[PATCH] UBI: add ubi_err() to report the failure of leb read

[hujianyang]

On 2014/12/16 17:57, Richard Weinberger wrote:
> Then every single embedded vendor will use this flag to keep the broken MTD/UBI/UBIFS setups running
> as long as possible no mater of how corrupted the data is. :-)
> IIRC UBIFS will either mount and work correctly as expected or fail hard.

You are right~!

Maybe we can set filesystem to RO if it is mounted with --force, and
allow users to copy their data to other place.

How about this?

> 
>>> You can dump the raw data and inspect the corrupted data.
>>> Maybe you can fix it by hand.
>>
>> Yes, I want a try~! If we have to introduce a new feature or new mount
>> option. So would you like to help me? Do you think it's a valuable
>> work?
> 
> I'm not a fan of such a mount option.
> What we really need is a fsck.ubifs and a ubifs dump tool to fix and recover
> broken UBIFS images.

I think it's better, but a bit harder. As I know, my UBIDUMP is far
from what you expect. I should spend more time on it.

After all, I was asked to fix this error. My plan is do something
after an ECC error is detected, not directly breakout to allow
this partition to be mounted. I don't think this solution will be
easily accept by mainline.

However, I'd like to show my work if I succeed.

Thanks~!

Hu