Here you go, all patched super block attached.

Thanks,
Qu

On 2018年04月08日 10:14, Ben Parsons wrote:
> Super block of sdb as requested
> 
> Thanks,
> Ben
> 
> On 8 April 2018 at 11:53, Qu Wenruo <quwenruo.bt...@gmx.com> wrote:
>>
>>
>> On 2018年04月08日 08:57, Ben Parsons wrote:
>>> See attached for requested output.
>>>
>>> Do I still need to recover the super block of sdb?
>>
>> Yep. Please also attach the binary dump of superblock of sdb.
>>
>>>
>>> Could you please point me the right direction for doing the inplace 
>>> recovery?
>>
>> I'll provide the patched superblock for both disks (sdb and sdc1)
>>
>> And with them written back to disk, just run "btrfs check" first, if
>> nothing wrong, mount it RW and run scrub.
>>
>> Pretty straightforward.
>>
>> Thanks,
>> Qu
>>>
>>> I have not rebooterd or tried to recover / mount the disc btw.
>>>
>>> Thanks,
>>> Ben
>>>
>>> On 8 April 2018 at 10:02, Qu Wenruo <quwenruo.bt...@gmx.com> wrote:
>>>>
>>>>
>>>> On 2018年04月08日 07:29, Ben Parsons wrote:
>>>>> On 7 April 2018 at 22:09, Qu Wenruo <quwenruo.bt...@gmx.com> wrote:
>>>>>>
>>>>>>
>>>>>> On 2018年04月07日 10:31, Ben Parsons wrote:
>>>>>> [snip]
>>>>>>>> Pretty common hard power reset.
>>>>>>>>
>>>>>>>>> looking at journalctl, there is a large stacktrace from kernel: amdgpu
>>>>>>>>> (see attached).
>>>>>>>>> then when I booted back up the pool (2 disks, 1TB + 2TB) wouldn't 
>>>>>>>>> mount.
>>>>>>>>
>>>>>>>> I'd say such corruption is pretty serious.
>>>>>>>>
>>>>>>>> And what's the profile of the btrfs? If metadata is raid1, we could at
>>>>>>>> least try to recovery the superblock from the remaining disk.
>>>>>>>
>>>>>>> I am not sure what the metadata was but the two disks had no parity
>>>>>>> and just appeared as a single disk with total space of the two disks
>>>>>>
>>>>>> Strangely, for the 2nd disk, it's sdc1, which means it has partition 
>>>>>> table.
>>>>>> While for the 1st disk, it's sda, without partition table at all.
>>>>>> Is there any possibility that you just took run partition?
>>>>>> (Or did some program uses it incorrectly?)
>>>>>>
>>>>>
>>>>> I dont quite understand what you are asking.
>>>>> I was always under the impression I could run mount on either
>>>>> partition and it would mount the pool
>>>>>
>>>>>>>
>>>>>>> how would i got about recovering the 2nd disk? attached is
>>>>>>
>>>>>> The 2nd disk looks good, however it's csum_type is wrong.
>>>>>> 41700 looks like garbage.
>>>>>>
>>>>>> Despite that, incompact_flags also has garbage.
>>>>>>
>>>>>> The good news is, the system (and metadata) profile is RAID1, so it's
>>>>>> highly possible for us to salvage (to be more accurate, rebuild) the
>>>>>> superblock for the 1st device.
>>>>>>
>>>>>> Please dump the superblock of the 2nd device (sdc1) by the following
>>>>>> command:
>>>>>>
>>>>>> # dd if=/dev/sdc1 of=super_dump.sdc1 bs=1 count=4096 skip=64k
>>>>>>
>>>>>
>>>>> See attached.
>>>>>
>>>>>>
>>>>>> Unfortunately, btrfs-sb-mod tool added recently doesn't have all needed
>>>>>> fields, so I'm afraid I need to manually modify it.
>>>>>>
>>>>>> And just in case, please paste the following output to help us verify if
>>>>>> it's really sda without offset:
>>>>>>
>>>>>> # lsblk /dev/sda
>>>>>> # grep -obUaP "\x5F\x42\x48\x52\x66\x53\x5F\x4D"
>>>>>>
>>>>>
>>>>> dd if=/dev/sdb of=toGrep.sdb bs=1 count=128M status=progress
>>>>> cat toGrep.sdb | grep -obUaP "\x5F\x42\x48\x52\x66\x53\x5F\x4D"
>>>>>
>>>>> 65600:_BHRfS_M
>>>>> 67108928:_BHRfS_M
>>>>
>>>> Well, the magic number is completely correct, and at correct location.
>>>>
>>>> Would you please run "btrfs inspect dump-super -fFa /dev/sdb" again?
>>>> This time it should provide good data.
>>>>
>>>>>
>>>>>>
>>>>>> Above grep could be very slow since it will try to iterate the whole
>>>>>> disk. It's recommended to dump the first 128M of the disk and then grep
>>>>>> on that 128M image.
>>>>>>
>>>>>>
>>>>>> BTW, with superblock of sdc1 patched, you should be able to mount the fs
>>>>>> with -o ro,degraded, and salvage some data.
>>>>>>
>>>>>> Thanks,
>>>>>> Qu
>>>>>
>>>>> Thank you so much!
>>>>>
>>>>> I am better off copying the data to another disk and then rebuilding the 
>>>>> pool?
>>>>> or can I just run a scrub after the super block is fixed?
>>>>
>>>> According to your latest grep output, strangely the 1st device is not
>>>> that corrupted as before.
>>>>
>>>> So I think in-place recover should save you a lot of time.
>>>>
>>>> Thanks,
>>>> Qu
>>>>
>>>>>
>>>>> For reference here is lsblk:
>>>>>
>>>>> sda      8:0    0 465.8G  0 disk
>>>>> ├─sda1   8:1    0   512M  0 part /boot
>>>>> ├─sda2   8:2    0 455.3G  0 part /
>>>>> └─sda3   8:3    0    10G  0 part [SWAP]
>>>>>
>>>>> sdb      8:16   0 931.5G  0 disk
>>>>> -- first disk
>>>>>
>>>>> sdc      8:32   0   1.8T  0 disk
>>>>> └─sdc1   8:33   0   1.8T  0 part
>>>>> -- 2nd disk
>>>>>

Attachment: super_dump.sdb
Description: Binary data

Attachment: super_dump.sdc1
Description: Binary data

Reply via email to