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

[Petr Vorel <pvorel@suse.cz>]

Hi all,


> > 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 client-side nfsstat changes are fully backported to all
> TS kernels. But should they have been?

> The server-side nfsstat changes appear in only v6.9. Should
> they be backported to the other LTS kernels, or not?

First, thanks a lot for having a look into the issue.

It looks to me as a functional change, thus I would not backport
changes unless changes they are needed to be backported (part some larger fix).
Thus maybe revert?

And if backported, I would expect changes on both sides (client and server)
would be backported (not just server side).

Kind regards,
Petr

> >> so your check for kernel version "6.9" in the test may need to be adjusted, if LTP is intended to be run on stable kernels?
> >> best wishes,
> >> calum.
> >> [1] https://lore.kernel.org/ltp/20240620111129.594449-1-pvorel@suse.cz/
> >> [2] https://patchwork.ozlabs.org/project/ltp/ patch/20240620111129.594449-1-pvorel@suse.cz/
> >> [3] https://lore.kernel.org/linux-nfs/ cover.1708026931.git.josef@toxicpanda.com/