Signed-off-by: Pali Rohár <pali@kernel.org>
---
fs/hfs/super.c | 31 +++++++++++++++++++++++++++++++
fs/hfs/trans.c | 38 ++++++++++++++------------------------
2 files changed, 45 insertions(+), 24 deletions(-)

diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 12d9bae39363..86bc46746c7f 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c

@@ -351,6 +351,37 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)

		}
	}

+	if (hsb->nls_io && !hsb->nls_disk) {
+		/*
+		 * Previous version of hfs driver did something unexpected:
+		 * When codepage was not defined but iocharset was then
+		 * hfs driver copied 8bit character from disk directly to
+		 * 16bit unicode wchar_t type. Which means it did conversion
+		 * from Latin1 (ISO-8859-1) to Unicode because first 256
+		 * Unicode code points matches 8bit ISO-8859-1 codepage table.
+		 * So when iocharset was specified and codepage not, then
+		 * codepage used implicit value "iso8859-1".
+		 *
+		 * To not change this previous default behavior as some users
+		 * may depend on it, we load iso8859-1 NLS table explicitly
+		 * to simplify code and make it more reable what happens.
+		 *
+		 * In context of hfs driver it is really strange to use
+		 * ISO-8859-1 codepage table for storing data to disk, but
+		 * nothing forbids it. Just it is highly incompatible with
+		 * Mac OS systems. So via pr_warn() inform user that this
+		 * is not probably what he wants.
+		 */
+		pr_warn("iocharset was specified but codepage not, "
+			"using default codepage=iso8859-1\n");
+		pr_warn("this default codepage=iso8859-1 is incompatible with "
+			"Mac OS systems and may be changed in the future");
+		hsb->nls_disk = load_nls("iso8859-1");
+		if (!hsb->nls_disk) {
+			pr_err("unable to load iso8859-1 codepage\n");
+			return 0;
+		}
+	}
	if (hsb->nls_disk && !hsb->nls_io) {
		hsb->nls_io = load_nls_default();
		if (!hsb->nls_io) {

diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
index 39f5e343bf4d..c75682c61b06 100644
--- a/fs/hfs/trans.c
+++ b/fs/hfs/trans.c

@@ -48,18 +48,13 @@ int hfs_mac2asc(struct super_block *sb, char *out, const struct hfs_name *in)

		wchar_t ch;

		while (srclen > 0) {
-			if (nls_disk) {
-				size = nls_disk->char2uni(src, srclen, &ch);
-				if (size <= 0) {
-					ch = '?';
-					size = 1;
-				}
-				src += size;
-				srclen -= size;
-			} else {
-				ch = *src++;
-				srclen--;
+			size = nls_disk->char2uni(src, srclen, &ch);
+			if (size <= 0) {
+				ch = '?';
+				size = 1;
			}
+			src += size;
+			srclen -= size;
			if (ch == '/')
				ch = ':';
			size = nls_io->uni2char(ch, dst, dstlen);

@@ -119,20 +114,15 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr

			srclen -= size;
			if (ch == ':')
				ch = '/';
-			if (nls_disk) {
-				size = nls_disk->uni2char(ch, dst, dstlen);
-				if (size < 0) {
-					if (size == -ENAMETOOLONG)
-						goto out;
-					*dst = '?';
-					size = 1;
-				}
-				dst += size;
-				dstlen -= size;
-			} else {
-				*dst++ = ch > 0xff ? '?' : ch;
-				dstlen--;
+			size = nls_disk->uni2char(ch, dst, dstlen);
+			if (size < 0) {
+				if (size == -ENAMETOOLONG)
+					goto out;
+				*dst = '?';
+				size = 1;
			}
+			dst += size;
+			dstlen -= size;
		}
	} else {
		char ch;
-- 
2.20.1