diff mbox series

[v6,1/5] unicode: Add standard casefolded d_ops

Message ID 20200128230328.183524-2-drosen@google.com
State Not Applicable
Delegated to: Richard Weinberger
Headers show
Series Support fof Casefolding and Encryption | expand

Commit Message

Daniel Rosenberg Jan. 28, 2020, 11:03 p.m. UTC 
This adds dentry_operations implementations for d_hash and d_compare
which can be used by any filesystem using utf8 casefolding, unifying the
existing ext4 and f2fs functions.
In order to do this, we add new variables to struct super_block and
switch ext4 and f2fs over to those instead of maintaining their own
versions.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
 fs/ext4/dir.c           | 45 ++----------------------------
 fs/ext4/ext4.h          |  4 ---
 fs/ext4/hash.c          |  2 +-
 fs/ext4/namei.c         | 20 ++++++--------
 fs/ext4/super.c         | 10 +++----
 fs/f2fs/dir.c           | 60 +++++++---------------------------------
 fs/f2fs/f2fs.h          |  4 ---
 fs/f2fs/hash.c          |  2 +-
 fs/f2fs/super.c         | 10 +++----
 fs/f2fs/sysfs.c         |  8 +++---
 fs/unicode/utf8-core.c  | 61 +++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h      | 10 +++++++
 include/linux/unicode.h | 17 ++++++++++++
 13 files changed, 124 insertions(+), 129 deletions(-)

Comments

Gabriel Krisman Bertazi Feb. 3, 2020, 1:45 a.m. UTC | #1 
Daniel Rosenberg <drosen@google.com> writes:

> diff --git a/include/linux/unicode.h b/include/linux/unicode.h
> index 990aa97d80496..5de313abeaf98 100644
> --- a/include/linux/unicode.h
> +++ b/include/linux/unicode.h
> @@ -4,6 +4,8 @@
>  
>  #include <linux/init.h>
>  #include <linux/dcache.h>
> +#include <linux/fscrypt.h>
> +#include <linux/fs.h>
>  
>  struct unicode_map {
>  	const char *charset;
> @@ -30,4 +32,19 @@ int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
>  struct unicode_map *utf8_load(const char *version);
>  void utf8_unload(struct unicode_map *um);
>  
> +int utf8_ci_d_hash(const struct dentry *dentry, struct qstr *str);
> +int utf8_ci_d_compare(const struct dentry *dentry, unsigned int len,
> +			  const char *str, const struct qstr *name);


I don't think fs/unicode is the right place for these very specific
filesystem functions, just because they happen to use unicode.  It is an
encoding library, it doesn't care about dentries, nor should know how to
handle them.  It exposes a simple api to manipulate and convert utf8 strings.

I saw change was after the desire to not have these functions polluting
the VFS hot path, but that has nothing to do with placing them here.

Would libfs be better?  or a casefolding library in fs/casefold.c?
Daniel Rosenberg Feb. 5, 2020, 3:05 a.m. UTC | #2 
On Sun, Feb 2, 2020 at 5:46 PM Gabriel Krisman Bertazi
<krisman@collabora.com> wrote:
>
>
> I don't think fs/unicode is the right place for these very specific
> filesystem functions, just because they happen to use unicode.  It is an
> encoding library, it doesn't care about dentries, nor should know how to
> handle them.  It exposes a simple api to manipulate and convert utf8 strings.
>
> I saw change was after the desire to not have these functions polluting
> the VFS hot path, but that has nothing to do with placing them here.
>
> Would libfs be better?  or a casefolding library in fs/casefold.c?
>
>
> --
> Gabriel Krisman Bertazi

The hash function needs access to utf8ncursor, but apart from that,
libfs would make sense. utf8ncursor is the only reason I have them
here. How do you feel about exposing utf8cursor or something similar?
Gabriel Krisman Bertazi Feb. 5, 2020, 4:21 a.m. UTC | #3 
Daniel Rosenberg <drosen@google.com> writes:

> On Sun, Feb 2, 2020 at 5:46 PM Gabriel Krisman Bertazi
> <krisman@collabora.com> wrote:
>>
>>
>> I don't think fs/unicode is the right place for these very specific
>> filesystem functions, just because they happen to use unicode.  It is an
>> encoding library, it doesn't care about dentries, nor should know how to
>> handle them.  It exposes a simple api to manipulate and convert utf8 strings.
>>
>> I saw change was after the desire to not have these functions polluting
>> the VFS hot path, but that has nothing to do with placing them here.
>>
>> Would libfs be better?  or a casefolding library in fs/casefold.c?
>>
>>
>> --
>> Gabriel Krisman Bertazi
>
> The hash function needs access to utf8ncursor, but apart from that,
> libfs would make sense. utf8ncursor is the only reason I have them
> here. How do you feel about exposing utf8cursor or something similar?

Hi,

It was designed to be an internal thing, but I'm ok with exposing it.
Daniel Rosenberg Feb. 5, 2020, 11:40 p.m. UTC | #4 
On Tue, Feb 4, 2020 at 8:21 PM Gabriel Krisman Bertazi
<krisman@collabora.com> wrote:
>
> Daniel Rosenberg <drosen@google.com> writes:
>
> Hi,
>
> It was designed to be an internal thing, but I'm ok with exposing it.
>
> --
> Gabriel Krisman Bertazi

We could also avoid exposing it by creating an iterator function that
accepts a context struct with some actor function pointer, similar to
iterate_dir. I'm currently reworking around that and moving the fs
specific functions to libfs. I can move the generic op_set code there
as well.

-Daniel Rosenberg
diff mbox series

Patch

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 4e093277c8bfb..e9f7c32089dfc 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -668,49 +668,8 @@  const struct file_operations ext4_dir_operations = {
 };
 
 #ifdef CONFIG_UNICODE
-static int ext4_d_compare(const struct dentry *dentry, unsigned int len,
-			  const char *str, const struct qstr *name)
-{
-	struct qstr qstr = {.name = str, .len = len };
-	struct inode *inode = dentry->d_parent->d_inode;
-
-	if (!IS_CASEFOLDED(inode) || !EXT4_SB(inode->i_sb)->s_encoding) {
-		if (len != name->len)
-			return -1;
-		return memcmp(str, name->name, len);
-	}
-
-	return ext4_ci_compare(inode, name, &qstr, false);
-}
-
-static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)
-{
-	const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
-	const struct unicode_map *um = sbi->s_encoding;
-	unsigned char *norm;
-	int len, ret = 0;
-
-	if (!IS_CASEFOLDED(dentry->d_inode) || !um)
-		return 0;
-
-	norm = kmalloc(PATH_MAX, GFP_ATOMIC);
-	if (!norm)
-		return -ENOMEM;
-
-	len = utf8_casefold(um, str, norm, PATH_MAX);
-	if (len < 0) {
-		if (ext4_has_strict_mode(sbi))
-			ret = -EINVAL;
-		goto out;
-	}
-	str->hash = full_name_hash(dentry, norm, len);
-out:
-	kfree(norm);
-	return ret;
-}
-
 const struct dentry_operations ext4_dentry_ops = {
-	.d_hash = ext4_d_hash,
-	.d_compare = ext4_d_compare,
+	.d_hash = utf8_ci_d_hash,
+	.d_compare = utf8_ci_d_compare,
 };
 #endif
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index f8578caba40d5..3162ef2e53d46 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1430,10 +1430,6 @@  struct ext4_sb_info {
 	struct kobject s_kobj;
 	struct completion s_kobj_unregister;
 	struct super_block *s_sb;
-#ifdef CONFIG_UNICODE
-	struct unicode_map *s_encoding;
-	__u16 s_encoding_flags;
-#endif
 
 	/* Journaling */
 	struct journal_s *s_journal;
diff --git a/fs/ext4/hash.c b/fs/ext4/hash.c
index 3e133793a5a34..143b0073b3f46 100644
--- a/fs/ext4/hash.c
+++ b/fs/ext4/hash.c
@@ -275,7 +275,7 @@  int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
 		   struct dx_hash_info *hinfo)
 {
 #ifdef CONFIG_UNICODE
-	const struct unicode_map *um = EXT4_SB(dir->i_sb)->s_encoding;
+	const struct unicode_map *um = dir->i_sb->s_encoding;
 	int r, dlen;
 	unsigned char *buff;
 	struct qstr qstr = {.name = name, .len = len };
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 1cb42d9407847..7f4e625ab2f9b 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1282,8 +1282,8 @@  static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
 int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
 		    const struct qstr *entry, bool quick)
 {
-	const struct ext4_sb_info *sbi = EXT4_SB(parent->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
+	const struct super_block *sb = parent->i_sb;
+	const struct unicode_map *um = sb->s_encoding;
 	int ret;
 
 	if (quick)
@@ -1295,7 +1295,7 @@  int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
 		/* Handle invalid character sequence as either an error
 		 * or as an opaque byte sequence.
 		 */
-		if (ext4_has_strict_mode(sbi))
+		if (sb_has_enc_strict_mode(sb))
 			return -EINVAL;
 
 		if (name->len != entry->len)
@@ -1312,7 +1312,7 @@  void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 {
 	int len;
 
-	if (!IS_CASEFOLDED(dir) || !EXT4_SB(dir->i_sb)->s_encoding) {
+	if (!needs_casefold(dir)) {
 		cf_name->name = NULL;
 		return;
 	}
@@ -1321,7 +1321,7 @@  void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 	if (!cf_name->name)
 		return;
 
-	len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,
+	len = utf8_casefold(dir->i_sb->s_encoding,
 			    iname, cf_name->name,
 			    EXT4_NAME_LEN);
 	if (len <= 0) {
@@ -1358,7 +1358,7 @@  static inline bool ext4_match(const struct inode *parent,
 #endif
 
 #ifdef CONFIG_UNICODE
-	if (EXT4_SB(parent->i_sb)->s_encoding && IS_CASEFOLDED(parent)) {
+	if (needs_casefold(parent)) {
 		if (fname->cf_name.name) {
 			struct qstr cf = {.name = fname->cf_name.name,
 					  .len = fname->cf_name.len};
@@ -2164,9 +2164,6 @@  static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 	struct buffer_head *bh = NULL;
 	struct ext4_dir_entry_2 *de;
 	struct super_block *sb;
-#ifdef CONFIG_UNICODE
-	struct ext4_sb_info *sbi;
-#endif
 	struct ext4_filename fname;
 	int	retval;
 	int	dx_fallback=0;
@@ -2183,9 +2180,8 @@  static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 		return -EINVAL;
 
 #ifdef CONFIG_UNICODE
-	sbi = EXT4_SB(sb);
-	if (ext4_has_strict_mode(sbi) && IS_CASEFOLDED(dir) &&
-	    sbi->s_encoding && utf8_validate(sbi->s_encoding, &dentry->d_name))
+	if (sb_has_enc_strict_mode(sb) && IS_CASEFOLDED(dir) &&
+	    sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
 		return -EINVAL;
 #endif
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2937a8873fe13..b7e9f0310ec23 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1056,7 +1056,7 @@  static void ext4_put_super(struct super_block *sb)
 	kfree(sbi->s_blockgroup_lock);
 	fs_put_dax(sbi->s_daxdev);
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 	kfree(sbi);
 }
@@ -3850,7 +3850,7 @@  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 
 #ifdef CONFIG_UNICODE
-	if (ext4_has_feature_casefold(sb) && !sbi->s_encoding) {
+	if (ext4_has_feature_casefold(sb) && !sb->s_encoding) {
 		const struct ext4_sb_encodings *encoding_info;
 		struct unicode_map *encoding;
 		__u16 encoding_flags;
@@ -3881,8 +3881,8 @@  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 			 "%s-%s with flags 0x%hx", encoding_info->name,
 			 encoding_info->version?:"\b", encoding_flags);
 
-		sbi->s_encoding = encoding;
-		sbi->s_encoding_flags = encoding_flags;
+		sb->s_encoding = encoding;
+		sb->s_encoding_flags = encoding_flags;
 	}
 #endif
 
@@ -4684,7 +4684,7 @@  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		crypto_free_shash(sbi->s_chksum_driver);
 
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 
 #ifdef CONFIG_QUOTA
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index d9ad842945df5..a1dd9939e20bf 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -114,8 +114,8 @@  static struct f2fs_dir_entry *find_in_block(struct inode *dir,
 int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
 				const struct qstr *entry, bool quick)
 {
-	const struct f2fs_sb_info *sbi = F2FS_SB(parent->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
+	const struct super_block *sb = parent->i_sb;
+	const struct unicode_map *um = sb->s_encoding;
 	int ret;
 
 	if (quick)
@@ -127,7 +127,7 @@  int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
 		/* Handle invalid character sequence as either an error
 		 * or as an opaque byte sequence.
 		 */
-		if (f2fs_has_strict_mode(sbi))
+		if (sb_has_enc_strict_mode(sb))
 			return -EINVAL;
 
 		if (name->len != entry->len)
@@ -154,7 +154,7 @@  static void f2fs_fname_setup_ci_filename(struct inode *dir,
 	if (!cf_name->name)
 		return;
 
-	cf_name->len = utf8_casefold(sbi->s_encoding,
+	cf_name->len = utf8_casefold(dir->i_sb->s_encoding,
 					iname, cf_name->name,
 					F2FS_NAME_LEN);
 	if ((int)cf_name->len <= 0) {
@@ -173,7 +173,7 @@  static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
 {
 #ifdef CONFIG_UNICODE
 	struct inode *parent = d->inode;
-	struct f2fs_sb_info *sbi = F2FS_I_SB(parent);
+	struct super_block *sb = parent->i_sb;
 	struct qstr entry;
 #endif
 
@@ -184,7 +184,7 @@  static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
 	entry.name = d->filename[bit_pos];
 	entry.len = de->name_len;
 
-	if (sbi->s_encoding && IS_CASEFOLDED(parent)) {
+	if (sb->s_encoding && IS_CASEFOLDED(parent)) {
 		if (cf_str->name) {
 			struct qstr cf = {.name = cf_str->name,
 					  .len = cf_str->len};
@@ -357,8 +357,8 @@  struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 	int err;
 
 #ifdef CONFIG_UNICODE
-	if (f2fs_has_strict_mode(F2FS_I_SB(dir)) && IS_CASEFOLDED(dir) &&
-			utf8_validate(F2FS_I_SB(dir)->s_encoding, child)) {
+	if (sb_has_enc_strict_mode(dir->i_sb) && IS_CASEFOLDED(dir) &&
+			utf8_validate(dir->i_sb->s_encoding, child)) {
 		*res_page = ERR_PTR(-EINVAL);
 		return NULL;
 	}
@@ -1065,48 +1065,8 @@  const struct file_operations f2fs_dir_operations = {
 };
 
 #ifdef CONFIG_UNICODE
-static int f2fs_d_compare(const struct dentry *dentry, unsigned int len,
-			  const char *str, const struct qstr *name)
-{
-	struct qstr qstr = {.name = str, .len = len };
-
-	if (!IS_CASEFOLDED(dentry->d_parent->d_inode)) {
-		if (len != name->len)
-			return -1;
-		return memcmp(str, name, len);
-	}
-
-	return f2fs_ci_compare(dentry->d_parent->d_inode, name, &qstr, false);
-}
-
-static int f2fs_d_hash(const struct dentry *dentry, struct qstr *str)
-{
-	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
-	const struct unicode_map *um = sbi->s_encoding;
-	unsigned char *norm;
-	int len, ret = 0;
-
-	if (!IS_CASEFOLDED(dentry->d_inode))
-		return 0;
-
-	norm = f2fs_kmalloc(sbi, PATH_MAX, GFP_ATOMIC);
-	if (!norm)
-		return -ENOMEM;
-
-	len = utf8_casefold(um, str, norm, PATH_MAX);
-	if (len < 0) {
-		if (f2fs_has_strict_mode(sbi))
-			ret = -EINVAL;
-		goto out;
-	}
-	str->hash = full_name_hash(dentry, norm, len);
-out:
-	kvfree(norm);
-	return ret;
-}
-
 const struct dentry_operations f2fs_dentry_ops = {
-	.d_hash = f2fs_d_hash,
-	.d_compare = f2fs_d_compare,
+	.d_hash = utf8_ci_d_hash,
+	.d_compare = utf8_ci_d_compare,
 };
 #endif
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 5a888a063c7f1..9f302de477022 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1184,10 +1184,6 @@  struct f2fs_sb_info {
 	int valid_super_block;			/* valid super block no */
 	unsigned long s_flag;				/* flags for sbi */
 	struct mutex writepages;		/* mutex for writepages() */
-#ifdef CONFIG_UNICODE
-	struct unicode_map *s_encoding;
-	__u16 s_encoding_flags;
-#endif
 
 #ifdef CONFIG_BLK_DEV_ZONED
 	unsigned int blocks_per_blkz;		/* F2FS blocks per zone */
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index 5bc4dcd8fc03f..28acb24e7a7a8 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -110,7 +110,7 @@  f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
 {
 #ifdef CONFIG_UNICODE
 	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
+	const struct unicode_map *um = dir->i_sb->s_encoding;
 	int r, dlen;
 	unsigned char *buff;
 	struct qstr folded;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 5111e1ffe58ab..5de587f20ed35 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1144,7 +1144,7 @@  static void f2fs_put_super(struct super_block *sb)
 	for (i = 0; i < NR_PAGE_TYPE; i++)
 		kvfree(sbi->write_io[i]);
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 	kvfree(sbi);
 }
@@ -3136,7 +3136,7 @@  static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 {
 #ifdef CONFIG_UNICODE
-	if (f2fs_sb_has_casefold(sbi) && !sbi->s_encoding) {
+	if (f2fs_sb_has_casefold(sbi) && !sbi->sb->s_encoding) {
 		const struct f2fs_sb_encodings *encoding_info;
 		struct unicode_map *encoding;
 		__u16 encoding_flags;
@@ -3167,8 +3167,8 @@  static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 			 "%s-%s with flags 0x%hx", encoding_info->name,
 			 encoding_info->version?:"\b", encoding_flags);
 
-		sbi->s_encoding = encoding;
-		sbi->s_encoding_flags = encoding_flags;
+		sbi->sb->s_encoding = encoding;
+		sbi->sb->s_encoding_flags = encoding_flags;
 		sbi->sb->s_d_op = &f2fs_dentry_ops;
 	}
 #else
@@ -3637,7 +3637,7 @@  static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		kvfree(sbi->write_io[i]);
 
 #ifdef CONFIG_UNICODE
-	utf8_unload(sbi->s_encoding);
+	utf8_unload(sb->s_encoding);
 #endif
 free_options:
 #ifdef CONFIG_QUOTA
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 70945ceb9c0ca..7fd37c8c9733a 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -88,10 +88,10 @@  static ssize_t encoding_show(struct f2fs_attr *a,
 #ifdef CONFIG_UNICODE
 	if (f2fs_sb_has_casefold(sbi))
 		return snprintf(buf, PAGE_SIZE, "%s (%d.%d.%d)\n",
-			sbi->s_encoding->charset,
-			(sbi->s_encoding->version >> 16) & 0xff,
-			(sbi->s_encoding->version >> 8) & 0xff,
-			sbi->s_encoding->version & 0xff);
+			sbi->sb->s_encoding->charset,
+			(sbi->sb->s_encoding->version >> 16) & 0xff,
+			(sbi->sb->s_encoding->version >> 8) & 0xff,
+			sbi->sb->s_encoding->version & 0xff);
 #endif
 	return snprintf(buf, PAGE_SIZE, "(none)");
 }
diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
index 2a878b739115d..129a9e3fa91a4 100644
--- a/fs/unicode/utf8-core.c
+++ b/fs/unicode/utf8-core.c
@@ -6,6 +6,7 @@ 
 #include <linux/parser.h>
 #include <linux/errno.h>
 #include <linux/unicode.h>
+#include <linux/stringhash.h>
 
 #include "utf8n.h"
 
@@ -212,4 +213,64 @@  void utf8_unload(struct unicode_map *um)
 }
 EXPORT_SYMBOL(utf8_unload);
 
+int utf8_ci_d_compare(const struct dentry *dentry, unsigned int len,
+			  const char *str, const struct qstr *name)
+{
+	const struct dentry *parent = READ_ONCE(dentry->d_parent);
+	const struct inode *inode = READ_ONCE(parent->d_inode);
+	const struct super_block *sb = dentry->d_sb;
+	const struct unicode_map *um = sb->s_encoding;
+	struct qstr entry = QSTR_INIT(str, len);
+	int ret;
+
+	if (!inode || !needs_casefold(inode))
+		goto fallback;
+
+	ret = utf8_strncasecmp(um, name, &entry);
+	if (ret >= 0)
+		return ret;
+
+	if (sb_has_enc_strict_mode(sb))
+		return -EINVAL;
+fallback:
+	if (len != name->len)
+		return 1;
+	return !!memcmp(str, name->name, len);
+}
+EXPORT_SYMBOL(utf8_ci_d_compare);
+
+int utf8_ci_d_hash(const struct dentry *dentry, struct qstr *str)
+{
+	const struct inode *inode = READ_ONCE(dentry->d_inode);
+	struct super_block *sb = dentry->d_sb;
+	const struct unicode_map *um = sb->s_encoding;
+	int ret = 0;
+	unsigned long hash;
+	const struct utf8data *data;
+	struct utf8cursor cur;
+	int c;
+
+	if (!inode || !needs_casefold(inode))
+		return 0;
+
+	hash = init_name_hash(dentry);
+	data = utf8nfdicf(um->version);
+	if (utf8ncursor(&cur, data, str->name, str->len) < 0)
+		goto err;
+
+	while ((c = utf8byte(&cur))) {
+		if (c < 0)
+			goto err;
+		hash = partial_name_hash((unsigned char)c, hash);
+	}
+
+	str->hash = end_name_hash(hash);
+	return 0;
+err:
+	if (sb_has_enc_strict_mode(sb))
+		ret = -EINVAL;
+	return ret;
+}
+EXPORT_SYMBOL(utf8_ci_d_hash);
+
 MODULE_LICENSE("GPL v2");
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98e0349adb526..9a7092449e94f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1382,6 +1382,12 @@  extern int send_sigurg(struct fown_struct *fown);
 #define SB_ACTIVE	(1<<30)
 #define SB_NOUSER	(1<<31)
 
+/* These flags relate to encoding and casefolding */
+#define SB_ENC_STRICT_MODE_FL	(1 << 0)
+
+#define sb_has_enc_strict_mode(sb) \
+	(sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL)
+
 /*
  *	Umount options
  */
@@ -1449,6 +1455,10 @@  struct super_block {
 #endif
 #ifdef CONFIG_FS_VERITY
 	const struct fsverity_operations *s_vop;
+#endif
+#ifdef CONFIG_UNICODE
+	struct unicode_map *s_encoding;
+	__u16 s_encoding_flags;
 #endif
 	struct hlist_bl_head	s_roots;	/* alternate root dentries for NFS */
 	struct list_head	s_mounts;	/* list of mounts; _not_ for fs use */
diff --git a/include/linux/unicode.h b/include/linux/unicode.h
index 990aa97d80496..5de313abeaf98 100644
--- a/include/linux/unicode.h
+++ b/include/linux/unicode.h
@@ -4,6 +4,8 @@ 
 
 #include <linux/init.h>
 #include <linux/dcache.h>
+#include <linux/fscrypt.h>
+#include <linux/fs.h>
 
 struct unicode_map {
 	const char *charset;
@@ -30,4 +32,19 @@  int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
 struct unicode_map *utf8_load(const char *version);
 void utf8_unload(struct unicode_map *um);
 
+int utf8_ci_d_hash(const struct dentry *dentry, struct qstr *str);
+int utf8_ci_d_compare(const struct dentry *dentry, unsigned int len,
+			  const char *str, const struct qstr *name);
+#ifdef CONFIG_UNICODE
+static inline bool needs_casefold(const struct inode *dir)
+{
+	return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding &&
+			(!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir));
+}
+#else
+static inline bool needs_casefold(const struct inode *dir)
+{
+	return 0;
+}
+#endif
 #endif /* _LINUX_UNICODE_H */