Re: BTRFS RAID filesystem unmountable

[Michael Wade <spikewade@gmail.com>]

Hi Qu,

Oh dear that is not good news!

I have been running the find root command since yesterday but it only
seems to be only be outputting the following message:

ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096
ERROR: tree block bytenr 0 is not aligned to sectorsize 4096

I tried with the latest btrfs tools compiled from source and the ones
I have installed with the same result. Is there a CLI utility I could
use to determine if the log contains any other content?

Kind regards
Michael


On 30 April 2018 at 04:02, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>
>
> On 2018年04月29日 22:08, Michael Wade wrote:
>> Hi Qu,
>>
>> Got this error message:
>>
>> ./btrfs inspect dump-tree -b 20800943685632 /dev/md127
>> btrfs-progs v4.16.1
>> bytenr mismatch, want=20800943685632, have=3118598835113619663
>> ERROR: cannot read chunk root
>> ERROR: unable to open /dev/md127
>>
>> I have attached the dumps for:
>>
>> dd if=/dev/md127 of=/tmp/chunk_root.copy1 bs=1 count=32K skip=266325721088
>> dd if=/dev/md127 of=/tmp/chunk_root.copy2 bs=1 count=32K skip=266359275520
>
> Unfortunately, both dumps are corrupted and contain mostly garbage.
> I think it's the underlying stack (mdraid) has something wrong or failed
> to recover its data.
>
> This means your last chance will be btrfs-find-root.
>
> Please try:
> # btrfs-find-root -o 3 <device>
>
> And provide all the output.
>
> But please keep in mind, chunk root is a critical tree, and so far it's
> already heavily damaged.
> Although I could still continue try to recover, there is pretty low
> chance now.
>
> Thanks,
> Qu
>>
>> Kind regards
>> Michael
>>
>>
>> On 29 April 2018 at 10:33, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>>>
>>>
>>> On 2018年04月29日 16:59, Michael Wade wrote:
>>>> Ok, will it be possible for me to install the new version of the tools
>>>> on my current kernel without overriding the existing install? Hesitant
>>>> to update kernel/btrfs as it might break the ReadyNAS interface /
>>>> future firmware upgrades.
>>>>
>>>> Perhaps I could grab this:
>>>> https://github.com/kdave/btrfs-progs/releases/tag/v4.16.1 and
>>>> hopefully build from source and then run the binaries directly?
>>>
>>> Of course, that's how most of us test btrfs-progs builds.
>>>
>>> Thanks,
>>> Qu
>>>
>>>>
>>>> Kind regards
>>>>
>>>> On 29 April 2018 at 09:33, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>>>>>
>>>>>
>>>>> On 2018年04月29日 16:11, Michael Wade wrote:
>>>>>> Thanks Qu,
>>>>>>
>>>>>> Please find attached the log file for the chunk recover command.
>>>>>
>>>>> Strangely, btrfs chunk recovery found no extra chunk beyond current
>>>>> system chunk range.
>>>>>
>>>>> Which means, it's chunk tree corrupted.
>>>>>
>>>>> Please dump the chunk tree with latest btrfs-progs (which provides the
>>>>> new --follow option).
>>>>>
>>>>> # btrfs inspect dump-tree -b 20800943685632 <device>
>>>>>
>>>>> If it doesn't work, please provide the following binary dump:
>>>>>
>>>>> # dd if=<dev> of=/tmp/chunk_root.copy1 bs=1 count=32K skip=266325721088
>>>>> # dd if=<dev> of=/tmp/chunk_root.copy2 bs=1 count=32K skip=266359275520
>>>>> (And will need to repeat similar dump for several times according to
>>>>> above dump)
>>>>>
>>>>> Thanks,
>>>>> Qu
>>>>>
>>>>>
>>>>>>
>>>>>> Kind regards
>>>>>> Michael
>>>>>>
>>>>>> On 28 April 2018 at 12:38, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>>>>>>>
>>>>>>>
>>>>>>> On 2018年04月28日 17:37, Michael Wade wrote:
>>>>>>>> Hi Qu,
>>>>>>>>
>>>>>>>> Thanks for your reply. I will investigate upgrading the kernel,
>>>>>>>> however I worry that future ReadyNAS firmware upgrades would fail on a
>>>>>>>> newer kernel version (I don't have much linux experience so maybe my
>>>>>>>> concerns are unfounded!?).
>>>>>>>>
>>>>>>>> I have attached the output of the dump super command.
>>>>>>>>
>>>>>>>> I did actually run chunk recover before, without the verbose option,
>>>>>>>> it took around 24 hours to finish but did not resolve my issue. Happy
>>>>>>>> to start that again if you need its output.
>>>>>>>
>>>>>>> The system chunk only contains the following chunks:
>>>>>>> [0, 4194304]:           Initial temporary chunk, not used at all
>>>>>>> [20971520, 29360128]:   System chunk created by mkfs, should be full
>>>>>>>                         used up
>>>>>>> [20800943685632, 20800977240064]:
>>>>>>>                         The newly created large system chunk.
>>>>>>>
>>>>>>> The chunk root is still in 2nd chunk thus valid, but some of its leaf is
>>>>>>> out of the range.
>>>>>>>
>>>>>>> If you can't wait 24h for chunk recovery to run, my advice would be move
>>>>>>> the disk to some other computer, and use latest btrfs-progs to execute
>>>>>>> the following command:
>>>>>>>
>>>>>>> # btrfs inpsect dump-tree -b 20800943685632 --follow
>>>>>>>
>>>>>>> If we're lucky enough, we may read out the tree leaf containing the new
>>>>>>> system chunk and save a day.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Qu
>>>>>>>
>>>>>>>>
>>>>>>>> Thanks so much for your help.
>>>>>>>>
>>>>>>>> Kind regards
>>>>>>>> Michael
>>>>>>>>
>>>>>>>> On 28 April 2018 at 09:45, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 2018年04月28日 16:30, Michael Wade wrote:
>>>>>>>>>> Hi all,
>>>>>>>>>>
>>>>>>>>>> I was hoping that someone would be able to help me resolve the issues
>>>>>>>>>> I am having with my ReadyNAS BTRFS volume. Basically my trouble
>>>>>>>>>> started after a power cut, subsequently the volume would not mount.
>>>>>>>>>> Here are the details of my setup as it is at the moment:
>>>>>>>>>>
>>>>>>>>>> uname -a
>>>>>>>>>> Linux QAI 4.4.116.alpine.1 #1 SMP Mon Feb 19 21:58:38 PST 2018 armv7l GNU/Linux
>>>>>>>>>
>>>>>>>>> The kernel is pretty old for btrfs.
>>>>>>>>> Strongly recommended to upgrade.
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> btrfs --version
>>>>>>>>>> btrfs-progs v4.12
>>>>>>>>>
>>>>>>>>> So is the user tools.
>>>>>>>>>
>>>>>>>>> Although I think it won't be a big problem, as needed tool should be there.
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> btrfs fi show
>>>>>>>>>> Label: '11baed92:data'  uuid: 20628cda-d98f-4f85-955c-932a367f8821
>>>>>>>>>> Total devices 1 FS bytes used 5.12TiB
>>>>>>>>>> devid    1 size 7.27TiB used 6.24TiB path /dev/md127
>>>>>>>>>
>>>>>>>>> So, it's btrfs on mdraid.
>>>>>>>>> It would normally make things harder to debug, so I could only provide
>>>>>>>>> advice from the respect of btrfs.
>>>>>>>>> For mdraid part, I can't ensure anything.
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Here are the relevant dmesg logs for the current state of the device:
>>>>>>>>>>
>>>>>>>>>> [   19.119391] md: md127 stopped.
>>>>>>>>>> [   19.120841] md: bind<sdb3>
>>>>>>>>>> [   19.121120] md: bind<sdc3>
>>>>>>>>>> [   19.121380] md: bind<sda3>
>>>>>>>>>> [   19.125535] md/raid:md127: device sda3 operational as raid disk 0
>>>>>>>>>> [   19.125547] md/raid:md127: device sdc3 operational as raid disk 2
>>>>>>>>>> [   19.125554] md/raid:md127: device sdb3 operational as raid disk 1
>>>>>>>>>> [   19.126712] md/raid:md127: allocated 3240kB
>>>>>>>>>> [   19.126778] md/raid:md127: raid level 5 active with 3 out of 3
>>>>>>>>>> devices, algorithm 2
>>>>>>>>>> [   19.126784] RAID conf printout:
>>>>>>>>>> [   19.126789]  --- level:5 rd:3 wd:3
>>>>>>>>>> [   19.126794]  disk 0, o:1, dev:sda3
>>>>>>>>>> [   19.126799]  disk 1, o:1, dev:sdb3
>>>>>>>>>> [   19.126804]  disk 2, o:1, dev:sdc3
>>>>>>>>>> [   19.128118] md127: detected capacity change from 0 to 7991637573632
>>>>>>>>>> [   19.395112] Adding 523708k swap on /dev/md1.  Priority:-1 extents:1
>>>>>>>>>> across:523708k
>>>>>>>>>> [   19.434956] BTRFS: device label 11baed92:data devid 1 transid
>>>>>>>>>> 151800 /dev/md127
>>>>>>>>>> [   19.739276] BTRFS info (device md127): setting nodatasum
>>>>>>>>>> [   19.740440] BTRFS critical (device md127): unable to find logical
>>>>>>>>>> 3208757641216 len 4096
>>>>>>>>>> [   19.740450] BTRFS critical (device md127): unable to find logical
>>>>>>>>>> 3208757641216 len 4096
>>>>>>>>>> [   19.740498] BTRFS critical (device md127): unable to find logical
>>>>>>>>>> 3208757641216 len 4096
>>>>>>>>>> [   19.740512] BTRFS critical (device md127): unable to find logical
>>>>>>>>>> 3208757641216 len 4096
>>>>>>>>>> [   19.740552] BTRFS critical (device md127): unable to find logical
>>>>>>>>>> 3208757641216 len 4096
>>>>>>>>>> [   19.740560] BTRFS critical (device md127): unable to find logical
>>>>>>>>>> 3208757641216 len 4096
>>>>>>>>>> [   19.740576] BTRFS error (device md127): failed to read chunk root
>>>>>>>>>
>>>>>>>>> This shows it pretty clear, btrfs fails to read chunk root.
>>>>>>>>> And according your above "len 4096" it's pretty old fs, as it's still
>>>>>>>>> using 4K nodesize other than 16K nodesize.
>>>>>>>>>
>>>>>>>>> According to above output, it means your superblock by somehow lacks the
>>>>>>>>> needed system chunk mapping, which is used to initialize chunk mapping.
>>>>>>>>>
>>>>>>>>> Please provide the following command output:
>>>>>>>>>
>>>>>>>>> # btrfs inspect dump-super -fFa /dev/md127
>>>>>>>>>
>>>>>>>>> Also, please consider run the following command and dump all its output:
>>>>>>>>>
>>>>>>>>> # btrfs rescue chunk-recover -v /dev/md127.
>>>>>>>>>
>>>>>>>>> Please note that, above command can take a long time to finish, and if
>>>>>>>>> it works without problem, it may solve your problem.
>>>>>>>>> But if it doesn't work, the output could help me to manually craft a fix
>>>>>>>>> to your super block.
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Qu
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> [   19.783975] BTRFS error (device md127): open_ctree failed
>>>>>>>>>>
>>>>>>>>>> In an attempt to recover the volume myself I run a few BTRFS commands
>>>>>>>>>> mostly using advice from here:
>>>>>>>>>> https://lists.opensuse.org/opensuse/2017-02/msg00930.html. However
>>>>>>>>>> that actually seems to have made things worse as I can no longer mount
>>>>>>>>>> the file system, not even in readonly mode.
>>>>>>>>>>
>>>>>>>>>> So starting from the beginning here is a list of things I have done so
>>>>>>>>>> far (hopefully I remembered the order in which I ran them!)
>>>>>>>>>>
>>>>>>>>>> 1. Noticed that my backups to the NAS were not running (didn't get
>>>>>>>>>> notified that the volume had basically "died")
>>>>>>>>>> 2. ReadyNAS UI indicated that the volume was inactive.
>>>>>>>>>> 3. SSHed onto the box and found that the first drive was not marked as
>>>>>>>>>> operational (log showed I/O errors / UNKOWN (0x2003))  so I replaced
>>>>>>>>>> the disk and let the array resync.
>>>>>>>>>> 4. After resync the volume still was unaccessible so I looked at the
>>>>>>>>>> logs once more and saw something like the following which seemed to
>>>>>>>>>> indicate that the replay log had been corrupted when the power went
>>>>>>>>>> out:
>>>>>>>>>>
>>>>>>>>>> BTRFS critical (device md127): corrupt leaf, non-root leaf's nritems
>>>>>>>>>> is 0: block=232292352, root=7, slot=0
>>>>>>>>>> BTRFS critical (device md127): corrupt leaf, non-root leaf's nritems
>>>>>>>>>> is 0: block=232292352, root=7, slot=0
>>>>>>>>>> BTRFS: error (device md127) in btrfs_replay_log:2524: errno=-5 IO
>>>>>>>>>> failure (Failed to recover log tree)
>>>>>>>>>> BTRFS error (device md127): pending csums is 155648
>>>>>>>>>> BTRFS error (device md127): cleaner transaction attach returned -30
>>>>>>>>>> BTRFS critical (device md127): corrupt leaf, non-root leaf's nritems
>>>>>>>>>> is 0: block=232292352, root=7, slot=0
>>>>>>>>>>
>>>>>>>>>> 5. Then:
>>>>>>>>>>
>>>>>>>>>> btrfs rescue zero-log
>>>>>>>>>>
>>>>>>>>>> 6. Was then able to mount the volume in readonly mode.
>>>>>>>>>>
>>>>>>>>>> btrfs scrub start
>>>>>>>>>>
>>>>>>>>>> Which fixed some errors but not all:
>>>>>>>>>>
>>>>>>>>>> scrub status for 20628cda-d98f-4f85-955c-932a367f8821
>>>>>>>>>>
>>>>>>>>>> scrub started at Tue Apr 24 17:27:44 2018, running for 04:00:34
>>>>>>>>>> total bytes scrubbed: 224.26GiB with 6 errors
>>>>>>>>>> error details: csum=6
>>>>>>>>>> corrected errors: 0, uncorrectable errors: 6, unverified errors: 0
>>>>>>>>>>
>>>>>>>>>> scrub status for 20628cda-d98f-4f85-955c-932a367f8821
>>>>>>>>>> scrub started at Tue Apr 24 17:27:44 2018, running for 04:34:43
>>>>>>>>>> total bytes scrubbed: 224.26GiB with 6 errors
>>>>>>>>>> error details: csum=6
>>>>>>>>>> corrected errors: 0, uncorrectable errors: 6, unverified errors: 0
>>>>>>>>>>
>>>>>>>>>> 6. Seeing this hanging I rebooted the NAS
>>>>>>>>>> 7. Think this is when the volume would not mount at all.
>>>>>>>>>> 8. Seeing log entries like these:
>>>>>>>>>>
>>>>>>>>>> BTRFS warning (device md127): checksum error at logical 20800943685632
>>>>>>>>>> on dev /dev/md127, sector 520167424: metadata node (level 1) in tree 3
>>>>>>>>>>
>>>>>>>>>> I ran
>>>>>>>>>>
>>>>>>>>>> btrfs check --fix-crc
>>>>>>>>>>
>>>>>>>>>> And that brings us to where I am now: Some seemly corrupted BTRFS
>>>>>>>>>> metadata and unable to mount the drive even with the recovery option.
>>>>>>>>>>
>>>>>>>>>> Any help you can give is much appreciated!
>>>>>>>>>>
>>>>>>>>>> Kind regards
>>>>>>>>>> Michael
>>>>>>>>>> --
>>>>>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>>>>>>>>>> the body of a message to majordomo@vger.kernel.org
>>>>>>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>>>>>>>
>>>>>>>>>
>>>>>>>
>>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>