HDFS-4124. Merge r1403304 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1471500 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -53,6 +53,13 @@ Release 2.0.5-beta - UNRELEASED
     HDFS-3817. Avoid printing SafeModeException stack trace.
     (Brandon Li via suresh)
 
+    HDFS-4112. A few improvements on INodeDirectory include adding a utility
+    method for casting; avoiding creation of new empty lists; cleaning up 
+    some code and rewriting some javadoc. (szetszwo)
+
+    HDFS-4124. Refactor INodeDirectory#getExistingPathINodes() to enable 
+    returning more than INode array. (Jing Zhao via suresh)
+
     HDFS-4129. Add utility methods to dump NameNode in memory tree for 
     testing. (szetszwo via suresh)
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java

@@ -44,10 +44,10 @@ import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
-import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.FSLimitException;
 import org.apache.hadoop.hdfs.protocol.FSLimitException.MaxDirectoryItemsExceededException;
 import org.apache.hadoop.hdfs.protocol.FSLimitException.PathComponentTooLongException;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.HdfsLocatedFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
@@ -57,6 +57,7 @@ import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
+import org.apache.hadoop.hdfs.server.namenode.INodeDirectory.INodesInPath;
 import org.apache.hadoop.hdfs.util.ByteArray;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -551,8 +552,9 @@ public class FSDirectory implements Closeable {
     }
     
     byte[][] dstComponents = INode.getPathComponents(dst);
-    INode[] dstInodes = new INode[dstComponents.length];
-    rootDir.getExistingPathINodes(dstComponents, dstInodes, false);
+    INodesInPath dstInodesInPath = rootDir.getExistingPathINodes(dstComponents,
+        dstComponents.length, false);
+    INode[] dstInodes = dstInodesInPath.getINodes();
     if (dstInodes[dstInodes.length-1] != null) {
       NameNode.stateChangeLog.warn("DIR* FSDirectory.unprotectedRenameTo: "
                                    +"failed to rename "+src+" to "+dst+ 
@@ -567,7 +569,7 @@ public class FSDirectory implements Closeable {
     }
     
     // Ensure dst has quota to accommodate rename
-    verifyQuotaForRename(srcInodes,dstInodes);
+    verifyQuotaForRename(srcInodes, dstInodes);
     
     INode dstChild = null;
     INode srcChild = null;
@@ -673,8 +675,9 @@ public class FSDirectory implements Closeable {
       throw new IOException(error);
     }
     final byte[][] dstComponents = INode.getPathComponents(dst);
-    final INode[] dstInodes = new INode[dstComponents.length];
-    rootDir.getExistingPathINodes(dstComponents, dstInodes, false);
+    INodesInPath dstInodesInPath = rootDir.getExistingPathINodes(dstComponents,
+        dstComponents.length, false);
+    final INode[] dstInodes = dstInodesInPath.getINodes();
     INode dstInode = dstInodes[dstInodes.length - 1];
     if (dstInodes.length == 1) {
       error = "rename destination cannot be the root";
@@ -1455,12 +1458,13 @@ public class FSDirectory implements Closeable {
     src = normalizePath(src);
     String[] names = INode.getPathNames(src);
     byte[][] components = INode.getPathComponents(names);
-    INode[] inodes = new INode[components.length];
-    final int lastInodeIndex = inodes.length - 1;
+    final int lastInodeIndex = components.length - 1;
 
     writeLock();
     try {
-      rootDir.getExistingPathINodes(components, inodes, false);
+      INodesInPath inodesInPath = rootDir.getExistingPathINodes(components,
+          components.length, false);
+      INode[] inodes = inodesInPath.getINodes();
 
       // find the index of the first null in inodes[]
       StringBuilder pathbuilder = new StringBuilder();
@@ -1530,16 +1534,14 @@ public class FSDirectory implements Closeable {
     return true;
   }
 
-  /**
-   */
   INode unprotectedMkdir(String src, PermissionStatus permissions,
                           long timestamp) throws QuotaExceededException,
                           UnresolvedLinkException {
     assert hasWriteLock();
     byte[][] components = INode.getPathComponents(src);
-    INode[] inodes = new INode[components.length];
-
-    rootDir.getExistingPathINodes(components, inodes, false);
+    INodesInPath inodesInPath = rootDir.getExistingPathINodes(components,
+        components.length, false);
+    INode[] inodes = inodesInPath.getINodes();
     unprotectedMkdir(inodes, inodes.length-1, components[inodes.length-1],
         permissions, timestamp);
     return inodes[inodes.length-1];
@@ -1568,10 +1570,11 @@ public class FSDirectory implements Closeable {
     byte[] path = components[components.length-1];
     child.setLocalName(path);
     cacheName(child);
-    INode[] inodes = new INode[components.length];
     writeLock();
     try {
-      rootDir.getExistingPathINodes(components, inodes, false);
+      INodesInPath inodesInPath = rootDir.getExistingPathINodes(components,
+          components.length, false);
+      INode[] inodes = inodesInPath.getINodes();
       return addChild(inodes, inodes.length-1, child, childDiskspace);
     } finally {
       writeUnlock();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeDirectory.java

@@ -131,9 +131,9 @@ class INodeDirectory extends INode {
    */
   private INode getNode(byte[][] components, boolean resolveLink
       ) throws UnresolvedLinkException {
-    INode[] inode  = new INode[1];
-    getExistingPathINodes(components, inode, resolveLink);
-    return inode[0];
+    INodesInPath inodesInPath = getExistingPathINodes(components, 1,
+        resolveLink);
+    return inodesInPath.inodes[0];
   }
 
   /**
@@ -181,27 +181,29 @@ class INodeDirectory extends INode {
    * fill the array with [rootINode,c1,c2,null]
    * 
    * @param components array of path component name
-   * @param existing array to fill with existing INodes
+   * @param numOfINodes number of INodes to return
    * @param resolveLink indicates whether UnresolvedLinkException should
    *        be thrown when the path refers to a symbolic link.
-   * @return number of existing INodes in the path
+   * @return the specified number of existing INodes in the path
    */
-  int getExistingPathINodes(byte[][] components, INode[] existing, 
-      boolean resolveLink) throws UnresolvedLinkException {
+  INodesInPath getExistingPathINodes(byte[][] components, int numOfINodes,
+      boolean resolveLink)
+      throws UnresolvedLinkException {
     assert this.compareTo(components[0]) == 0 :
         "Incorrect name " + getLocalName() + " expected "
         + (components[0] == null? null: DFSUtil.bytes2String(components[0]));
 
+    INodesInPath existing = new INodesInPath(numOfINodes);
     INode curNode = this;
     int count = 0;
-    int index = existing.length - components.length;
+    int index = numOfINodes - components.length;
     if (index > 0) {
       index = 0;
     }
     while (count < components.length && curNode != null) {
       final boolean lastComp = (count == components.length - 1);      
       if (index >= 0) {
-        existing[index] = curNode;
+        existing.inodes[index] = curNode;
       }
       if (curNode.isSymlink() && (!lastComp || (lastComp && resolveLink))) {
         final String path = constructPath(components, 0, components.length);
@@ -226,7 +228,7 @@ class INodeDirectory extends INode {
       count++;
       index++;
     }
-    return count;
+    return existing;
   }
 
   /**
@@ -247,11 +249,9 @@ class INodeDirectory extends INode {
   INode[] getExistingPathINodes(String path, boolean resolveLink) 
     throws UnresolvedLinkException {
     byte[][] components = getPathComponents(path);
-    INode[] inodes = new INode[components.length];
-
-    this.getExistingPathINodes(components, inodes, resolveLink);
-    
-    return inodes;
+    INodesInPath inodes = this.getExistingPathINodes(components,
+        components.length, resolveLink);
+    return inodes.inodes;
   }
 
   /**
@@ -342,9 +342,8 @@ class INodeDirectory extends INode {
     if (pathComponents.length < 2)  // add root
       return null;
     // Gets the parent INode
-    INode[] inodes  = new INode[2];
-    getExistingPathINodes(pathComponents, inodes, false);
-    INode inode = inodes[0];
+    INodesInPath inodes =  getExistingPathINodes(pathComponents, 2, false);
+    INode inode = inodes.inodes[0];
     if (inode == null) {
       throw new FileNotFoundException("Parent path does not exist: "+
           DFSUtil.byteArray2String(pathComponents));
@@ -492,4 +491,22 @@ class INodeDirectory extends INode {
     }
     prefix.setLength(prefix.length() - 2);
   }
+  
+  /**
+   * Used by
+   * {@link INodeDirectory#getExistingPathINodes(byte[][], int, boolean)}.
+   * Containing INodes information resolved from a given path.
+   */
+  static class INodesInPath {
+    private INode[] inodes;
+    
+    public INodesInPath(int number) {
+      assert (number >= 0);
+      this.inodes = new INode[number];
+    }
+    
+    INode[] getINodes() {
+      return inodes;
+    }
+  }
 }