[PATCH 2/2] f2fs: optimize case-insensitive lookups

From: Chao Yu
Date: Wed Aug 21 2019 - 11:20:30 EST


From: Chao Yu <yuchao0@xxxxxxxxxx>

This patch ports below casefold enhancement patch from ext4 to f2fs

commit 3ae72562ad91 ("ext4: optimize case-insensitive lookups")

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
fs/f2fs/dir.c | 57 ++++++++++++++++++++++++++++++++++++++++++++------
fs/f2fs/f2fs.h | 3 ++-
2 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index e34c17106084..7498b789518a 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -112,13 +112,17 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
* doesn't match or less than zero on error.
*/
int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
- const struct qstr *entry)
+ 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;
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.
@@ -134,11 +138,36 @@ int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,

return ret;
}
+
+void f2fs_fname_setup_ci_filename(struct inode *dir,
+ const struct qstr *iname,
+ struct fscrypt_str *cf_name)
+{
+ struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
+
+ if (!IS_CASEFOLDED(dir)) {
+ cf_name->name = NULL;
+ return;
+ }
+
+ cf_name->name = f2fs_kmalloc(sbi, F2FS_NAME_LEN, GFP_NOFS);
+ if (!cf_name->name)
+ return;
+
+ cf_name->len = utf8_casefold(sbi->s_encoding,
+ iname, cf_name->name,
+ F2FS_NAME_LEN);
+ if (cf_name->len <= 0) {
+ kvfree(cf_name->name);
+ cf_name->name = NULL;
+ }
+}
#endif

static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
struct f2fs_dir_entry *de,
struct fscrypt_name *fname,
+ struct fscrypt_str *cf_str,
unsigned long bit_pos,
f2fs_hash_t namehash)
{
@@ -155,8 +184,15 @@ 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))
- return !f2fs_ci_compare(parent, fname->usr_fname, &entry);
+ if (sbi->s_encoding && IS_CASEFOLDED(parent)) {
+ if (cf_str->name) {
+ struct qstr cf = {.name = cf_str->name,
+ .len = cf_str->len};
+ return !f2fs_ci_compare(parent, &cf, &entry, true);
+ }
+ return !f2fs_ci_compare(parent, fname->usr_fname, &entry,
+ false);
+ }
#endif
if (fscrypt_match_name(fname, d->filename[bit_pos],
le16_to_cpu(de->name_len)))
@@ -169,9 +205,14 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
struct f2fs_dentry_ptr *d)
{
struct f2fs_dir_entry *de;
+ struct fscrypt_str cf_str = { .name = NULL, .len = 0 };
unsigned long bit_pos = 0;
int max_len = 0;

+#ifdef CONFIG_UNICODE
+ f2fs_fname_setup_ci_filename(d->inode, fname->usr_fname, &cf_str);
+#endif
+
if (max_slots)
*max_slots = 0;
while (bit_pos < d->max) {
@@ -188,7 +229,7 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
continue;
}

- if (f2fs_match_name(d, de, fname, bit_pos, namehash))
+ if (f2fs_match_name(d, de, fname, &cf_str, bit_pos, namehash))
goto found;

if (max_slots && max_len > *max_slots)
@@ -202,6 +243,10 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
found:
if (max_slots && max_len > *max_slots)
*max_slots = max_len;
+
+#ifdef CONFIG_UNICODE
+ kvfree(cf_str.name);
+#endif
return de;
}

@@ -1025,7 +1070,7 @@ static int f2fs_d_compare(const struct dentry *dentry, unsigned int len,
return memcmp(str, name, len);
}

- return f2fs_ci_compare(dentry->d_parent->d_inode, name, &qstr);
+ return f2fs_ci_compare(dentry->d_parent->d_inode, name, &qstr, false);
}

static int f2fs_d_hash(const struct dentry *dentry, struct qstr *str)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2d0cab0cd620..52174aae3299 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2951,7 +2951,8 @@ struct dentry *f2fs_get_parent(struct dentry *child);

extern int f2fs_ci_compare(const struct inode *parent,
const struct qstr *name,
- const struct qstr *entry);
+ const struct qstr *entry,
+ bool quick);

/*
* dir.c
--
2.22.0