GIT: unionfs2-2.6.27.y: Unionfs: clarify usage.txt mount options
Erez Zadok
ezk at fsl.cs.sunysb.edu
Thu Aug 12 23:17:32 EDT 2010
commit d5110b319f4464a7bd68d35e902a20c51be59d02
Author: Erez Zadok <ezk at cs.sunysb.edu>
Date: Thu Dec 13 17:11:30 2007 -0500
Unionfs: clarify usage.txt mount options
CC: Jim Kissel <jlk at osml.eu>
Signed-off-by: Erez Zadok <ezk at cs.sunysb.edu>
diff --git a/Documentation/filesystems/unionfs/usage.txt b/Documentation/filesystems/unionfs/usage.txt
index a6b1aca..59c4f28 100644
--- a/Documentation/filesystems/unionfs/usage.txt
+++ b/Documentation/filesystems/unionfs/usage.txt
@@ -7,17 +7,32 @@ read-write branches, as well as insertion and deletion of branches anywhere
in the fan-out. To maintain Unix semantics, Unionfs handles elimination of
duplicates, partial-error conditions, and more.
-# mount -t unionfs -o branch-option[,union-options[,...]] none MOUNTPOINT
+GENERAL SYNTAX
+==============
-The available branch-option for the mount command is:
+# mount -t unionfs -o <OPTIONS>,<BRANCH-OPTIONS> none MOUNTPOINT
+
+OPTIONS can be any legal combination one of:
+
+- ro # mount file system read-only
+- rw # mount file system read-write
+- remount # remount the file system (see Branch Management below)
+- incgen # increment generation no. (see Cache Consistency below)
+
+BRANCH-OPTIONS can be either (1) a list of branches given to the "dirs="
+option, or (2) a list of individual branch manipulation commands, described
+in the "Branch Management" section below.
+
+The syntax for the "dirs=" mount option is:
dirs=branch[=ro|=rw][:...]
-specifies a separated list of which directories compose the union.
-Directories that come earlier in the list have a higher precedence than
-those which come later. Additionally, read-only or read-write permissions of
-the branch can be specified by appending =ro or =rw (default) to each
-directory.
+The "dirs=" option takes a colon-delimited list of directories to compose
+the union, with an optional branch mode for each of those directories.
+Directories that come earlier (specified first, on the left) in the list
+have a higher precedence than those which come later. Additionally,
+read-only or read-write permissions of the branch can be specified by
+appending =ro or =rw (default) to each directory.
Syntax:
@@ -28,11 +43,12 @@ Example:
dirs=/writable_branch=rw:/read-only_branch=ro
-DYNAMIC BRANCH MANAGEMENT AND REMOUNTS
-======================================
+BRANCH MANAGEMENT
+=================
-You can remount a union and change its overall mode, or reconfigure the
-branches, as follows.
+Once you mount your union for the first time, using the "dirs=" option, you
+can then change the union's overall mode or reconfigure the branches, using
+the remount option, as follows.
To downgrade a union from read-write to read-only:
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