Revert FAT NLS changes.

It's causing massive user confusion, and breaks installers by
mounting the filesystem read-only.

Cset exclude: hirofumi@mail.parknet.co.jp[torvalds]|ChangeSet|20040802210150|02337

2 files changed, 103 insertions, 74 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index 083ee1440ad25a..a4035fba9b18d6 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -554,6 +554,44 @@ menu "DOS/FAT/NT Filesystems"
 config FAT_FS
 	tristate
 	select NLS
+	help
+	  If you want to use one of the FAT-based file systems (the MS-DOS,
+	  VFAT (Windows 95) and UMSDOS (used to run Linux on top of an
+	  ordinary DOS partition) file systems), then you must say Y or M here
+	  to include FAT support. You will then be able to mount partitions or
+	  diskettes with FAT-based file systems and transparently access the
+	  files on them, i.e. MSDOS files will look and behave just like all
+	  other Unix files.
+
+	  This FAT support is not a file system in itself, it only provides
+	  the foundation for the other file systems. You will have to say Y or
+	  M to at least one of "MSDOS fs support" or "VFAT fs support" in
+	  order to make use of it.
+
+	  Another way to read and write MSDOS floppies and hard drive
+	  partitions from within Linux (but not transparently) is with the
+	  mtools ("man mtools") program suite. You don't need to say Y here in
+	  order to do that.
+
+	  If you need to move large files on floppies between a DOS and a
+	  Linux box, say Y here, mount the floppy under Linux with an MSDOS
+	  file system and use GNU tar's M option. GNU tar is a program
+	  available for Unix and DOS ("man tar" or "info tar").
+
+	  It is now also becoming possible to read and write compressed FAT
+	  file systems; read <file:Documentation/filesystems/fat_cvf.txt> for
+	  details.
+
+	  The FAT support will enlarge your kernel by about 37 KB. If unsure,
+	  say Y.
+
+	  To compile this as a module, choose M here: the module will be called
+	  fat.  Note that if you compile the FAT support as a module, you
+	  cannot compile any of the FAT-based file systems into the kernel
+	  -- they will have to be modules as well.
+	  The file system of your root partition (the one containing the
+	  directory /) cannot be a module, so don't say M here if you intend
+	  to use UMSDOS as your root file system.
 
 config MSDOS_FS
 	tristate "MSDOS fs support"
@@ -606,6 +644,25 @@ config VFAT_FS
 	  To compile this as a module, choose M here: the module will be called
 	  vfat.
 
+config FAT_DEFAULT_CODEPAGE
+	int "Default codepage for FAT"
+	depends on MSDOS_FS || VFAT_FS
+	default 437
+	help
+	  This option should be set to the codepage of your FAT filesystems.
+	  It can be overridden with the 'codepage' mount option.
+
+config FAT_DEFAULT_IOCHARSET
+	string "Default iocharset for FAT"
+	depends on VFAT_FS
+	default "iso8859-1"
+	help
+	  Set this to the default I/O character set you'd like FAT to use.
+	  It should probably match the character set that most of your
+	  FAT filesystems use, and can be overridded with the 'iocharset'
+	  mount option for FAT filesystems.  Note that UTF8 is *not* a
+	  supported charset for FAT filesystems.
+
 config UMSDOS_FS
 #dep_tristate '    UMSDOS: Unix-like file system on top of standard MSDOS fs' CONFIG_UMSDOS_FS $CONFIG_MSDOS_FS
 # UMSDOS is temprory broken
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index b4ee8c93e67f6a..c0fc6b7d6a9874 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -23,6 +23,14 @@
 #include <linux/parser.h>
 #include <asm/unaligned.h>
 
+#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
+/* if user don't select VFAT, this is undefined. */
+#define CONFIG_FAT_DEFAULT_IOCHARSET	""
+#endif
+
+static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
+static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
+
 /*
  * New FAT inode stuff. We do the following:
  *	a) i_ino is constant and has nothing with on-disk location.
@@ -166,15 +174,15 @@ void fat_put_super(struct super_block *sb)
 	if (sbi->nls_disk) {
 		unload_nls(sbi->nls_disk);
 		sbi->nls_disk = NULL;
-		sbi->options.codepage = 0;
+		sbi->options.codepage = fat_default_codepage;
 	}
 	if (sbi->nls_io) {
 		unload_nls(sbi->nls_io);
 		sbi->nls_io = NULL;
 	}
-	if (sbi->options.iocharset) {
+	if (sbi->options.iocharset != fat_default_iocharset) {
 		kfree(sbi->options.iocharset);
-		sbi->options.iocharset = NULL;
+		sbi->options.iocharset = fat_default_iocharset;
 	}
 
 	sb->s_fs_info = NULL;
@@ -193,10 +201,11 @@ static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
 		seq_printf(m, ",gid=%u", opts->fs_gid);
 	seq_printf(m, ",fmask=%04o", opts->fs_fmask);
 	seq_printf(m, ",dmask=%04o", opts->fs_dmask);
-	if (sbi->nls_disk && opts->codepage)
+	if (sbi->nls_disk && opts->codepage != fat_default_codepage)
 		seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
 	if (isvfat) {
-		if (sbi->nls_io && opts->iocharset)
+		if (sbi->nls_io &&
+		    strcmp(opts->iocharset, fat_default_iocharset))
 			seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
 
 		switch (opts->shortname) {
@@ -327,14 +336,15 @@ static int parse_options(char *options, int is_vfat, int *debug,
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int option;
+	char *iocharset;
 
 	opts->isvfat = is_vfat;
 
 	opts->fs_uid = current->uid;
 	opts->fs_gid = current->gid;
 	opts->fs_fmask = opts->fs_dmask = current->fs->umask;
-	opts->codepage = 0;
-	opts->iocharset = NULL;
+	opts->codepage = fat_default_codepage;
+	opts->iocharset = fat_default_iocharset;
 	if (is_vfat)
 		opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
 	else
@@ -433,11 +443,12 @@ static int parse_options(char *options, int is_vfat, int *debug,
 
 		/* vfat specific */
 		case Opt_charset:
-			if (opts->iocharset)
+			if (opts->iocharset != fat_default_iocharset)
 				kfree(opts->iocharset);
-			opts->iocharset = match_strdup(&args[0]);
-			if (opts->iocharset == NULL)
+			iocharset = match_strdup(&args[0]);
+			if (!iocharset)
 				return -ENOMEM;
+			opts->iocharset = iocharset;
 			break;
 		case Opt_shortname_lower:
 			opts->shortname = VFAT_SFN_DISPLAY_LOWER
@@ -486,9 +497,15 @@ static int parse_options(char *options, int is_vfat, int *debug,
 			return -EINVAL;
 		}
 	}
+	/* UTF8 doesn't provide FAT semantics */
+	if (!strcmp(opts->iocharset, "utf8")) {
+		printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
+		       " for FAT filesystems, filesystem will be case sensitive!\n");
+	}
+
 	if (opts->unicode_xlate)
 		opts->utf8 = 0;
-
+	
 	return 0;
 }
 
@@ -768,66 +785,6 @@ static struct export_operations fat_export_ops = {
 	.get_parent	= fat_get_parent,
 };
 
-static int fat_load_nls(struct super_block *sb)
-{
-	struct msdos_sb_info *sbi = MSDOS_SB(sb);
-	struct fat_mount_options *opts = &sbi->options;
-	char codepage[50], *iocharset;
-	int error = 0, not_specified = 0;
-
-	if (opts->codepage)
-		snprintf(codepage, sizeof(codepage), "cp%d", opts->codepage);
-	else {
-		not_specified = 1;
-		strcpy(codepage, "default");
-	}
-	sbi->nls_disk = load_nls(codepage);
-	if (sbi->nls_disk == NULL) {
-		printk(KERN_ERR "FAT: codepage %s not found\n", codepage);
-		error = -EINVAL;
-		goto out;
-	}
-
-	if (opts->isvfat) {
-		if (opts->iocharset)
-			iocharset = opts->iocharset;
-		else {
-			not_specified = 1;
-			iocharset = "default";
-		}
-		/*
-		 * FIXME: utf8 is using iocharset for upper/lower conversion
-		 * UTF8 doesn't provide FAT semantics
-		 */
-		if (!strcmp(iocharset, "utf8")) {
-			printk(KERN_WARNING
-			       "FAT: utf8 is not a recommended IO charset"
-			       " for FAT filesystem,"
-			       " filesystem will be case sensitive!\n");
-		}
-		sbi->nls_io = load_nls(iocharset);
-		if (sbi->nls_io == NULL) {
-			printk(KERN_ERR "FAT: IO charset %s not found\n",
-			       iocharset);
-			error = -EINVAL;
-			goto out;
-		}
-	}
-
-	if (not_specified) {
-		unsigned long not_ro = !(sb->s_flags & MS_RDONLY);
-		if (not_ro)
-			sb->s_flags |= MS_RDONLY;
-
-		printk(KERN_INFO "FAT: %s option didn't specified\n"
-		       "     File name can not access proper%s\n",
-		       opts->isvfat ? "codepage or iocharset" : "codepage",
-		       not_ro ? " (mounted as read-only)" : "");
-	}
-out:
-	return error;
-}
-
 /*
  * Read the super block of an MS-DOS FS.
  */
@@ -843,6 +800,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 	int debug, first;
 	unsigned int media;
 	long error;
+	char buf[50];
 
 	sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
 	if (!sbi)
@@ -1057,9 +1015,23 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 		goto out_invalid;
 	}
 
-	error = fat_load_nls(sb);
-	if (error)
+	error = -EINVAL;
+	sprintf(buf, "cp%d", sbi->options.codepage);
+	sbi->nls_disk = load_nls(buf);
+	if (!sbi->nls_disk) {
+		printk(KERN_ERR "FAT: codepage %s not found\n", buf);
 		goto out_fail;
+	}
+
+	/* FIXME: utf8 is using iocharset for upper/lower conversion */
+	if (sbi->options.isvfat) {
+		sbi->nls_io = load_nls(sbi->options.iocharset);
+		if (!sbi->nls_io) {
+			printk(KERN_ERR "FAT: IO charset %s not found\n",
+			       sbi->options.iocharset);
+			goto out_fail;
+		}
+	}
 
 	error = -ENOMEM;
 	root_inode = new_inode(sb);
@@ -1093,7 +1065,7 @@ out_fail:
 		unload_nls(sbi->nls_io);
 	if (sbi->nls_disk)
 		unload_nls(sbi->nls_disk);
-	if (sbi->options.iocharset)
+	if (sbi->options.iocharset != fat_default_iocharset)
 		kfree(sbi->options.iocharset);
 	sb->s_fs_info = NULL;
 	kfree(sbi);