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Commit e9ca3689 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Jaegeuk Kim
Browse files

ext4: optimize case-insensitive lookups 



Temporarily cache a casefolded version of the file name under lookup in
ext4_filename, to avoid repeatedly casefolding it.  I got up to 30%
speedup on lookups of large directories (>100k entries), depending on
the length of the string under lookup.

Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent e9bc9003

fs/ext4/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -674,7 +674,7 @@ static int ext4_d_compare(const struct dentry *dentry, unsigned int len, 
		return memcmp(str, name->name, len);

	}



	return ext4_ci_compare(dentry->d_parent->d_inode, name, &qstr);

	return ext4_ci_compare(dentry->d_parent->d_inode, name, &qstr, false);

}



static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)

fs/ext4/ext4.h

+36 −3
Original line number Diff line number Diff line
@@ -2077,6 +2077,9 @@ struct ext4_filename { 
#ifdef CONFIG_FS_ENCRYPTION

	struct fscrypt_str crypto_buf;

#endif

#ifdef CONFIG_UNICODE

	struct fscrypt_str cf_name;

#endif

};



#define fname_name(p) ((p)->disk_name.name)
@@ -2302,6 +2305,12 @@ extern unsigned ext4_free_clusters_after_init(struct super_block *sb, 
					      struct ext4_group_desc *gdp);

ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);



#ifdef CONFIG_UNICODE

extern void ext4_fname_setup_ci_filename(struct inode *dir,

					 const struct qstr *iname,

					 struct fscrypt_str *fname);

#endif



#ifdef CONFIG_FS_ENCRYPTION

static inline void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,

						const struct fscrypt_name *src)
@@ -2328,6 +2337,10 @@ static inline int ext4_fname_setup_filename(struct inode *dir, 
		return err;



	ext4_fname_from_fscrypt_name(fname, &name);



#ifdef CONFIG_UNICODE

	ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name);

#endif

	return 0;

}
@@ -2343,6 +2356,10 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir, 
		return err;



	ext4_fname_from_fscrypt_name(fname, &name);



#ifdef CONFIG_UNICODE

	ext4_fname_setup_ci_filename(dir, &dentry->d_name, &fname->cf_name);

#endif

	return 0;

}
@@ -2356,6 +2373,11 @@ static inline void ext4_fname_free_filename(struct ext4_filename *fname) 
	fname->crypto_buf.name = NULL;

	fname->usr_fname = NULL;

	fname->disk_name.name = NULL;



#ifdef CONFIG_UNICODE

	kfree(fname->cf_name.name);

	fname->cf_name.name = NULL;

#endif

}

#else /* !CONFIG_FS_ENCRYPTION */

static inline int ext4_fname_setup_filename(struct inode *dir,
@@ -2366,6 +2388,11 @@ static inline int ext4_fname_setup_filename(struct inode *dir, 
	fname->usr_fname = iname;

	fname->disk_name.name = (unsigned char *) iname->name;

	fname->disk_name.len = iname->len;



#ifdef CONFIG_UNICODE

	ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name);

#endif



	return 0;

}
@@ -2376,7 +2403,13 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir, 
	return ext4_fname_setup_filename(dir, &dentry->d_name, 1, fname);

}



static inline void ext4_fname_free_filename(struct ext4_filename *fname) { }

static inline void ext4_fname_free_filename(struct ext4_filename *fname)

{

#ifdef CONFIG_UNICODE

	kfree(fname->cf_name.name);

	fname->cf_name.name = NULL;

#endif

}

#endif /* !CONFIG_FS_ENCRYPTION */



/* dir.c */
@@ -3106,8 +3139,8 @@ extern int ext4_handle_dirty_dirent_node(handle_t *handle, 
					 struct inode *inode,

					 struct buffer_head *bh);

extern int ext4_ci_compare(const struct inode *parent,

			   const struct qstr *name,

			   const struct qstr *entry);

			   const struct qstr *fname,

			   const struct qstr *entry, bool quick);



#define S_SHIFT 12

static const unsigned char ext4_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {

fs/ext4/namei.c

+38 −5
Original line number Diff line number Diff line
@@ -1255,19 +1255,24 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block) 
#ifdef CONFIG_UNICODE

/*

 * Test whether a case-insensitive directory entry matches the filename

 * being searched for.

 * being searched for.  If quick is set, assume the name being looked up

 * is already in the casefolded form.

 *

 * Returns: 0 if the directory entry matches, more than 0 if it

 * doesn't match or less than zero on error.

 */

int ext4_ci_compare(const struct inode *parent, const struct qstr *name,

		    const struct qstr *entry)

		    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;

	int ret;



	if (quick)

		ret = utf8_strncasecmp_folded(um, name, entry);

	else

		ret = utf8_strncasecmp(um, name, entry);



	if (ret < 0) {

		/* Handle invalid character sequence as either an error

		 * or as an opaque byte sequence.
@@ -1283,6 +1288,27 @@ int ext4_ci_compare(const struct inode *parent, const struct qstr *name, 


	return ret;

}



void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,

				  struct fscrypt_str *cf_name)

{

	if (!IS_CASEFOLDED(dir)) {

		cf_name->name = NULL;

		return;

	}



	cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);

	if (!cf_name->name)

		return;



	cf_name->len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,

				     iname, cf_name->name,

				     EXT4_NAME_LEN);

	if (cf_name->len <= 0) {

		kfree(cf_name->name);

		cf_name->name = NULL;

	}

}

#endif



/*
@@ -1309,8 +1335,15 @@ static inline bool ext4_match(const struct inode *parent, 
#endif



#ifdef CONFIG_UNICODE

	if (EXT4_SB(parent->i_sb)->s_encoding && IS_CASEFOLDED(parent))

		return (ext4_ci_compare(parent, fname->usr_fname, &entry) == 0);

	if (EXT4_SB(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};

			return !ext4_ci_compare(parent, &cf, &entry, true);

		}

		return !ext4_ci_compare(parent, fname->usr_fname, &entry,

					false);

	}

#endif



	return fscrypt_match_name(&f, de->name, de->name_len);

fs/unicode/utf8-core.c

+28 −0
Original line number Diff line number Diff line
@@ -73,6 +73,34 @@ int utf8_strncasecmp(const struct unicode_map *um, 
}

EXPORT_SYMBOL(utf8_strncasecmp);



/* String cf is expected to be a valid UTF-8 casefolded

 * string.

 */

int utf8_strncasecmp_folded(const struct unicode_map *um,

			    const struct qstr *cf,

			    const struct qstr *s1)

{

	const struct utf8data *data = utf8nfdicf(um->version);

	struct utf8cursor cur1;

	int c1, c2;

	int i = 0;



	if (utf8ncursor(&cur1, data, s1->name, s1->len) < 0)

		return -EINVAL;



	do {

		c1 = utf8byte(&cur1);

		c2 = cf->name[i++];

		if (c1 < 0)

			return -EINVAL;

		if (c1 != c2)

			return 1;

	} while (c1);



	return 0;

}

EXPORT_SYMBOL(utf8_strncasecmp_folded);



int utf8_casefold(const struct unicode_map *um, const struct qstr *str,

		  unsigned char *dest, size_t dlen)

{

include/linux/unicode.h

+3 −0
Original line number Diff line number Diff line
@@ -17,6 +17,9 @@ int utf8_strncmp(const struct unicode_map *um, 


int utf8_strncasecmp(const struct unicode_map *um,

		 const struct qstr *s1, const struct qstr *s2);

int utf8_strncasecmp_folded(const struct unicode_map *um,

			    const struct qstr *cf,

			    const struct qstr *s1);



int utf8_normalize(const struct unicode_map *um, const struct qstr *str,

		   unsigned char *dest, size_t dlen);