/**
* 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.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.NoSuchElementException;
import com.google.common.collect.ImmutableList;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.UnresolvedLinkException;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.protocol.UnresolvedPathException;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
import org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature;
import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
import com.google.common.base.Preconditions;
import static org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot.CURRENT_STATE_ID;
import static org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot.ID_INTEGER_COMPARATOR;
/**
* Contains INodes information resolved from a given path.
*/
public class INodesInPath {
public static final Log LOG = LogFactory.getLog(INodesInPath.class);
/**
* @return true if path component is {@link HdfsConstants#DOT_SNAPSHOT_DIR}
*/
private static boolean isDotSnapshotDir(byte[] pathComponent) {
return pathComponent != null &&
Arrays.equals(HdfsServerConstants.DOT_SNAPSHOT_DIR_BYTES, pathComponent);
}
static INodesInPath fromINode(INode inode) {
int depth = 0, index;
INode tmp = inode;
while (tmp != null) {
depth++;
tmp = tmp.getParent();
}
final byte[][] path = new byte[depth][];
final INode[] inodes = new INode[depth];
tmp = inode;
index = depth;
while (tmp != null) {
index--;
path[index] = tmp.getKey();
inodes[index] = tmp;
tmp = tmp.getParent();
}
return new INodesInPath(inodes, path);
}
/**
* Given some components, create a path name.
* @param components The path components
* @param start index
* @param end index
* @return concatenated path
*/
private static String constructPath(byte[][] components, int start, int end) {
StringBuilder buf = new StringBuilder();
for (int i = start; i < end; i++) {
buf.append(DFSUtil.bytes2String(components[i]));
if (i < end - 1) {
buf.append(Path.SEPARATOR);
}
}
return buf.toString();
}
/**
* Retrieve existing INodes from a path. For non-snapshot path,
* the number of INodes is equal to the number of path components. For
* snapshot path (e.g., /foo/.snapshot/s1/bar), the number of INodes is
* (number_of_path_components - 1).
*
* An UnresolvedPathException is always thrown when an intermediate path
* component refers to a symbolic link. If the final path component refers
* to a symbolic link then an UnresolvedPathException is only thrown if
* resolveLink is true.
*
* <p>
* Example: <br>
* Given the path /c1/c2/c3 where only /c1/c2 exists, resulting in the
* following path components: ["","c1","c2","c3"]
*
* <p>
* <code>getExistingPathINodes(["","c1","c2"])</code> should fill
* the array with [rootINode,c1,c2], <br>
* <code>getExistingPathINodes(["","c1","c2","c3"])</code> should
* fill the array with [rootINode,c1,c2,null]
*
* @param startingDir the starting directory
* @param components array of path component name
* @param resolveLink indicates whether UnresolvedLinkException should
* be thrown when the path refers to a symbolic link.
* @return the specified number of existing INodes in the path
*/
static INodesInPath resolve(final INodeDirectory startingDir,
final byte[][] components, final boolean resolveLink)
throws UnresolvedLinkException {
Preconditions.checkArgument(startingDir.compareTo(components[0]) == 0);
INode curNode = startingDir;
int count = 0;
int inodeNum = 0;
INode[] inodes = new INode[components.length];
boolean isSnapshot = false;
int snapshotId = CURRENT_STATE_ID;
while (count < components.length && curNode != null) {
final boolean lastComp = (count == components.length - 1);
inodes[inodeNum++] = curNode;
final boolean isRef = curNode.isReference();
final boolean isDir = curNode.isDirectory();
final INodeDirectory dir = isDir? curNode.asDirectory(): null;
if (!isRef && isDir && dir.isWithSnapshot()) {
//if the path is a non-snapshot path, update the latest snapshot.
if (!isSnapshot && shouldUpdateLatestId(
dir.getDirectoryWithSnapshotFeature().getLastSnapshotId(),
snapshotId)) {
snapshotId = dir.getDirectoryWithSnapshotFeature().getLastSnapshotId();
}
} else if (isRef && isDir && !lastComp) {
// If the curNode is a reference node, need to check its dstSnapshot:
// 1. if the existing snapshot is no later than the dstSnapshot (which
// is the latest snapshot in dst before the rename), the changes
// should be recorded in previous snapshots (belonging to src).
// 2. however, if the ref node is already the last component, we still
// need to know the latest snapshot among the ref node's ancestors,
// in case of processing a deletion operation. Thus we do not overwrite
// the latest snapshot if lastComp is true. In case of the operation is
// a modification operation, we do a similar check in corresponding
// recordModification method.
if (!isSnapshot) {
int dstSnapshotId = curNode.asReference().getDstSnapshotId();
if (snapshotId == CURRENT_STATE_ID || // no snapshot in dst tree of rename
(dstSnapshotId != CURRENT_STATE_ID &&
dstSnapshotId >= snapshotId)) { // the above scenario
int lastSnapshot = CURRENT_STATE_ID;
DirectoryWithSnapshotFeature sf;
if (curNode.isDirectory() &&
(sf = curNode.asDirectory().getDirectoryWithSnapshotFeature()) != null) {
lastSnapshot = sf.getLastSnapshotId();
}
snapshotId = lastSnapshot;
}
}
}
if (curNode.isSymlink() && (!lastComp || resolveLink)) {
final String path = constructPath(components, 0, components.length);
final String preceding = constructPath(components, 0, count);
final String remainder =
constructPath(components, count + 1, components.length);
final String link = DFSUtil.bytes2String(components[count]);
final String target = curNode.asSymlink().getSymlinkString();
if (LOG.isDebugEnabled()) {
LOG.debug("UnresolvedPathException " +
" path: " + path + " preceding: " + preceding +
" count: " + count + " link: " + link + " target: " + target +
" remainder: " + remainder);
}
throw new UnresolvedPathException(path, preceding, remainder, target);
}
if (lastComp || !isDir) {
break;
}
final byte[] childName = components[count + 1];
// check if the next byte[] in components is for ".snapshot"
if (isDotSnapshotDir(childName) && dir.isSnapshottable()) {
// skip the ".snapshot" in components
count++;
isSnapshot = true;
// check if ".snapshot" is the last element of components
if (count == components.length - 1) {
break;
}
// Resolve snapshot root
final Snapshot s = dir.getSnapshot(components[count + 1]);
if (s == null) {
curNode = null; // snapshot not found
} else {
curNode = s.getRoot();
snapshotId = s.getId();
}
} else {
// normal case, and also for resolving file/dir under snapshot root
curNode = dir.getChild(childName,
isSnapshot ? snapshotId : CURRENT_STATE_ID);
}
count++;
}
if (isSnapshot && !isDotSnapshotDir(components[components.length - 1])) {
// for snapshot path shrink the inode array. however, for path ending with
// .snapshot, still keep last the null inode in the array
INode[] newNodes = new INode[components.length - 1];
System.arraycopy(inodes, 0, newNodes, 0, newNodes.length);
inodes = newNodes;
}
return new INodesInPath(inodes, components, isSnapshot, snapshotId);
}
private static boolean shouldUpdateLatestId(int sid, int snapshotId) {
return snapshotId == CURRENT_STATE_ID || (sid != CURRENT_STATE_ID &&
ID_INTEGER_COMPARATOR.compare(snapshotId, sid) < 0);
}
/**
* Replace an inode of the given INodesInPath in the given position. We do a
* deep copy of the INode array.
* @param pos the position of the replacement
* @param inode the new inode
* @return a new INodesInPath instance
*/
public static INodesInPath replace(INodesInPath iip, int pos, INode inode) {
Preconditions.checkArgument(iip.length() > 0 && pos > 0 // no for root
&& pos < iip.length());
if (iip.getINode(pos) == null) {
Preconditions.checkState(iip.getINode(pos - 1) != null);
}
INode[] inodes = new INode[iip.inodes.length];
System.arraycopy(iip.inodes, 0, inodes, 0, inodes.length);
inodes[pos] = inode;
return new INodesInPath(inodes, iip.path, iip.isSnapshot, iip.snapshotId);
}
/**
* Extend a given INodesInPath with a child INode. The child INode will be
* appended to the end of the new INodesInPath.
*/
public static INodesInPath append(INodesInPath iip, INode child,
byte[] childName) {
Preconditions.checkArgument(!iip.isSnapshot && iip.length() > 0);
Preconditions.checkArgument(iip.getLastINode() != null && iip
.getLastINode().isDirectory());
INode[] inodes = new INode[iip.length() + 1];
System.arraycopy(iip.inodes, 0, inodes, 0, inodes.length - 1);
inodes[inodes.length - 1] = child;
byte[][] path = new byte[iip.path.length + 1][];
System.arraycopy(iip.path, 0, path, 0, path.length - 1);
path[path.length - 1] = childName;
return new INodesInPath(inodes, path, false, iip.snapshotId);
}
private final byte[][] path;
/**
* Array with the specified number of INodes resolved for a given path.
*/
private final INode[] inodes;
/**
* true if this path corresponds to a snapshot
*/
private final boolean isSnapshot;
/**
* For snapshot paths, it is the id of the snapshot; or
* {@link Snapshot#CURRENT_STATE_ID} if the snapshot does not exist. For
* non-snapshot paths, it is the id of the latest snapshot found in the path;
* or {@link Snapshot#CURRENT_STATE_ID} if no snapshot is found.
*/
private final int snapshotId;
private INodesInPath(INode[] inodes, byte[][] path, boolean isSnapshot,
int snapshotId) {
Preconditions.checkArgument(inodes != null && path != null);
this.inodes = inodes;
this.path = path;
this.isSnapshot = isSnapshot;
this.snapshotId = snapshotId;
}
private INodesInPath(INode[] inodes, byte[][] path) {
this(inodes, path, false, CURRENT_STATE_ID);
}
/**
* For non-snapshot paths, return the latest snapshot id found in the path.
*/
public int getLatestSnapshotId() {
Preconditions.checkState(!isSnapshot);
return snapshotId;
}
/**
* For snapshot paths, return the id of the snapshot specified in the path.
* For non-snapshot paths, return {@link Snapshot#CURRENT_STATE_ID}.
*/
public int getPathSnapshotId() {
return isSnapshot ? snapshotId : CURRENT_STATE_ID;
}
/**
* @return the i-th inode if i >= 0;
* otherwise, i < 0, return the (length + i)-th inode.
*/
public INode getINode(int i) {
if (inodes == null || inodes.length == 0) {
throw new NoSuchElementException("inodes is null or empty");
}
int index = i >= 0 ? i : inodes.length + i;
if (index < inodes.length && index >= 0) {
return inodes[index];
} else {
throw new NoSuchElementException("inodes.length == " + inodes.length);
}
}
/** @return the last inode. */
public INode getLastINode() {
return getINode(-1);
}
byte[] getLastLocalName() {
return path[path.length - 1];
}
public byte[][] getPathComponents() {
return path;
}
/** @return the full path in string form */
public String getPath() {
return DFSUtil.byteArray2PathString(path);
}
public String getParentPath() {
return getPath(path.length - 1);
}
public String getPath(int pos) {
return DFSUtil.byteArray2PathString(path, 0, pos);
}
/**
* @param offset start endpoint (inclusive)
* @param length number of path components
* @return sub-list of the path
*/
public List<String> getPath(int offset, int length) {
Preconditions.checkArgument(offset >= 0 && length >= 0 && offset + length
<= path.length);
ImmutableList.Builder<String> components = ImmutableList.builder();
for (int i = offset; i < offset + length; i++) {
components.add(DFSUtil.bytes2String(path[i]));
}
return components.build();
}
public int length() {
return inodes.length;
}
public List<INode> getReadOnlyINodes() {
return Collections.unmodifiableList(Arrays.asList(inodes));
}
public INode[] getINodesArray() {
INode[] retArr = new INode[inodes.length];
System.arraycopy(inodes, 0, retArr, 0, inodes.length);
return retArr;
}
/**
* @param length number of ancestral INodes in the returned INodesInPath
* instance
* @return the INodesInPath instance containing ancestral INodes. Note that
* this method only handles non-snapshot paths.
*/
private INodesInPath getAncestorINodesInPath(int length) {
Preconditions.checkArgument(length >= 0 && length < inodes.length);
Preconditions.checkState(!isSnapshot());
final INode[] anodes = new INode[length];
final byte[][] apath = new byte[length][];
System.arraycopy(this.inodes, 0, anodes, 0, length);
System.arraycopy(this.path, 0, apath, 0, length);
return new INodesInPath(anodes, apath, false, snapshotId);
}
/**
* @return an INodesInPath instance containing all the INodes in the parent
* path. We do a deep copy here.
*/
public INodesInPath getParentINodesInPath() {
return inodes.length > 1 ? getAncestorINodesInPath(inodes.length - 1) :
null;
}
/**
* @return a new INodesInPath instance that only contains exisitng INodes.
* Note that this method only handles non-snapshot paths.
*/
public INodesInPath getExistingINodes() {
Preconditions.checkState(!isSnapshot());
int i = 0;
for (; i < inodes.length; i++) {
if (inodes[i] == null) {
break;
}
}
INode[] existing = new INode[i];
byte[][] existingPath = new byte[i][];
System.arraycopy(inodes, 0, existing, 0, i);
System.arraycopy(path, 0, existingPath, 0, i);
return new INodesInPath(existing, existingPath, false, snapshotId);
}
/**
* @return isSnapshot true for a snapshot path
*/
boolean isSnapshot() {
return this.isSnapshot;
}
private static String toString(INode inode) {
return inode == null? null: inode.getLocalName();
}
@Override
public String toString() {
return toString(true);
}
private String toString(boolean vaildateObject) {
if (vaildateObject) {
validate();
}
final StringBuilder b = new StringBuilder(getClass().getSimpleName())
.append(": path = ").append(DFSUtil.byteArray2PathString(path))
.append("\n inodes = ");
if (inodes == null) {
b.append("null");
} else if (inodes.length == 0) {
b.append("[]");
} else {
b.append("[").append(toString(inodes[0]));
for(int i = 1; i < inodes.length; i++) {
b.append(", ").append(toString(inodes[i]));
}
b.append("], length=").append(inodes.length);
}
b.append("\n isSnapshot = ").append(isSnapshot)
.append("\n snapshotId = ").append(snapshotId);
return b.toString();
}
void validate() {
// check parent up to snapshotRootIndex if this is a snapshot path
int i = 0;
if (inodes[i] != null) {
for(i++; i < inodes.length && inodes[i] != null; i++) {
final INodeDirectory parent_i = inodes[i].getParent();
final INodeDirectory parent_i_1 = inodes[i-1].getParent();
if (parent_i != inodes[i-1] &&
(parent_i_1 == null || !parent_i_1.isSnapshottable()
|| parent_i != parent_i_1)) {
throw new AssertionError(
"inodes[" + i + "].getParent() != inodes[" + (i-1)
+ "]\n inodes[" + i + "]=" + inodes[i].toDetailString()
+ "\n inodes[" + (i-1) + "]=" + inodes[i-1].toDetailString()
+ "\n this=" + toString(false));
}
}
}
if (i != inodes.length) {
throw new AssertionError("i = " + i + " != " + inodes.length
+ ", this=" + toString(false));
}
}
}