[PATCH] allow iocharset=none mount optio (6 of 7)

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2005/02/18 16:41:17-06:00 [email protected] 
#   JFS: allow iocharset=none mount option
#   
#   iocharset=none is an explicit option to specify the default
#   character translation be used (no translation).  This allows
#   remounting a partition which was mounted with a different setting,
#   and allows the same mount options to be used between 2.6 and 2.4
#   kernels, where there is a different default.
#   
#   Signed-off-by: Dave Kleikamp <[email protected]>
# 
diff -Nru a/Documentation/filesystems/jfs.txt b/Documentation/filesystems/jfs.txt
--- a/Documentation/filesystems/jfs.txt	2005-02-18 17:02:32 -06:00
+++ b/Documentation/filesystems/jfs.txt	2005-02-18 17:02:32 -06:00
@@ -1,13 +1,6 @@
 IBM's Journaled File System (JFS) for Linux
 
-JFS Homepage:  http://oss.software.ibm.com/jfs/
-
-Team members
-------------
-Dave Kleikamp      [email protected]  
-Dave Blaschke      [email protected]
-Steve Best         [email protected]
-Barry Arndt        [email protected]
+JFS Homepage:  http://jfs.sourceforge.net/
 
 The following mount options are supported:
 
@@ -15,6 +8,7 @@
 		ASCII.  The default is to do no conversion.  Use
 		iocharset=utf8 for UTF8 translations.  This requires
 		CONFIG_NLS_UTF8 to be set in the kernel .config file.
+		iocharset=none specifies the default behavior explicitly.
 
 resize=value	Resize the volume to <value> blocks.  JFS only supports
 		growing a volume, not shrinking it.  This option is only
@@ -38,4 +32,4 @@
 Please send bugs, comments, cards and letters to [email protected].
 
 The JFS mailing list can be subscribed to by using the link labeled
-"Mail list Subscribe" at our web page http://oss.software.ibm.com/jfs/.
+"Mail list Subscribe" at our web page http://jfs.sourceforge.net/
diff -Nru a/fs/jfs/super.c b/fs/jfs/super.c
--- a/fs/jfs/super.c	2005-02-18 17:02:32 -06:00
+++ b/fs/jfs/super.c	2005-02-18 17:02:32 -06:00
@@ -235,7 +235,7 @@
 static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
 			 int *flag)
 {
-	void *nls_map = NULL;
+	void *nls_map = (void *)-1;	/* -1: no change;  NULL: none */
 	char *p;
 	struct jfs_sb_info *sbi = JFS_SBI(sb);
 
@@ -263,12 +263,17 @@
 			/* Don't do anything ;-) */
 			break;
 		case Opt_iocharset:
-			if (nls_map)	/* specified iocharset twice! */
+			if (nls_map && nls_map != (void *) -1)
 				unload_nls(nls_map);
-			nls_map = load_nls(args[0].from);
-			if (!nls_map) {
-				printk(KERN_ERR "JFS: charset not found\n");
-				goto cleanup;
+			if (!strcmp(args[0].from, "none"))
+				nls_map = NULL;
+			else {
+				nls_map = load_nls(args[0].from);
+				if (!nls_map) {
+					printk(KERN_ERR
+					       "JFS: charset not found\n");
+					goto cleanup;
+				}
 			}
 			break;
 		case Opt_resize:
@@ -318,7 +323,7 @@
 		}
 	}
 
-	if (nls_map) {
+	if (nls_map != (void *) -1) {
 		/* Discard old (if remount) */
 		if (sbi->nls_tab)
 			unload_nls(sbi->nls_tab);
@@ -327,7 +332,7 @@
 	return 1;
 
 cleanup:
-	if (nls_map)
+	if (nls_map && nls_map != (void *) -1)
 		unload_nls(nls_map);
 	return 0;
 }