Re: Apparent metadata corruption (file that simultaneously does/does not exist) on kernel 3.17.3

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

Hi Daniel,

With your btrfs-image dump, I tested with my patchset sent to maillist, 
my patchset succeeds fixing the image.

You can get the patchset and then apply it on 3.17.2, and --repair 
should fix it.
The file with nlink error will be moved to 'lost+found' dir.

Although the best fixing should be just adding the missing dir_index,
but currently the patchset does quite well and does not need to do any 
modify.

The patchset can be extracted using patchwork:
0001: https://patchwork.kernel.org/patch/5364131/mbox/
0002: https://patchwork.kernel.org/patch/5364141/mbox/
0003: https://patchwork.kernel.org/patch/5364101/mbox/
0004 v2: https://patchwork.kernel.org/patch/5383611/mbox/
0005 v2: https://patchwork.kernel.org/patch/5383601/mbox/
0006: https://patchwork.kernel.org/patch/5364151/mbox

Any feedback is welcomed to improve the patches.

Thanks,
Qu


-------- Original Message --------
Subject: Re: Apparent metadata corruption (file that simultaneously 
does/does not exist) on kernel 3.17.3
From: Daniel Miranda <danielkza2@gmail.com>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Date: 2014年11月25日 15:42
> I just ran the repair but the ghost file has not disappeared, unfortunately.
>
> On Tue, Nov 25, 2014 at 5:26 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
>> -------- Original Message --------
>> Subject: Re: Apparent metadata corruption (file that simultaneously
>> does/does not exist) on kernel 3.17.3
>> From: Daniel Miranda <danielkza2@gmail.com>
>> To: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> Date: 2014年11月25日 15:20
>>> Here are the logs. I'll send you a link to my dump directly after I
>>> finish uploading it. Please notify me when you have downloaded it so I
>>> can delete it.
>>>
>>> checking extents
>>> checking free space cache
>>> checking fs roots
>>> root 5 inode 17149868 errors 2000, link count wrong
>>>       unresolved ref dir 17182377 index 245 namelen 8 name string.h
>>> filetype 1 errors 1, no dir item
>> link count error seems resolved by Josef's patch commit already in 3.17.2.
>> If using 3.17.2, josef's commit will rebuild the dir item and dir index.
>>> root 5 inode 17182377 errors 200, dir isize wrong
>> This isize error seems caused by previous line.
>> If 3.17.2 can repair above problem, it should not be a problem and will
>> disappear.
>>
>> According to the above output, btrfsck --repair with btrfs-progs 3.17.2 has
>> a good chance repairing it.
>> Just have a try.
>>
>> Thanks,
>> Qu
>>
>>> Checking filesystem on /dev/mapper/fedora_daniel--pc-root
>>> UUID: fef8f718-0622-4cb1-9597-749650d366a4
>>> found 55108022156 bytes used err is 1
>>> total csum bytes: 89787396
>>> total tree bytes: 2303455232
>>> total fs tree bytes: 2024841216
>>> total extent tree bytes: 145272832
>>> btree space waste bytes: 529672422
>>> file data blocks allocated: 253414481920
>>>    referenced 94127726592
>>> Btrfs v3.17
>>>
>>>
>>> Regards,
>>> Daniel
>>>
>>> On Tue, Nov 25, 2014 at 3:20 AM, Qu Wenruo <quwenruo@cn.fujitsu.com>
>>> wrote:
>>>> -------- Original Message --------
>>>> Subject: Re: Apparent metadata corruption (file that simultaneously
>>>> does/does not exist) on kernel 3.17.3
>>>> From: Daniel Miranda <danielkza2@gmail.com>
>>>> To: Qu Wenruo <quwenruo@cn.fujitsu.com>
>>>> Date: 2014年11月25日 13:14
>>>>> I'll go run that and get you the output.
>>>> Thanks.
>>>>>
>>>>> I can do the image dump, sure. I don't know how long it might take to
>>>>> upload it somewhere though. Right now `btrfs fi df` shows about 2GiB
>>>>> of metadata (it's a 120GiB volume). I'll see how large it ends up
>>>>> after compression.
>>>> 120G volume seems quite small, compared the images I received recently
>>>> (1T
>>>> x2 RAID1 and 4T single).
>>>> With '-c 9' it shouldn't be too huge I think(The 1T raid1 is about 1G
>>>> metadata with -c9).
>>>>
>>>> BTW, btrfs-image dump will have all the filenames and hierarchy, even
>>>> without its data,
>>>> it is still better considering your privacy twice before uploading.
>>>>
>>>> Thanks,
>>>> Qu
>>>>
>>>>> Thanks for the quick response,
>>>>> Daniel
>>>>>
>>>>> On Tue, Nov 25, 2014 at 3:10 AM, Qu Wenruo <quwenruo@cn.fujitsu.com>
>>>>> wrote:
>>>>>> Hi,
>>>>>>
>>>>>> What's the btrfsck output? Without --repair option.
>>>>>>
>>>>>> Also, if it is OK for you, would you please dump the btrfs with
>>>>>> 'btrfs-image' command?
>>>>>> '-c 9' option is highly recommended considering the size of it.
>>>>>> This will helps a lot for developers to test the btrfsck repair
>>>>>> function.
>>>>>>
>>>>>> Thanks,
>>>>>> Qu
>>>>>>
>>>>>>
>>>>>> -------- Original Message --------
>>>>>> Subject: Apparent metadata corruption (file that simultaneously
>>>>>> does/does
>>>>>> not exist) on kernel 3.17.3
>>>>>> From: Daniel Miranda <danielkza2@gmail.com>
>>>>>> To: <linux-btrfs@vger.kernel.org>
>>>>>> Date: 2014年11月25日 13:04
>>>>>>> Hello,
>>>>>>>
>>>>>>> After I had some brief stability issues with my computer, it seems
>>>>>>> some form of metadata corruption took place in my BTRFS filesystem,
>>>>>>> and now a particular file seems to exist, but I cannot access any
>>>>>>> details on it or delete it.
>>>>>>>
>>>>>>> If I try to `ls` in the directory it is in, that's what I get:
>>>>>>>
>>>>>>> ls: cannot access string.h: No such file or directory
>>>>>>> total 0
>>>>>>> drwxr-xr-x. 1 danielkza mock 16 Nov 21 14:18 ./
>>>>>>> drwxr-xr-x. 1 danielkza mock  6 Nov 21 14:18 ../
>>>>>>> -?????????? ? ?         ?     ?            ? string.h
>>>>>>>
>>>>>>> If I try to delete it I get:
>>>>>>>
>>>>>>> rm: cannot remove ‘string.h’: No such file or directory
>>>>>>>
>>>>>>> I'm using kernel 3.17.3 from Fedora 21. I got no messages on dmesg or
>>>>>>> anything of the sort. I know the btrfs fsck situation is complicated,
>>>>>>> but is there any utility I should use to try and repair this? Losing
>>>>>>> this file is not a problem, it's just one header from the kernel I was
>>>>>>> building.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Daniel Miranda
>>>>>>> --
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>>>>>>