Re: Undelete files / directory

[Konstantinos Skarlatos <k.skarlatos@gmail.com>]

On 28/8/2014 8:04 μμ, Jean-Denis Girard wrote:
> Hi Chris,
>
> Thanks for your detailed answer.
>
> Le 28/08/2014 06:25, Chris Murphy a écrit :
>> 9. btrfs-find-root /dev/sdc
>> Super think's the tree root is at 29917184, chunk root 20987904
>> Well block 4194304 seems great, but generation doesn't match, have=2, want=9 level 0
>> Well block 4243456 seems great, but generation doesn't match, have=3, want=9 level 0
>> Well block 29376512 seems great, but generation doesn't match, have=4, want=9 level 0
>> Well block 29474816 seems great, but generation doesn't match, have=5, want=9 level 0
>> Well block 29556736 seems great, but generation doesn't match, have=6, want=9 level 0
>> Well block 29736960 seems great, but generation doesn't match, have=7, want=9 level 0
>> Well block 29900800 seems great, but generation doesn't match, have=8, want=9 level 0
Hi all,

I did a successful btrfs restore a few months ago, saving all of my 
deleted files except 2 (So i lost about 1GB on a 4TB filesystem)
Here is what i did (this is from memory and from my .zsh_history file, 
so i may be missing something)

btrfs-find-root  /dev/sdd -o 5 > b1.txt
I think the -o 5 option is quite important here.
After that, i ran this

for i in `awk '{print $3}' b1.txt`; do echo "------------------------  
$i --------------------" && btrfs restore /dev/sdd /storage/A3/ -Dv -f 
$i  ; done

I think i did that in order to brute force a correct offset

I also have done this, in order to find the offset that gave the largest 
number of files
for i in `awk '{print $3}' b1.txt`; do echo "------------------------  
$i --------------------" && btrfs restore /dev/sdd /storage/A3/ -Dv -f 
$i |wc -l ; done


Then i did some test restores using various addresses
btrfs restore /dev/sdd /storage/A3/B1/  -vD -f 2149617336320
btrfs restore /dev/sdd /storage/A3/B1/  -vD -f 1607682736128
btrfs restore /dev/sdd /storage/A3/B1/  -vD -f 2688721551360

and then i finally did the restore using the offset that looked best

btrfs restore /dev/sdd /storage/A3/B1/  -v -f 2688721551360

I hope this helps, good luck!


> Here is what the command returns :
>
> [root@x220 ~]# btrfs-find-root /dev/mapper/home
> Super think's the tree root is at 115230801920, chunk root 131072
> Went past the fs size, exiting[root@x220 ~]#
>
> I just tried with latest btrfs-progs (from git), it returns exactly the
> same.
>
> The btrfs partition is on top of dm-crypt, could it be a problem?
>
>
> Thanks,
> Jean-Denis Girard
>
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-- 
Konstantinos Skarlatos