On 2019/4/1 上午2:44, btrfs@avgustinov.eu wrote:
> Dear all,
> 
> 
> I am a big fan of btrfs, and I am using it since 2013 - in the meantime
> on at least four different computers. During this time, I suffered at
> least four bad btrfs-failures leading to unmountable, unreadable and
> unrecoverable file system. Since in three of the cases I did not manage
> to recover even a single file, I am beginning to lose my confidence in
> btrfs: for 35-years working with different computers no other file
> system was so bad at recovering files!
> 
> Considering the importance of btrfs and keeping in mind the number of
> similar failures, described in countless forums on the net, I have got
> an idea: to donate my last two damaged filesystems for investigation
> purposes and thus hopefully contribute to the improvement of btrfs. One
> condition: any recovered personal data (mostly pictures and audio files)
> should remain undisclosed and be deleted.
> 
> Should anybody be interested in this - feel free to contact me
> personally (I am not reading the list regularly!), otherwise I am going
> to reformat and reuse both systems in two weeks from today.
> 
> Some more info:
> 
>   - The smaller system is 83.6GB, I could either send you an image of
> this system on an unneeded hard drive or put it into a dedicated
> computer and give you root rights and ssh-access to it (the network lin
> is 100Mb down, 50Mb up, so it should be acceptable).

I'm a little more interested in this case, as it's easier to debug.

However there is one requirement before debugging.

*NO* btrfs check --repair/--init-* run at all.
btrfs check --repair is known to cause transid error.


And, I'm afraid even with some debugging, the result would be pretty
predictable.

It will be 90% transid error.
And if it's tree block from future, then it's something barrier related.
If it's tree block from the past, then it's some tree block doesn't
reach disk.

We have being chasing the spectre for a long time, had several
assumption but never pinned it down.


But anyway, more info is always better.

I'd like to get the ssh access for this smaller image.

Thanks,
Qu

> 
>   - The used space on the other file system is about 3 TB (4 TB
> capacity) and it is distributed among 5 drives, so I can only offer
> remote access to this, but I will need time to organize it.
> 
> If you need additional information - please ask, but keep in mind that I
> have almost no "free time" and the answer could need a day or two.
> 
> Kind regards,
> 
> Nik.
> 
> -- 
> 
>