HDFS-5104. Merging change r1515043 from branch-2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1515044 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -15,6 +15,8 @@ Release 2.1.1-beta - UNRELEASED
     HDFS-5076 Add MXBean methods to query NN's transaction information and 
     JournalNode's journal status. (jing9)
 
+    HDFS-5104 Support dotdot name in NFS LOOKUP operation (brandonli)
+
   IMPROVEMENTS
 
     HDFS-4513. Clarify in the WebHDFS REST API that all JSON respsonses may

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java

@@ -73,6 +73,7 @@ import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocolPB.ClientDatanodeProtocolTranslatorPB;
+import org.apache.hadoop.hdfs.server.namenode.FSDirectory;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.io.retry.RetryPolicies;
 import org.apache.hadoop.io.retry.RetryPolicy;
@@ -210,13 +211,20 @@ public class DFSUtil {
     String[] components = StringUtils.split(src, '/');
     for (int i = 0; i < components.length; i++) {
       String element = components[i];
-      if (element.equals("..") || 
-          element.equals(".")  ||
+      if (element.equals(".")  ||
           (element.indexOf(":") >= 0)  ||
           (element.indexOf("/") >= 0)) {
         return false;
       }
-      
+      // ".." is allowed in path starting with /.reserved/.inodes
+      if (element.equals("..")) {
+        if (components.length > 4
+            && components[1].equals(FSDirectory.DOT_RESERVED_STRING)
+            && components[2].equals(FSDirectory.DOT_INODES_STRING)) {
+          continue;
+        }
+        return false;
+      }
       // The string may start or end with a /, but not have
       // "//" in the middle.
       if (element.isEmpty() && i != components.length - 1 &&

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

@@ -2731,6 +2731,19 @@ public class FSDirectory implements Closeable {
       throw new FileNotFoundException(
           "File for given inode path does not exist: " + src);
     }
+    
+    // Handle single ".." for NFS lookup support.
+    if ((pathComponents.length > 4)
+        && DFSUtil.bytes2String(pathComponents[4]).equals("..")) {
+      INode parent = inode.getParent();
+      if (parent == null || parent.getId() == INodeId.ROOT_INODE_ID) {
+        // inode is root, or its parent is root.
+        return Path.SEPARATOR;
+      } else {
+        return parent.getFullPathName();
+      }
+    }
+
     StringBuilder path = id == INodeId.ROOT_INODE_ID ? new StringBuilder()
         : new StringBuilder(inode.getFullPathName());
     for (int i = 4; i < pathComponents.length; i++) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java

@@ -44,6 +44,7 @@ import org.apache.hadoop.fs.PathIsNotDirectoryException;
 import org.apache.hadoop.fs.RemoteIterator;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.PermissionStatus;
+import org.apache.hadoop.hdfs.DFSClient;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.DFSUtil;
@@ -892,4 +893,34 @@ public class TestINodeFile {
       assertTrue(e instanceof FileNotFoundException);
     }
   }
+  
+  @Test
+  public void testDotdotInodePath() throws Exception {
+    final Configuration conf = new Configuration();
+    MiniDFSCluster cluster = null;
+    try {
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
+      cluster.waitActive();
+      final DistributedFileSystem hdfs = cluster.getFileSystem();
+      final FSDirectory fsdir = cluster.getNamesystem().getFSDirectory();
+
+      final Path dir = new Path("/dir");
+      hdfs.mkdirs(dir);
+      long dirId = fsdir.getINode(dir.toString()).getId();
+      long parentId = fsdir.getINode("/").getId();
+      String testPath = "/.reserved/.inodes/" + dirId + "/..";
+
+      DFSClient client = new DFSClient(NameNode.getAddress(conf), conf);
+      HdfsFileStatus status = client.getFileInfo(testPath);
+      assertTrue(parentId == status.getFileId());
+      
+      // Test root's parent is still root
+      testPath = "/.reserved/.inodes/" + parentId + "/..";
+      status = client.getFileInfo(testPath);
+      assertTrue(parentId == status.getFileId());
+      
+    } finally {
+      cluster.shutdown();
+    }
+  }
 }