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From: Theodore Ts'o <tytso@mit.edu>
To: Lukas Czerner <lczerner@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, ceph-devel@vger.kernel.org,
	linux-ext4@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [PATCH 3/4] fs: Remove i_size check from do_fallocate
Date: Sat, 12 Apr 2014 09:59:06 -0400	[thread overview]
Message-ID: <20140412135906.GC13837@thunk.org> (raw)
In-Reply-To: <1397242665-2183-3-git-send-email-lczerner@redhat.com>

On Fri, Apr 11, 2014 at 08:57:44PM +0200, Lukas Czerner wrote:
> Currently in do_fallocate in collapse range case we're checking whether
> offset + len is not bigger than i_size. However there is nothing which
> would prevent i_size from changing so the check is pointless. It should
> be done in the file system itself and the file system needs to make sure
> that i_size is not going to change.
> 
> As it is now we can easily crash kernel by having two processes doing
> truncate and fallocate collapse range at the same time. This can be
> reproduced on ext4 and it is theoretically possible on xfs even though I
> was not able to trigger it with this simple test.
> 
> This commit removes the check from do_fallocate and adds it to the file
> system.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
>  fs/ext4/extents.c | 11 +++++++++--
>  fs/open.c         |  8 --------
>  fs/xfs/xfs_file.c | 10 +++++++++-
>  3 files changed, 18 insertions(+), 11 deletions(-)

Looks good to me.  Do the xfs folks mind if I carry this in the ext4
tree and push it to Linus shortly after -rc1?  If so, please send me
an ack'ed by.

If folks have a strong preference to handle this differently, let me
know.

Cheers,

						- Ted


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  reply	other threads:[~2014-04-12 13:59 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-11 18:57 [PATCH 1/4] ext4: Remove unnecessary check for APPEND and IMMUTABLE Lukas Czerner
2014-04-11 18:57 ` [PATCH 2/4] fs: Prevent doing FALLOC_FL_ZERO_RANGE on append only file Lukas Czerner
2014-04-11 18:57   ` Lukas Czerner
2014-04-12 13:49   ` Theodore Ts'o
2014-04-12 13:49     ` Theodore Ts'o
2014-04-12 15:19   ` Christoph Hellwig
2014-04-12 15:19     ` Christoph Hellwig
2014-04-15 13:09     ` Lukáš Czerner
2014-04-15 21:36       ` Dave Chinner
2014-04-15 21:36         ` Dave Chinner
2014-04-11 18:57 ` [PATCH 3/4] fs: Remove i_size check from do_fallocate Lukas Czerner
2014-04-12 13:59   ` Theodore Ts'o [this message]
2014-04-13 23:39     ` Dave Chinner
2014-04-13 23:39       ` Dave Chinner
2014-04-12 15:21   ` Christoph Hellwig
2014-04-12 15:21     ` Christoph Hellwig
2014-04-15 13:10     ` Lukáš Czerner
2014-04-15 15:36       ` Theodore Ts'o
2014-04-15 15:36         ` Theodore Ts'o
2014-04-15 16:09         ` Lukáš Czerner
2014-04-15 19:40           ` Theodore Ts'o
2014-04-15 19:57             ` Lukáš Czerner
2014-04-11 18:57 ` [PATCH 4/4] fs: Disallow all fallocate operation on active swapfile Lukas Czerner
2014-04-11 18:57   ` Lukas Czerner
2014-04-12 14:06   ` Theodore Ts'o
2014-04-12 15:22   ` Christoph Hellwig
2014-04-12 15:22     ` Christoph Hellwig
2014-04-15 13:19     ` Lukáš Czerner
2014-04-12 13:48 ` [PATCH 1/4] ext4: Remove unnecessary check for APPEND and IMMUTABLE Theodore Ts'o
2014-04-12 13:48   ` Theodore Ts'o

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