Re: Upgraded from Buster to Bullseye, unmountable Btrfs filesystem

["S." <sb56637@gmail.com>]

On 11/10/21 02:01, Qu Wenruo wrote:
> If you can revert to older kernel/distro, then you can mount the fs with
> "-o rescan_uuid" to regenerate the UUID tree using the old kernel.
> 
> Then it would rebuild the UUID tree, no need for a tool in user space.

Thanks very much for the explanation and for the suggestions.
Fortunately the system saved a copy of the old 4.19 kernel and initrd image. You are correct that the old kernel can still boot the filesystem without errors. Then I unmounted it and remounted it with `-o rescan_uuid_tree`. This also appeared to work, as it was able to mount. However, after rebooting into the new Bullseye kernel the filesystem is still unmountable:

------------------------
[  115.250774] BTRFS info (device sda3): flagging fs with big metadata feature
[  115.257773] BTRFS info (device sda3): disk space caching is enabled
[  115.264089] BTRFS info (device sda3): has skinny extents
[  115.414229] BTRFS critical (device sda3): corrupt leaf: root=9 block=170459136 slot=0, invalid key objectid, have 1101835439474057344 expect to be aligned to 4096
[  115.428780] BTRFS error (device sda3): block=170459136 read time tree block corruption detected
[  115.459643] BTRFS critical (device sda3): corrupt leaf: root=9 block=170459136 slot=0, invalid key objectid, have 1101835439474057344 expect to be aligned to 4096
[  115.474296] BTRFS error (device sda3): block=170459136 read time tree block corruption detected
[  115.483109] BTRFS warning (device sda3): failed to read root (objectid=9): -5
[  115.534748] BTRFS error (device sda3): open_ctree failed
------------------------

Any more ideas? Thanks again.