| /** |
| * 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.hdfs.server.namenode; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.util.List; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.hdfs.server.common.HdfsServerConstants; |
| import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory; |
| |
| /** |
| * Interface responsible for inspecting a set of storage directories and devising |
| * a plan to load the namespace from them. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| abstract class FSImageStorageInspector { |
| /** |
| * Inspect the contents of the given storage directory. |
| */ |
| abstract void inspectDirectory(StorageDirectory sd) throws IOException; |
| |
| /** |
| * @return false if any of the storage directories have an unfinalized upgrade |
| */ |
| abstract boolean isUpgradeFinalized(); |
| |
| /** |
| * Get the image files which should be loaded into the filesystem. |
| * @throws IOException if not enough files are available (eg no image found in any directory) |
| */ |
| abstract List<FSImageFile> getLatestImages() throws IOException; |
| |
| /** |
| * Get the minimum tx id which should be loaded with this set of images. |
| */ |
| abstract long getMaxSeenTxId(); |
| |
| /** |
| * @return true if the directories are in such a state that the image should be re-saved |
| * following the load |
| */ |
| abstract boolean needToSave(); |
| |
| /** |
| * Record of an image that has been located and had its filename parsed. |
| */ |
| static class FSImageFile { |
| final StorageDirectory sd; |
| final long txId; |
| private final File file; |
| |
| FSImageFile(StorageDirectory sd, File file, long txId) { |
| assert txId >= 0 || txId == HdfsServerConstants.INVALID_TXID |
| : "Invalid txid on " + file +": " + txId; |
| |
| this.sd = sd; |
| this.txId = txId; |
| this.file = file; |
| } |
| |
| File getFile() { |
| return file; |
| } |
| |
| public long getCheckpointTxId() { |
| return txId; |
| } |
| |
| @Override |
| public String toString() { |
| return String.format("FSImageFile(file=%s, cpktTxId=%019d)", |
| file.toString(), txId); |
| } |
| } |
| |
| } |