Re: [PATCH 1/1] NFSD: don't start nfsd if sv_permsocks is empty

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

On 10/31/25 7:41 PM, NeilBrown wrote:
> On Fri, 31 Oct 2025, Chuck Lever wrote:
>> On 10/30/25 12:35 PM, Olga Kornievskaia wrote:
>>> Previously, while trying to create a server instance, if no
>>> listening sockets were present then default parameter udp
>>> and tcp listeners were created. It's unclear what purpose
>>> was of starting these listeners were and how this could have
>>> been triggered by the userland setup. This patch proposed
>>> to ensure the reverse that we never end in a situation where
>>> no listener sockets are created and we are trying to create
>>> nfsd threads.
>>>
>>> The problem it solves is: when nfs.conf only has tcp=n (and
>>> nothing else for the choice of transports), nfsdctl would
>>> still start the server and create udp and tcp listeners.
>>>
>>
>> Fixes: ?
>>
>> One more below.
>>
>>
>>> Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
>>> ---
>>>  fs/nfsd/nfssvc.c | 28 +++++-----------------------
>>>  1 file changed, 5 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
>>> index 7057ddd7a0a8..40592b61b04b 100644
>>> --- a/fs/nfsd/nfssvc.c
>>> +++ b/fs/nfsd/nfssvc.c
>>> @@ -249,27 +249,6 @@ int nfsd_nrthreads(struct net *net)
>>>  	return rv;
>>>  }
>>>  
>>> -static int nfsd_init_socks(struct net *net, const struct cred *cred)
>>> -{
>>> -	int error;
>>> -	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>>> -
>>> -	if (!list_empty(&nn->nfsd_serv->sv_permsocks))
>>> -		return 0;
>>> -
>>> -	error = svc_xprt_create(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
>>> -				SVC_SOCK_DEFAULTS, cred);
>>> -	if (error < 0)
>>> -		return error;
>>> -
>>> -	error = svc_xprt_create(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
>>> -				SVC_SOCK_DEFAULTS, cred);
>>> -	if (error < 0)
>>> -		return error;
>>> -
>>> -	return 0;
>>> -}
>>> -
>>>  static int nfsd_users = 0;
>>>  
>>>  static int nfsd_startup_generic(void)
>>> @@ -377,9 +356,12 @@ static int nfsd_startup_net(struct net *net, const struct cred *cred)
>>>  	ret = nfsd_startup_generic();
>>>  	if (ret)
>>>  		return ret;
>>> -	ret = nfsd_init_socks(net, cred);
>>> -	if (ret)
>>> +
>>> +	if (list_empty(&nn->nfsd_serv->sv_permsocks)) {
>>> +		pr_warn("NFSD: not starting because no listening sockets found\n");
>>
>> I know the code refers to sockets, but the term doesn't refer to RDMA
>> listeners at all, and this warning seems applicable to both socket-based
>> and RDMA transports. How about:
>>
>> NFSD: No available listeners
> 
> "configured" rather than "available" ??
> "network listeners"?  "network request listeners" ??
> "ports" rather than "sockets" ??
> 
>  NFSD: No network ports configured for listening
> ??
> 
> I did consider suggesting that the message isn't needed.

I lean towards having a notice that something didn't go as planned.
My final pitch:

NFSD: Failed to start, no listeners configured.


-- 
Chuck Lever