Re: Massive filesystem corruption since kernel 5.2 (ARCH)

[Qu Wenruo]

On 2019/8/2 上午2:56, Swâmi Petaramesh wrote:
> Le 01/08/2019 à 15:46, Anand Jain a écrit :
>>  Swami, Do you have the kernel logs around this time frame?
>
> No, it really got lost.
>
> ॐ
>
Follow up questions about the corruption.

Is there enough free space (not only unallocated, but allocated bg) for
metadata?

As further digging into the case, it looks like btrfs is even harder to
get corrupted for tree blocks.

If we have enough metadata free space, we will try to allocate tree
blocks at bytenr sequence, without reusing old bytenr until there is not
enough space or hit the end of the block group.

This means, even we have something wrong implementing barrier, we still
won't write new data to old tree blocks (even several trans ago).

Thanks,
Qu