diff options
Diffstat (limited to 'fs/f2fs/dir.c')
| -rw-r--r-- | fs/f2fs/dir.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 29f70f2295cc..d35976785e8c 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -1114,11 +1114,27 @@ static int f2fs_d_compare(const struct dentry *dentry, unsigned int len, const struct inode *dir = READ_ONCE(parent->d_inode); const struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb); struct qstr entry = QSTR_INIT(str, len); + char strbuf[DNAME_INLINE_LEN]; int res; if (!dir || !IS_CASEFOLDED(dir)) goto fallback; + /* + * 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 + * the lookup, so it doesn't matter what ->d_compare() returns. + * However, it's unsafe to call utf8_strncasecmp() with an unstable + * string. Therefore, we have to copy the name into a temporary buffer. + */ + if (len <= DNAME_INLINE_LEN - 1) { + memcpy(strbuf, str, len); + strbuf[len] = 0; + entry.name = strbuf; + /* prevent compiler from optimizing out the temporary buffer */ + barrier(); + } + res = utf8_strncasecmp(sbi->s_encoding, name, &entry); if (res >= 0) return res; |