Re: [OE-core] [PATCH 0/1] wic: updated fstab does not preserve metadata of the original file

["Mathieu Dubois-Briand" <mathieu.dubois-briand@bootlin.com>]

Hi Daniel,

Sorry, but I'm not sure to get your point.

I ran the test locally, and it does fail. It also fails if I modify it
to use squashfs instead of ext4.

My reproduction procedure:
git clone https://git.yoctoproject.org/poky-ci-archive -b autobuilder.yoctoproject.org/valkyrie/a-full-2320
. oe-init-build-env
echo 'SANITY_TESTED_DISTROS = ""' >> conf/local.conf
oe-selftest -r wic.Wic.test_no_fstab_update

Thanks,
Mathieu

On Tue Sep 23, 2025 at 5:05 PM CEST, Daniel Andrade wrote:
> Good Afternoon,
>
> I have been trying to figure it out and something seems off.
> The specific test you refer to may be hiding a problem or maybe I have my
> testbench compromised and I would like your help to test.
> The test `test_no_fstab_update ` verifies if the fstab was updated or not
> because on the wks file used to do it there is a --no-fstab-update. The
> thing is, I think this test is passing because what is forcing it to not
> update is a constraint that I removed previously on the patch (the one that
> checks if the system is ext* or msdos) and not because the flag is
> triggering its intended functionality.
> The crosscheck I did was modifying the fstype from ext4 to squashfs and
> indeed the test failed.
> Can someone also verify this?
>
> Daniel
>
> Daniel Andrade <dani.barra25@gmail.com> escreveu (sábado, 13/09/2025 à(s)
> 11:02):
>
>> Hello guys, sorry for the delay.
>> I have been busy, but I hope to provide you with a fix in the next few
>> days.
>>
>> Sorry about that,
>> Daniel
>>
>> Randy MacLeod <randy.macleod@windriver.com> escreveu (quinta, 11/09/2025
>> à(s) 17:56):
>>
>>> On 2025-09-04 11:58 a.m., Mathieu Dubois-Briand via
>>> lists.openembedded.org wrote:
>>>
>>> On Tue Sep 2, 2025 at 9:05 PM CEST, dani.barra25 via lists.openembedded.org wrote:
>>>
>>> From: Daniel Andrade <dani.barra25@gmail.com> <dani.barra25@gmail.com>
>>>
>>> Using `install` in the rootfs plugin forces fstab to be replaced entirely, meaning that even its Inodes will change, leading xattrs and SELinux context stored by pseudo not to be applied.
>>> The fix just uses `cp` without preserving attributes from the temporary fstab since none of them are needed, just the content.
>>> Same thing happens with the predefined mechanisms for ext4 and msdos. Using debugfs there is no way to replace contents while maintaining metadata, so the approach taken on the path was to remove the different fstab logic for those fstypes and also use the same modified cp command. Reviewing the builds I did it seems to work for all of the fstypes.
>>>
>>> Another problem is that the timestamp applied to fstab is not the same as every other file. It seems like the `SOURCE_DATE_EPOCH` variable goes to the fallback timestamp (`SOURCE_DATE_EPOCH_FALLBACK`).
>>> Since you are using that variable everywhere, it is not the same value as ` REPRODUCIBLE_TIMESTAMP_ROOTFS` under `poky/meta/conf/bitbake.conf` that is applied in every other file.
>>>
>>> Daniel Andrade (1):
>>>   wic: Content of the temporary updated fstab should be copied into the
>>>     original not replacing it entirely.
>>>
>>>  meta/conf/bitbake.conf                   |  4 +++-
>>>  scripts/lib/wic/partition.py             | 15 +--------------
>>>  scripts/lib/wic/plugins/source/rootfs.py |  4 ++--
>>>  3 files changed, 6 insertions(+), 17 deletions(-)
>>>
>>> Hi Daniel,
>>>
>>> Thanks for your patch.
>>>
>>> It looks like it is breaking a test:
>>>
>>> 2025-09-04 15:28:11,112 - oe-selftest - INFO - wic.Wic.test_no_fstab_update (subunit.RemotedTestCase)
>>> 2025-09-04 15:28:11,113 - oe-selftest - INFO -  ... FAIL
>>> ...
>>> 2025-09-04 15:28:11,114 - oe-selftest - INFO - testtools.testresult.real._StringException: Traceback (most recent call last):
>>>   File "/srv/pokybuild/yocto-worker/oe-selftest-armhost/build/meta/lib/oeqa/selftest/cases/wic.py", line 859, in test_no_fstab_update
>>>     self.assertEqual(bf_fstab_md5sum, part_fstab_md5sum[1])
>>>   File "/usr/lib/python3.12/unittest/case.py", line 885, in assertEqual
>>>     assertion_func(first, second, msg=msg)
>>>   File "/usr/lib/python3.12/unittest/case.py", line 1251, in assertMultiLineEqual
>>>     self.fail(self._formatMessage(msg, standardMsg))
>>>   File "/usr/lib/python3.12/unittest/case.py", line 715, in fail
>>>     raise self.failureException(msg)
>>> AssertionError: 'af3c087d6c9131735c8d1f270a226892' != '9edb8255abd217fdb20e118833afb856'
>>> - af3c087d6c9131735c8d1f270a226892
>>> + 9edb8255abd217fdb20e118833afb856
>>> https://autobuilder.yoctoproject.org/valkyrie/#/builders/23/builds/2412https://autobuilder.yoctoproject.org/valkyrie/#/builders/35/builds/2268
>>>
>>> Can you fix it please?
>>>
>>> Ping?
>>>
>>> I think this is being tracked by:
>>>
>>> https://bugzilla.yoctoproject.org/show_bug.cgi?id=15947
>>>
>>> "WIC does not preserve metadata when updating fstab"
>>>
>>> Btw, we were just following the "Need Info" process during the bug review
>>> meeting
>>> so that's why I'm sending this email.
>>>
>>> ../Randy
>>>
>>> Thanks,
>>> Mathieu
>>>
>>>
>>>
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>>>
>>> --
>>> # Randy MacLeod
>>> # Wind River Linux
>>>
>>>




-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com