From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH v1 04/22] libext2fs: handle inline data in dir iterator function Date: Sun, 13 Oct 2013 18:51:12 -0400 Message-ID: <20131013225112.GA9609@thunk.org> References: <1375436989-18948-1-git-send-email-wenqing.lz@taobao.com> <1375436989-18948-5-git-send-email-wenqing.lz@taobao.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Zheng Liu To: Zheng Liu Return-path: Received: from imap.thunk.org ([74.207.234.97]:45604 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755268Ab3JMWvQ (ORCPT ); Sun, 13 Oct 2013 18:51:16 -0400 Content-Disposition: inline In-Reply-To: <1375436989-18948-5-git-send-email-wenqing.lz@taobao.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Aug 02, 2013 at 05:49:31PM +0800, Zheng Liu wrote: > +int ext2fs_process_dir_inline_data(ext2_filsys fs, > + char *buf, > + unsigned int buf_len, > + e2_blkcnt_t blockcnt, > + struct ext2_inode_large *inode, > + void *priv_data) > +{ It looks like there is a lot of code in this function which is in common with ext2fs_process_dir_block(), so I'd suggest refactoring out the common code to reduce duplication. This will reduce code size, and more importantly, improve maintenance of the code. > +errcode_t ext2fs_inline_data_iterate(ext2_filsys fs, > + ext2_ino_t ino, > + int flags, > + char *block_buf, > + int (*func)(ext2_filsys fs, > + char *buf, > + unsigned int buf_len, > + e2_blkcnt_t blockcnt, > + struct ext2_inode_large *inode, > + void *priv_data), > + void *priv_data) This function is misnamed, which worries me a little. First of all, it only makes sense when called on directories, so some name that indicates that it is meant to iterate over directories is a good idea. so some name such as ext2fs_process_inline_data_dir might be a better choice. Secondly, it would a really good idea if there was a check to make sure it was passed an inode number which corresponds to an directory and that the inline data flag is set. A little paranoia is really healthy thing --- if we have some application bug where this function gets called accidentally on an inappropriate inode, we want to return a clean error code and not stumble on until something bad happens. > + dirent.inode = (__u32)*inode->i_block; I'd be much happier with: dirent.inode = inode->i_block[0]; We shouldn't use casts unless absolutely necessary, and it's not necessary here. Also, I suspect we have some byte-swapping problems here. It doesn't appear there is any allownaces for byte swapping in the inline data patches. Currently, the ext2fs_read_inode() function will take care of byte swapping i_blocks[], so that will be OK here, but in the case of an inode with inline data, if we byte swap all of i_blocks[] then ext2fs_read_inline_data() will malfunction since the data bytes stored in the rest of i_blocks[] will be byte swapped. And that would be wrong. So I think what you will need to do is to avoid byte swapping the i_blocks[] array if the inode contains inline_data, and then in the case where this is a directory, we will need to byte swap i_block[0] if we are running on a big-endian system. Cheers, - Ted