From 6a3cf32b8b4054b86ad12a126dfca871bc5d31d4 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <namjae.jeon@samsung.com>
Date: Sun, 31 May 2020 21:30:59 +0900
Subject: [PATCH] exfat: add the dummy mount options to be backward compatible
 with staging/exfat

As Ubuntu and Fedora release new version used kernel version equal to or
higher than v5.4, They started to support kernel exfat filesystem.

Linus reported a mount error with new version of exfat on Fedora:

        exfat: Unknown parameter 'namecase'

This is because there is a difference in mount option between old
staging/exfat and new exfat.  And utf8, debug, and codepage options as
well as namecase have been removed from new exfat.

This patch add the dummy mount options as deprecated option to be
backward compatible with old one.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 super.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/super.c b/super.c
index e48a92e940ac..860b40c8f6b0 100644
--- a/super.c
+++ b/super.c
@@ -238,6 +238,12 @@ enum {
 	Opt_errors,
 	Opt_discard,
 	Opt_time_offset,
+
+	/* Deprecated options */
+	Opt_utf8,
+	Opt_debug,
+	Opt_namecase,
+	Opt_codepage,
 };
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
@@ -275,6 +281,14 @@ static const struct fs_parameter_spec exfat_param_specs[] = {
 #endif
 	fsparam_flag("discard",			Opt_discard),
 	fsparam_s32("time_offset",		Opt_time_offset),
+	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,
+		  NULL),
+	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
+		  NULL),
+	__fsparam(fs_param_is_u32, "namecase",	Opt_namecase,
+		  fs_param_deprecated, NULL),
+	__fsparam(fs_param_is_u32, "codepage",	Opt_codepage,
+		  fs_param_deprecated, NULL),
 	{}
 };
 
@@ -342,6 +356,11 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 			return -EINVAL;
 		opts->time_offset = result.int_32;
 		break;
+	case Opt_utf8:
+	case Opt_debug:
+	case Opt_namecase:
+	case Opt_codepage:
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -363,6 +382,12 @@ enum {
 	Opt_err,
 	Opt_discard,
 	Opt_time_offset,
+
+	/* Deprecated options */
+	Opt_utf8,
+	Opt_debug,
+	Opt_namecase,
+	Opt_codepage,
 	Opt_fs,
 };
 
@@ -378,6 +403,10 @@ static const match_table_t exfat_tokens = {
 	{Opt_err_panic, "errors=panic"},
 	{Opt_err_ro, "errors=remount-ro"},
 	{Opt_discard, "discard"},
+	{Opt_codepage, "codepage=%u"},
+	{Opt_namecase, "namecase=%u"},
+	{Opt_debug, "debug"},
+	{Opt_utf8, "utf8"},
 	{Opt_err, NULL}
 };
 
@@ -464,6 +493,11 @@ static int parse_options(struct super_block *sb, char *options, int silent,
 					return -EINVAL;
 				opts->time_offset = option;
 				break;
+			case Opt_utf8:
+			case Opt_debug:
+			case Opt_namecase:
+			case Opt_codepage:
+				break;
 			default:
 				if (!silent) {
 					exfat_msg(sb, KERN_ERR,