UBIFS Corrupt during power failure

[Artem Bityutskiy]

On Wed, 2009-07-15 at 15:35 -0600, Eric Holmberg wrote:
> Test Results - PASS
> -------------------
> I just finished a test run of 3 boards with a total of 8104 power cycles
> during read/modify/write operations on UBIFS.  The system cuts power
> randomly after mounting the UBIFS image while performing read/write file
> operations on the UBIFS root file system.
> 
> I experienced 0 failures.  Typically, I was getting less than 100 cycles
> before failures.
> 
> Software:
>  * 2.6.27-rc9 kernel
>  * UBIFS patches up to July 10
>  * CFI Write buffer size limited to 8 bytes (NOR chip supports 32 bytes)
>  * No power cycling during mount
> 
> Patch:
> http://git.infradead.org/users/dedekind/ubifs-v2.6.27.git?a=commit;h=201
> fce21a67d74e9703127af0d6c6084003796bb

I'm also running a power cut tests. But I do not have any buffer size
limiting patch. I'm running the 'fsstress' program from the LTP test
suite with the following parameters:

fsstress -d /mnt/ubifs -l0 -r -n1000 -p2

And I cut power randomly after 0-300 seconds after the start.

So far so good.

> Remaining tasks:
>  * Anybody:  Add support to UBI/UBIFS to allow for block-write sizes
> greater than 8 bytes

Yeah, this is in my TODO. I just wanted to first reproduce this issue,
then trying to fix it. Cannot reproduce it so far.

>  * Test with power failures during deferred recovery

Good thing to test. I did not test this.

Just in case: I assume by "deferred" recovery you mean the situation
when you mount the FS which needs recovery first R/O, so the recovery
is deferred, and it happens when you re-mount it R/W, right?

> Thanks for everybody's help so far!  I will hopefully get a chance to
> setup the power-failures during deferred recovery this weekend.

Thanks for cooperation. We are interested to make UBIFS robust.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)