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From: Christoph Hellwig <hch@infradead.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
	Theodore Ts'o <tytso@mit.edu>,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-fsdevel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] f2fs: remove broken support for allocating DIO writes
Date: Tue, 17 Aug 2021 06:42:18 +0100	[thread overview]
Message-ID: <YRtMOqzZU4c1Vjje@infradead.org> (raw)
In-Reply-To: <YRsY6dyHyaChkQ6n@gmail.com>

On Mon, Aug 16, 2021 at 07:03:21PM -0700, Eric Biggers wrote:
> Freeing preallocated blocks on error would be better than nothing, although note
> that the preallocated blocks may have filled an arbitrary sequence of holes --
> so simply truncating past EOF would *not* be sufficient.
> 
> But really filesystems need to be designed to never expose uninitialized data,
> even if I/O errors or a sudden power failure occurs.  It is unfortunate that
> f2fs apparently wasn't designed with that goal in mind.
> 
> In any case, I don't think we can proceed with any other f2fs direct I/O
> improvements until this data leakage bug can be solved one way or another.  If
> my patch to remove support for allocating writes isn't acceptable and the
> desired solution is going to require some more invasive f2fs surgery, are you or
> Chao going to work on it?  I'm not sure there's much I can do here.

Btw, this is generally a problem for buffered I/O as well, although the
window for exposing uninitialized blocks on a crash tends to be smaller.

  reply	other threads:[~2021-08-17  5:42 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28  1:51 [PATCH] f2fs: remove broken support for allocating DIO writes Eric Biggers
2021-07-30 19:17 ` Eric Biggers
2021-07-30 22:12   ` Jaegeuk Kim
2021-07-30 22:19     ` Eric Biggers
2021-07-31  1:05       ` Jaegeuk Kim
2021-07-31  1:18         ` Eric Biggers
2021-07-31  2:46   ` Theodore Ts'o
2021-08-02  4:39     ` Eric Biggers
2021-08-02  9:00       ` Chao Yu
2021-08-02 18:23         ` Jaegeuk Kim
2021-08-03  1:19           ` Chao Yu
2021-08-03  1:34             ` Jaegeuk Kim
2021-08-17  2:03               ` Eric Biggers
2021-08-17  5:42                 ` Christoph Hellwig [this message]
2021-08-17 18:57                   ` Jaegeuk Kim
2021-08-17 20:27                     ` Eric Biggers
2021-08-17 21:33                       ` Jaegeuk Kim
2021-08-18  0:06                         ` Eric Biggers
2021-08-20  9:35                 ` Chao Yu
2021-08-20 18:11                   ` Eric Biggers
2021-08-20 22:01                     ` Chao Yu

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