Re: nfs-utils regression on IPv6-less kernels

[Steve Dickson <SteveD@redhat.com>]

On 08/17/2015 12:06 PM, Christoph Hellwig wrote:
> On Mon, Aug 17, 2015 at 08:40:25AM -0700, Chuck Lever wrote:
>> Probably stopped working with "rpc.nfsd: Squelch DNS errors when
>> using --host option".
>>
>> getaddrinfo(3) returns a list of addresses, some of which are
>> IPv6 addresses. It gets the list from /etc/hosts, or DNS. Even
>> on kernels which do not support IPv6, there may be at least one
>> IPv6 address in the list.
>>
>> nfssvc_setfds() then loops over this list. The error handling
>> in nfssvc_setfds() causes the loop to exit if the socket(2)
>> call fails. It should "continue" if the error is EAFNOSUPPORT.
>> In fact, that xlog notice can also be removed.
>>
>> I'm traveling this week. Is this enough for you to generate a
>> fix?
> 
> Yes, that works:
> 
> ---
> From: Christoph Hellwig <hch@lst.de>
> Subject: nfsd: ignore unsupported address types in nfssvc_setfds
> 
> Just continue and try a different record returned from getaddrinfo
> if the kernel does not support an address family.  This fixes nfsd
> startup on kernels without IPv6 support.
> 
> Suggested-by: Chuck Lever <chuck.lever@oracle.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Sorry it took so long... committed!

steved.

> 
> diff --git a/utils/nfsd/nfssvc.c b/utils/nfsd/nfssvc.c
> index a2b11d8..fc11d23 100644
> --- a/utils/nfsd/nfssvc.c
> +++ b/utils/nfsd/nfssvc.c
> @@ -174,15 +174,14 @@ nfssvc_setfds(const struct addrinfo *hints, const char *node, const char *port)
>  		sockfd = socket(addr->ai_family, addr->ai_socktype,
>  				addr->ai_protocol);
>  		if (sockfd < 0) {
> -			if (errno == EAFNOSUPPORT)
> -				xlog(L_NOTICE, "address family %s not "
> -						"supported by protocol %s",
> -						family, proto);
> -			else
> +			if (errno != EAFNOSUPPORT) {
>  				xlog(L_ERROR, "unable to create %s %s socket: "
>  				     "errno %d (%m)", family, proto, errno);
> -			rc = errno;
> -			goto error;
> +				rc = errno;
> +				goto error;
> +			}
> +			addr = addr->ai_next;
> +			continue;
>  		}
>  #ifdef IPV6_SUPPORTED
>  		if (addr->ai_family == AF_INET6 &&
>