Commit f8f4acb6 authored by Daniel Rosenberg's avatar Daniel Rosenberg Committed by Theodore Ts'o
Browse files

ext4: use generic casefolding support 



This switches ext4 over to the generic support provided in libfs.

Since casefolded dentries behave the same in ext4 and f2fs, we decrease
the maintenance burden by unifying them, and any optimizations will
immediately apply to both.

Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Reviewed-by: default avatarEric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20201028050820.1636571-1-drosen@google.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent d7dce9e0

fs/ext4/dir.c

+2 −62
Original line number Diff line number Diff line
@@ -669,68 +669,8 @@ 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 };

	const struct dentry *parent = READ_ONCE(dentry->d_parent);

	const struct inode *inode = d_inode_rcu(parent);

	char strbuf[DNAME_INLINE_LEN];



	if (!inode || !IS_CASEFOLDED(inode) ||

	    !EXT4_SB(inode->i_sb)->s_encoding) {

		if (len != name->len)

			return -1;

		return memcmp(str, name->name, len);

	}



	/*

	 * If the dentry name is stored in-line, then it may be concurrently

	 * modified by a rename.  If this happens, the VFS will eventually retry

	 * the lookup, so it doesn't matter what ->d_compare() returns.

	 * However, it's unsafe to call utf8_strncasecmp() with an unstable

	 * string.  Therefore, we have to copy the name into a temporary buffer.

	 */

	if (len <= DNAME_INLINE_LEN - 1) {

		memcpy(strbuf, str, len);

		strbuf[len] = 0;

		qstr.name = strbuf;

		/* prevent compiler from optimizing out the temporary buffer */

		barrier();

	}



	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;

	const struct inode *inode = d_inode_rcu(dentry);

	unsigned char *norm;

	int len, ret = 0;



	if (!inode || !IS_CASEFOLDED(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 = generic_ci_d_hash,

	.d_compare = generic_ci_d_compare,

};

#endif

fs/ext4/ext4.h

+0 −12
Original line number Diff line number Diff line
@@ -1443,14 +1443,6 @@ struct ext4_super_block { 


#define EXT4_ENC_UTF8_12_1	1



/*

 * Flags for ext4_sb_info.s_encoding_flags.

 */

#define EXT4_ENC_STRICT_MODE_FL	(1 << 0)



#define ext4_has_strict_mode(sbi) \

	(sbi->s_encoding_flags & EXT4_ENC_STRICT_MODE_FL)



/*

 * fourth extended-fs super-block data in memory

 */
@@ -1500,10 +1492,6 @@ 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;

fs/ext4/hash.c

+1 −1
Original line number Diff line number Diff line
@@ -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 };

fs/ext4/namei.c

+8 −12
Original line number Diff line number Diff line
@@ -1285,8 +1285,8 @@ 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)
@@ -1298,7 +1298,7 @@ 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_strict_encoding(sb))

			return -EINVAL;



		if (name->len != entry->len)
@@ -1315,7 +1315,7 @@ 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 (!IS_CASEFOLDED(dir) || !dir->i_sb->s_encoding) {

		cf_name->name = NULL;

		return;

	}
@@ -1324,7 +1324,7 @@ 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) {
@@ -1361,7 +1361,7 @@ 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 (parent->i_sb->s_encoding && IS_CASEFOLDED(parent)) {

		if (fname->cf_name.name) {

			struct qstr cf = {.name = fname->cf_name.name,

					  .len = fname->cf_name.len};
@@ -2180,9 +2180,6 @@ 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;
@@ -2199,9 +2196,8 @@ 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_strict_encoding(sb) && IS_CASEFOLDED(dir) &&

	    sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))

		return -EINVAL;

#endif

fs/ext4/super.c

+6 −6
Original line number Diff line number Diff line
@@ -1288,7 +1288,7 @@ static void ext4_put_super(struct super_block *sb) 
	fs_put_dax(sbi->s_daxdev);

	fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);

#ifdef CONFIG_UNICODE

	utf8_unload(sbi->s_encoding);

	utf8_unload(sb->s_encoding);

#endif

	kfree(sbi);

}
@@ -4303,7 +4303,7 @@ 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;
@@ -4334,8 +4334,8 @@ 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
@@ -4975,7 +4975,7 @@ no_journal: 
	}



#ifdef CONFIG_UNICODE

	if (sbi->s_encoding)

	if (sb->s_encoding)

		sb->s_d_op = &ext4_dentry_ops;

#endif
@@ -5184,7 +5184,7 @@ failed_mount: 
		crypto_free_shash(sbi->s_chksum_driver);



#ifdef CONFIG_UNICODE

	utf8_unload(sbi->s_encoding);

	utf8_unload(sb->s_encoding);

#endif



#ifdef CONFIG_QUOTA

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