1 files changed, 57 insertions, 0 deletions

diff --git a/Documentation/filesystems/adfs.txt b/Documentation/filesystems/adfs.txt
new file mode 100644
index 000000000000..060abb0c7004
--- /dev/null
+++ b/Documentation/filesystems/adfs.txt
@@ -0,0 +1,57 @@
+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.