Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1595 insertions, 0 deletions

diff --git a/fs/hfsplus/unicode_test.c b/fs/hfsplus/unicode_test.c
new file mode 100644
index 000000000..7f6b2a3c6
--- /dev/null
+++ b/fs/hfsplus/unicode_test.c
@@ -0,0 +1,1595 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit tests for HFS+ Unicode string operations
+ *
+ * Copyright (C) 2025 Viacheslav Dubeyko <slava@dubeyko.com>
+ */
+
+#include <kunit/test.h>
+#include <linux/nls.h>
+#include <linux/dcache.h>
+#include <linux/stringhash.h>
+#include "hfsplus_fs.h"
+
+struct test_mock_string_env {
+	struct hfsplus_unistr str1;
+	struct hfsplus_unistr str2;
+	char *buf;
+	u32 buf_size;
+};
+
+static struct test_mock_string_env *setup_mock_str_env(u32 buf_size)
+{
+	struct test_mock_string_env *env;
+
+	env = kzalloc_obj(struct test_mock_string_env);
+	if (!env)
+		return NULL;
+
+	env->buf = kzalloc(buf_size, GFP_KERNEL);
+	if (!env->buf) {
+		kfree(env);
+		return NULL;
+	}
+
+	env->buf_size = buf_size;
+
+	return env;
+}
+
+static void free_mock_str_env(struct test_mock_string_env *env)
+{
+	kfree(env->buf);
+	kfree(env);
+}
+
+/* Helper function to create hfsplus_unistr */
+static void create_unistr(struct hfsplus_unistr *ustr, const char *ascii_str)
+{
+	int len = strlen(ascii_str);
+	int i;
+
+	memset(ustr->unicode, 0, sizeof(ustr->unicode));
+
+	ustr->length = cpu_to_be16(len);
+	for (i = 0; i < len && i < HFSPLUS_MAX_STRLEN; i++)
+		ustr->unicode[i] = cpu_to_be16((u16)ascii_str[i]);
+}
+
+static void corrupt_unistr(struct hfsplus_unistr *ustr)
+{
+	ustr->length = cpu_to_be16(U16_MAX);
+}
+
+/* Test hfsplus_strcasecmp function */
+static void hfsplus_strcasecmp_test(struct kunit *test)
+{
+	struct test_mock_string_env *mock_env;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	/* Test identical strings */
+	create_unistr(&mock_env->str1, "hello");
+	create_unistr(&mock_env->str2, "hello");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	/* Test case insensitive comparison */
+	create_unistr(&mock_env->str1, "Hello");
+	create_unistr(&mock_env->str2, "hello");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	create_unistr(&mock_env->str1, "HELLO");
+	create_unistr(&mock_env->str2, "hello");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	/* Test different strings */
+	create_unistr(&mock_env->str1, "apple");
+	create_unistr(&mock_env->str2, "banana");
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "zebra");
+	create_unistr(&mock_env->str2, "apple");
+	KUNIT_EXPECT_GT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	/* Test different lengths */
+	create_unistr(&mock_env->str1, "test");
+	create_unistr(&mock_env->str2, "testing");
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "testing");
+	create_unistr(&mock_env->str2, "test");
+	KUNIT_EXPECT_GT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	/* Test empty strings */
+	create_unistr(&mock_env->str1, "");
+	create_unistr(&mock_env->str2, "");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	create_unistr(&mock_env->str1, "");
+	create_unistr(&mock_env->str2, "test");
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	/* Test single characters */
+	create_unistr(&mock_env->str1, "A");
+	create_unistr(&mock_env->str2, "a");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	create_unistr(&mock_env->str1, "A");
+	create_unistr(&mock_env->str2, "B");
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	/* Test maximum length strings */
+	memset(mock_env->buf, 'a', HFSPLUS_MAX_STRLEN);
+	mock_env->buf[HFSPLUS_MAX_STRLEN] = '\0';
+	create_unistr(&mock_env->str1, mock_env->buf);
+	create_unistr(&mock_env->str2, mock_env->buf);
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	/* Change one character in the middle */
+	mock_env->buf[HFSPLUS_MAX_STRLEN / 2] = 'b';
+	create_unistr(&mock_env->str2, mock_env->buf);
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	/* Test corrupted strings */
+	create_unistr(&mock_env->str1, "");
+	corrupt_unistr(&mock_env->str1);
+	create_unistr(&mock_env->str2, "");
+	KUNIT_EXPECT_NE(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	create_unistr(&mock_env->str1, "");
+	create_unistr(&mock_env->str2, "");
+	corrupt_unistr(&mock_env->str2);
+	KUNIT_EXPECT_NE(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	create_unistr(&mock_env->str1, "test");
+	corrupt_unistr(&mock_env->str1);
+	create_unistr(&mock_env->str2, "testing");
+	KUNIT_EXPECT_GT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "test");
+	create_unistr(&mock_env->str2, "testing");
+	corrupt_unistr(&mock_env->str2);
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "testing");
+	corrupt_unistr(&mock_env->str1);
+	create_unistr(&mock_env->str2, "test");
+	KUNIT_EXPECT_GT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "testing");
+	create_unistr(&mock_env->str2, "test");
+	corrupt_unistr(&mock_env->str2);
+	KUNIT_EXPECT_LT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	free_mock_str_env(mock_env);
+}
+
+/* Test hfsplus_strcmp function (case-sensitive) */
+static void hfsplus_strcmp_test(struct kunit *test)
+{
+	struct test_mock_string_env *mock_env;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	/* Test identical strings */
+	create_unistr(&mock_env->str1, "hello");
+	create_unistr(&mock_env->str2, "hello");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	/* Test case sensitive comparison - should NOT be equal */
+	create_unistr(&mock_env->str1, "Hello");
+	create_unistr(&mock_env->str2, "hello");
+	KUNIT_EXPECT_NE(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+	 /* 'H' < 'h' in Unicode */
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	/* Test lexicographic ordering */
+	create_unistr(&mock_env->str1, "apple");
+	create_unistr(&mock_env->str2, "banana");
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "zebra");
+	create_unistr(&mock_env->str2, "apple");
+	KUNIT_EXPECT_GT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	/* Test different lengths with common prefix */
+	create_unistr(&mock_env->str1, "test");
+	create_unistr(&mock_env->str2, "testing");
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "testing");
+	create_unistr(&mock_env->str2, "test");
+	KUNIT_EXPECT_GT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	/* Test empty strings */
+	create_unistr(&mock_env->str1, "");
+	create_unistr(&mock_env->str2, "");
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	/* Test maximum length strings */
+	memset(mock_env->buf, 'a', HFSPLUS_MAX_STRLEN);
+	mock_env->buf[HFSPLUS_MAX_STRLEN] = '\0';
+	create_unistr(&mock_env->str1, mock_env->buf);
+	create_unistr(&mock_env->str2, mock_env->buf);
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	/* Change one character in the middle */
+	mock_env->buf[HFSPLUS_MAX_STRLEN / 2] = 'b';
+	create_unistr(&mock_env->str2, mock_env->buf);
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	/* Test corrupted strings */
+	create_unistr(&mock_env->str1, "");
+	corrupt_unistr(&mock_env->str1);
+	create_unistr(&mock_env->str2, "");
+	KUNIT_EXPECT_NE(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	create_unistr(&mock_env->str1, "");
+	create_unistr(&mock_env->str2, "");
+	corrupt_unistr(&mock_env->str2);
+	KUNIT_EXPECT_NE(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	create_unistr(&mock_env->str1, "test");
+	corrupt_unistr(&mock_env->str1);
+	create_unistr(&mock_env->str2, "testing");
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "test");
+	create_unistr(&mock_env->str2, "testing");
+	corrupt_unistr(&mock_env->str2);
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "testing");
+	corrupt_unistr(&mock_env->str1);
+	create_unistr(&mock_env->str2, "test");
+	KUNIT_EXPECT_GT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	create_unistr(&mock_env->str1, "testing");
+	create_unistr(&mock_env->str2, "test");
+	corrupt_unistr(&mock_env->str2);
+	KUNIT_EXPECT_GT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	free_mock_str_env(mock_env);
+}
+
+/* Test Unicode edge cases */
+static void hfsplus_unicode_edge_cases_test(struct kunit *test)
+{
+	struct test_mock_string_env *mock_env;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	/* Test with special characters */
+	mock_env->str1.length = cpu_to_be16(3);
+	mock_env->str1.unicode[0] = cpu_to_be16(0x00E9); /* é */
+	mock_env->str1.unicode[1] = cpu_to_be16(0x00F1); /* ñ */
+	mock_env->str1.unicode[2] = cpu_to_be16(0x00FC); /* ü */
+
+	mock_env->str2.length = cpu_to_be16(3);
+	mock_env->str2.unicode[0] = cpu_to_be16(0x00E9); /* é */
+	mock_env->str2.unicode[1] = cpu_to_be16(0x00F1); /* ñ */
+	mock_env->str2.unicode[2] = cpu_to_be16(0x00FC); /* ü */
+
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	/* Test with different special characters */
+	mock_env->str2.unicode[1] = cpu_to_be16(0x00F2); /* ò */
+	KUNIT_EXPECT_NE(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	/* Test null characters within string (should be handled correctly) */
+	mock_env->str1.length = cpu_to_be16(3);
+	mock_env->str1.unicode[0] = cpu_to_be16('a');
+	mock_env->str1.unicode[1] = cpu_to_be16(0x0000); /* null */
+	mock_env->str1.unicode[2] = cpu_to_be16('b');
+
+	mock_env->str2.length = cpu_to_be16(3);
+	mock_env->str2.unicode[0] = cpu_to_be16('a');
+	mock_env->str2.unicode[1] = cpu_to_be16(0x0000); /* null */
+	mock_env->str2.unicode[2] = cpu_to_be16('b');
+
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	free_mock_str_env(mock_env);
+}
+
+/* Test boundary conditions */
+static void hfsplus_unicode_boundary_test(struct kunit *test)
+{
+	struct test_mock_string_env *mock_env;
+	int i;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	/* Test maximum length boundary */
+	mock_env->str1.length = cpu_to_be16(HFSPLUS_MAX_STRLEN);
+	mock_env->str2.length = cpu_to_be16(HFSPLUS_MAX_STRLEN);
+
+	for (i = 0; i < HFSPLUS_MAX_STRLEN; i++) {
+		mock_env->str1.unicode[i] = cpu_to_be16('A');
+		mock_env->str2.unicode[i] = cpu_to_be16('A');
+	}
+
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+
+	/* Change last character */
+	mock_env->str2.unicode[HFSPLUS_MAX_STRLEN - 1] = cpu_to_be16('B');
+	KUNIT_EXPECT_LT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+
+	/* Test zero length strings */
+	mock_env->str1.length = cpu_to_be16(0);
+	mock_env->str2.length = cpu_to_be16(0);
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcmp(&mock_env->str1,
+						&mock_env->str2));
+	KUNIT_EXPECT_EQ(test, 0, hfsplus_strcasecmp(&mock_env->str1,
+						    &mock_env->str2));
+
+	/* Test one character vs empty */
+	mock_env->str1.length = cpu_to_be16(1);
+	mock_env->str1.unicode[0] = cpu_to_be16('A');
+	mock_env->str2.length = cpu_to_be16(0);
+	KUNIT_EXPECT_GT(test, hfsplus_strcmp(&mock_env->str1,
+					     &mock_env->str2), 0);
+	KUNIT_EXPECT_GT(test, hfsplus_strcasecmp(&mock_env->str1,
+						 &mock_env->str2), 0);
+
+	free_mock_str_env(mock_env);
+}
+
+/* Mock superblock and NLS table for testing hfsplus_uni2asc */
+struct test_mock_sb {
+	struct nls_table nls;
+	struct hfsplus_sb_info sb_info;
+	struct super_block sb;
+};
+
+static struct test_mock_sb *setup_mock_sb(void)
+{
+	struct test_mock_sb *ptr;
+
+	ptr = kzalloc_obj(struct test_mock_sb);
+	if (!ptr)
+		return NULL;
+
+	ptr->nls.charset = "utf8";
+	ptr->nls.uni2char = NULL; /* Will use default behavior */
+	ptr->sb_info.nls = &ptr->nls;
+	ptr->sb.s_fs_info = &ptr->sb_info;
+
+	/* Set default flags - no decomposition, no case folding */
+	clear_bit(HFSPLUS_SB_NODECOMPOSE, &ptr->sb_info.flags);
+	clear_bit(HFSPLUS_SB_CASEFOLD, &ptr->sb_info.flags);
+
+	return ptr;
+}
+
+static void free_mock_sb(struct test_mock_sb *ptr)
+{
+	kfree(ptr);
+}
+
+/* Simple uni2char implementation for testing */
+static int test_uni2char(wchar_t uni, unsigned char *out, int boundlen)
+{
+	if (boundlen <= 0)
+		return -ENAMETOOLONG;
+
+	if (uni < 0x80) {
+		*out = (unsigned char)uni;
+		return 1;
+	}
+
+	/* For non-ASCII, just use '?' as fallback */
+	*out = '?';
+	return 1;
+}
+
+/* Test hfsplus_uni2asc basic functionality */
+static void hfsplus_uni2asc_basic_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int len, result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.uni2char = test_uni2char;
+
+	/* Test simple ASCII string conversion */
+	create_unistr(&mock_env->str1, "hello");
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 5, len);
+	KUNIT_EXPECT_STREQ(test, "hello", mock_env->buf);
+
+	/* Test empty string */
+	create_unistr(&mock_env->str1, "");
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 0, len);
+
+	/* Test single character */
+	create_unistr(&mock_env->str1, "A");
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 1, len);
+	KUNIT_EXPECT_EQ(test, 'A', mock_env->buf[0]);
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test special character handling */
+static void hfsplus_uni2asc_special_chars_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int len, result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.uni2char = test_uni2char;
+
+	/* Test null character conversion (should become 0x2400) */
+	mock_env->str1.length = cpu_to_be16(1);
+	mock_env->str1.unicode[0] = cpu_to_be16(0x0000);
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 1, len);
+	/* Our test implementation returns '?' for non-ASCII */
+	KUNIT_EXPECT_EQ(test, '?', mock_env->buf[0]);
+
+	/* Test forward slash conversion (should become colon) */
+	mock_env->str1.length = cpu_to_be16(1);
+	mock_env->str1.unicode[0] = cpu_to_be16('/');
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 1, len);
+	KUNIT_EXPECT_EQ(test, ':', mock_env->buf[0]);
+
+	/* Test string with mixed special characters */
+	mock_env->str1.length = cpu_to_be16(3);
+	mock_env->str1.unicode[0] = cpu_to_be16('a');
+	mock_env->str1.unicode[1] = cpu_to_be16('/');
+	mock_env->str1.unicode[2] = cpu_to_be16('b');
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 3, len);
+	KUNIT_EXPECT_EQ(test, 'a', mock_env->buf[0]);
+	KUNIT_EXPECT_EQ(test, ':', mock_env->buf[1]);
+	KUNIT_EXPECT_EQ(test, 'b', mock_env->buf[2]);
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test buffer length handling */
+static void hfsplus_uni2asc_buffer_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int len, result;
+
+	mock_env = setup_mock_str_env(10);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.uni2char = test_uni2char;
+
+	/* Test insufficient buffer space */
+	create_unistr(&mock_env->str1, "toolongstring");
+	len = 5; /* Buffer too small */
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, -ENAMETOOLONG, result);
+	KUNIT_EXPECT_EQ(test, 5, len); /* Should be set to consumed length */
+
+	/* Test exact buffer size */
+	create_unistr(&mock_env->str1, "exact");
+	len = 5;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 5, len);
+
+	/* Test zero length buffer */
+	create_unistr(&mock_env->str1, "test");
+	len = 0;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, -ENAMETOOLONG, result);
+	KUNIT_EXPECT_EQ(test, 0, len);
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test corrupted unicode string handling */
+static void hfsplus_uni2asc_corrupted_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int len, result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.uni2char = test_uni2char;
+
+	/* Test corrupted length (too large) */
+	create_unistr(&mock_env->str1, "test");
+	corrupt_unistr(&mock_env->str1); /* Sets length to U16_MAX */
+	len = mock_env->buf_size;
+
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	/* Should still work but with corrected length */
+	KUNIT_EXPECT_EQ(test, 0, result);
+	/*
+	 * Length should be corrected to HFSPLUS_MAX_STRLEN
+	 * and processed accordingly
+	 */
+	KUNIT_EXPECT_GT(test, len, 0);
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test edge cases and boundary conditions */
+static void hfsplus_uni2asc_edge_cases_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int len, result;
+	int i;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN * 2);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.uni2char = test_uni2char;
+
+	/* Test maximum length string */
+	mock_env->str1.length = cpu_to_be16(HFSPLUS_MAX_STRLEN);
+	for (i = 0; i < HFSPLUS_MAX_STRLEN; i++)
+		mock_env->str1.unicode[i] = cpu_to_be16('a');
+
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, HFSPLUS_MAX_STRLEN, len);
+
+	/* Verify all characters are 'a' */
+	for (i = 0; i < HFSPLUS_MAX_STRLEN; i++)
+		KUNIT_EXPECT_EQ(test, 'a', mock_env->buf[i]);
+
+	/* Test string with high Unicode values (non-ASCII) */
+	mock_env->str1.length = cpu_to_be16(3);
+	mock_env->str1.unicode[0] = cpu_to_be16(0x00E9); /* é */
+	mock_env->str1.unicode[1] = cpu_to_be16(0x00F1); /* ñ */
+	mock_env->str1.unicode[2] = cpu_to_be16(0x00FC); /* ü */
+	len = mock_env->buf_size;
+	result = hfsplus_uni2asc_str(&mock_sb->sb, &mock_env->str1,
+				     mock_env->buf, &len);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 3, len);
+	/* Our test implementation converts non-ASCII to '?' */
+	KUNIT_EXPECT_EQ(test, '?', mock_env->buf[0]);
+	KUNIT_EXPECT_EQ(test, '?', mock_env->buf[1]);
+	KUNIT_EXPECT_EQ(test, '?', mock_env->buf[2]);
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Simple char2uni implementation for testing */
+static int test_char2uni(const unsigned char *rawstring,
+			 int boundlen, wchar_t *uni)
+{
+	if (boundlen <= 0)
+		return -EINVAL;
+
+	*uni = (wchar_t)*rawstring;
+	return 1;
+}
+
+/* Helper function to check unicode string contents */
+static void check_unistr_content(struct kunit *test,
+				 struct hfsplus_unistr *ustr,
+				 const char *expected_ascii)
+{
+	int expected_len = strlen(expected_ascii);
+	int actual_len = be16_to_cpu(ustr->length);
+	int i;
+
+	KUNIT_EXPECT_EQ(test, expected_len, actual_len);
+
+	for (i = 0; i < expected_len && i < actual_len; i++) {
+		u16 expected_char = (u16)expected_ascii[i];
+		u16 actual_char = be16_to_cpu(ustr->unicode[i]);
+
+		KUNIT_EXPECT_EQ(test, expected_char, actual_char);
+	}
+}
+
+/* Test hfsplus_asc2uni basic functionality */
+static void hfsplus_asc2uni_basic_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test simple ASCII string conversion */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, "hello", 5,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &mock_env->str1, "hello");
+
+	/* Test empty string */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, "", 0,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 0, be16_to_cpu(mock_env->str1.length));
+
+	/* Test single character */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, "A", 1,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &mock_env->str1, "A");
+
+	/* Test null-terminated string with explicit length */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, "test\0extra", 4,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &mock_env->str1, "test");
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test special character handling in asc2uni */
+static void hfsplus_asc2uni_special_chars_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test colon conversion (should become forward slash) */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, ":", 1,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 1, be16_to_cpu(mock_env->str1.length));
+	KUNIT_EXPECT_EQ(test, '/', be16_to_cpu(mock_env->str1.unicode[0]));
+
+	/* Test string with mixed special characters */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, "a:b", 3,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 3, be16_to_cpu(mock_env->str1.length));
+	KUNIT_EXPECT_EQ(test, 'a', be16_to_cpu(mock_env->str1.unicode[0]));
+	KUNIT_EXPECT_EQ(test, '/', be16_to_cpu(mock_env->str1.unicode[1]));
+	KUNIT_EXPECT_EQ(test, 'b', be16_to_cpu(mock_env->str1.unicode[2]));
+
+	/* Test multiple special characters */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, ":::", 3,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 3, be16_to_cpu(mock_env->str1.length));
+	KUNIT_EXPECT_EQ(test, '/', be16_to_cpu(mock_env->str1.unicode[0]));
+	KUNIT_EXPECT_EQ(test, '/', be16_to_cpu(mock_env->str1.unicode[1]));
+	KUNIT_EXPECT_EQ(test, '/', be16_to_cpu(mock_env->str1.unicode[2]));
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test buffer length limits */
+static void hfsplus_asc2uni_buffer_limits_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 10);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test exact maximum length */
+	memset(mock_env->buf, 'a', HFSPLUS_MAX_STRLEN);
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &mock_env->str1, HFSPLUS_MAX_STRLEN,
+				 mock_env->buf, HFSPLUS_MAX_STRLEN,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, HFSPLUS_MAX_STRLEN,
+			be16_to_cpu(mock_env->str1.length));
+
+	/* Test exceeding maximum length */
+	memset(mock_env->buf, 'a', HFSPLUS_MAX_STRLEN + 5);
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &mock_env->str1, HFSPLUS_MAX_STRLEN,
+				 mock_env->buf, HFSPLUS_MAX_STRLEN + 5,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, -ENAMETOOLONG, result);
+	KUNIT_EXPECT_EQ(test, HFSPLUS_MAX_STRLEN,
+			be16_to_cpu(mock_env->str1.length));
+
+	/* Test with smaller max_unistr_len */
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &mock_env->str1, 5, "toolongstring", 13,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, -ENAMETOOLONG, result);
+	KUNIT_EXPECT_EQ(test, 5, be16_to_cpu(mock_env->str1.length));
+
+	/* Test zero max length */
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1, 0, "test", 4,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, -ENAMETOOLONG, result);
+	KUNIT_EXPECT_EQ(test, 0, be16_to_cpu(mock_env->str1.length));
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test error handling and edge cases */
+static void hfsplus_asc2uni_edge_cases_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct hfsplus_unistr ustr;
+	char test_str[] = {'a', '\0', 'b'};
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test zero length input */
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &ustr, HFSPLUS_MAX_STRLEN, "test", 0,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 0, be16_to_cpu(ustr.length));
+
+	/* Test input with length mismatch */
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &ustr, HFSPLUS_MAX_STRLEN, "hello", 3,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &ustr, "hel");
+
+	/* Test with various printable ASCII characters */
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &ustr, HFSPLUS_MAX_STRLEN, "ABC123!@#", 9,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &ustr, "ABC123!@#");
+
+	/* Test null character in the middle */
+	result = hfsplus_asc2uni(&mock_sb->sb,
+				 &ustr, HFSPLUS_MAX_STRLEN, test_str, 3,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, 3, be16_to_cpu(ustr.length));
+	KUNIT_EXPECT_EQ(test, 'a', be16_to_cpu(ustr.unicode[0]));
+	KUNIT_EXPECT_EQ(test, 0, be16_to_cpu(ustr.unicode[1]));
+	KUNIT_EXPECT_EQ(test, 'b', be16_to_cpu(ustr.unicode[2]));
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test decomposition flag behavior */
+static void hfsplus_asc2uni_decompose_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	int result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test with decomposition disabled (default) */
+	clear_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str1,
+				 HFSPLUS_MAX_STRLEN, "test", 4,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &mock_env->str1, "test");
+
+	/* Test with decomposition enabled */
+	set_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+	result = hfsplus_asc2uni(&mock_sb->sb, &mock_env->str2,
+				 HFSPLUS_MAX_STRLEN, "test", 4,
+				 HFS_REGULAR_NAME);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	check_unistr_content(test, &mock_env->str2, "test");
+
+	/* For simple ASCII, both should produce the same result */
+	KUNIT_EXPECT_EQ(test,
+			be16_to_cpu(mock_env->str1.length),
+			be16_to_cpu(mock_env->str2.length));
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Mock dentry for testing hfsplus_hash_dentry */
+static struct dentry test_dentry;
+
+static void setup_mock_dentry(struct super_block *sb)
+{
+	memset(&test_dentry, 0, sizeof(test_dentry));
+	test_dentry.d_sb = sb;
+}
+
+/* Helper function to create qstr */
+static void create_qstr(struct qstr *str, const char *name)
+{
+	str->name = name;
+	str->len = strlen(name);
+	str->hash = 0; /* Will be set by hash function */
+}
+
+/* Test hfsplus_hash_dentry basic functionality */
+static void hfsplus_hash_dentry_basic_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr str1, str2;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test basic string hashing */
+	create_qstr(&str1, "hello");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_NE(test, 0, str1.hash);
+
+	/* Test that identical strings produce identical hashes */
+	create_qstr(&str2, "hello");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, str1.hash, str2.hash);
+
+	/* Test empty string */
+	create_qstr(&str1, "");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+
+	/* Empty string should still produce a hash */
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test single character */
+	create_qstr(&str1, "A");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_NE(test, 0, str1.hash);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test case folding behavior in hash */
+static void hfsplus_hash_dentry_casefold_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr str1, str2;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test with case folding disabled (default) */
+	clear_bit(HFSPLUS_SB_CASEFOLD, &mock_sb->sb_info.flags);
+
+	create_qstr(&str1, "Hello");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&str2, "hello");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/*
+	 * Without case folding, different cases
+	 * should produce different hashes
+	 */
+	KUNIT_EXPECT_NE(test, str1.hash, str2.hash);
+
+	/* Test with case folding enabled */
+	set_bit(HFSPLUS_SB_CASEFOLD, &mock_sb->sb_info.flags);
+
+	create_qstr(&str1, "Hello");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&str2, "hello");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* With case folding, different cases should produce same hash */
+	KUNIT_EXPECT_EQ(test, str1.hash, str2.hash);
+
+	/* Test mixed case */
+	create_qstr(&str1, "HeLLo");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_EQ(test, str1.hash, str2.hash);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test special character handling in hash */
+static void hfsplus_hash_dentry_special_chars_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr str1, str2;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test colon conversion (: becomes /) */
+	create_qstr(&str1, "file:name");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&str2, "file/name");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* After conversion, these should produce the same hash */
+	KUNIT_EXPECT_EQ(test, str1.hash, str2.hash);
+
+	/* Test multiple special characters */
+	create_qstr(&str1, ":::");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&str2, "///");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	KUNIT_EXPECT_EQ(test, str1.hash, str2.hash);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test decomposition flag behavior in hash */
+static void hfsplus_hash_dentry_decompose_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr str1, str2;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test with decomposition disabled (default) */
+	clear_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+
+	create_qstr(&str1, "test");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test with decomposition enabled */
+	set_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+
+	create_qstr(&str2, "test");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/*
+	 * For simple ASCII, decomposition shouldn't change
+	 * the hash much but the function should still work correctly
+	 */
+	KUNIT_EXPECT_NE(test, 0, str2.hash);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test hash consistency and distribution */
+static void hfsplus_hash_dentry_consistency_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr str1, str2, str3;
+	unsigned long hash1;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test that same string always produces same hash */
+	create_qstr(&str1, "consistent");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+	hash1 = str1.hash;
+
+	create_qstr(&str2, "consistent");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	KUNIT_EXPECT_EQ(test, hash1, str2.hash);
+
+	/* Test that different strings produce different hashes */
+	create_qstr(&str3, "different");
+	result = hfsplus_hash_dentry(&test_dentry, &str3);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	KUNIT_EXPECT_NE(test, str1.hash, str3.hash);
+
+	/* Test similar strings should have different hashes */
+	create_qstr(&str1, "file1");
+	result = hfsplus_hash_dentry(&test_dentry, &str1);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&str2, "file2");
+	result = hfsplus_hash_dentry(&test_dentry, &str2);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	KUNIT_EXPECT_NE(test, str1.hash, str2.hash);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test edge cases and boundary conditions */
+static void hfsplus_hash_dentry_edge_cases_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct test_mock_string_env *mock_env;
+	struct qstr str;
+	int result;
+
+	mock_env = setup_mock_str_env(HFSPLUS_MAX_STRLEN + 1);
+	KUNIT_ASSERT_NOT_NULL(test, mock_env);
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test very long filename */
+	memset(mock_env->buf, 'a', mock_env->buf_size - 1);
+	mock_env->buf[mock_env->buf_size - 1] = '\0';
+
+	create_qstr(&str, mock_env->buf);
+	result = hfsplus_hash_dentry(&test_dentry, &str);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_NE(test, 0, str.hash);
+
+	/* Test filename with all printable ASCII characters */
+	create_qstr(&str, "!@#$%^&*()_+-=[]{}|;':\",./<>?");
+	result = hfsplus_hash_dentry(&test_dentry, &str);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_NE(test, 0, str.hash);
+
+	/* Test with embedded null (though not typical for filenames) */
+	str.name = "file\0hidden";
+	str.len = 11; /* Include the null and text after it */
+	str.hash = 0;
+	result = hfsplus_hash_dentry(&test_dentry, &str);
+
+	KUNIT_EXPECT_EQ(test, 0, result);
+	KUNIT_EXPECT_NE(test, 0, str.hash);
+
+	free_mock_str_env(mock_env);
+	free_mock_sb(mock_sb);
+}
+
+/* Test hfsplus_compare_dentry basic functionality */
+static void hfsplus_compare_dentry_basic_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test identical strings */
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "hello", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test different strings - lexicographic order */
+	create_qstr(&name, "world");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "hello", &name);
+	KUNIT_EXPECT_LT(test, result, 0); /* "hello" < "world" */
+
+	result = hfsplus_compare_dentry(&test_dentry, 5, "world", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "world", &name);
+	KUNIT_EXPECT_GT(test, result, 0); /* "world" > "hello" */
+
+	/* Test empty strings */
+	create_qstr(&name, "");
+	result = hfsplus_compare_dentry(&test_dentry, 0, "", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test one empty, one non-empty */
+	create_qstr(&name, "test");
+	result = hfsplus_compare_dentry(&test_dentry, 0, "", &name);
+	KUNIT_EXPECT_LT(test, result, 0); /* "" < "test" */
+
+	create_qstr(&name, "");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "test", &name);
+	KUNIT_EXPECT_GT(test, result, 0); /* "test" > "" */
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test case folding behavior in comparison */
+static void hfsplus_compare_dentry_casefold_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test with case folding disabled (default) */
+	clear_bit(HFSPLUS_SB_CASEFOLD, &mock_sb->sb_info.flags);
+
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "Hello", &name);
+	/* Case sensitive: "Hello" != "hello" */
+	KUNIT_EXPECT_NE(test, 0, result);
+
+	create_qstr(&name, "Hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "hello", &name);
+	/* Case sensitive: "hello" != "Hello" */
+	KUNIT_EXPECT_NE(test, 0, result);
+
+	/* Test with case folding enabled */
+	set_bit(HFSPLUS_SB_CASEFOLD, &mock_sb->sb_info.flags);
+
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "Hello", &name);
+	/* Case insensitive: "Hello" == "hello" */
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&name, "Hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "hello", &name);
+	/* Case insensitive: "hello" == "Hello" */
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test mixed case */
+	create_qstr(&name, "TeSt");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "test", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&name, "test");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "TEST", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test special character handling in comparison */
+static void hfsplus_compare_dentry_special_chars_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test colon conversion (: becomes /) */
+	create_qstr(&name, "file/name");
+	result = hfsplus_compare_dentry(&test_dentry, 9, "file:name", &name);
+	/* "file:name" == "file/name" after conversion */
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	create_qstr(&name, "file:name");
+	result = hfsplus_compare_dentry(&test_dentry, 9, "file/name", &name);
+	/* "file/name" == "file:name" after conversion */
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test multiple special characters */
+	create_qstr(&name, "///");
+	result = hfsplus_compare_dentry(&test_dentry, 3, ":::", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test mixed special and regular characters */
+	create_qstr(&name, "a/b:c");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "a:b/c", &name);
+	/* Both become "a/b/c" after conversion */
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test length differences */
+static void hfsplus_compare_dentry_length_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test different lengths with common prefix */
+	create_qstr(&name, "testing");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "test", &name);
+	KUNIT_EXPECT_LT(test, result, 0); /* "test" < "testing" */
+
+	create_qstr(&name, "test");
+	result = hfsplus_compare_dentry(&test_dentry, 7, "testing", &name);
+	KUNIT_EXPECT_GT(test, result, 0); /* "testing" > "test" */
+
+	/* Test exact length match */
+	create_qstr(&name, "exact");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "exact", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test length parameter vs actual string content */
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 3, "hel", &name);
+	KUNIT_EXPECT_LT(test, result, 0); /* "hel" < "hello" */
+
+	/* Test longer first string but shorter length parameter */
+	create_qstr(&name, "hi");
+	result = hfsplus_compare_dentry(&test_dentry, 2, "hello", &name);
+	/* "he" < "hi" (only first 2 chars compared) */
+	KUNIT_EXPECT_LT(test, result, 0);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test decomposition flag behavior */
+static void hfsplus_compare_dentry_decompose_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test with decomposition disabled (default) */
+	clear_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+
+	create_qstr(&name, "test");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "test", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test with decomposition enabled */
+	set_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+
+	create_qstr(&name, "test");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "test", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* For simple ASCII, decomposition shouldn't affect the result */
+	create_qstr(&name, "different");
+	result = hfsplus_compare_dentry(&test_dentry, 4, "test", &name);
+	KUNIT_EXPECT_NE(test, 0, result);
+
+	free_mock_sb(mock_sb);
+}
+
+/* Test edge cases and boundary conditions */
+static void hfsplus_compare_dentry_edge_cases_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	char *long_str;
+	char *long_str2;
+	u32 str_size = HFSPLUS_MAX_STRLEN + 1;
+	struct qstr null_name = {
+		.name = "a\0b",
+		.len = 3,
+		.hash = 0
+	};
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	long_str = kzalloc(str_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, long_str);
+
+	long_str2 = kzalloc(str_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, long_str2);
+
+	/* Test very long strings */
+	memset(long_str, 'a', str_size - 1);
+	long_str[str_size - 1] = '\0';
+
+	create_qstr(&name, long_str);
+	result = hfsplus_compare_dentry(&test_dentry, str_size - 1,
+					long_str, &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test with difference at the end of long strings */
+	memset(long_str2, 'a', str_size - 1);
+	long_str2[str_size - 1] = '\0';
+	long_str2[str_size - 2] = 'b';
+	create_qstr(&name, long_str2);
+	result = hfsplus_compare_dentry(&test_dentry, str_size - 1,
+					long_str, &name);
+	KUNIT_EXPECT_LT(test, result, 0); /* 'a' < 'b' */
+
+	/* Test single character differences */
+	create_qstr(&name, "b");
+	result = hfsplus_compare_dentry(&test_dentry, 1, "a", &name);
+	KUNIT_EXPECT_LT(test, result, 0); /* 'a' < 'b' */
+
+	create_qstr(&name, "a");
+	result = hfsplus_compare_dentry(&test_dentry, 1, "b", &name);
+	KUNIT_EXPECT_GT(test, result, 0); /* 'b' > 'a' */
+
+	/* Test with null characters in the middle */
+	result = hfsplus_compare_dentry(&test_dentry, 3, "a\0b", &null_name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test all printable ASCII characters */
+	create_qstr(&name, "!@#$%^&*()");
+	result = hfsplus_compare_dentry(&test_dentry, 10, "!@#$%^&*()", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	kfree(long_str);
+	kfree(long_str2);
+	free_mock_sb(mock_sb);
+}
+
+/* Test combined flag behaviors */
+static void hfsplus_compare_dentry_combined_flags_test(struct kunit *test)
+{
+	struct test_mock_sb *mock_sb;
+	struct qstr name;
+	int result;
+
+	mock_sb = setup_mock_sb();
+	KUNIT_ASSERT_NOT_NULL(test, mock_sb);
+
+	setup_mock_dentry(&mock_sb->sb);
+	mock_sb->nls.char2uni = test_char2uni;
+
+	/* Test with both casefold and decompose enabled */
+	set_bit(HFSPLUS_SB_CASEFOLD, &mock_sb->sb_info.flags);
+	set_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "HELLO", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test special chars with case folding */
+	create_qstr(&name, "File/Name");
+	result = hfsplus_compare_dentry(&test_dentry, 9, "file:name", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	/* Test with both flags disabled */
+	clear_bit(HFSPLUS_SB_CASEFOLD, &mock_sb->sb_info.flags);
+	clear_bit(HFSPLUS_SB_NODECOMPOSE, &mock_sb->sb_info.flags);
+
+	create_qstr(&name, "hello");
+	result = hfsplus_compare_dentry(&test_dentry, 5, "HELLO", &name);
+	KUNIT_EXPECT_NE(test, 0, result); /* Case sensitive */
+
+	/* But special chars should still be converted */
+	create_qstr(&name, "file/name");
+	result = hfsplus_compare_dentry(&test_dentry, 9, "file:name", &name);
+	KUNIT_EXPECT_EQ(test, 0, result);
+
+	free_mock_sb(mock_sb);
+}
+
+static struct kunit_case hfsplus_unicode_test_cases[] = {
+	KUNIT_CASE(hfsplus_strcasecmp_test),
+	KUNIT_CASE(hfsplus_strcmp_test),
+	KUNIT_CASE(hfsplus_unicode_edge_cases_test),
+	KUNIT_CASE(hfsplus_unicode_boundary_test),
+	KUNIT_CASE(hfsplus_uni2asc_basic_test),
+	KUNIT_CASE(hfsplus_uni2asc_special_chars_test),
+	KUNIT_CASE(hfsplus_uni2asc_buffer_test),
+	KUNIT_CASE(hfsplus_uni2asc_corrupted_test),
+	KUNIT_CASE(hfsplus_uni2asc_edge_cases_test),
+	KUNIT_CASE(hfsplus_asc2uni_basic_test),
+	KUNIT_CASE(hfsplus_asc2uni_special_chars_test),
+	KUNIT_CASE(hfsplus_asc2uni_buffer_limits_test),
+	KUNIT_CASE(hfsplus_asc2uni_edge_cases_test),
+	KUNIT_CASE(hfsplus_asc2uni_decompose_test),
+	KUNIT_CASE(hfsplus_hash_dentry_basic_test),
+	KUNIT_CASE(hfsplus_hash_dentry_casefold_test),
+	KUNIT_CASE(hfsplus_hash_dentry_special_chars_test),
+	KUNIT_CASE(hfsplus_hash_dentry_decompose_test),
+	KUNIT_CASE(hfsplus_hash_dentry_consistency_test),
+	KUNIT_CASE(hfsplus_hash_dentry_edge_cases_test),
+	KUNIT_CASE(hfsplus_compare_dentry_basic_test),
+	KUNIT_CASE(hfsplus_compare_dentry_casefold_test),
+	KUNIT_CASE(hfsplus_compare_dentry_special_chars_test),
+	KUNIT_CASE(hfsplus_compare_dentry_length_test),
+	KUNIT_CASE(hfsplus_compare_dentry_decompose_test),
+	KUNIT_CASE(hfsplus_compare_dentry_edge_cases_test),
+	KUNIT_CASE(hfsplus_compare_dentry_combined_flags_test),
+	{}
+};
+
+static struct kunit_suite hfsplus_unicode_test_suite = {
+	.name = "hfsplus_unicode",
+	.test_cases = hfsplus_unicode_test_cases,
+};
+
+kunit_test_suite(hfsplus_unicode_test_suite);
+
+MODULE_DESCRIPTION("KUnit tests for HFS+ Unicode string operations");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");