Re: BTRFS-errors on a 20TB filesystem

Paul-Erik Törrönen
2020-07-06T11:33:35Z

Aand I messed up by sending this to the person only. Sorry for that.

On 2020-07-06 13:55, Qu Wenruo wrote:
> Some older extents are affected by older kernel not handling extents
> length correctly.
>
> 18446744073709481984 = -69632, which means there is some underflow.
>
> Recent upstream kernel caught it and reject the whole tree block to
> prevent furhter problem.

Ok, so if I understand this correctly, the issue is essentially created
by using a new (5.x) kernel, whereas the server was running 3.10 (CentOS
7.8 version with btrfs-support) -> CentOS 8.2.

> Would you please provide the dump for this bytenr?
> I'm a little interested in this.

I'll provide you the dumps you requested in the evening. Should I email
them to the list, or directly to you?

> Thanks for your detailed report, this would help us to enhance
> btrfs-progs to fix them.

Glad to be of help.

> For now, you can just mount them with older kernel, find the offending
> inode using the ino number in the dmesg, and delete the offending file.
> With all offending inodes deleted, the fs would come back to normal
> status.

Ah, well. As mentioned in the previous email, I reinstalled the server
with CentOS8. Unfortunately RHEL/CentOS8 dropped support for btrfs (as
well as megaraid_sas), so I will be running this machine on the UEK
kernel for the forseeable future and planning on replacing/recreating
the FS on the partition.

Poltsi