Re: All Three Superblocks Damaged After Kernel Panic

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

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On 2021/10/12 18:35, K Chapman wrote:
> Qu,
>
> RE: If you don't have the tool to do it by your own, please send the 4K
> super block (dd if=/dev/mapper/home bs=1 skip=65536 count=4096
> of=/tmp/sb.dump) to me so I could do that for you.
>
> See attached.

Re-csumed super block is attached.

It passes my local test using btrfs-ins-dump-super.
Thus the csum should be correct.

Wish you good luck salvaging your data.

I would try mount with "-o ro,rescue=all" first, if no luck then
btrfs-restore --dry-run to see what can be salvaged.

But I doubt how many can be salvaged, consider how corrupted the backup
super blocks are.

Thanks,
Qu

>
> RE: Power loss and data writes.
>
> I believe the possibility is present but remote. I have not had a panic
> on x86 in many years during general work, this is more of an indication
> of some sort of problem than simply removing power at a bad time. It
> seems more likely, that for whatever reason, the kernel wrote spurious
> data to certain sectors, it will be interesting to see.
>
> Thank you!
>
> Kyle C.

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