(TableState.State.ENABLED, registry.getMetaTableState().get().getState());
+      LOG.info("META ENABLED");
+      try (Admin admin = TEST_UTIL.getConnection().getAdmin()) {
+        admin.disableTable(TableName.META_TABLE_NAME);
+        assertEquals(TableState.State.DISABLED, registry.getMetaTableState().get().getState());
+        TEST_UTIL.waitUntilNoRegionsInTransition(ritTimeout);
+        LOG.info("META DISABLED");
+        admin.enableTable(TableName.META_TABLE_NAME);
+        assertEquals(TableState.State.ENABLED, registry.getMetaTableState().get().getState());
+        TEST_UTIL.waitUntilNoRegionsInTransition(ritTimeout);
+        LOG.info("META ENABLED");
+      }
+    }
+  }
 }

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

@@ -322,8 +322,13 @@ public class TestFSTableDescriptors {
     }
 
     Map<String, TableDescriptor> tables = tds.getAll();
+    // Remove hbase:meta from list. It shows up now since we  made it dynamic. The schema
+    // is written into the fs by the FSTableDescriptors constructor now where before it
+    // didn't.
+    tables.remove(TableName.META_TABLE_NAME.getNameAsString());
     assertEquals(4, tables.size());
 
+
     String[] tableNamesOrdered =
         new String[] { "bar:foo", "default:bar", "default:foo", "foo:bar" };
     int i = 0;
@@ -359,12 +364,13 @@ public class TestFSTableDescriptors {
 
     assertTrue(nonchtds.getAll().size() == chtds.getAll().size());
 
-    // add a new entry for hbase:meta
+    // add a new entry for random table name.
-    TableDescriptor htd = TableDescriptorBuilder.newBuilder(TableName.META_TABLE_NAME).build();
+    TableName random = TableName.valueOf("random");
+    TableDescriptor htd = TableDescriptorBuilder.newBuilder(random).build();
     nonchtds.createTableDescriptor(htd);
 
-    // hbase:meta will only increase the cachehit by 1
+    // random will only increase the cachehit by 1
-    assertTrue(nonchtds.getAll().size() == chtds.getAll().size());
+    assertEquals(nonchtds.getAll().size(), chtds.getAll().size() + 1);
 
     for (Map.Entry<String, TableDescriptor> entry: nonchtds.getAll().entrySet()) {
       String t = (String) entry.getKey();

hbase-shell/src/main/ruby/shell/commands/describe.rb

@@ -44,6 +44,8 @@ EOF
           puts
         end
         formatter.footer
+        if table.to_s != 'hbase:meta'
+          # No QUOTAS if hbase:meta table
           puts
           formatter.header(%w[QUOTAS])
           count = quotas_admin.list_quotas(TABLE => table.to_s) do |_, quota|
@@ -51,6 +53,7 @@ EOF
           end
           formatter.footer(count)
         end
+      end
       # rubocop:enable Metrics/AbcSize, Metrics/MethodLength
     end
   end

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
@@ -61,14 +61,6 @@ 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.
@@ -266,7 +258,7 @@ public final class MetaTableLocator {
   }
 
   /**
-   * Load the meta region state from the meta server ZNode.
+   * Load the meta region state from the meta region server ZNode.
    *
    * @param zkw reference to the {@link ZKWatcher} which also contains configuration and operation
    * @param replicaId the ID of the replica
@@ -306,10 +298,8 @@ public final class MetaTableLocator {
     if (serverName == null) {
       state = RegionState.State.OFFLINE;
     }
-    return new RegionState(
+    return new RegionState(RegionReplicaUtil.getRegionInfoForReplica(
-        RegionReplicaUtil.getRegionInfoForReplica(
+        RegionInfoBuilder.FIRST_META_REGIONINFO, replicaId), state, serverName);
-            RegionInfoBuilder.FIRST_META_REGIONINFO, replicaId),
-        state, serverName);
   }
 
   /**

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

@@ -2056,7 +2056,7 @@ public final class ZKUtil {
       " byte(s) of data from znode " + znode +
       (watcherSet? " and set watcher; ": "; data=") +
       (data == null? "null": data.length == 0? "empty": (
-          znode.startsWith(zkw.getZNodePaths().metaZNodePrefix)?
+          zkw.getZNodePaths().isMetaZNodePrefix(znode)?
             getServerNameOrEmptyString(data):
           znode.startsWith(zkw.getZNodePaths().backupMasterAddressesZNode)?
             getServerNameOrEmptyString(data):