Re: [PATCH v5 0/9] ovl: Enable support for casefold layers

["André Almeida" <andrealmeid@igalia.com>]

Em 17/08/2025 12:03, Amir Goldstein escreveu:
> On Fri, Aug 15, 2025 at 3:50 PM Amir Goldstein <amir73il@gmail.com> wrote:
>>
>> On Fri, Aug 15, 2025 at 3:34 PM André Almeida <andrealmeid@igalia.com> wrote:
>>>
>>> Hi Amir,
>>>
>>> On 8/14/25 21:06, Amir Goldstein wrote:
>>>> On Thu, Aug 14, 2025 at 7:30 PM André Almeida <andrealmeid@igalia.com> wrote:
>>>>> Em 14/08/2025 14:22, André Almeida escreveu:
>>>>>> Hi all,
>>>>>>
>>>>>> We would like to support the usage of casefold layers with overlayfs to
>>>>>> be used with container tools. This use case requires a simple setup,
>>>>>> where every layer will have the same encoding setting (i.e. Unicode
>>>>>> version and flags), using one upper and one lower layer.
>>>>>>
>>>>> Amir,
>>>>>
>>>>> I tried to run your xfstest for casefolded ovl[1] but I can see that it
>>>>> still requires some work. I tried to fix some of the TODO's but I didn't
>>>>> managed to mkfs the base fs with casefold enabled...
>>>> When you write mkfs the base fs, I suspect that you are running
>>>> check -overlay or something.
>>>>
>>>> This is not how this test should be run.
>>>> It should run as a normal test on ext4 or any other fs  that supports casefold.
>>>>
>>>> When you run check -g casefold, the generic test generic/556 will
>>>> be run if the test fs supports casefold (e.g. ext4).
>>>>
>>>> The new added test belongs to the same group and should run
>>>> if you run check -g casefold if the test fs supports casefold (e.g. ext4).
>>>>
>>> I see, I used `check -overlay` indeed, thanks!
>>>
>>
>> Yeh that's a bit confusing I'll admit.
>> It's an overlayfs test that "does not run on overlayfs"
>> but requires extra overlayfs:
>>
>> _exclude_fs overlay
>> _require_extra_fs overlay
>>
>> Because it does the overlayfs mount itself.
>> That's the easiest way to test features (e.g. casefold) in basefs
>>
> 
> I tried to run the new test, which is able to mount an overlayfs
> with layers with disabled casefolding with kernel 6.17-rc1.
> 
> It does not even succeed in passing this simple test with
> your patches, so something is clearly off.

Apart from the other changes I had done for v6, I also had to change the 
test itself. The directories need to be empty to set the +F attribute, 
so I had to do this change:

--- a/tests/generic/999
+++ b/tests/generic/999
@@ -104,6 +104,9 @@ mount_overlay $lowerdir >>$seqres.full
  ls $merge/casefold/subdir |& _filter_scratch
  unmount_overlay

+# workdir needs to be empty to set casefold attribute
+rm -rf $workdir/*
+
  _casefold_set_attr $upperdir >>$seqres.full
  _casefold_set_attr $workdir >>$seqres.full

@@ -112,7 +115,10 @@ mount_overlay $lowerdir >>$seqres.full 2>&1 && \
         echo "Overlayfs mount with casefold enabled upperdir should 
have failed" && \
         unmount_overlay

+# lowerdir needs to be empty to set casefold attribute
+rm -rf $lowerdir/*
  _casefold_set_attr $lowerdir >>$seqres.full
+mkdir $casefolddir

  # Try to mount an overlay with casefold enabled layers.
  # On kernels older than v6.18 expect failure and skip the rest of the test

> 
>> You should also run check -overlay -g overlay/quick,
>> but that's only to verify your patches did not regress any
>> non-casefolded test.
>>
>>
> 
> My tests also indicate that there are several regressions, so your patches
> must have changed code paths that should not have been changed.
> 
> Thanks,
> Amir.