Re: Drive won't mount, please help

Chris Murphy
2020-10-10T03:44:24Z

On Wed, Oct 7, 2020 at 2:31 PM J J <j333111@icloud.com> wrote:
>
> Thanks Chris. The results :
>
> btrfs insp dump-t -t 1 /dev/mapper/sda-crypt | grep -A1 'ROOT_REF'
> parent transid verify failed on 2639007596544 wanted 395882 found 395362
> parent transid verify failed on 2639007596544 wanted 395882 found 395362
> parent transid verify failed on 2639007596544 wanted 395882 found 395362
> parent transid verify failed on 2639007596544 wanted 395882 found 395362
> Ignoring transid failure
> leaf parent key incorrect 2639007596544
>
> I dont see an output like your example

OK we'll have to find a tree that isn't this broken. But what version
of btrfs-progs is this? I suggest something relatively recent 5.4 or
newer. 5.7 is current.

btrfs inspect-internal dump-super --full /dev/

That'll get some possible alternatives for root tree. And plug that
into 'dump-tree' as the value for -b.

btrfs insp dump-t -t 1 /dev/whatever | grep -A1 'ROOT_REF'

becomes

btrfs insp dump-t -t 1 -b <byteforbackuproot> /dev/whatever | grep -A1
'ROOT_REF'

There are some other ways to get info what's in subvolume's, using
dry-run or -d to get a basic listing and then infer from the output
what subvolume it is. Older subvolumes (smaller ID number) might be
more intact. But they will also not contain as much current data.

--
Chris Murphy