Re: [PATCH] Btrfs-progs: fsck: disable --init-extent-tree option when using snapshots

Wang Shilong
2014-03-14T13:36:11Z

Hi Josef,

Just ping this again.

Did you have any good ideas to rebuild extent tree if broken filesystem
is filled with snapshots.?

I was working on this recently, i was blocked that i can not verify if an extent
is *FULL BACKREF* mode or not. As a *FULL BACKREF* extent's refs can be 1
and more than 1..

I am willing to test codes or have a try if you could give me some advice etc.

-Wang

> On 03/10/2014 11:50 PM, Josef Bacik wrote:
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>> On 03/10/2014 08:12 AM, Shilong Wang wrote:
>>> Hi Josef,
>>>
>>> As i haven't thought any better ideas to rebuild extent tree which
>>> contains extent that owns 'FULL BACKREF' flag.
>>>
>>> Considering an extent's refs can be equal or more than 1 if this
>>> extent has *FULL BACKREF* flag, so we could not make sure an
>>> extent's flag by only searching fs/file tree any more.
>>>
>>> So until now, i just disable this option if snapshots exists,
>>> please correct me if i miss something here. Or you have any better
>>> ideas to solve this problem.~_~
>>>
>>>
>> I thought the fsck stuff rebuilds full backref refs properly, does it
>> not? If it doesn't we need to fix that, however I'm fine with
>> disabling the option if snapshots exist for the time being. Thanks,
> If there are no snapshots, --init-extent-tree can works as expected.
> I just have not thought a better idea to rebuild extent tree if we do have
> snapshots which means we may have an extent with *FULL BACKREF*
> flag.
>
> Thanks,
> Wang
>>
>> Josef
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