hfsplus: fix generic/523 test-case failure

The xfstests' test-case generic/523 fails to execute
correctly:

FSTYP -- hfsplus
PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.15.0-rc4+ #8 SMP PREEMPT_DYNAMIC Thu May 1 16:43:22 PDT 2025
MKFS_OPTIONS -- /dev/loop51
MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch

generic/523 - output mismatch (see xfstests-dev/results//generic/523.out.bad)

The test-case expects to have '/' in the xattr name.
However, HFS+ unicode logic makes conversion of '/'
into ':'. In HFS+, a filename can contain '/' because
':' is the separator. The slash is a valid filename
character on macOS. But on Linux, / is the path separator
and it cannot appear in a filename component. But xattr
name can contain any of these symbols. It means that
this unicode logic conversion doesn't need to be executed
for the case of xattr name.

This patch adds distinguishing the regular and xattr names.
If we have a regular name, then this conversion of special
symbols will be executed. Otherwise, the conversion is skipped
for the case of xattr names.

sudo ./check -g auto
FSTYP         -- hfsplus
PLATFORM      -- Linux/x86_64 hfsplus-testing-0001 7.0.0-rc1+ #24 SMP PREEMPT_DYNAMIC Fri Mar 20 12:36:49 PDT 2026
MKFS_OPTIONS  -- /dev/loop51
MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch

<skipped>
generic/523 33s ...  25s
<skipped>

Closes: hfs-linux-kernel/hfs-linux-kernel#178
cc: John Paul Adrian Glaubitz <[email protected]>
cc: Yangtao Li <[email protected]>
cc: [email protected]
Signed-off-by: Viacheslav Dubeyko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Viacheslav Dubeyko <[email protected]>

Author: dubeyko

fs/hfsplus/attributes.c

@@ -57,7 +57,8 @@ int hfsplus_attr_build_key(struct super_block *sb, hfsplus_btree_key *key,
 	if (name) {
 		int res = hfsplus_asc2uni(sb,
 				(struct hfsplus_unistr *)&key->attr.key_name,
-				HFSPLUS_ATTR_MAX_STRLEN, name, strlen(name));
+				HFSPLUS_ATTR_MAX_STRLEN, name, strlen(name),
+				HFS_XATTR_NAME);
 		if (res)
 			return res;
 		len = be16_to_cpu(key->attr.key_name.length);

fs/hfsplus/catalog.c

@@ -47,7 +47,7 @@ int hfsplus_cat_build_key(struct super_block *sb,
 
 	key->cat.parent = cpu_to_be32(parent);
 	err = hfsplus_asc2uni(sb, &key->cat.name, HFSPLUS_MAX_STRLEN,
-			str->name, str->len);
+			      str->name, str->len, HFS_REGULAR_NAME);
 	if (unlikely(err < 0))
 		return err;
 
@@ -183,7 +183,7 @@ static int hfsplus_fill_cat_thread(struct super_block *sb,
 	entry->thread.reserved = 0;
 	entry->thread.parentID = cpu_to_be32(parentid);
 	err = hfsplus_asc2uni(sb, &entry->thread.nodeName, HFSPLUS_MAX_STRLEN,
-				str->name, str->len);
+				str->name, str->len, HFS_REGULAR_NAME);
 	if (unlikely(err < 0))
 		return err;
 

fs/hfsplus/hfsplus_fs.h

@@ -506,7 +506,8 @@ int hfsplus_uni2asc_xattr_str(struct super_block *sb,
 			      const struct hfsplus_attr_unistr *ustr,
 			      char *astr, int *len_p);
 int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr,
-		    int max_unistr_len, const char *astr, int len);
+		    int max_unistr_len, const char *astr, int len,
+		    int name_type);
 int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str);
 int hfsplus_compare_dentry(const struct dentry *dentry, unsigned int len,
 			   const char *str, const struct qstr *name);

fs/hfsplus/unicode.c

@@ -147,9 +147,44 @@ static u16 *hfsplus_compose_lookup(u16 *p, u16 cc)
 	return NULL;
 }
 
+/*
+ * In HFS+, a filename can contain / because : is the separator.
+ * The slash is a valid filename character on macOS.
+ * But on Linux, / is the path separator and
+ * it cannot appear in a filename component.
+ * There's a parallel mapping for the NUL character (0 -> U+2400).
+ * NUL terminates strings in C/POSIX but is valid in HFS+ filenames.
+ */
+static inline
+void hfsplus_mac2linux_compatibility_check(u16 symbol, u16 *conversion,
+					   int name_type)
+{
+	*conversion = symbol;
+
+	switch (name_type) {
+	case HFS_XATTR_NAME:
+		/* ignore conversion */
+		return;
+
+	default:
+		/* continue logic */
+		break;
+	}
+
+	switch (symbol) {
+	case 0:
+		*conversion = 0x2400;
+		break;
+	case '/':
+		*conversion = ':';
+		break;
+	}
+}
+
 static int hfsplus_uni2asc(struct super_block *sb,
 			   const struct hfsplus_unistr *ustr,
-			   int max_len, char *astr, int *len_p)
+			   int max_len, char *astr, int *len_p,
+			   int name_type)
 {
 	const hfsplus_unichr *ip;
 	struct nls_table *nls = HFSPLUS_SB(sb)->nls;
@@ -217,14 +252,8 @@ static int hfsplus_uni2asc(struct super_block *sb,
 					hfsplus_compose_table, c1);
 			if (ce1)
 				break;
-			switch (c0) {
-			case 0:
-				c0 = 0x2400;
-				break;
-			case '/':
-				c0 = ':';
-				break;
-			}
+			hfsplus_mac2linux_compatibility_check(c0, &c0,
+							      name_type);
 			res = nls->uni2char(c0, op, len);
 			if (res < 0) {
 				if (res == -ENAMETOOLONG)
@@ -257,16 +286,8 @@ static int hfsplus_uni2asc(struct super_block *sb,
 			}
 		}
 same:
-		switch (c0) {
-		case 0:
-			cc = 0x2400;
-			break;
-		case '/':
-			cc = ':';
-			break;
-		default:
-			cc = c0;
-		}
+		hfsplus_mac2linux_compatibility_check(c0, &cc,
+						      name_type);
 done:
 		res = nls->uni2char(cc, op, len);
 		if (res < 0) {
@@ -288,7 +309,10 @@ inline int hfsplus_uni2asc_str(struct super_block *sb,
 			       const struct hfsplus_unistr *ustr, char *astr,
 			       int *len_p)
 {
-	return hfsplus_uni2asc(sb, ustr, HFSPLUS_MAX_STRLEN, astr, len_p);
+	return hfsplus_uni2asc(sb,
+				ustr, HFSPLUS_MAX_STRLEN,
+				astr, len_p,
+				HFS_REGULAR_NAME);
 }
 EXPORT_SYMBOL_IF_KUNIT(hfsplus_uni2asc_str);
 
@@ -297,22 +321,32 @@ inline int hfsplus_uni2asc_xattr_str(struct super_block *sb,
 				     char *astr, int *len_p)
 {
 	return hfsplus_uni2asc(sb, (const struct hfsplus_unistr *)ustr,
-			       HFSPLUS_ATTR_MAX_STRLEN, astr, len_p);
+				HFSPLUS_ATTR_MAX_STRLEN, astr, len_p,
+				HFS_XATTR_NAME);
 }
 EXPORT_SYMBOL_IF_KUNIT(hfsplus_uni2asc_xattr_str);
 
 /*
- * Convert one or more ASCII characters into a single unicode character.
- * Returns the number of ASCII characters corresponding to the unicode char.
+ * In HFS+, a filename can contain / because : is the separator.
+ * The slash is a valid filename character on macOS.
+ * But on Linux, / is the path separator and
+ * it cannot appear in a filename component.
+ * There's a parallel mapping for the NUL character (0 -> U+2400).
+ * NUL terminates strings in C/POSIX but is valid in HFS+ filenames.
  */
-static inline int asc2unichar(struct super_block *sb, const char *astr, int len,
-			      wchar_t *uc)
+static inline
+void hfsplus_linux2mac_compatibility_check(wchar_t *uc, int name_type)
 {
-	int size = HFSPLUS_SB(sb)->nls->char2uni(astr, len, uc);
-	if (size <= 0) {
-		*uc = '?';
-		size = 1;
+	switch (name_type) {
+	case HFS_XATTR_NAME:
+		/* ignore conversion */
+		return;
+
+	default:
+		/* continue logic */
+		break;
 	}
+
 	switch (*uc) {
 	case 0x2400:
 		*uc = 0;
@@ -321,6 +355,23 @@ static inline int asc2unichar(struct super_block *sb, const char *astr, int len,
 		*uc = '/';
 		break;
 	}
+}
+
+/*
+ * Convert one or more ASCII characters into a single unicode character.
+ * Returns the number of ASCII characters corresponding to the unicode char.
+ */
+static inline int asc2unichar(struct super_block *sb, const char *astr, int len,
+			      wchar_t *uc, int name_type)
+{
+	int size = HFSPLUS_SB(sb)->nls->char2uni(astr, len, uc);
+
+	if (size <= 0) {
+		*uc = '?';
+		size = 1;
+	}
+
+	hfsplus_linux2mac_compatibility_check(uc, name_type);
 	return size;
 }
 
@@ -395,7 +446,7 @@ static u16 *decompose_unichar(wchar_t uc, int *size, u16 *hangul_buffer)
 
 int hfsplus_asc2uni(struct super_block *sb,
 		    struct hfsplus_unistr *ustr, int max_unistr_len,
-		    const char *astr, int len)
+		    const char *astr, int len, int name_type)
 {
 	int size, dsize, decompose;
 	u16 *dstr, outlen = 0;
@@ -404,7 +455,7 @@ int hfsplus_asc2uni(struct super_block *sb,
 
 	decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
 	while (outlen < max_unistr_len && len > 0) {
-		size = asc2unichar(sb, astr, len, &c);
+		size = asc2unichar(sb, astr, len, &c, name_type);
 
 		if (decompose)
 			dstr = decompose_unichar(c, &dsize, dhangul);
@@ -452,7 +503,7 @@ int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str)
 	len = str->len;
 	while (len > 0) {
 		int dsize;
-		size = asc2unichar(sb, astr, len, &c);
+		size = asc2unichar(sb, astr, len, &c, HFS_REGULAR_NAME);
 		astr += size;
 		len -= size;
 
@@ -510,7 +561,8 @@ int hfsplus_compare_dentry(const struct dentry *dentry,
 
 	while (len1 > 0 && len2 > 0) {
 		if (!dsize1) {
-			size = asc2unichar(sb, astr1, len1, &c);
+			size = asc2unichar(sb, astr1, len1, &c,
+					   HFS_REGULAR_NAME);
 			astr1 += size;
 			len1 -= size;
 
@@ -525,7 +577,8 @@ int hfsplus_compare_dentry(const struct dentry *dentry,
 		}
 
 		if (!dsize2) {
-			size = asc2unichar(sb, astr2, len2, &c);
+			size = asc2unichar(sb, astr2, len2, &c,
+					   HFS_REGULAR_NAME);
 			astr2 += size;
 			len2 -= size;