From: "Dilger, Andreas" Subject: problem in ext2fs_get_next_inode_full() ? Date: Thu, 18 Feb 2016 22:05:44 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Cc: "linux-ext4@vger.kernel.org" To: Theodore Ts'o Return-path: Received: from mga04.intel.com ([192.55.52.120]:56403 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423513AbcBRWFq convert rfc822-to-8bit (ORCPT ); Thu, 18 Feb 2016 17:05:46 -0500 Content-Language: en-US Content-ID: <79B3B3F8F68B634684F26641A23F7ECB@intel.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: I was just looking at ext2fs_get_next_inode_full() to trace where we are using large inodes and whether we could change the APIs to just pass large inodes around instead of typecasting them. It has the following hunk of code: if (extra_bytes) { memcpy(scan->temp_buffer+extra_bytes, scan->ptr, scan->inode_size - extra_bytes); scan->ptr += scan->inode_size - extra_bytes; scan->bytes_left -= scan->inode_size - extra_bytes; #ifdef WORDS_BIGENDIAN memset(inode, 0, bufsize); ext2fs_swap_inode_full(scan->fs, (struct ext2_inode_large *) inode, (struct ext2_inode_large *) scan->temp_buffer, 0, bufsize); #else *inode = *((struct ext2_inode *) scan->temp_buffer); #endif So if the inode is being swabbed then it handles the full inode size, but if it is not being swabbed (the common case) it appears that it is only copying the small inode into "*inode" using a struct assignment. This appears like it would be dropping the large inode data, but I'm not sure if or when this "extra_bytes" case is hit. The "else" clause appears to copy the requested (full) inode size properly via "memcpy(..., bufsize)". Should the struct assignment be changed similarly to use memcpy()? Cheers, Andreas -- Andreas Dilger Lustre Principal Architect Intel High Performance Data Division