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Date: Mon, 17 Jun 2019 15:02:40 -0400
From: Gabriel Krisman Bertazi <krisman@...labora.com>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org,
Gabriel Krisman Bertazi <krisman@...labora.com>,
kernel@...labora.com
Subject: [PATCH] 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.
v2:
- Dinamically allocate space for the casefolded version.
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
fs/ext4/dir.c | 2 +-
fs/ext4/ext4.h | 39 ++++++++++++++++++++++++++++++++++---
fs/ext4/namei.c | 43 ++++++++++++++++++++++++++++++++++++-----
fs/unicode/utf8-core.c | 28 +++++++++++++++++++++++++++
include/linux/unicode.h | 3 +++
5 files changed, 106 insertions(+), 9 deletions(-)
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index c7843b149a1e..0a427e18584a 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -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)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1cb67859e051..c0793d9e5d12 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -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 */
@@ -3119,8 +3152,8 @@ 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] = {
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index cd01c4a67ffb..4909ced4e672 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -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);
diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
index 6afab4fdce90..71ca4d047d65 100644
--- a/fs/unicode/utf8-core.c
+++ b/fs/unicode/utf8-core.c
@@ -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)
{
diff --git a/include/linux/unicode.h b/include/linux/unicode.h
index aec2c6d800aa..990aa97d8049 100644
--- a/include/linux/unicode.h
+++ b/include/linux/unicode.h
@@ -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);
--
2.20.1
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