Re: Clarification on PyNFS Test Case Behavior for st_lookupp.testLink in Versions 4.0 and 4.1

[Chuck Lever <chuck.lever@oracle.com>]

On 1/1/25 4:38 PM, J. Bruce Fields wrote:
> On Wed, Jan 01, 2025 at 06:28:12AM +0000, Gaikwad, Shubham wrote:
>> Hi Bruce/PyNFS team,
>> I hope this email finds you well.
> 
> Thanks, yes, but I'm not actually maintaining pynfs anymore and I don't
> remember who is....

Calum Mackay, copied.


>> I am reaching out to seek clarification regarding the PyNFS test case
>> 'st_lookupp.testLink' (flag: lookupp, code: LOOKP2a/LKPP1a) included
>> in the PyNFS test suite for v4.0 and v4.1. Specifically, I would like
>> to understand the expected behavior relating to the error codes for
>> this test case.
>>
>> In the PyNFS test suite for v4.0, the test case LOOKP2a (located at
>> nfs4.0/servertests/st_lookupp.py::testLink) initially checked for the
>> error code NFS4ERR_NOTDIR. Subsequently, an update was made to this
>> test case to also expect NFS4ERR_SYMLINK in addition to NFS4ERR_NOTDIR
>> [reference: git.linux-nfs.org Git - bfields/pynfs.git/commitdiff].
>> However, in the PyNFS test suite for v4.1, the corresponding test case
>> LKPP1a (located at nfs4.1/server41tests/st_lookupp.py::testLink)
>> continues to check only for NFS4ERR_SYMLINK as the expected error
>> code.
>>
>> Given the discrepancy, should the test case for v4.1 (LKPP1a) be
>> updated to also check for NFS4ERR_NOTDIR, similar to the modification
>> made for the v4.0 test case (LOOKP2a)? Additionally, while the RFC
>> 8881 section on the lookupp operation [reference: Section 18.14:
>> Operation 16: LOOKUPP - Lookup Parent Directory] does not explicitly
>> mention the error code NFS4ERR_SYMLINK, it is noted in Sections 15.2
>> [reference: Operations and Their Valid Errors] and section 15.4
>> [reference: Errors and the Operations That Use Them]. Therefore, would
>> it be reasonable to update the test case LKPP1a to allow both
>> NFS4ERR_SYMLINK and NFS4ERR_NOTDIR as valid error codes, ensuring the
>> test case passes if either error code is received from the server?
> 
> Not sure!  In theory I guess 4.1 could be stricter about the error code
> than 4.0.  Language for other operations (e.g. LOOKUP, 18.13.4) does
> seem to prefer ERR_SYMLINK in the case of a symlink.  I think the Linux
> client probably only uses LOOKUPP in the export code, where the choice
> of error is unlikely to matter.

There are some differences between NFSv4.0 and NFSv4.1. Neil recently
did some work in this area. See:

https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?id=438f81e0e92a780b117097503599eb030b77dabe

Perhaps he missed a spot.


> I'd guess it doesn't matter much.  What motivates the question?
> 
> --b.
> 
>>
>> Your insight on this matter would be greatly appreciated.
>>
>> References: 1. git.linux-nfs.org Git - bfields/pynfs.git/commitdiff --
>> https://git.linux-nfs.org/?p=bfields/pynfs.git;a=commitdiff;h=6044afcc8ab7deea1beb77be53956fc36713a5b3;hp=19e4c878f8538881af2b6e83672fb94d785aea33
>> 2. Section 18.14: Operation 16: LOOKUPP - Lookup Parent Directory --
>> https://www.rfc-editor.org/rfc/rfc8881.html#name-operation-16-lookupp-lookup
>> 3. Operations and Their Valid Errors --
>> https://www.rfc-editor.org/rfc/rfc8881.html#name-operations-and-their-valid-
>> 4. Errors and the Operations That Use Them --
>> https://www.rfc-editor.org/rfc/rfc8881.html#name-errors-and-the-operations-t
>>
>> Best regards, Shubham Gaikwad
> 


-- 
Chuck Lever