| /** |
| * 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.snapshot; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.text.SimpleDateFormat; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.Date; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.hdfs.DFSUtil; |
| import org.apache.hadoop.hdfs.protocol.HdfsConstants; |
| import org.apache.hadoop.hdfs.server.namenode.AclFeature; |
| import org.apache.hadoop.hdfs.server.namenode.ContentSummaryComputationContext; |
| import org.apache.hadoop.hdfs.server.namenode.FSImageFormat; |
| import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization; |
| import org.apache.hadoop.hdfs.server.namenode.INode; |
| import org.apache.hadoop.hdfs.server.namenode.INodeDirectory; |
| import org.apache.hadoop.hdfs.server.namenode.XAttrFeature; |
| import org.apache.hadoop.hdfs.util.ReadOnlyList; |
| |
| import com.google.common.base.Predicate; |
| import com.google.common.collect.Iterables; |
| import com.google.common.collect.Lists; |
| |
| /** Snapshot of a sub-tree in the namesystem. */ |
| @InterfaceAudience.Private |
| public class Snapshot implements Comparable<byte[]> { |
| /** |
| * This id is used to indicate the current state (vs. snapshots) |
| */ |
| public static final int CURRENT_STATE_ID = Integer.MAX_VALUE - 1; |
| public static final int NO_SNAPSHOT_ID = -1; |
| |
| /** |
| * The pattern for generating the default snapshot name. |
| * E.g. s20130412-151029.033 |
| */ |
| private static final String DEFAULT_SNAPSHOT_NAME_PATTERN = "'s'yyyyMMdd-HHmmss.SSS"; |
| |
| public static String generateDefaultSnapshotName() { |
| return new SimpleDateFormat(DEFAULT_SNAPSHOT_NAME_PATTERN).format(new Date()); |
| } |
| |
| public static String getSnapshotPath(String snapshottableDir, |
| String snapshotRelativePath) { |
| final StringBuilder b = new StringBuilder(snapshottableDir); |
| if (b.charAt(b.length() - 1) != Path.SEPARATOR_CHAR) { |
| b.append(Path.SEPARATOR); |
| } |
| return b.append(HdfsConstants.DOT_SNAPSHOT_DIR) |
| .append(Path.SEPARATOR) |
| .append(snapshotRelativePath) |
| .toString(); |
| } |
| |
| /** |
| * Get the name of the given snapshot. |
| * @param s The given snapshot. |
| * @return The name of the snapshot, or an empty string if {@code s} is null |
| */ |
| static String getSnapshotName(Snapshot s) { |
| return s != null ? s.getRoot().getLocalName() : ""; |
| } |
| |
| public static int getSnapshotId(Snapshot s) { |
| return s == null ? CURRENT_STATE_ID : s.getId(); |
| } |
| |
| /** |
| * Compare snapshot with IDs, where null indicates the current status thus |
| * is greater than any non-null snapshot. |
| */ |
| public static final Comparator<Snapshot> ID_COMPARATOR |
| = new Comparator<Snapshot>() { |
| @Override |
| public int compare(Snapshot left, Snapshot right) { |
| return ID_INTEGER_COMPARATOR.compare(Snapshot.getSnapshotId(left), |
| Snapshot.getSnapshotId(right)); |
| } |
| }; |
| |
| /** |
| * Compare snapshot with IDs, where null indicates the current status thus |
| * is greater than any non-null ID. |
| */ |
| public static final Comparator<Integer> ID_INTEGER_COMPARATOR |
| = new Comparator<Integer>() { |
| @Override |
| public int compare(Integer left, Integer right) { |
| // Snapshot.CURRENT_STATE_ID means the current state, thus should be the |
| // largest |
| return left - right; |
| } |
| }; |
| |
| /** |
| * Find the latest snapshot that 1) covers the given inode (which means the |
| * snapshot was either taken on the inode or taken on an ancestor of the |
| * inode), and 2) was taken before the given snapshot (if the given snapshot |
| * is not null). |
| * |
| * @param inode the given inode that the returned snapshot needs to cover |
| * @param anchor the returned snapshot should be taken before this given id. |
| * @return id of the latest snapshot that covers the given inode and was taken |
| * before the the given snapshot (if it is not null). |
| */ |
| public static int findLatestSnapshot(INode inode, final int anchor) { |
| int latest = NO_SNAPSHOT_ID; |
| for(; inode != null; inode = inode.getParent()) { |
| if (inode.isDirectory()) { |
| final INodeDirectory dir = inode.asDirectory(); |
| if (dir.isWithSnapshot()) { |
| latest = dir.getDiffs().updatePrior(anchor, latest); |
| } |
| } |
| } |
| return latest; |
| } |
| |
| static Snapshot read(DataInput in, FSImageFormat.Loader loader) |
| throws IOException { |
| final int snapshotId = in.readInt(); |
| final INode root = loader.loadINodeWithLocalName(false, in, false); |
| return new Snapshot(snapshotId, root.asDirectory(), null); |
| } |
| |
| /** The root directory of the snapshot. */ |
| static public class Root extends INodeDirectory { |
| Root(INodeDirectory other) { |
| // Always preserve ACL, XAttr. |
| super(other, false, Lists.newArrayList( |
| Iterables.filter(Arrays.asList(other.getFeatures()), new Predicate<Feature>() { |
| |
| @Override |
| public boolean apply(Feature input) { |
| if (AclFeature.class.isInstance(input) |
| || XAttrFeature.class.isInstance(input)) { |
| return true; |
| } |
| return false; |
| } |
| |
| })) |
| .toArray(new Feature[0])); |
| } |
| |
| @Override |
| public ReadOnlyList<INode> getChildrenList(int snapshotId) { |
| return getParent().getChildrenList(snapshotId); |
| } |
| |
| @Override |
| public INode getChild(byte[] name, int snapshotId) { |
| return getParent().getChild(name, snapshotId); |
| } |
| |
| @Override |
| public ContentSummaryComputationContext computeContentSummary( |
| int snapshotId, ContentSummaryComputationContext summary) { |
| return computeDirectoryContentSummary(summary, snapshotId); |
| } |
| |
| @Override |
| public String getFullPathName() { |
| return getSnapshotPath(getParent().getFullPathName(), getLocalName()); |
| } |
| |
| /** |
| * Get the full path name of the root directory of this snapshot. |
| * @return full path to the root directory of the snapshot |
| */ |
| public String getRootFullPathName() { |
| return getParent().getFullPathName(); |
| } |
| } |
| |
| /** Snapshot ID. */ |
| private final int id; |
| /** The root directory of the snapshot. */ |
| private final Root root; |
| |
| Snapshot(int id, String name, INodeDirectory dir) { |
| this(id, dir, dir); |
| this.root.setLocalName(DFSUtil.string2Bytes(name)); |
| } |
| |
| Snapshot(int id, INodeDirectory dir, INodeDirectory parent) { |
| this.id = id; |
| this.root = new Root(dir); |
| this.root.setParent(parent); |
| } |
| |
| public int getId() { |
| return id; |
| } |
| |
| /** @return the root directory of the snapshot. */ |
| public Root getRoot() { |
| return root; |
| } |
| |
| @Override |
| public int compareTo(byte[] bytes) { |
| return root.compareTo(bytes); |
| } |
| |
| @Override |
| public boolean equals(Object that) { |
| if (this == that) { |
| return true; |
| } else if (that == null || !(that instanceof Snapshot)) { |
| return false; |
| } |
| return this.id == ((Snapshot)that).id; |
| } |
| |
| @Override |
| public int hashCode() { |
| return id; |
| } |
| |
| @Override |
| public String toString() { |
| return getClass().getSimpleName() + "." + root.getLocalName() + "(id=" + id + ")"; |
| } |
| |
| /** Serialize the fields to out */ |
| void write(DataOutput out) throws IOException { |
| out.writeInt(id); |
| // write root |
| FSImageSerialization.writeINodeDirectory(root, out); |
| } |
| } |