Re: 12 TB btrfs file system on virtual machine broke again

[Andrei Borzenkov <arvidjaar@gmail.com>]

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06.01.2020 02:50, Qu Wenruo пишет:
> 
> 
> On 2020/1/5 下午10:17, Christian Wimmer wrote:
>> Hi Qu,
>>
>>
>>> On 5. Jan 2020, at 01:25, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>>>
>>>
>>>
>>> On 2020/1/5 上午1:07, Christian Wimmer wrote:
>>>> Hi guys, 
>>>>
>>>> I run again in a problem with my btrfs files system.
>>>> I start wondering if this filesystem type is right for my needs.
>>>> Could you please help me in recovering my 12TB partition?
>>>>
>>>> What happened? 
>>>> -> This time I was just rebooting normally my virtual machine. I discovered during the past days that the system hangs for some seconds so I thought it would be a good idea to reboot my SUSE Linux after 14 days of working. The machine powered off normally but when starting it run into messages like the pasted ones.
>>>>
>>>> I immediately powered off again and started my Arch Linux where I have btrfs-progs version 5.4 installed.
>>>> I tried one of the commands that you gave me in the past (restore) and I got following messages:
>>>>
>>>>
>>>> btrfs-progs-5.4]# ./btrfs restore -l /dev/sdb1
>>>> checksum verify failed on 3181912915968 found 000000A9 wanted 00000064
>>>> checksum verify failed on 3181912915968 found 00000071 wanted 00000066
>>>> checksum verify failed on 3181912915968 found 000000A9 wanted 00000064
>>>> bad tree block 3181912915968, bytenr mismatch, want=3181912915968, have=4908658797358025935
>>>
>>> All these tree blocks are garbage. This doesn't look good at all.
>>>
>>> The weird found csum pattern make no sense at all.
>>>
>>> Are you using fstrim or discard mount option? If so, there could be some
>>> old bug causing the problem.
>>
>>
>> Seems that I am using fstrim (I did not know this, what is it?):
>>
>> BTW, sda2 is here my root partition which is practically the same configuration (just smaller) than the 12TB hard disc
>>
>> 2020-01-03T11:30:47.479028-03:00 linux-ze6w kernel: [1297857.324177] sda2: rw=2051, want=532656128, limit=419430400
>> 2020-01-03T11:30:47.479538-03:00 linux-ze6w kernel: [1297857.324658] BTRFS warning (device sda2): failed to trim 1 device(s), last error -5
>> 2020-01-03T11:30:48.376543-03:00 linux-ze6w fstrim[27910]: fstrim: /opt: FITRIM ioctl failed: Input/output error
> 
> That's the cause. The older kernel had a bug where btrfs can trim
> unrelated data, causing data loss.
> 
> And I'm afraid that bug trimmed some of your tree blocks, screwing up
> the whole fs.
> 
> 
>> 2020-01-03T11:30:48.378998-03:00 linux-ze6w kernel: [1297858.223675] attempt to access beyond end of device
>> 2020-01-03T11:30:48.379012-03:00 linux-ze6w kernel: [1297858.223677] sda2: rw=3, want=421570540, limit=419430400
>> 2020-01-03T11:30:48.379013-03:00 linux-ze6w kernel: [1297858.223678] attempt to access beyond end of device
>> 2020-01-03T11:30:48.379013-03:00 linux-ze6w kernel: [1297858.223678] sda2: rw=3, want=429959147, limit=419430400
>> 2020-01-03T11:30:48.379014-03:00 linux-ze6w kernel: [1297858.223679] attempt to access beyond end of device
>> 2020-01-03T11:30:48.379014-03:00 linux-ze6w kernel: [1297858.223679] sda2: rw=3, want=438347754, limit=419430400
>> 2020-01-03T11:30:48.379014-03:00 linux-ze6w kernel: [1297858.223680] attempt to access beyond end of device
>>
>> Could this be the problem?
>>
>>
>> Suse Kernel version is 4.12.14-lp151.28.13-default #1 SMP
> I can't find any source tag matching your version. 

This is commit 3e458e04fab3ee8b0d234acf09db1d9279f356d9 of kernel-source.

> So I can't be 100%
> sure about the bug, but that error message still shows the same symptom.
> 
> I recommend to check updates about your distro.
> 
> Thanks,
> Qu
> 



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