HDFS-15321. Make DFSAdmin tool to work with ViewFileSystemOverloadScheme

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFileSystemOverloadScheme.java

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.fs.viewfs;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
@@ -27,6 +28,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FsConstants;
+import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.UnsupportedFileSystemException;
 
 /******************************************************************************
@@ -227,4 +229,31 @@ private <T> T newInstance(Class<T> theClass, URI uri, Configuration conf) {
 
   }
 
+  /**
+   * This is an admin only API to give access to its child raw file system, if
+   * the path is link. If the given path is an internal directory(path is from
+   * mount paths tree), it will initialize the file system of given path uri
+   * directly. If path cannot be resolved to any internal directory or link, it
+   * will throw NotInMountpointException. Please note, this API will not return
+   * chrooted file system. Instead, this API will get actual raw file system
+   * instances.
+   *
+   * @param path - fs uri path
+   * @param conf - configuration
+   * @throws IOException
+   */
+  public FileSystem getRawFileSystem(Path path, Configuration conf)
+      throws IOException {
+    InodeTree.ResolveResult<FileSystem> res;
+    try {
+      res = fsState.resolve(getUriPath(path), true);
+      return res.isInternalDir() ? fsGetter().get(path.toUri(), conf)
+          : ((ChRootedFileSystem) res.targetFileSystem).getMyFs();
+    } catch (FileNotFoundException e) {
+      // No link configured with passed path.
+      throw new NotInMountpointException(path,
+          "No link found for the given path.");
+    }
+  }
+
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/viewfs/ViewFsTestSetup.java

@@ -192,7 +192,7 @@ static void addMountLinksToFile(String mountTable, String[] sources,
    * Adds the given mount links to the configuration. Mount link mappings are
    * in sources, targets at their respective index locations.
    */
-  static void addMountLinksToConf(String mountTable, String[] sources,
+  public static void addMountLinksToConf(String mountTable, String[] sources,
       String[] targets, Configuration config) throws URISyntaxException {
     for (int i = 0; i < sources.length; i++) {
       String src = sources[i];

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/AdminHelper.java

@@ -1,4 +1,5 @@
 /**
+
  * 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
@@ -21,6 +22,8 @@
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.viewfs.ViewFileSystemOverloadScheme;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
@@ -43,19 +46,29 @@ public class AdminHelper {
   static DistributedFileSystem getDFS(Configuration conf)
       throws IOException {
     FileSystem fs = FileSystem.get(conf);
-    if (!(fs instanceof DistributedFileSystem)) {
-      throw new IllegalArgumentException("FileSystem " + fs.getUri() +
-          " is not an HDFS file system");
-    }
-    return (DistributedFileSystem)fs;
+    return checkAndGetDFS(fs, conf);
   }
 
   static DistributedFileSystem getDFS(URI uri, Configuration conf)
       throws IOException {
     FileSystem fs = FileSystem.get(uri, conf);
+    return checkAndGetDFS(fs, conf);
+  }
+
+  static DistributedFileSystem checkAndGetDFS(FileSystem fs, Configuration conf)
+      throws IOException {
+    if ((fs instanceof ViewFileSystemOverloadScheme)) {
+      // With ViewFSOverloadScheme, the admin will pass -fs option with intended
+      // child fs mount path. GenericOptionsParser would have set the given -fs
+      // as FileSystem's defaultURI. So, we are using FileSystem.getDefaultUri
+      // to use the given -fs path.
+      fs = ((ViewFileSystemOverloadScheme) fs)
+          .getRawFileSystem(new Path(FileSystem.getDefaultUri(conf)), conf);
+    }
     if (!(fs instanceof DistributedFileSystem)) {
       throw new IllegalArgumentException("FileSystem " + fs.getUri()
-          + " is not an HDFS file system");
+          + " is not an HDFS file system. The fs class is: "
+          + fs.getClass().getName());
     }
     return (DistributedFileSystem) fs;
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java

@@ -130,11 +130,7 @@ public DFSAdminCommand(Configuration conf) {
     @Override
     public void run(PathData pathData) throws IOException {
       FileSystem fs = pathData.fs;
-      if (!(fs instanceof DistributedFileSystem)) {
-        throw new IllegalArgumentException("FileSystem " + fs.getUri()
-            + " is not an HDFS file system");
-      }
-      this.dfs = (DistributedFileSystem) fs;
+      this.dfs = AdminHelper.checkAndGetDFS(fs, getConf());
       run(pathData.path);
     }
   }
@@ -485,12 +481,7 @@ public DFSAdmin(Configuration conf) {
   }
 
   protected DistributedFileSystem getDFS() throws IOException {
-    FileSystem fs = getFS();
-    if (!(fs instanceof DistributedFileSystem)) {
-      throw new IllegalArgumentException("FileSystem " + fs.getUri() + 
-      " is not an HDFS file system");
-    }
-    return (DistributedFileSystem)fs;
+    return AdminHelper.getDFS(getConf());
   }
 
   /**