On 2021/10/25 16:46, Mia wrote:

Hello,
I need support since my root filesystem just went readonly :(

[641955.981560] BTRFS error (device sda3): tree block 342685007872 owner
7 already locked by pid=8099, extent tree corruption detected

This line explains itself.

Your extent tree is no corrupted, thus it allocated a new tree block
which is in fact already hold by other tree.

This means your metadata is no longer protected properly by COW.

"btrfs check" is highly recommended to expose the root cause.

root@rx1 ~ # btrfs fi show
Label: none  uuid: 21306973-6bf3-4877-9543-633d472dcb46
     Total devices 1 FS bytes used 189.12GiB
     devid    1 size 319.00GiB used 199.08GiB path /dev/sda3

root@rx1 ~ # btrfs fi df /
Data, single: total=194.89GiB, used=187.46GiB
System, single: total=32.00MiB, used=48.00KiB
Metadata, single: total=4.16GiB, used=1.65GiB
GlobalReserve, single: total=380.45MiB, used=0.00B

root@rx1 ~ # btrfs --version
                                                :(
btrfs-progs v4.20.1


root@rx1 ~ # uname -a
Linux rx1 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64
GNU/Linux

This is a little old for btrfs, but I don't think that's the cause.

Thanks,
Qu

Hope someone can help.
Regrads
Mia