[LTP] [PATCH 1/1] nfsstat01: Update client RPC calls for kernel 6.9

[Sherry Yang]

> On Jul 6, 2024, at 12:11 AM, Greg KH <greg@kroah.com> wrote:
> 
> On Fri, Jul 05, 2024 at 02:19:18PM +0000, Chuck Lever III wrote:
>> 
>> 
>>> On Jul 2, 2024, at 6:55 PM, Calum Mackay <calum.mackay@oracle.com> wrote:
>>> 
>>> To clarify…
>>> 
>>> On 02/07/2024 5:54 pm, Calum Mackay wrote:
>>>> hi Petr,
>>>> I noticed your LTP patch [1][2] which adjusts the nfsstat01 test on v6.9 kernels, to account for Josef's changes [3], which restrict the NFS/RPC stats per-namespace.
>>>> I see that Josef's changes were backported, as far back as longterm v5.4,
>>> 
>>> Sorry, that's not quite accurate.
>>> 
>>> Josef's NFS client changes were all backported from v6.9, as far as longterm v5.4.y:
>>> 
>>> 2057a48d0dd0 sunrpc: add a struct rpc_stats arg to rpc_create_args
>>> d47151b79e32 nfs: expose /proc/net/sunrpc/nfs in net namespaces
>>> 1548036ef120 nfs: make the rpc_stat per net namespace
>>> 
>>> 
>>> Of Josef's NFS server changes, four were backported from v6.9 to v6.8:
>>> 
>>> 418b9687dece sunrpc: use the struct net as the svc proc private
>>> d98416cc2154 nfsd: rename NFSD_NET_* to NFSD_STATS_*
>>> 93483ac5fec6 nfsd: expose /proc/net/sunrpc/nfsd in net namespaces
>>> 4b14885411f7 nfsd: make all of the nfsd stats per-network namespace
>>> 
>>> and the others remained only in v6.9:
>>> 
>>> ab42f4d9a26f sunrpc: don't change ->sv_stats if it doesn't exist
>>> a2214ed588fb nfsd: stop setting ->pg_stats for unused stats
>>> f09432386766 sunrpc: pass in the sv_stats struct through svc_create_pooled
>>> 3f6ef182f144 sunrpc: remove ->pg_stats from svc_program
>>> e41ee44cc6a4 nfsd: remove nfsd_stats, make th_cnt a global counter
>>> 16fb9808ab2c nfsd: make svc_stat per-network namespace instead of global
>>> 
>>> 
>>> 
>>> I'm wondering if this difference between NFS client, and NFS server, stat behaviour, across kernel versions, may perhaps cause some user confusion?
>> 
>> As a refresher for the stable folken, Josef's changes make
>> nfsstats silo'd, so they no longer show counts from the whole
>> system, but only for NFS operations relating to the local net
>> namespace. That is a surprising change for some users, tools,
>> and testing.
>> 
>> I'm not clear on whether there are any rules/guidelines around
>> LTS backports causing behavior changes that user tools, like
>> nfsstat, might be impacted by.
> 
> The same rules that apply for Linus's tree (i.e. no userspace
> regressions.)

Given the current data we have, LTP nfsstat01[1] failed on LTS v5.4.278 because of kernel commit 1548036ef1204 ("nfs:
make the rpc_stat per net namespace") [2]. Other LTS which backported the same commit are very likely troubled with the same LTP test failure.

The following are the LTP nfsstat01 failure output

========
network 1 TINFO: initialize 'lhost' 'ltp_ns_veth2' interface
network 1 TINFO: add local addr 10.0.0.2/24
network 1 TINFO: add local addr fd00:1:1:1::2/64
network 1 TINFO: initialize 'rhost' 'ltp_ns_veth1' interface
network 1 TINFO: add remote addr 10.0.0.1/24
network 1 TINFO: add remote addr fd00:1:1:1::1/64
network 1 TINFO: Network config (local -- remote):
network 1 TINFO: ltp_ns_veth2 -- ltp_ns_veth1
network 1 TINFO: 10.0.0.2/24 -- 10.0.0.1/24
network 1 TINFO: fd00:1:1:1::2/64 -- fd00:1:1:1::1/64
<<<test_start>>>
tag=veth|nfsstat3_01 stime=1719943586
cmdline="nfsstat01"
contacts=""
analysis=exit
<<<test_output>>>
incrementing stop
nfsstat01 1 TINFO: timeout per run is 0h 20m 0s
nfsstat01 1 TINFO: setup NFSv3, socket type udp
nfsstat01 1 TINFO: Mounting NFS: mount -t nfs -o proto=udp,vers=3 10.0.0.2:/tmp/netpan-4577/LTP_nfsstat01.lz6zhgQHoV/3/udp /tmp/netpan-4577/LTP_nfsstat01.lz6zhgQHoV/3/0
nfsstat01 1 TINFO: checking RPC calls for server/client
nfsstat01 1 TINFO: calls 98/0
nfsstat01 1 TINFO: Checking for tracking of RPC calls for server/client
nfsstat01 1 TINFO: new calls 102/0
nfsstat01 1 TPASS: server RPC calls increased
nfsstat01 1 TFAIL: client RPC calls not increased
nfsstat01 1 TINFO: checking NFS calls for server/client
nfsstat01 1 TINFO: calls 2/2
nfsstat01 1 TINFO: Checking for tracking of NFS calls for server/client
nfsstat01 1 TINFO: new calls 3/3
nfsstat01 1 TPASS: server NFS calls increased
nfsstat01 1 TPASS: client NFS calls increased
nfsstat01 2 TINFO: Cleaning up testcase
nfsstat01 2 TINFO: SELinux enabled in enforcing mode, this may affect test results
nfsstat01 2 TINFO: it can be disabled with TST_DISABLE_SELINUX=1 (requires super/root)
nfsstat01 2 TINFO: install seinfo to find used SELinux profiles
nfsstat01 2 TINFO: loaded SELinux profiles: none

Summary:
passed 3
failed 1
skipped 0
warnings 0
<<<execution_status>>>
initiation_status="ok"
duration=1 termination_type=exited termination_id=1 corefile=no
cutime=11 cstime=16
<<<test_end>>>
ltp-pan reported FAIL
========

We can observe the number of RPC client calls is 0, which is wired. And this happens from the kernel commit 57d1ce96d7655 ("nfs: make the rpc_stat per net namespace”). So now we’re not sure the kernel backport of nfs client changes is proper, or the LTP tests / userspace need to be modified.

If no userspace regression, should we revert the Josef’s NFS client-side changes on LTS?

Thanks,
Sherry

Reference:
[1] https://github.com/linux-test-project/ltp/blob/master/testcases/network/nfs/nfsstat01/nfsstat01.sh
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1548036ef1204df65ca5a16e8b199c858cb80075
> 
> thanks,
> 
> greg k-h