Re: [PATCH v3 1/5] selftests/mm: skip COW tmpfile cases when fallocate() is unsupported

[Muhammad Usama Anjum]

On 13/08/2026 11:20 am, David Hildenbrand (Arm) wrote:
> On 7/27/26 11:52, Muhammad Usama Anjum wrote:
>> The tmpfile-backed COW cases allocate a one-page file with fallocate()
>> before exercising private and shared mappings.  When the filesystem
>> backing tmpfile() does not implement fallocate(), setup fails with
>> EOPNOTSUPP and no COW behavior is exercised.
>>
>> This occurs when the temporary directory resides on a filesystem with
>> limited allocation support, such as NFSv3.  Reporting a failure adds
>> noise because the test prerequisite is absent rather than the COW
>> implementation being broken.
>>
>> Report EOPNOTSUPP as a skip.  Continue treating every other fallocate()
>> error as a failure so unexpected setup regressions remain visible.
>>
>> Tested-by: Sarthak Sharma <sarthak.sharma@xxxxxxx>
>> Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxx>
>> ---
> 
> Worth a Fixes: ? I think so.

Thanks for reviewing!

Fixes: f8664f3c4a08 ("selftests/vm: cow: basic COW tests for non-anonymous pages")

> 
> Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>



-- 
Thanks,
Usama