Re: Massive filesystem corruption since kernel 5.2 (ARCH)

[Filipe Manana <fdmanana@gmail.com>]

On Sat, Aug 24, 2019 at 6:53 PM Christoph Anton Mitterer
<calestyo@scientia.net> wrote:
>
> Hey.
>
> Anything new about the issue described here:
> https://www.spinics.net/lists/linux-btrfs/msg91046.html
>
> It was said that it might be a regression in 5.2 actually and not a
> hardware thing... so I just wonder whether I can safely move to 5.2?

So we definitely have a serious regression introduced on 5.2.
I sent out a fix for it yesterday:  https://patchwork.kernel.org/patch/11141559/

Two things can happen:

1) either a hang when committing a transaction, reported by several
users recently and hit it myself too twice when running fstests (test
case generic/475 and generic/561) after I upgradaded my development
branch from a 5.1.x kernel to a 5.3-rcX kernel. If this happens you
risk no corruption, still the hang is very inconvenient of course, as
you have to reboot.

2) writeback for some btree nodes may never be started and we end up
committing a transaction without noticing that. This is really serious
and that will lead to the "parent transid verify failed on ..."
messages.

Until the fix gets merged to 5.2 kernels (and 5.3), I don't really
recommend running 5.2 or 5.3.

>
>
> Cheers,
> Chris.
>


-- 
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”