Re: [PATCH 0/3] btrfs-progs: Add check and repair for invalid inode generation

Ferry Toth
2019-10-19T16:25:11Z

Hi,

Op 19-10-2019 om 01:50 schreef Qu WenRuo:
>
>
> On 2019/10/19 上午4:32, Ferry Toth wrote:
>> Op 24-09-2019 om 10:11 schreef Qu Wenruo:
>>> We have at least two user reports about bad inode generation makes
>>> kernel reject the fs.
>>
>> May I add my report? I just upgraded Ubuntu from 19.04 -> 19.10 so
>> kernel went from 5.0 -> 5.3 (but I was using 4.15 too).
>>
>> Booting 5.3 leaves me in initramfs as I have /boot on @boot and / on /@
>>
>> In initramfs I can try to mount but get something like
>> btrfs critical corrupt leaf invalid inode generation open_ctree failed
>>
>> Booting old kernel works just as before, no errors.
>>
>>> According to the creation time, the inode is created by some 2014
>>> kernel.
>>
>> How do I get the creation time?
>
> # btrfs ins dump-tree -b <the bytenr reported by kernel> <your device>

I just went back to the office to reboot to 5.3 and check the creation
times and found they were 2013 - 2014.

>>
>>> And the generation member of INODE_ITEM is not updated (unlike the
>>> transid member) so the error persists until latest tree-checker detects.
>>>
>>> Even the situation can be fixed by reverting back to older kernel and
>>> copying the offending dir/file to another inode and delete the offending
>>> one, it still should be done by btrfs-progs.
>>>
>> How to find the offending dir/file from the command line manually?
>
> # find <mount point> -inum <inode number>

This works, thanks.

But appears unpractical. After fix 2 files and reboot, I found 4 more,
then 16, then I gave up.

> Thanks,
> Qu
>
>>
>>> This patchset adds such check and repair ability to btrfs-check, with a
>>> simple test image.
>>>
>>> Qu Wenruo (3):
>>>    btrfs-progs: check/lowmem: Add check and repair for invalid inode
>>>      generation
>>>    btrfs-progs: check/original: Add check and repair for invalid inode
>>>      generation
>>>    btrfs-progs: fsck-tests: Add test image for invalid inode generation
>>>      repair
>>>
>>>   check/main.c                                  |  50 +++++++++++-
>>>   check/mode-lowmem.c                           |  76 ++++++++++++++++++
>>>   check/mode-original.h                         |   1 +
>>>   .../.lowmem_repairable                        |   0
>>>   .../bad_inode_geneartion.img.xz               | Bin 0 -> 2012 bytes
>>>   5 files changed, 126 insertions(+), 1 deletion(-)
>>>   create mode 100644
>>> tests/fsck-tests/043-bad-inode-generation/.lowmem_repairable
>>>   create mode 100644
>>> tests/fsck-tests/043-bad-inode-generation/bad_inode_geneartion.img.xz
>>>
>>

I checked out and built v5.3-rc1 of btrfs-progs. Then ran it on my
mounted rootfs with linux 5.0 and captured the log (~1800 lines 209
errors).

I'm not sure if using the v5.0 kernel and/or checking mounted distorts
the results? Else I'm going to need a live usb with a v5.3 kernel and
v5.3 btrfs-progs.

If you like I can share the log. Let me know.

This issue can potentially cause a lot of grief. Our company server runs
Ubuntu LTS (18.04.02) with a 4.15 kernel on a btrfs boot/rootfs with
~100 snapshots. I guess the problematic inodes need to be fixed on each
snapshot prior to upgrading to 20.04 LTS (which might be on kernel ~5.6)?

Do I understand correctly that this FTB is caused by more strict
checking of the fs by the kernel, while the tools to fix the detected
corruptions are not yet released?