udf: Fix iocharset=utf8 mount option

Currently iocharset=utf8 mount option is broken. To use UTF-8 as iocharset,
it is required to use utf8 mount option.

Fix iocharset=utf8 mount option to use be equivalent to the utf8 mount
option.

If UTF-8 as iocharset is used then s_nls_map is set to NULL. So simplify
code around, remove UDF_FLAG_NLS_MAP and UDF_FLAG_UTF8 flags as to
distinguish between UTF-8 and non-UTF-8 it is needed just to check if
s_nls_map set to NULL or not.

Link: https://lore.kernel.org/r/20210808162453.1653-4-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/super.c

@@ -343,10 +343,10 @@ static int udf_show_options(struct seq_file *seq, struct dentry *root)
 		seq_printf(seq, ",lastblock=%u", sbi->s_last_block);
 	if (sbi->s_anchor != 0)
 		seq_printf(seq, ",anchor=%u", sbi->s_anchor);
-	if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8))
-		seq_puts(seq, ",utf8");
-	if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP) && sbi->s_nls_map)
+	if (sbi->s_nls_map)
 		seq_printf(seq, ",iocharset=%s", sbi->s_nls_map->charset);
+	else
+		seq_puts(seq, ",iocharset=utf8");
 
 	return 0;
 }
@@ -552,19 +552,24 @@ static int udf_parse_options(char *options, struct udf_options *uopt,
 			/* Ignored (never implemented properly) */
 			break;
 		case Opt_utf8:
-			uopt->flags |= (1 << UDF_FLAG_UTF8);
+			if (!remount) {
+				unload_nls(uopt->nls_map);
+				uopt->nls_map = NULL;
+			}
 			break;
 		case Opt_iocharset:
 			if (!remount) {
-				if (uopt->nls_map)
-					unload_nls(uopt->nls_map);
-				/*
-				 * load_nls() failure is handled later in
-				 * udf_fill_super() after all options are
-				 * parsed.
-				 */
+				unload_nls(uopt->nls_map);
+				uopt->nls_map = NULL;
+			}
+			/* When nls_map is not loaded then UTF-8 is used */
+			if (!remount && strcmp(args[0].from, "utf8") != 0) {
 				uopt->nls_map = load_nls(args[0].from);
-				uopt->flags |= (1 << UDF_FLAG_NLS_MAP);
+				if (!uopt->nls_map) {
+					pr_err("iocharset %s not found\n",
+						args[0].from);
+					return 0;
+				}
 			}
 			break;
 		case Opt_uforget:
@@ -2146,21 +2151,6 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 	if (!udf_parse_options((char *)options, &uopt, false))
 		goto parse_options_failure;
 
-	if (uopt.flags & (1 << UDF_FLAG_UTF8) &&
-	    uopt.flags & (1 << UDF_FLAG_NLS_MAP)) {
-		udf_err(sb, "utf8 cannot be combined with iocharset\n");
-		goto parse_options_failure;
-	}
-	if ((uopt.flags & (1 << UDF_FLAG_NLS_MAP)) && !uopt.nls_map) {
-		uopt.nls_map = load_nls_default();
-		if (!uopt.nls_map)
-			uopt.flags &= ~(1 << UDF_FLAG_NLS_MAP);
-		else
-			udf_debug("Using default NLS map\n");
-	}
-	if (!(uopt.flags & (1 << UDF_FLAG_NLS_MAP)))
-		uopt.flags |= (1 << UDF_FLAG_UTF8);
-
 	fileset.logicalBlockNum = 0xFFFFFFFF;
 	fileset.partitionReferenceNum = 0xFFFF;
 
@@ -2315,8 +2305,7 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 error_out:
 	iput(sbi->s_vat_inode);
 parse_options_failure:
-	if (uopt.nls_map)
-		unload_nls(uopt.nls_map);
+	unload_nls(uopt.nls_map);
 	if (lvid_open)
 		udf_close_lvid(sb);
 	brelse(sbi->s_lvid_bh);
@@ -2366,8 +2355,7 @@ static void udf_put_super(struct super_block *sb)
 	sbi = UDF_SB(sb);
 
 	iput(sbi->s_vat_inode);
-	if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP))
-		unload_nls(sbi->s_nls_map);
+	unload_nls(sbi->s_nls_map);
 	if (!sb_rdonly(sb))
 		udf_close_lvid(sb);
 	brelse(sbi->s_lvid_bh);

fs/udf/udf_sb.h

@@ -20,8 +20,6 @@
 #define UDF_FLAG_UNDELETE		6
 #define UDF_FLAG_UNHIDE			7
 #define UDF_FLAG_VARCONV		8
-#define UDF_FLAG_NLS_MAP		9
-#define UDF_FLAG_UTF8			10
 #define UDF_FLAG_UID_FORGET     11    /* save -1 for uid to disk */
 #define UDF_FLAG_GID_FORGET     12
 #define UDF_FLAG_UID_SET	13

fs/udf/unicode.c

@@ -177,7 +177,7 @@ static int udf_name_from_CS0(struct super_block *sb,
 		return 0;
 	}
 
-	if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP))
+	if (UDF_SB(sb)->s_nls_map)
 		conv_f = UDF_SB(sb)->s_nls_map->uni2char;
 	else
 		conv_f = NULL;
@@ -285,7 +285,7 @@ static int udf_name_to_CS0(struct super_block *sb,
 	if (ocu_max_len <= 0)
 		return 0;
 
-	if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP))
+	if (UDF_SB(sb)->s_nls_map)
 		conv_f = UDF_SB(sb)->s_nls_map->char2uni;
 	else
 		conv_f = NULL;