linux-kernel - Re: [PATCH 2/3] ext4: Fix data / filesystem corruption when write fails to copy data

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Message-ID: <20091209022622.GX27692@thunk.org>
Date:	Tue, 8 Dec 2009 21:26:22 -0500
From:	tytso@....edu
To:	Jan Kara <jack@...e.cz>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 2/3] ext4: Fix data / filesystem corruption when write
 fails to copy data

On Wed, Dec 02, 2009 at 08:16:48PM +0100, Jan Kara wrote:
> When ext4_write_begin fails after allocating some blocks or
> generic_perform_write fails to copy data to write, we truncate blocks already
> instantiated beyond i_size. Although these blocks were never inside i_size, we
> have to truncate pagecache of these blocks so that corresponding buffers get
> unmapped. Otherwise subsequent __block_prepare_write (called because we are
> retrying the write) will find the buffers mapped, not call ->get_block, and
> thus the page will be backed by already freed blocks leading to filesystem and
> data corruption.

Added to the ext4 patch queue.

						- Ted
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