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	for linux-mtd@lists.infradead.org; Fri, 17 Apr 2009 14:37:22 +0000
Subject: Re: UBIFS Corrupt during power failure
From: Artem Bityutskiy <dedekind@infradead.org>
To: Jamie Lokier <jamie@shareable.org>
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Date: Fri, 17 Apr 2009 17:36:58 +0300
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Cc: Urs Muff <urs_muff@Trimble.com>, Eric Holmberg <Eric_Holmberg@Trimble.com>,
	linux-mtd@lists.infradead.org, Adrian Hunter <adrian.hunter@nokia.com>
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On Fri, 2009-04-17 at 14:51 +0100, Jamie Lokier wrote:
> Artem Bityutskiy wrote:
> > Jamie, thanks for feedback!
> 
> Thanks for the new sections in the UBI FAQ!
> > Yeah...
> > 
> > >    That makes the range of parallel writes, and so
> > >    corruption-on-power-loss, even larger than max(N * strip_size, N *
> > >    block_size).  The range is as large as the whole write, if one chip
> > >    is writing much faster than the others, so it cannot be represented
> > >    by a small number.
> > 
> > Then I guess we should just introduce mtd->max_corruption ? This would
> > mean maximum amount of bytes corruption may span in vase of power cuts?
> 
> With that name maybe whoever implements striping will remember think
> about parallelism and limit it :-)
> 
>   /* Max size of corrupted block when a write command is interrupted
>      by reset or power failure. */
>   u32 max_write_corruption;

Yeah, let's wait for Eric's results and then will work on
extending MTD device model with this parameter.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)