UBIFS automatic recovery

[Johan Borkhuis]

Richard,

Thanks for your quick response!

> On Fri, May 13, 2016 at 10:47 AM, Johan Borkhuis <maillist at borkhuis.com>
> wrote:
>> However, when I continue to pull the power on a system with a broken
>> partition (without running the test-application, this is only started
>> when
>> all partitions are mounted correctly) after some time (this can be a few
>> reboots, or a couple of 100 reboots) the system fixes the partition
>> itself, and I can access the data again, without any indications in the
>> log.
>
> This should not happen. Either the UBIFS is broken and not mountable
> or it can recover.
> Something else seems to interact here.

This was also what I was expecting, and why I was surprised when units
started to recover.

>> When it fails it shows the following during a mount (also shown
>> sometimes for LEB 3 and 6):
>> UBIFS: recovery needed
>> UBIFS error (pid 640): ubifs_recover_log_leb: unrecoverable log
>> corruption
>> in LEB 5
>>
>> Another UBIFS message I see during a failed mount is:
>> UBIFS error (pid 637): ubifs_recover_master_node: dumping first master
>> node
>>
>> As long the mount fails the same message is repeated.
>
> UBIFS must not break due to power cuts.
> So, something else is broken.
> Do both MTD and UBI tests pass?

You mean the kernel startup? Or some specific MTD/UBI test tools?
On startup there is no difference in the console-output between a good and
bad startup, so MTD and UBI are initialised correctly. The first sign is
the fact that a mount fails.

>> Or is there another way to fix/repair a broken partition without loosing
>> the data that is stored on it?
>
> No. What you need is figuring out *why* UBIFS breaks while doing
> power cuts. Both UBI and UBIFS are power cut aware by design.
> In most cases UBIFS suffers from MTD problems. May it a faulty driver
> or bad hardware...

We are using a Micon 2Mb flash chip and the kernel sources from TI. The
output during boot:
omap2-nand driver initializing
NAND device: Manufacturer ID: 0x2c, Chip ID: 0xca (Micron )
Creating 6 MTD partitions on "omap2-nand.0":
....

Regards,
    Johan