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From: Theodore Ts'o <tytso@mit.edu>
To: Eryu Guan <guaneryu@gmail.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH v2] ext4: don't remove reserved inodes in ext4_unlink()
Date: Mon, 13 Oct 2014 12:21:00 -0400	[thread overview]
Message-ID: <20141013162100.GF9738@thunk.org> (raw)
In-Reply-To: <1413103858-2258-1-git-send-email-guaneryu@gmail.com>

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

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 <sami.liedes@iki.fi>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

					- Ted



  parent reply	other threads:[~2014-10-13 16:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-25  6:58 [PATCH] ext4: don't remove reserved inodes in ext4_unlink() Eryu Guan
2014-02-12 16:38 ` Theodore Ts'o
2014-02-14  5:04   ` Eryu Guan
2014-10-12  8:50   ` [PATCH v2] " Eryu Guan
2014-10-13 16:04     ` Darrick J. Wong
2014-10-13 16:21     ` Theodore Ts'o [this message]
2014-10-14  3:19       ` Eryu Guan

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