Re: [PATCH] fstests: vfstest: skip rejected tmpfile creation

=E5=9C=A8 2026/7/20 17:40, Christoph Hellwig =E5=86=99=E9=81=93:
> Christian indicated the fixes for this are in the (somewhat confusingly
> titled) "[PATCH 0/2] Support overlayfs in the idmapped mount tests"
> series.
>=20
> It would be good to get a proper review for this as it's beyond my
> pay grade.

Thanks a lot for pointing that series out.

That series hit me but the name didn't ring my bell initially.

But the commit message of the first patch makes more sense now, and=20
please drop this patch.

This one is really masking the problem, meanwhile that first patch of=20
that series is fixing it in a better way.

Please drop this patch.

Thanks,
Qu
>=20
> On Fri, Jul 17, 2026 at 04:37:17PM +0930, Qu Wenruo wrote:
>> Since kernel commit 539dce114465 ("fs: refuse O_TMPFILE creation with a=
n
>> unmapped fsuid or fsgid"), tmpfile creation can be rejected with
>> EOVERFLOW, so also skip that error number to avoid false alerts like th=
e
>> following:
>>
>>   FSTYP         -- ext4
>>   PLATFORM      -- Linux/x86_64 btrfs-vm 7.2.0-rc3-custom+ #411 SMP PRE=
EMPT_DYNAMIC Fri Jul 17 16:24:34 ACST 2026
>>   MKFS_OPTIONS  -- -F /dev/mapper/test-scratch1
>>   MOUNT_OPTIONS -- -o acl,user_xattr /dev/mapper/test-scratch1 /mnt/scr=
atch
>>
>>   generic/633  1s ... - output mismatch (see /home/adam/xfstests/result=
s//generic/633.out.bad)
>>      --- tests/generic/633.out	2022-05-11 11:25:30.816666664 +0930
>>      +++ /home/adam/xfstests/results//generic/633.out.bad	2026-07-17 16=
:25:45.033967541 +0930
>>      @@ -1,2 +1,4 @@
>>       QA output created by 633
>>       Silence is golden
>>      +utils.c: 948: openat_tmpfile_supported - Value too large for defi=
ned data type - failure: create
>>      +utils.c: 948: openat_tmpfile_supported - Value too large for defi=
ned data type - failure: create
>>      ...
>>      (Run 'diff -u /home/adam/xfstests/tests/generic/633.out /home/adam=
/xfstests/results//generic/633.out.bad'  to see the entire diff)
>>   Ran: generic/633
>>   Failures: generic/633
>>   Failed 1 of 1 tests
>>
>> Signed-off-by: Qu Wenruo <[email protected]>
>> ---
>>   src/vfs/utils.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/vfs/utils.c b/src/vfs/utils.c
>> index 0b435afe..d2922cc3 100644
>> --- a/src/vfs/utils.c
>> +++ b/src/vfs/utils.c
>> @@ -941,7 +941,11 @@ bool openat_tmpfile_supported(int dirfd)
>>  =20
>>   	fd =3D openat(dirfd, ".", O_TMPFILE | O_RDWR, S_IXGRP | S_ISGID);
>>   	if (fd =3D=3D -1) {
>> -		if (errno =3D=3D ENOTSUP) {
>> +		/*
>> +		 * Kernel commit 539dce114465 ("fs: refuse O_TMPFILE creation
>> +		 * with an unmapped fsuid or fsgid") will reject such operation.
>> +		 */
>> +		if (errno =3D=3D ENOTSUP || errno =3D=3D EOVERFLOW) {
>>   			errno =3D 0; /* Don't report misleading errno. */
>>   			return false;
>>   		} else {
>> --=20
>> 2.51.2
>>
>>
> ---end quoted text---
>=20