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

[Ferry Toth <fntoth@gmail.com>]

Op 20-10-2019 om 15:15 schreef Qu WenRuo:
> 
> 
> On 2019/10/20 下午9:04, Ferry Toth wrote:
>> Op 20-10-2019 om 02:51 schreef Qu Wenruo:
>>>
>>>
>>> On 2019/10/20 上午8:26, Qu Wenruo wrote:
>>>>
>>>>
>>>> On 2019/10/20 上午12:24, Ferry Toth wrote:
>>>>> 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.
>>>
>>> Another solution is use "find" to locate the files with creation time
>>> before 2015, and copy them to a new file, then replace the old file with
>>> the new file.
>>
>> Hmm. But how do I "find" by creation time (otime)? Do you have a
>> suggestion for this?
> 
> $ touch -t 201501010000 /tmp/sample
> $ find <mnt> -not -cnewer /tmp/sample

AFAIK this compares file modified date with status changed date. So, no 
search for creation date.

And stat /tmp/sample (sorry dutch lang output):

ferry@ferry-quad:~$ stat /tmp/sample
   Bestand: /tmp/sample
   Grootte: 0            Blokken: 0            IO-blok: 4096   leeg 
normaal bestand
Apparaat: 1bh/27d   Inode: 62005381     Koppelingen: 1
Toegang: (0664/-rw-rw-r--)   UID: ( 1001/   ferry)   GID: ( 1001/   ferry)
Toegang:   2015-01-01 00:00:00.000000000 +0100
Gewijzigd: 2015-01-01 00:00:00.000000000 +0100
Veranderd: 2019-10-20 15:20:50.366163766 +0200
Ontstaan:  -


> If you want, you can add -exec to that find, but I'd only add that after
> confirming the execution load is verified.
> 
> Thanks,
> Qu
> 
>>
>>> It would be much safer than btrfs check --repair.
>>>
>>> Thanks,
>>> Qu
>>>
>>>
>>>>>
>>>>>> 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).
>>>>
>>>> It's really not recommended to run btrfs check, especially repair on the
>>>> mounted fs, unless it's RO.
>>>>
>>>> A new transaction from kernel can easily screw up the repaired fs.
>>>>>
>>>>> 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)?
>>>>
>>>> Yes.
>>>>
>>>>>
>>>>> 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?
>>>>
>>>> Yes.
>>>>
>>>> Thanks,
>>>> Qu
>>>>
>>>
>>