Re: Can btrfs repair this ?

[Joe Salmeri <jmscdba@gmail.com>]

On 11/5/23 18:45, Qu Wenruo wrote:
>
>
> On 2023/11/6 07:08, Joe Salmeri wrote:
>> Hi,
>>
>> I was running openSUSE Tumbleweed build 20231001 when I first found this
>> issue but updated to TW build 20231031 the other day and it still
>> reports the same issue.
>>
>> Kernel 6.5.9-1 btrfsprogs 6.5.1-1.2 Device Samsung 860 EVO 500 GB
>> Partion #5 root btrfs filesystem, no RAID or other drives
>>
>> I run "btrfs device stats /" about once a week and no problems are
>> reported.
>>
>> I run "btrfs scrub start /"   regularly too and no problem are reported
>>
>> I ran "btrfs check --readonly --force /dev/sda5" the other day and got
>> the following errors:
>>
>>          Opening filesystem to check...
>>
>>          WARNING: filesystem mounted, continuing because of --force
>>          Checking filesystem on /dev/sda5
>>          UUID: 7591d83f-f78e-402b-afe5-fab23dad0ffe
>>          [1/7] checking root items
>>          [2/7] checking extents
>>          [3/7] checking free space cache
>>          [4/7] checking fs roots
>>          root 262 inode 31996735 errors 1, no inode item
>>                  unresolved ref dir 132030 index 769 namelen 36 name
>> 02179466-b671-4313-8fa5-0eb87d716f92 filetype 2 errors 5, no dir item,
>> no inode ref
>>                  unresolved ref dir 132030 index 769 namelen 36 name
>> 77ef9cd4-0efe-46af-bf7f-47f582851e16 filetype 2 errors 2, no dir index
>>          ERROR: errors found in fs roots
>>          found 33034690560 bytes used, error(s) found
>>          total csum bytes: 28819244
>>          total tree bytes: 986251264
>>          total fs tree bytes: 876134400
>>          total extent tree bytes: 62521344
>>          btree space waste bytes: 277302161
>>          file data blocks allocated: 141608800256
>>           referenced 39054090240
>>
>> Running "find -inum 31996735" identifies the item is is complaining
>> about as
>>
>>          /usr/bin/find: File system loop detected;
>> ‘./.snapshots/1/snapshot’ is part of the same file system loop as ‘.’.
>>          /usr/bin/find:
>> ‘./home/denise/.config/skypeforlinux/blob_storage/02179466-b671-4313-8fa5-0eb87d716f92’: 
>> No such file or directory
>>
>> Running "ls -al /home/denise/.config/skypeforlinux/blob_storage/" also
>> shows that this is correct item
>>
>>      drwx------ 1 denise joe-denise   72 Nov  1 22:49 .
>>      drwxr-xr-x 1 denise joe-denise 3.7K Nov  1 20:07 ..
>>      d????????? ? ?      ?             ?            ?
>> 02179466-b671-4313-8fa5-0eb87d716f92
>>
>> When I originally ran btrfs check there were actually a bunch of other
>> items listed, however, I have timeline snapshots turned on for the
>> /@home subvolume and all the other items were because of that item in
>> each of the other snapshots.
>>
>> I removed all the other "home" snapshots and now btrfs check only
>> reports that one item as shown above.
>>
>> I have heard that btrfs check --repair is generally not recommended but
>> I have been unable to find a way to have btrfs remove the item it is
>> complaining about.
>
> --repair can fix the problem.
>
> But for your particular problem, please also do a memtest just in case.
>
> This problem looks like a bad hash, which may be caused by memory 
> bitflip.
>
I ran the memtests last night multiple times and no problems reported.

I have heard that --repair usage is usually not recommended.

I cannot afford to have this system have to be rebuilt right now.

Is it definitely safe in this case ?   Otherwise, I would just ignore it 
since I know why it exists and that it is not a hw problem.

Since this is the root fs, I assume I have to boot a USB live 
environment and do the repair from there or can it be done on the 
mounted btrfs root fs with the --force option ?

>
>> I have tried rmdir, rm -rf, as well as find -inum 31996735 -delete and
>> all report the same issue with not found.
>>
>> If I understand correctly, the parent directory entry ( so
>> /home/denise/.config/skypeforlinux/blob_storage/ ) has the entry for
>> /home/denise/.config/skypeforlinux/blob_storage/02179466-b671-4313-8fa5-0eb87d716f92 
>> with inode of 31996735 but it doesn't really exist.
>>
>> I do not consider this a HW issue because btrfs stats, scrub, and smart
>> do not report any errors and I also track all the smart info ( health,
>> reallocated sector, wear leveling, etc ) for SSDs and there are no
>> errors reported and I am not having any other issues.
>>
>> I suspect that this occurred the other day when Skype crashed. The item
>> is not needed, I just cannot figure out how to remove it.
>>
>> So, is it possible for me to remove this item and if so how do I do it ?
>>
I find it interesting that interesting that I can remove a snapshot which contains the item using the normal delete snapshot functionality but that none of the built in tools have a way to do it.



-- 
Regards,

Joe