Re: Drive won't mount, please help

J J
2020-09-24T22:36:26Z

Thanks for your help Qu.
So is the data lost? Should I follow the procedure to recover what I can to another disk?
Any other suggestions for next steps?

> On Sep 14, 2020, at 4:34 AM, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>
>
>
> On 2020/9/14 上午4:56, J J wrote:
>> I’m new to a lot of this, just trying to use a NAS at home, single usb external disk, not RAID. Was working great for a few months, I’m not sure what changed today when it stopped mounting. Any advice appreciated.
>
> Transid mismatch, and the expected transid is newer than the on-disk
> transid.
>
> This means, either btrfs has some bug that causes metadata writeback not
> following COW, or the disk controller/disk itself ignores Flush/FUA
> commands.
>
> Considering it's usb external disk, I doubt the later case.
>
> In that case, any fs would experience similar problem if a sudden power
> loss or cable loss happened.
>
> You may workaround such problem by disabling the writecache, but I doubt
> if the USB->Sata convert would follow the request.
>
> Thanks,
> Qu
>>
>> Dmesg log attached
>>
>>
>> uname -a
>> Linux rock64 4.4.190-1233-rockchip-ayufan-gd3f1be0ed310 #1 SMP Wed Aug 28 08:59:34 UTC 2019 aarch64 GNU/Linux
>>
>>
>>
>> btrfs --version
>> btrfs-progs v4.7.3
>>
>>
>>
>> btrfs fi show
>> Label: '3TBRock64' uuid: 71eda2e3-384c-4868-b5d4-683f222865e6
>> Total devices 1 FS bytes used 2.48TiB
>> devid 1 size 2.73TiB used 2.59TiB path /dev/mapper/sda-crypt
>>
>>
>> btrfs fi df /dev/mapper/sda-crypt
>> ERROR: not a btrfs filesystem: /dev/mapper/sda-crypt
>>
>>
>> btrfs inspect-internal dump-super /dev/mapper/sda-crypt
>> superblock: bytenr=65536, device=/dev/mapper/sda-crypt
>> ---------------------------------------------------------
>> csum_type 0 (crc32c)
>> csum_size 4
>> csum 0x9e8b0c33 [match]
>> bytenr 65536
>> flags 0x1
>> ( WRITTEN )
>> magic _BHRfS_M [match]
>> fsid 71eda2e3-384c-4868-b5d4-683f222865e6
>> label 3TBRock64
>> generation 395886
>> root 2638934654976
>> sys_array_size 129
>> chunk_root_generation 377485
>> root_level 1
>> chunk_root 20971520
>> chunk_root_level 1
>> log_root 2638952366080
>> log_root_transid 0
>> log_root_level 0
>> total_bytes 3000556847104
>> bytes_used 2729422221312
>> sectorsize 4096
>> nodesize 16384
>> leafsize 16384
>> stripesize 4096
>> root_dir 6
>> num_devices 1
>> compat_flags 0x0
>> compat_ro_flags 0x0
>> incompat_flags 0x161
>> ( MIXED_BACKREF |
>> BIG_METADATA |
>> EXTENDED_IREF |
>> SKINNY_METADATA )
>> cache_generation 395886
>> uuid_tree_generation 395886
>> dev_item.uuid b7f4386a-18e0-437b-9588-6064ff483fd5
>> dev_item.fsid 71eda2e3-384c-4868-b5d4-683f222865e6 [match]
>> dev_item.type 0
>> dev_item.total_bytes 3000556847104
>> dev_item.bytes_used 2843293515776
>> dev_item.io_align 4096
>> dev_item.io_width 4096
>> dev_item.sector_size 4096
>> dev_item.devid 1
>> dev_item.dev_group 0
>> dev_item.seek_speed 0
>> dev_item.bandwidth 0
>>
>>
>> dev_item.generation 0
>>
>