diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index 3e15a8fdac4c..5c0e280c83ee 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -396,11 +396,39 @@ found: struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p) { - struct nilfs_dir_entry *de = nilfs_get_page(dir, 0, p); + struct page *page; + struct nilfs_dir_entry *de, *next_de; + size_t limit; + char *msg; + de = nilfs_get_page(dir, 0, &page); if (IS_ERR(de)) return NULL; - return nilfs_next_entry(de); + + limit = nilfs_last_byte(dir, 0); /* is a multiple of chunk size */ + if (unlikely(!limit || le64_to_cpu(de->inode) != dir->i_ino || + !nilfs_match(1, ".", de))) { + msg = "missing '.'"; + goto fail; + } + + next_de = nilfs_next_entry(de); + /* + * If "next_de" has not reached the end of the chunk, there is + * at least one more record. Check whether it matches "..". + */ + if (unlikely((char *)next_de == (char *)de + nilfs_chunk_size(dir) || + !nilfs_match(2, "..", next_de))) { + msg = "missing '..'"; + goto fail; + } + *p = page; + return next_de; + +fail: + nilfs_error(dir->i_sb, "directory #%lu %s", dir->i_ino, msg); + nilfs_put_page(page); + return NULL; } ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)