Re: Drive won't mount, please help

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

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On 2020/9/25 上午6:28, J J wrote:
> 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?

btrfs-restore is the normally the tool you need to salvage your data.

Thanks,
Qu
> 
>> 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
>>>
>>
> 


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