Re: btrfs pool failure - bad superblock

Re: btrfs pool failure - bad superblock

[Zak Lantz]

Hello,

I recently had a drive fail in my btrfs pool. I rebooted to pull the
bad drive. Upon boot, I can no longer mount the remaining drive's
partition. I have tried btrfs restore as well and both complain about
a bad superblock as well as the backup superblock.
If I try and run a super-recover, all supers display as being good.
Any help would be appreciated.

Thanks

root@stylophora:~# mount -o degraded,usebackuproot,ro /dev/sdc1
/mnt/user/btrfsbackup
mount: /mnt/user/btrfsbackup: wrong fs type, bad option, bad
superblock on /dev/sdc1, missing codepage or helper program, or other
error.
root@stylophora:~# btrfs restore -v -u 1 /dev/sdc1 /mnt/user/Backup/cachebck
warning, device 2 is missing
bad tree block 578836021248, bytenr mismatch, want=578836021248, have=0
ERROR: cannot read chunk root
Could not open root, trying backup super
warning, device 2 is missing
bad tree block 578836021248, bytenr mismatch, want=578836021248, have=0
ERROR: cannot read chunk root
Could not open root, trying backup super
root@stylophora:~# btrfs rescue super-recover -v /dev/sdc1
All Devices:
        Device: id = 3, name = /dev/sdc1

Before Recovering:
        [All good supers]:
                device name = /dev/sdc1
                superblock bytenr = 65536

                device name = /dev/sdc1
                superblock bytenr = 67108864

                device name = /dev/sdc1
                superblock bytenr = 274877906944

        [All bad supers]:

All supers are valid, no need to recover
root@stylophora:~# uname -a
  btrfs --version
Linux stylophora 4.19.98-Unraid #1 SMP Sun Feb 2 20:47:34 GMT 2020
x86_64 Intel(R) Xeon(R) CPU           X5680  @ 3.33GHz GenuineIntel
GNU/Linux
root@stylophora:~#   btrfs --version
btrfs-progs v5.4
root@stylophora:~#   btrfs fi show
Label: none  uuid: fe361bb0-4606-4eb0-a18f-f741b163c052
        Total devices 1 FS bytes used 376.00KiB
        devid    1 size 50.00GiB used 536.00MiB path /dev/loop2

Label: none  uuid: aea70e3c-11b6-43f9-b08d-c4c38dda2887
        Total devices 1 FS bytes used 332.00KiB
        devid    1 size 1.00GiB used 126.38MiB path /dev/loop3

warning, device 2 is missing
bad tree block 578836021248, bytenr mismatch, want=578836021248, have=0
ERROR: cannot read chunk root
Label: none  uuid: eccae6e7-e489-4019-9e4d-501445eff3d8
        Total devices 2 FS bytes used 507.73GiB
        devid    3 size 931.51GiB used 523.00GiB path /dev/sdc1
        *** Some devices missing


On Thu, Apr 9, 2020 at 10:16 AM Zak Lantz <zakodewald@gmail.com> wrote:
>
> Hello,
>
> I recently had a drive fail in my btrfs pool. I rebooted to pull the bad drive. Upon boot, I can no longer mount the remaining drive's partition. I have tried btrfs restore as well and both complain about a bad superblock as well as the backup superblock.
> If I try and run a super-recover, all supers display as being good.
> Any help would be appreciated.
>
> Thanks
>
> root@stylophora:~# mount -o degraded,usebackuproot,ro /dev/sdc1 /mnt/user/btrfsbackup
> mount: /mnt/user/btrfsbackup: wrong fs type, bad option, bad superblock on /dev/sdc1, missing codepage or helper program, or other error.
> root@stylophora:~# btrfs restore -v -u 1 /dev/sdc1 /mnt/user/Backup/cachebck
> warning, device 2 is missing
> bad tree block 578836021248, bytenr mismatch, want=578836021248, have=0
> ERROR: cannot read chunk root
> Could not open root, trying backup super
> warning, device 2 is missing
> bad tree block 578836021248, bytenr mismatch, want=578836021248, have=0
> ERROR: cannot read chunk root
> Could not open root, trying backup super
> root@stylophora:~# btrfs rescue super-recover -v /dev/sdc1
> All Devices:
>         Device: id = 3, name = /dev/sdc1
>
> Before Recovering:
>         [All good supers]:
>                 device name = /dev/sdc1
>                 superblock bytenr = 65536
>
>                 device name = /dev/sdc1
>                 superblock bytenr = 67108864
>
>                 device name = /dev/sdc1
>                 superblock bytenr = 274877906944
>
>         [All bad supers]:
>
> All supers are valid, no need to recover
> root@stylophora:~# uname -a
>   btrfs --version
> Linux stylophora 4.19.98-Unraid #1 SMP Sun Feb 2 20:47:34 GMT 2020 x86_64 Intel(R) Xeon(R) CPU           X5680  @ 3.33GHz GenuineIntel GNU/Linux
> root@stylophora:~#   btrfs --version
> btrfs-progs v5.4
> root@stylophora:~#   btrfs fi show
> Label: none  uuid: fe361bb0-4606-4eb0-a18f-f741b163c052
>         Total devices 1 FS bytes used 376.00KiB
>         devid    1 size 50.00GiB used 536.00MiB path /dev/loop2
>
> Label: none  uuid: aea70e3c-11b6-43f9-b08d-c4c38dda2887
>         Total devices 1 FS bytes used 332.00KiB
>         devid    1 size 1.00GiB used 126.38MiB path /dev/loop3
>
> warning, device 2 is missing
> bad tree block 578836021248, bytenr mismatch, want=578836021248, have=0
> ERROR: cannot read chunk root
> Label: none  uuid: eccae6e7-e489-4019-9e4d-501445eff3d8
>         Total devices 2 FS bytes used 507.73GiB
>         devid    3 size 931.51GiB used 523.00GiB path /dev/sdc1
>         *** Some devices missing