UBI-FS Master Node failure

[Richard Weinberger]

Am 22.06.2015 um 11:20 schrieb David J Myers:
>>> Guys,
>>> I have an embedded product running a system based on linux-2.6.29, 
>>> originally from the IC supplier, but patched and modified to our spec.
> 
>> That's a very old kernel. Did you backport *all* stable patches?
> 
> I only back-ported the two patches as shown previously. These seemed to be the only two relevant patches I could find. Do you know of any other relevant patches?

UBI and UBIFS got a lot of fixes after 2.6.29. All are relevant.

>>> Recently we have had two units go down with the same UBI-FS Master 
>>> Node failure, both in LEB-2 at slightly different offsets. The console 
>>> log looks like this:-
>>>
>>> [    6.645845] UBIFS error (pid 1): ubifs_scan: corrupt empty space at LEB
>>> 2:86016
>>> [    6.653268] UBIFS error (pid 1): ubifs_scanned_corruption: corrupted data
>>> at LEB 2:86016
>>> [    6.668163] UBIFS error (pid 1): ubifs_scan: LEB 2 scanning failed
>>> [    6.889661] UBIFS error (pid 1): ubifs_recover_master_node: failed to
>>> recover master node
>>> [    6.898497] List of all partitions:
>>> [    6.902188] 1f00             128 mtdblock0 (driver?)
>>> [    6.907218] 1f01             768 mtdblock1 (driver?)
>>> [    6.912314] 1f02             128 mtdblock2 (driver?)
>>> [    6.917318] 1f03            4096 mtdblock3 (driver?)
>>> [    6.922395] 1f04            4096 mtdblock4 (driver?)
>>> [    6.927397] 1f05           65536 mtdblock5 (driver?)
>>> [    6.932464] 1f06          184320 mtdblock6 (driver?)
>>> [    6.937455] No filesystem could mount root, tried:  ubifs
>>> [    6.942988] Kernel panic - not syncing: VFS: Unable to mount root fs on
>>> unknown-block(0,0)
>>>
>>> I found two patches to fs/ubifs/recovery.c since 2.6.29 which I 
>>> applied, but they did not fix the corrupted flash. These two patches 
>>> were this one:-
> 
>> I fear it is not that easy.  Maybe you're facing a different issue.
>> And if the data is already corrupted there is no guarantee that a UBIFS recent UBIFS can fix it.
> 
> I was hoping these patches would recover the corrupt UBIFS, however I'll settle for preventing the same fault occurring in other units. Do you think this problem is fixed in the recent UBIFS implementations? How can I test this?

As written above, UBI and UIBFS faced a lot of issues which have been fixed.
Without a detailed analysis of the corrupted UBIFS I can't say much.

Thanks,
//richard