Re: Should we consider disable generic/563 for file systems that do not support cgroup2?

[Zorro Lang <zlang@kernel.org>]

On Fri, Jul 10, 2026 at 07:10:43PM +0000, Viacheslav Dubeyko wrote:
> Hello,
> 
> As far as I can see, the generic/563 test is dedicated to cgroup v2
> functionality. And several file systems fails to execute the test:
> 
> sudo ./check generic/563
> FSTYP         -- hfsplus
> PLATFORM      -- Linux/x86_64 hfsplus-testing-0001 7.2.0-rc1+ #55 SMP
> PREEMPT_DYNAMIC Fri Jul 10 11:21:38 PDT 2026
> MKFS_OPTIONS  -- /dev/loop51
> MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
> 
> generic/563        - output mismatch (see xfstests-
> dev/results//generic/563.out.bad)
>     --- tests/generic/563.out	2026-04-07 14:19:04.785079940 -0700
>     +++ xfstests-dev/results//generic/563.out.bad	2026-07-10
> 11:33:14.231562955 -0700
>     @@ -4,11 +4,13 @@
>      write is in range
>      write -> read/write
>      read is in range
>     -write is in range
>     +write has value of 0
>     +write is NOT in range 15938355.2 .. 17616076.8
>      read is in range
>     ...
>     (Run 'diff -u xfstests-dev/tests/generic/563.out xfstests-
> dev/results//generic/563.out.bad'  to see the entire diff)
> Ran: generic/563
> Failures: generic/563
> Failed 1 of 1 tests
> 
> sudo ./check generic/563
> FSTYP         -- vfat
> PLATFORM      -- Linux/x86_64 hfsplus-testing-0001 7.2.0-rc1+ #55 SMP
> PREEMPT_DYNAMIC Fri Jul 10 11:21:38 PDT 2026
> MKFS_OPTIONS  -- /dev/loop51
> MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
> 
> generic/563        - output mismatch (see xfstests-
> dev/results//generic/563.out.bad)
>     --- tests/generic/563.out	2026-04-07 14:19:04.785079940 -0700
>     +++ xfstests-dev/results//generic/563.out.bad	2026-07-10
> 11:36:02.221320239 -0700
>     @@ -1,14 +1,19 @@
>      QA output created by 563
>      read/write
>     -read is in range
>     +read has value of 22014464
>     +read is NOT in range 15938355.2 .. 17616076.8
>      write is in range
>      write -> read/write
>     ...
>     (Run 'diff -u xfstests-dev/tests/generic/563.out xfstests-
> dev/results//generic/563.out.bad'  to see the entire diff)
> Ran: generic/563
> Failures: generic/563
> Failed 1 of 1 tests
> 
> sudo ./check generic/563
> FSTYP         -- nilfs2
> PLATFORM      -- Linux/x86_64 hfsplus-testing-0001 7.2.0-rc1+ #55 SMP
> PREEMPT_DYNAMIC Fri Jul 10 11:21:38 PDT 2026
> MKFS_OPTIONS  -- /dev/loop51
> MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
> 
> generic/563        - output mismatch (see xfstests-
> dev/results//generic/563.out.bad)
>     --- tests/generic/563.out	2026-04-07 14:19:04.785079940 -0700
>     +++ xfstests-dev/results//generic/563.out.bad	2026-07-10
> 11:37:57.633280743 -0700
>     @@ -1,14 +1,18 @@
>      QA output created by 563
>      read/write
>      read is in range
>     -write is in range
>     +write has value of 0
>     +write is NOT in range 15938355.2 .. 17616076.8
>      write -> read/write
>     ...
>     (Run 'diff -u xfstests-dev/tests/generic/563.out xfstests-
> dev/results//generic/563.out.bad'  to see the entire diff)
> Ran: generic/563
> Failures: generic/563
> Failed 1 of 1 tests
> 
> Should file system (like HFS/HFS+, for example) implement cgroup2 support to
> pass the  generic/563 successfully? Is it generic enough test-case? Should we
> consider disable generic/563 for file systems that do not support cgroup2?

Hi Viacheslav,

I completely understand your frustration. The "generic" test suite in fstests
isn't a universal requirement document, so I can't really answer whether HFS+
should support cgroup2 or not..

File systems that are not supported by fstests good enough, frequently run into
false failures. When facing a test that is "destined" to fail on a specific
$FSTYP, you have below options (maybe more):

1. You can add this specific test (e.g., generic/563) to your daily local test
   exclusion list, refer to the -e or -E options with the ./check script.

2. You can modify the test case to explicitly skip a specific $FSTYP using the
   _exclude_fs helper, along with a short comment explaining why.

3. You can use or implement a _require_ function to check if a specific feature
   is supported, which will gracefully _notrun the test if it's missing. While
   _require_cgroup2() already exists, its granularity is currently too coarse to
   _notrun for HFS. You might want to consider refining it or introducing a new
   helper to help file systems like HFS+ _notrun properly.

I hope my reply help to clear something for you, please let me know if you have
any further questions.

Thanks,
Zorro

> 
> Thanks,
> Slava.