Bruce,
On 5/11/19 9:54 AM, J. Bruce Fields wrote:
> On Fri, May 10, 2019 at 05:54:45PM -0400, Jeff Layton wrote:
>> From: Jeff Layton <jlayton@xxxxxxxxxx>
>>
>> I occasionally see people that expect valid info when running showmount
>> against a server that may export some or all filesystems via NFSv4.
>> Let's make it clear that it only works by talking to the remote MNT
>> service, and that that may not be available from a v4-only server.
>
> Looks fine.
>
> I wonder if it'd also be helpful for showmount to detect this case and
> say something. E.g. the following (not even compileable, but you get
> the idea).
>
> We've also talked about trying to cobble together an export list by
> scanning the root filesystem over NFSv4, but that's likely to be
> complicated and wouldn't give all the same results without further
> protocol extensions anyway, so I think that idea's dead.
>
> --b.
I'm a bit confused... Does this patch go along with Jeff's manpage change?
steved.
>
> diff --git a/utils/showmount/showmount.c b/utils/showmount/showmount.c
> index 394f5284a219..de9a6d38783a 100644
> --- a/utils/showmount/showmount.c
> +++ b/utils/showmount/showmount.c
> @@ -115,6 +115,22 @@ static CLIENT *nfs_get_mount_client(const char *hostname, rpcvers_t vers)
> exit(1);
> }
>
> +void warn_if_v4_only(char *hostname)
> +{
> + struct sockaddr_in server_addr, client_addr;
> +
> + if (fill_ipv4_sockaddr(hostname, &serveraddr))
> + return;
> + server_addr.sin_port = htnos(NFS_PORT);
> + client_addr.sin_family = 0;
> + client_addr.sin_addr.s_addr = 0;
> + clnt_ping(&server_addr, NFS_PROGRAM, 4, "tcp", &client_addr);
> +
> + if (rpc.createerr == RPC_SUCCESS)
> + printf("Server responding to NFSv4 but not MNT; try mounting "
> + "%s:/ instead of showmount", hostname);
> +}
> +
> int main(int argc, char **argv)
> {
> char hostname_buf[MAXHOSTLEN];
> @@ -199,6 +215,7 @@ int main(int argc, char **argv)
> fprintf(stderr, "%s: unable to create RPC auth handle.\n",
> program_name);
> clnt_destroy(mclient);
> + warn_if_v4_only(hostname);
> exit(1);
> }
> total_timeout.tv_sec = TOTAL_TIMEOUT;
>
