From ff8b7bc253be4d595272bc28a153de4e12282579 Mon Sep 17 00:00:00 2001
From: Tsz-wo Sze <szetszwo@apache.org>
Date: Thu, 29 Jul 2010 17:58:55 +0000
Subject: [PATCH] HADOOP-6888. Add a new FileSystem API closeAllForUGI(..) for
 closing all file systems associated with a particular UGI.  Contributed by
 Kan Zhang

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@980523 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  3 ++
 src/java/org/apache/hadoop/fs/FileSystem.java | 37 +++++++++++++++++++
 .../hadoop/fs/TestFileSystemCaching.java      | 29 +++++++++++++++
 3 files changed, 69 insertions(+)

diff --git a/CHANGES.txt b/CHANGES.txt
index cd265868dc..dcc452a0e1 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -26,6 +26,9 @@ Trunk (unreleased changes)
     input path if recursive is true. Block locations are returned together
     with each file's status. (hairong)
 
+    HADOOP-6888. Add a new FileSystem API closeAllForUGI(..) for closing all
+    file systems associated with a particular UGI.  (Kan Zhang via szetszwo)
+
   IMPROVEMENTS
 
     HADOOP-6644. util.Shell getGROUPS_FOR_USER_COMMAND method name 
diff --git a/src/java/org/apache/hadoop/fs/FileSystem.java b/src/java/org/apache/hadoop/fs/FileSystem.java
index 534b334052..9a994e3556 100644
--- a/src/java/org/apache/hadoop/fs/FileSystem.java
+++ b/src/java/org/apache/hadoop/fs/FileSystem.java
@@ -311,6 +311,17 @@ public static void closeAll() throws IOException {
     CACHE.closeAll();
   }
 
+  /**
+   * Close all cached filesystems for a given UGI. Be sure those filesystems 
+   * are not used anymore.
+   * @param ugi
+   * @throws IOException
+   */
+  public static void closeAllForUGI(UserGroupInformation ugi) 
+  throws IOException {
+    CACHE.closeAll(ugi);
+  }
+
   /** Make sure that a path specifies a FileSystem. */
   public Path makeQualified(Path path) {
     checkPath(path);
@@ -1816,6 +1827,32 @@ public synchronized void run() {
       }
     }
 
+    synchronized void closeAll(UserGroupInformation ugi) throws IOException {
+      List<FileSystem> targetFSList = new ArrayList<FileSystem>();
+      //Make a pass over the list and collect the filesystems to close
+      //we cannot close inline since close() removes the entry from the Map
+      for (Map.Entry<Key, FileSystem> entry : map.entrySet()) {
+        final Key key = entry.getKey();
+        final FileSystem fs = entry.getValue();
+        if (ugi.equals(key.ugi) && fs != null) {
+          targetFSList.add(fs);   
+        }
+      }
+      List<IOException> exceptions = new ArrayList<IOException>();
+      //now make a pass over the target list and close each
+      for (FileSystem fs : targetFSList) {
+        try {
+          fs.close();
+        }
+        catch(IOException ioe) {
+          exceptions.add(ioe);
+        }
+      }
+      if (!exceptions.isEmpty()) {
+        throw MultipleIOException.createIOException(exceptions);
+      }
+    }
+
     /** FileSystem.Cache.Key */
     static class Key {
       final String scheme;
diff --git a/src/test/core/org/apache/hadoop/fs/TestFileSystemCaching.java b/src/test/core/org/apache/hadoop/fs/TestFileSystemCaching.java
index b545e2eeea..0ec8305a5e 100644
--- a/src/test/core/org/apache/hadoop/fs/TestFileSystemCaching.java
+++ b/src/test/core/org/apache/hadoop/fs/TestFileSystemCaching.java
@@ -179,4 +179,33 @@ public void testFsUniqueness() throws Exception {
     fs1.close();
     fs2.close();
   }
+  
+  @Test
+  public void testCloseAllForUGI() throws Exception {
+    final Configuration conf = new Configuration();
+    conf.set("fs.cachedfile.impl", conf.get("fs.file.impl"));
+    UserGroupInformation ugiA = UserGroupInformation.createRemoteUser("foo");
+    FileSystem fsA = ugiA.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      public FileSystem run() throws Exception {
+        return FileSystem.get(new URI("cachedfile://a"), conf);
+      }
+    });
+    //Now we should get the cached filesystem
+    FileSystem fsA1 = ugiA.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      public FileSystem run() throws Exception {
+        return FileSystem.get(new URI("cachedfile://a"), conf);
+      }
+    });
+    assertSame(fsA, fsA1);
+    
+    FileSystem.closeAllForUGI(ugiA);
+    
+    //Now we should get a different (newly created) filesystem
+    fsA1 = ugiA.doAs(new PrivilegedExceptionAction<FileSystem>() {
+      public FileSystem run() throws Exception {
+        return FileSystem.get(new URI("cachedfile://a"), conf);
+      }
+    });
+    assertNotSame(fsA, fsA1);
+  }
 }