From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eryu Guan Subject: Re: [PATCH v2] ext4: don't remove reserved inodes in ext4_unlink() Date: Tue, 14 Oct 2014 11:19:08 +0800 Message-ID: <20141014031907.GK13950@dhcp-13-216.nay.redhat.com> References: <20140212163825.GE14520@thunk.org> <1413103858-2258-1-git-send-email-guaneryu@gmail.com> <20141013162100.GF9738@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Theodore Ts'o Return-path: Received: from mail-pd0-f174.google.com ([209.85.192.174]:33625 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754340AbaJNDTO (ORCPT ); Mon, 13 Oct 2014 23:19:14 -0400 Received: by mail-pd0-f174.google.com with SMTP id y13so6575561pdi.19 for ; Mon, 13 Oct 2014 20:19:13 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20141013162100.GF9738@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Oct 13, 2014 at 12:21:00PM -0400, Theodore Ts'o wrote: > On Sun, Oct 12, 2014 at 04:50:58PM +0800, Eryu Guan wrote: > > Corrupted ext4_dir_entry_2 struct on disk may have wrong inode number, > > when the inode number is 8 (EXT4_JOURNAL_INO) and the file is deleted, > > the journal inode is gone, and unmounting such a fs could trigger the > > following BUG_ON() in start_this_handle().... > > > > I believe the bug that this patch is trying to fix has been addressed > by this commit: > > http://git.kernel.org/cgit/linux/kernel/git/tytso/ext4.git/commit/?h=dev&id=bf8ad98e1bffa5ce178ef5e4ea803a86ac30f9e5 Yes, this patch fixes the issue I'm seeing, thanks for pointing it out! I have one concern thouth, removing a reserved inode (I tested EXT4_JOURNAL_INO) on corrupted ext4 returns EIO as expect but the fs is not marked as containing error(as other EIOs in ext4_iget()) and no error logs in dmesg. User may have no idea what happened and the corruped fs is still being used as normal. I think EXT4_ERROR_INODE should be called too somewhere in such case. Thanks, Eryu > > ext4: add ext4_iget_normal() which is to be used for dir tree lookups > If there is a corrupted file system which has directory entries that > point at reserved, metadata inodes, prohibit them from being used by > treating them the same way we treat Boot Loader inodes --- that is, > mark them to be bad inodes. This prohibits them from being opened, > deleted, or modified via chmod, chown, utimes, etc. > > In particular, this prevents a corrupted file system which has a > directory entry which points at the journal inode from being deleted > and its blocks released, after which point Much Hilarity Ensues. > > Reported-by: Sami Liedes > Signed-off-by: Theodore Ts'o > Cc: stable@vger.kernel.org > > - Ted > >