diff --git a/Documentation/filesystems/adfs.txt b/Documentation/filesystems/adfs.txt
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+Mount options for ADFS
+----------------------
+
+  uid=nnn	All files in the partition will be owned by
+		user id nnn.  Default 0 (root).
+  gid=nnn	All files in the partition willbe in group
+		nnn.  Default 0 (root).
+  ownmask=nnn	The permission mask for ADFS 'owner' permissions
+		will be nnn.  Default 0700.
+  othmask=nnn	The permission mask for ADFS 'other' permissions
+		will be nnn.  Default 0077.
+
+Mapping of ADFS permissions to Linux permissions
+------------------------------------------------
+
+  ADFS permissions consist of the following:
+
+	Owner read
+	Owner write
+	Other read
+	Other write
+
+  (In older versions, an 'execute' permission did exist, but this
+   does not hold the same meaning as the Linux 'execute' permission
+   and is now obsolete).
+
+  The mapping is performed as follows:
+
+	Owner read				-> -r--r--r--
+	Owner write				-> --w--w---w
+	Owner read and filetype UnixExec	-> ---x--x--x
+    These are then masked by ownmask, eg 700	-> -rwx------
+	Possible owner mode permissions		-> -rwx------
+
+	Other read				-> -r--r--r--
+	Other write				-> --w--w--w-
+	Other read and filetype UnixExec	-> ---x--x--x
+    These are then masked by othmask, eg 077	-> ----rwxrwx
+	Possible other mode permissions		-> ----rwxrwx
+
+  Hence, with the default masks, if a file is owner read/write, and
+  not a UnixExec filetype, then the permissions will be:
+
+			-rw-------
+
+  However, if the masks were ownmask=0770,othmask=0007, then this would
+  be modified to:
+			-rw-rw----
+
+  There is no restriction on what you can do with these masks.  You may
+  wish that either read bits give read access to the file for all, but
+  keep the default write protection (ownmask=0755,othmask=0577):
+
+			-rw-r--r--
+
+  You can therefore tailor the permission translation to whatever you
+  desire the permissions should be under Linux.