diff --git a/Documentation/filesystems/isofs.txt b/Documentation/filesystems/isofs.txt
index 6973b98..3c367c3 100644
--- a/Documentation/filesystems/isofs.txt
+++ b/Documentation/filesystems/isofs.txt
@@ -23,8 +23,13 @@
   map=off       Do not map non-Rock Ridge filenames to lower case
   map=normal    Map non-Rock Ridge filenames to lower case
   map=acorn     As map=normal but also apply Acorn extensions if present
-  mode=xxx      Sets the permissions on files to xxx
-  dmode=xxx     Sets the permissions on directories to xxx
+  mode=xxx      Sets the permissions on files to xxx unless Rock Ridge
+		extensions set the permissions otherwise
+  dmode=xxx     Sets the permissions on directories to xxx unless Rock Ridge
+		extensions set the permissions otherwise
+  overriderockperm Set permissions on files and directories according to
+		'mode' and 'dmode' even though Rock Ridge extensions are
+		present.
   nojoliet      Ignore Joliet extensions if they are present.
   norock        Ignore Rock Ridge extensions if they are present.
   hide		Completely strip hidden files from the file system.