UBIFS partition on NOR flash not mountable after power cut test

Artem Bityutskiy dedekind1 at gmail.com
Fri Dec 3 05:28:05 EST 2010

On Fri, 2010-12-03 at 11:07 +0100, Anatolij Gustschin wrote:
> UBI: scrubbed PEB 149 (LEB 0:19), data moved to PEB 40
> My question is: should this PEB really be preserved? I think, no.
> It was prepared for erasure and would be entirely erased if no
> interruption would occur.

Well, in general, my thinking is, if only the EC header is corrupted, we
do not know why - may be this was just because of some bit-flips or
radiation, and UBI better preserves it, just in case. I mean, there is a
risk to destroy useful data otherwise.

Then the upper layer SW like UBIFS should know what it was erasing, and
should re-issue the erasure. This is also a requirement made by the
"unstable bits" problem Matthiew found on NAND, and challenged me with.

To put is simple: I think it is saver for UBI to preserve it. Upper
layers will erase it again if it is not needed.

Best Regards,
Artem Bityutskiy (Артём Битюцкий)

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