Distinguishing bitflips due to read-disturb or due to wear-out

[Shmulik Ladkani]

Quote from [1].
Started a new thread as this is off-topic.

[1]
http://lists.infradead.org/pipermail/linux-mtd/2012-March/040336.html

> The bigger issue is how to discern whether the degredation is due to 
> read-disturb (which can be recovered by erasing/reprogramming the block) 
> or the page physically wearing out (in which case it needs to be 
> retired).

Question is, do we really need to distinguish between the two?

If there is a "dangerously high" number of bit errors, then scrubbing
should be performed.
If the reason for the bit errors was due to read-disturb, then those
error are gone after scrubbing (for now, until read-disturb affects
again).
If the reason was wear-out, then it is likely that high number of bit
errors will be evident, again. But if the block is totally worn-out,
shouldn't the device return an error status for the erase operation,
eventually? (and as such, the MTD software will retire the block)?

Regards
Shmulik