Re: Updated to new kernel, and btrfs suddenly refuses to mount home directory fs.

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

On 2022/3/9 03:05, bill gates wrote:
> So, I recently attempted to upgrade from Linux kernel 4.19.82 to
> 5.15.23, and I'm getting a critical error in dmesg about a corrupt
> leaf (and no mounting of /home allowed with the options I'm aware of)
>
> [ 396.218964] BTRFS critical (device sda2): corrupt leaf: root=1
> block=10442806968320 sl
> ot=8 ino=6, invalid location key objectid: has 1 expect 6 or [256,
> 18446744073709551360]
> or 18446744073709551604

Please provide the following output:

# btrfs ins dump-tree -b 10442806968320 /dev/sda2


The error message means, we got a DIR_ITEM in root tree.

Normally that is used to indicate what default subvolume is.
Thus it's normally 6 or 5, or any valid subvolume id.

But in your case, it's 1, thus tree-checker is rejecting your root tree.

I didn't thought we could have 1 as default subvolume (as 1 is the root
tree, which is not a subvolume).

But it looks like we should update btrfs check to fix this case.

Is the fs created using older btrfs-progs? I guess that may be the cause...

Thanks,
Qu


> [ 396.218967] BTRFS error (device sda2): block=10442806968320 read
> time tree block corru
> ption detected
>
>
> Interestingly. that 18446... number is a power of 2, looks like maybe
> a bit flip? dmesg, uname, etc included in pastebin below. "btrfs
> check" found no problems with fs on either kernel version. Would like
> to figure out how to fix this, if possible.
>
> https://pastebin.com/0ESPU9Z6
>
> Thank you for any assistance,
> -- Laurence Michaels.