Re: Upgraded from Buster to Bullseye, unmountable Btrfs filesystem

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2021/11/10 10:55, S. wrote:
> Hi Qu, thank you very much for your fast response!
>
> Regarding memtest, normally in Linux I have never been able to run it
> from inside an installed Linux system because it needs access to
> protected kernel memory, and instead it has to run from a live USB or
> from the memtest86 live testing image. But since this system is a
> proprietary NAS with uboot and no video interface I don't know how to
> run a memtest.

There is a user space tool, memtester, which pins down a large chunk of
memory, and do tests in user space.

It would not be able to test memory space used by kernel, but it would
be mostly enough for memory test use case.

>
>> To be extra safe, please provide the dump of your UUID tree:
>
> ------------------
> root@OpenMediaVault:~# btrfs ins dump-tree -t uuid /dev/sda3
> btrfs-progs v5.10.1
> uuid tree key (UUID_TREE ROOT_ITEM 0)
> leaf 170459136 items 4 free space 16151 generation 366 owner UUID_TREE
> leaf 170459136 flags 0x1(WRITTEN) backref revision 1
> fs uuid 4a057760-998c-4c66-aa6a-2a08c51d5299
> chunk uuid 54b2fa0f-9907-49d1-af33-e172581cd25e
>      item 0 key (1101835439474057344 EXTENT_ITEM 56168916570538915)
> itemoff 16275 itemsize 8

Yep, exactly the problem.

>      item 1 key (0x0f4a817e92c9a080 UUID_KEY_SUBVOL 0xc78d54ff9b03a3a8)
> itemoff 16267 itemsize 8
>          subvol_id 5
>      item 2 key (0x421cfa6924ef510d UUID_KEY_SUBVOL 0xc8423812cf31288b)
> itemoff 16259 itemsize 8
>          subvol_id 269
>      item 3 key (0x45a64f82bc9152f1 UUID_KEY_SUBVOL 0x3859efe8688d6ea4)
> itemoff 16251 itemsize 8
>          subvol_id 274

And you haven't yet recevied any subovlume, it would be way much easier
to rebuild the tree.

Thanks,
Qu
> total bytes 1990110658560
> bytes used 704343715840
> uuid 4a057760-998c-4c66-aa6a-2a08c51d5299
> ------------------