From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755502AbZGBVNx (ORCPT ); Thu, 2 Jul 2009 17:13:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753456AbZGBVNp (ORCPT ); Thu, 2 Jul 2009 17:13:45 -0400 Received: from zrtps0kp.nortel.com ([47.140.192.56]:51813 "EHLO zrtps0kp.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753509AbZGBVNp (ORCPT ); Thu, 2 Jul 2009 17:13:45 -0400 Message-ID: <4A4D2306.2000208@nortel.com> Date: Thu, 02 Jul 2009 17:13:42 -0400 From: "Doug Graham" User-Agent: Thunderbird 1.5.0.12 (X11/20081216) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: V3 minixfs bug Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 02 Jul 2009 21:13:44.0648 (UTC) FILETIME=[FB799480:01C9FB59] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Is anybody interested in bugs in the minixfs V3 support that probably only turn up on big-endian machines, or on filesystems with more than 64K inodes? The problem is that that there are a few places (three that I've found) where the "inode" field of a minix_dir_entry is used without checking first to see if the dirent is really a minix3_dir_entry. The inode number in a V1/V2 dirent is 16 bits, whereas that in a V3 dirent is 32 bits. Accessing it as a 16 bit field when it really should be accessed as a 32 bit field probably kinda sorta works on a little-endian machine, but leads to some rather odd behaviour on big-endian machines. Here's a patch: --- linux-2.6.29.2/fs/minix/dir.c 2009/07/02 21:05:33 1.1 +++ linux-2.6.29.2/fs/minix/dir.c 2009/07/02 21:10:31 @@ -311,14 +311,18 @@ struct inode *inode = (struct inode*)mapping->host; char *kaddr = page_address(page); loff_t pos = page_offset(page) + (char*)de - kaddr; - unsigned len = minix_sb(inode->i_sb)->s_dirsize; + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + unsigned len = sbi->s_dirsize; int err; lock_page(page); err = __minix_write_begin(NULL, mapping, pos, len, AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); if (err == 0) { - de->inode = 0; + if (sbi->s_version == MINIX_V3) + ((minix3_dirent *) de)->inode = 0; + else + de->inode = 0; err = dir_commit_chunk(page, pos, len); } else { unlock_page(page); @@ -443,7 +447,10 @@ err = __minix_write_begin(NULL, mapping, pos, sbi->s_dirsize, AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); if (err == 0) { - de->inode = inode->i_ino; + if (sbi->s_version == MINIX_V3) + ((minix3_dirent *) de)->inode = inode->i_ino; + else + de->inode = inode->i_ino; err = dir_commit_chunk(page, pos, sbi->s_dirsize); } else { unlock_page(page); @@ -473,7 +480,14 @@ ino_t res = 0; if (de) { - res = de->inode; + struct address_space *mapping = page->mapping; + struct inode *inode = (struct inode*)mapping->host; + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + + if (sbi->s_version == MINIX_V3) + res = ((minix3_dirent *) de)->inode; + else + res = de->inode; dir_put_page(page); } return res; --Doug