diff --git a/lustre/ChangeLog b/lustre/ChangeLog
index 7bae3294361f1b59d1ac93079d0a174d1c6626bc..0e2d9b13e548267091c949695b170285a15e8958 100644
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -674,6 +674,11 @@ Details    : A lot of unlink operations with concurrent I/O can lead to a
 	     max_rpcs_in_flight per OSC and LDLM_FL_DISCARD_DATA blocking
 	     callbacks are processed in priority.
 
+Severity   : normal
+Bugzilla   : 13829
+Description: enable ACLs on MDS by default
+Details    : ACLs must be enabled on MDS by default.
+
 --------------------------------------------------------------------------------
 
 2007-08-10         Cluster File Systems, Inc. <info@clusterfs.com>
diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index 34620b810836eb54dd9feafcef07527eaabf6bbb..331f970fb469940ac5cf4d1bdf4269711191af21 100644
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -3713,6 +3713,15 @@ static void fsoptions_to_mdt_flags(struct mdt_device *m, char *options)
 {
         char *p = options;
 
+#ifdef CONFIG_FS_POSIX_ACL
+        /* ACLs should be enabled by default (b=13829) */
+        m->mdt_opts.mo_acl = 1;
+        LCONSOLE_INFO("Enabling ACL\n");
+#else
+        m->mdt_opts.mo_acl = 0;
+        LCONSOLE_INFO("Disabling ACL\n");
+#endif
+
         if (!options)
                 return;
 
@@ -3731,16 +3740,6 @@ static void fsoptions_to_mdt_flags(struct mdt_device *m, char *options)
                            (memcmp(options, "nouser_xattr", len) == 0)) {
                         m->mdt_opts.mo_user_xattr = 0;
                         LCONSOLE_INFO("Disabling user_xattr\n");
-                } else if ((len == sizeof("acl") - 1) &&
-                           (memcmp(options, "acl", len) == 0)) {
-#ifdef CONFIG_FS_POSIX_ACL
-                        m->mdt_opts.mo_acl = 1;
-                        LCONSOLE_INFO("Enabling ACL\n");
-#else
-                        m->mdt_opts.mo_acl = 0;
-                        CWARN("ignoring unsupported acl mount option\n");
-                        LCONSOLE_INFO("Disabling ACL\n");
-#endif
                 } else if ((len == sizeof("noacl") - 1) &&
                            (memcmp(options, "noacl", len) == 0)) {
                         m->mdt_opts.mo_acl = 0;