Re: [PATCH 1/1] NFSv4.1+ add trunking when server trunking detected

Olga Kornievskaia
2021-06-08T20:57:05Z

On Tue, Jun 8, 2021 at 4:41 PM Chuck Lever III <chuck.lever@oracle.com> wrote:
>
>
>
> > On Jun 8, 2021, at 2:45 PM, Olga Kornievskaia <olga.kornievskaia@gmail.com> wrote:
> >
> > From: Olga Kornievskaia <kolga@netapp.com>
> >
> > After trunking is discovered in nfs4_discover_server_trunking(),
> > add the transport to the old client structure before destroying
> > the new client structure (along with its transport).
> >
> > Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> > ---
> > fs/nfs/nfs4client.c | 40 ++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 40 insertions(+)
> >
> > diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
> > index 42719384e25f..984c851844d8 100644
> > --- a/fs/nfs/nfs4client.c
> > +++ b/fs/nfs/nfs4client.c
> > @@ -361,6 +361,44 @@ static int nfs4_init_client_minor_version(struct nfs_client *clp)
> > return nfs4_init_callback(clp);
> > }
> >
> > +static void nfs4_add_trunk(struct nfs_client *clp, struct nfs_client *old)
> > +{
> > + struct sockaddr_storage clp_addr, old_addr;
> > + struct sockaddr *clp_sap = (struct sockaddr *)&clp_addr;
> > + struct sockaddr *old_sap = (struct sockaddr *)&old_addr;
> > + size_t clp_salen, old_salen;
> > + struct xprt_create xprt_args = {
> > + .ident = old->cl_proto,
> > + .net = old->cl_net,
> > + .servername = old->cl_hostname,
> > + };
> > + struct nfs4_add_xprt_data xprtdata = {
> > + .clp = old,
> > + };
> > + struct rpc_add_xprt_test rpcdata = {
> > + .add_xprt_test = old->cl_mvops->session_trunk,
> > + .data = &xprtdata,
> > + };
> > +
> > + if (clp->cl_proto != old->cl_proto)
> > + return;
> > + clp_salen = rpc_peeraddr(clp->cl_rpcclient, clp_sap, sizeof(clp_addr));
> > + old_salen = rpc_peeraddr(old->cl_rpcclient, old_sap, sizeof(old_addr));
> > +
> > + if (clp_addr.ss_family != old_addr.ss_family)
> > + return;
> > +
> > + xprt_args.dstaddr = clp_sap;
> > + xprt_args.addrlen = clp_salen;
> > +
> > + xprtdata.cred = nfs4_get_clid_cred(old);
> > + rpc_clnt_add_xprt(old->cl_rpcclient, &xprt_args,
> > + rpc_clnt_setup_test_and_add_xprt, &rpcdata);
>
> Is there an upper bound on the number of transports that
> are added to the NFS client's switch?

I don't believe any limits exist right now. Why should there be a
limit? Are you saying that the client should limit trunking? While
this is not what's happening here, but say FS_LOCATION returned 100
ips for the server. Are you saying the client should be limiting how
many trunkable connections it would be establishing and picking just a
few addresses to try? What's happening with this patch is that say
there are 100mounts to 100 ips (each representing the same server or
trunkable server(s)), without this patch a single connection is kept,
with this patch we'll have 100 connections.

>
>
> > +
> > + if (xprtdata.cred)
> > + put_cred(xprtdata.cred);
> > +}
> > +
> > /**
> > * nfs4_init_client - Initialise an NFS4 client record
> > *
> > @@ -434,6 +472,8 @@ struct nfs_client *nfs4_init_client(struct nfs_client *clp,
> > * won't try to use it.
> > */
> > nfs_mark_client_ready(clp, -EPERM);
> > + if (old->cl_mvops->session_trunk)
> > + nfs4_add_trunk(clp, old);
> > }
> > clear_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags);
> > nfs_put_client(clp);
> > --
> > 2.27.0
> >
>
> --
> Chuck Lever
>
>
>