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ext4: optimize case-insensitive lookups

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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: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Gabriel Krisman Bertazi 2019-06-19 23:45:09 -04:00 committed by Theodore Ts'o
parent b03755ad6f
commit 3ae72562ad
5 changed files with 106 additions and 9 deletions
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2
fs/ext4/dir.c
View File

@ -677,7 +677,7 @@ 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)

39
fs/ext4/ext4.h
View File

@ -2078,6 +2078,9 @@ 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)
@ -2303,6 +2306,12 @@ 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)
@ -2329,6 +2338,10 @@ 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;
}
@ -2344,6 +2357,10 @@ 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;
}
@ -2357,6 +2374,11 @@ 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,
@ -2367,6 +2389,11 @@ 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;
}
@ -2377,7 +2404,13 @@ 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 */
@ -3120,8 +3153,8 @@ 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] = {

43
fs/ext4/namei.c
View File

@ -1259,19 +1259,24 @@ 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;
ret = utf8_strncasecmp(um, name, entry);
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.
@ -1287,6 +1292,27 @@ 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
/*
@ -1313,8 +1339,15 @@ 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);

28
fs/unicode/utf8-core.c
View File

@ -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)
{

3
include/linux/unicode.h
View File

@ -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);