I had a btrfs raid1 running on raspbian (linux 4.19 arm) which overheated. To fix corruptions I attached the raid1 on my workstation (linux 5.5 x86_64) and performed scrub, defrag and --full-balance (not necessarily in this order) and fixed the corruptions.

Back on raspbian a mount fails:

root@omv:~# mount /dev/disk/by-label/URAID /mnt/URAID/
mount: /mnt/URAID: wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error.

dmesg-4.19 attached.


root@omv:~# uname -a
Linux omv 4.19.97-v7l+ #1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l GNU/Linux
root@omv:~# btrfs --version
btrfs-progs v4.20.1 
root@omv:~# btrfs fi show
Label: 'URAID'  uuid: 489b8eca-1357-48ea-a9e2-050d3d78d383
	Total devices 2 FS bytes used 1.69TiB
	devid    7 size 3.64TiB used 2.45TiB path /dev/sda1
	devid    8 size 3.64TiB used 2.45TiB path /dev/sdb1


I cannot provide btrfs fi df /mnt from raspbian since the mount fails.

On my workstation I can mount the raid1 without problems.

On Arch Linux mailing list [1] Chris Murphy gained some more information and tried to help me with no success. Did I hit some known btrfs bug and should go to raspbian mailing list, or is this something new?

[1] https://lists.archlinux.org/pipermail/arch-general/2020-February/047463.html