diff options
| -rw-r--r-- | fs/libfs.c | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index eec6031b0155..306a0510b7dc 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1704,16 +1704,28 @@ bool is_empty_dir_inode(struct inode *inode) static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, const char *str, const struct qstr *name) { - const struct dentry *parent = READ_ONCE(dentry->d_parent); - const struct inode *dir = READ_ONCE(parent->d_inode); - const struct super_block *sb = dentry->d_sb; - const struct unicode_map *um = sb->s_encoding; - struct qstr qstr = QSTR_INIT(str, len); + const struct dentry *parent; + const struct inode *dir; char strbuf[DNAME_INLINE_LEN]; - int ret; + struct qstr qstr; + + /* + * Attempt a case-sensitive match first. It is cheaper and + * should cover most lookups, including all the sane + * applications that expect a case-sensitive filesystem. + * + * This comparison is safe under RCU because the caller + * guarantees the consistency between str and len. See + * __d_lookup_rcu_op_compare() for details. + */ + if (len == name->len && !memcmp(str, name->name, len)) + return 0; + parent = READ_ONCE(dentry->d_parent); + dir = READ_ONCE(parent->d_inode); if (!dir || !IS_CASEFOLDED(dir)) - goto fallback; + return 1; + /* * 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 @@ -1724,20 +1736,14 @@ static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, if (len <= DNAME_INLINE_LEN - 1) { memcpy(strbuf, str, len); strbuf[len] = 0; - qstr.name = strbuf; + str = strbuf; /* prevent compiler from optimizing out the temporary buffer */ barrier(); } - ret = utf8_strncasecmp(um, name, &qstr); - if (ret >= 0) - return ret; + qstr.len = len; + qstr.name = str; - if (sb_has_strict_encoding(sb)) - return -EINVAL; -fallback: - if (len != name->len) - return 1; - return !!memcmp(str, name->name, len); + return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr); } /** |