Re: [btrfs] commit bc27d6f0aa0e4de184b617aceeaf25818cc646de breaks update-grub

[Alex Romosan]

sorry about the html post (in case somebody actually got it). as i was
saying, just for the record it's still not fixed in 6.8-rc3. thanks.


On Sun, Feb 4, 2024 at 7:27 PM Alex Romosan <aromosan@xxxxxxxxx> wrote:
>
> just for the record it's still not fixed in 6.8-rc3 (obviously, since i've been looking at the btrfs patches being applied).
>
> On Thu, Feb 1, 2024 at 11:25 AM Linux regression tracking (Thorsten Leemhuis) <regressions@xxxxxxxxxxxxx> wrote:
>>
>> Hi, Thorsten here, the Linux kernel's regression tracker. Top-posting
>> for once, to make this easily accessible to everyone.
>>
>> Anand, what's the status wrt to below issue (which afaics seems to
>> affect quite a few people)? Things look stalled, but I might be missing
>> something, that's why I ask for a quick update.
>>
>> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
>> --
>> Everything you wanna know about Linux kernel regression tracking:
>> https://linux-regtracking.leemhuis.info/about/#tldr
>> If I did something stupid, please tell me, as explained on that page.
>>
>> #regzbot poke
>>
>> On 12.01.24 00:24, Anand Jain wrote:
>> > On 11/01/2024 22:36, David Sterba wrote:
>> >> On Thu, Jan 11, 2024 at 04:50:56PM +0100, David Sterba wrote:
>> >>> On Thu, Jan 11, 2024 at 12:45:50PM +0100, Thorsten Leemhuis wrote:
>> >>>>
>> >>>> On 08.01.24 15:11, Alex Romosan wrote:
>> >>>>>
>> >>>>> Running my own compiled kernel without initramfs on a lenovo thinkpad
>> >>>>> x1 carbon gen 7.
>> >>>>>
>> >>>>> Since version 6.7-rc1 i haven't been able to to a grub-update,
>> >>>>>
>> >>>>> instead i get this error:
>> >>>>>
>> >>>>> grub-probe: error: cannot find a device for / (is /dev mounted?) solid
>> >>>>> state drive
>> >>>>>
>> >>>>> 6.6 was the last version that worked.
>> >>>>>
>> >>>>> Today I did a git-bisect between these two versions which identified
>> >>>>> commit bc27d6f0aa0e4de184b617aceeaf25818cc646de btrfs: scan but don't
>> >>>>> register device on single device filesystem as the culprit. reverting
>> >>>>> this commit from 6.7 final allowed me to run update-grub again.
>> >>>>>
>> >>>>> not sure if this is the intended behavior or if i'm missing some other
>> >>>>> kernel options. any help/fixes would be appreciated.
>> >>>>
>> >>>> Thanks for the report. To be sure the issue doesn't fall through the
>> >>>> cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
>> >>>> tracking bot:
>> >>>>
>> >>>> #regzbot ^introduced bc27d6f0aa0e4de184b617aceeaf25818cc646de
>> >>>> #regzbot title btrfs: update-grub broken (cannot find a device for /
>> >>>> (is
>> >>>> /dev mounted?))
>> >>>> #regzbot ignore-activity
>> >>>
>> >>> The bug is also tracked at
>> >>> https://bugzilla.kernel.org/show_bug.cgi?id=218353 .
>> >>
>> >> About the fix: we can't simply revert the patch because the temp_fsid
>> >> depends on that. A workaround could be to check if the device path is
>> >> "/dev/root" and still register the device. But I'm not sure if this does
>> >> not break the use case that Steamdeck needs, as it's for the root
>> >> partition.
>> >
>> >
>> > Thank you for the report.
>> >
>> > The issue seems more complex than a simple scenario, as the following
>> > test-case works well:
>> >
>> >   $ mount /dev/sdb1 /btrfs
>> >   $ cat /proc/self/mountinfo | grep btrfs
>> > 345 63 0:34 / /btrfs rw,relatime shared:179 - btrfs /dev/sdb1
>> > rw,space_cache=v2,subvolid=5,subvol=/
>> >
>> > However, the relevant part of the commit
>> > bc27d6f0aa0e4de184b617aceeaf25818cc646de that may be failing could
>> > be in identifying a device, whether it is the same or different
>> > For this, we use:
>> >
>> >      lookup_bdev(path, &path_devt);
>> >
>> > and match with the devt(MAJ:MIN) saved in the btrfs_device;
>> > would this work during initrd? I need to dig more. Trying
>> > to figure out how can I reproduce this.
>> >
>> > Thanks, Anand
>> >
>> >