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Date:   Wed, 16 Jun 2021 08:22:38 -0400
From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Jan Kara <jack@suse.cz>
Cc:     linux-ext4@vger.kernel.org, Eric Whitney <enwlinux@gmail.com>,
        linux-fsdevel@vger.kernel.org,
        "Darrick J . Wong" <djwong@kernel.org>
Subject: Re: [PATCH 3/3] ext4: Fix overflow in ext4_iomap_alloc()
Message-ID: <YMntDuZjWcHEUokL@mit.edu>
References: <20210412102333.2676-1-jack@suse.cz>
 <20210412102333.2676-4-jack@suse.cz>
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On Mon, Apr 12, 2021 at 12:23:33PM +0200, Jan Kara wrote:
> A code in iomap alloc may overblock block number when converting it to
> byte offset. Luckily this is mostly harmless as we will just use more
> expensive method of writing using unwritten extents even though we are
> writing beyond i_size.
> 
> Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure")
> Signed-off-by: Jan Kara <jack@suse.cz>

This was part of the patch series "ext4: Fix data corruption when
extending DIO write races with buffered read" but which fixes an
unrelated problem.  The patch series was dropped in favor of a
different approach, but it looks like this patch is still applicable,
so I've applied with a minor typo fix in the commit description.

   		       	     	      - Ted