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Subject: Re: "corrupt empty space" error on boot?!?
From: Artem Bityutskiy <dedekind1@gmail.com>
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To: Steve deRosier <derosier@gmail.com>
Date: Tue, 03 Mar 2015 09:31:52 +0200
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On Mon, 2015-03-02 at 08:39 -0800, Steve deRosier wrote:
> Logically, it seems to me that a non ecc protected bit-flip in an
> empty page should be a non-issue. UBI should be able to move the
> block, erase the block, torture/return-to-service and move on with
> it's life.  No data is destroyed or even affected.

Yes, you are right, if there is a corruption, UBIFS can:

1. Try to understand if this is a corruption in empty space or not.
2. If yes, recover the LEB.

But this is not implemented. People keep hitting this issue, but no one
contributed fixes yet.

> A unit not mounting the rootfs because of a bit-flip in _empty_space_
> is unacceptable to us, so I've got to figure out a way to deal with
> this rare event.

Well, improving UBIFS would be one of the possible solutions.

Artem.