001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package org.apache.hadoop.hdfs.server.namenode;
020
021 import java.io.File;
022 import java.io.FileInputStream;
023 import java.io.IOException;
024 import java.io.BufferedInputStream;
025 import java.io.EOFException;
026 import java.io.DataInputStream;
027 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
028 import org.apache.hadoop.hdfs.server.common.Storage;
029 import org.apache.hadoop.io.IOUtils;
030 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
031
032 import com.google.common.annotations.VisibleForTesting;
033
034 /**
035 * An implementation of the abstract class {@link EditLogInputStream}, which
036 * reads edits from a local file.
037 */
038 public class EditLogFileInputStream extends EditLogInputStream {
039 private final File file;
040 private final FileInputStream fStream;
041 final private long firstTxId;
042 final private long lastTxId;
043 private final int logVersion;
044 private final FSEditLogOp.Reader reader;
045 private final FSEditLogLoader.PositionTrackingInputStream tracker;
046 private final boolean isInProgress;
047
048 /**
049 * Open an EditLogInputStream for the given file.
050 * The file is pretransactional, so has no txids
051 * @param name filename to open
052 * @throws LogHeaderCorruptException if the header is either missing or
053 * appears to be corrupt/truncated
054 * @throws IOException if an actual IO error occurs while reading the
055 * header
056 */
057 EditLogFileInputStream(File name)
058 throws LogHeaderCorruptException, IOException {
059 this(name, HdfsConstants.INVALID_TXID, HdfsConstants.INVALID_TXID, false);
060 }
061
062 /**
063 * Open an EditLogInputStream for the given file.
064 * @param name filename to open
065 * @param firstTxId first transaction found in file
066 * @param lastTxId last transaction id found in file
067 * @throws LogHeaderCorruptException if the header is either missing or
068 * appears to be corrupt/truncated
069 * @throws IOException if an actual IO error occurs while reading the
070 * header
071 */
072 public EditLogFileInputStream(File name, long firstTxId, long lastTxId,
073 boolean isInProgress)
074 throws LogHeaderCorruptException, IOException {
075 file = name;
076 fStream = new FileInputStream(name);
077
078 BufferedInputStream bin = new BufferedInputStream(fStream);
079 tracker = new FSEditLogLoader.PositionTrackingInputStream(bin);
080 DataInputStream in = new DataInputStream(tracker);
081
082 try {
083 logVersion = readLogVersion(in);
084 } catch (EOFException eofe) {
085 throw new LogHeaderCorruptException("No header found in log");
086 }
087
088 reader = new FSEditLogOp.Reader(in, logVersion);
089 this.firstTxId = firstTxId;
090 this.lastTxId = lastTxId;
091 this.isInProgress = isInProgress;
092 }
093
094 @Override
095 public long getFirstTxId() throws IOException {
096 return firstTxId;
097 }
098
099 @Override
100 public long getLastTxId() throws IOException {
101 return lastTxId;
102 }
103
104 @Override
105 public String getName() {
106 return file.getPath();
107 }
108
109 @Override
110 protected FSEditLogOp nextOp() throws IOException {
111 return reader.readOp(false);
112 }
113
114 @Override
115 protected FSEditLogOp nextValidOp() {
116 try {
117 return reader.readOp(true);
118 } catch (IOException e) {
119 return null;
120 }
121 }
122
123 @Override
124 public int getVersion() throws IOException {
125 return logVersion;
126 }
127
128 @Override
129 public long getPosition() {
130 return tracker.getPos();
131 }
132
133 @Override
134 public void close() throws IOException {
135 fStream.close();
136 }
137
138 @Override
139 public long length() throws IOException {
140 // file size + size of both buffers
141 return file.length();
142 }
143
144 @Override
145 public boolean isInProgress() {
146 return isInProgress;
147 }
148
149 @Override
150 public String toString() {
151 return getName();
152 }
153
154 static FSEditLogLoader.EditLogValidation validateEditLog(File file) throws IOException {
155 EditLogFileInputStream in;
156 try {
157 in = new EditLogFileInputStream(file);
158 } catch (LogHeaderCorruptException corrupt) {
159 // If the header is malformed or the wrong value, this indicates a corruption
160 FSImage.LOG.warn("Log at " + file + " has no valid header",
161 corrupt);
162 return new FSEditLogLoader.EditLogValidation(0,
163 HdfsConstants.INVALID_TXID, HdfsConstants.INVALID_TXID, true);
164 }
165
166 try {
167 return FSEditLogLoader.validateEditLog(in);
168 } finally {
169 IOUtils.closeStream(in);
170 }
171 }
172
173 /**
174 * Read the header of fsedit log
175 * @param in fsedit stream
176 * @return the edit log version number
177 * @throws IOException if error occurs
178 */
179 @VisibleForTesting
180 static int readLogVersion(DataInputStream in)
181 throws IOException, LogHeaderCorruptException {
182 int logVersion;
183 try {
184 logVersion = in.readInt();
185 } catch (EOFException eofe) {
186 throw new LogHeaderCorruptException(
187 "Reached EOF when reading log header");
188 }
189 if (logVersion < HdfsConstants.LAYOUT_VERSION || // future version
190 logVersion > Storage.LAST_UPGRADABLE_LAYOUT_VERSION) { // unsupported
191 throw new LogHeaderCorruptException(
192 "Unexpected version of the file system log file: "
193 + logVersion + ". Current version = "
194 + HdfsConstants.LAYOUT_VERSION + ".");
195 }
196 return logVersion;
197 }
198
199 /**
200 * Exception indicating that the header of an edits log file is
201 * corrupted. This can be because the header is not present,
202 * or because the header data is invalid (eg claims to be
203 * over a newer version than the running NameNode)
204 */
205 static class LogHeaderCorruptException extends IOException {
206 private static final long serialVersionUID = 1L;
207
208 private LogHeaderCorruptException(String msg) {
209 super(msg);
210 }
211 }
212 }