[PATCH] ubifs: Fix O_TMPFILE corner case in ubifs_link()

[Richard Weinberger]

Amir,

Am 06.04.2017 um 14:06 schrieb Amir Goldstein:
> On Thu, Mar 30, 2017 at 3:27 PM, Richard Weinberger <richard at nod.at> wrote:
>> Am 30.03.2017 um 13:57 schrieb Adrian Hunter:
>>>> Reading deeper into the proved that I was wrong.
>>>> AFAIKT UBIFS' journal has currently no way to revive a deleted inode.
>>>> So, we have to think about a new solution.
>>>
>>> Deleting the orphan looks right.  Just need to understand whether the
>>> recovery would do the right thing - actually it looks like O_TMPFILE might
>>> be OK and in other case we might be failing to remove nodes with sequence
>>> numbers greater than the deletion inode.
>>
>> Sadly it does not the right thing.
>> I'm currently investigating why and how to deal with it.
>>
>> I also managed to trigger that case. :(
>>
> 
> Richard,
> 
> Were you able to make any progress? still working on this?
> If this is too complicated to get in for this cycle, better send a patch
> to disable O_TMPFILE support for ubifs and fix the problem properly on
> followup merge cycle.
> Because right now ubifs O_TMPFILE support is broken and breaks overlayfs mount.

I have a test and currently testing it. As it looks the situation is less worse
than I thought first. :-)

Thanks,
//richard