From 3a1f981686835f64df4498f93dae73fde3f2c7a8 Mon Sep 17 00:00:00 2001
From: Allen Wittenauer <aw@apache.org>
Date: Fri, 26 Sep 2014 12:20:40 -0700
Subject: [PATCH] HDFS-6664. HDFS permissions guide documentation states
 incorrect default group mapping class. (Ray Chiang via aw)

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt         |  3 +++
 .../src/site/apt/HdfsPermissionsGuide.apt.vm        | 13 ++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 1297bc9acd5..0524cf0e227 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -972,6 +972,9 @@ Release 2.6.0 - UNRELEASED
     HDFS-7140. Add a tool to list all the existing block storage policies.
     (jing9)
 
+    HDFS-6664. HDFS permissions guide documentation states incorrect default 
+    group mapping class. (Ray Chiang via aw)
+
 Release 2.5.1 - 2014-09-05
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/HdfsPermissionsGuide.apt.vm b/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/HdfsPermissionsGuide.apt.vm
index f9aac0bf6c0..30119a6093a 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/HdfsPermissionsGuide.apt.vm
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/apt/HdfsPermissionsGuide.apt.vm
@@ -99,9 +99,16 @@ HDFS Permissions Guide
    Once a username has been determined as described above, the list of
    groups is determined by a group mapping service, configured by the
    hadoop.security.group.mapping property. The default implementation,
-   org.apache.hadoop.security.ShellBasedUnixGroupsMapping, will shell out
-   to the Unix bash -c groups command to resolve a list of groups for a
-   user.
+   org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback,
+   will determine if the Java Native Interface (JNI) is available.  If
+   JNI is available, the implementation will use the API within hadoop
+   to resolve a list of groups for a user. If JNI is not available
+   then the shell implementation,
+   org.apache.hadoop.security.ShellBasedUnixGroupsMapping, is used.
+   This implementation shells out with the <<<bash -c groups>>>
+   command (for a Linux/Unix environment) or the <<<net group>>>
+   command (for a Windows environment) to resolve a list of groups for
+   a user.
 
    An alternate implementation, which connects directly to an LDAP server
    to resolve the list of groups, is available via