Re: [PATCH] mount: enable retry for nfs23 to set the correct protocol for mount.

[Steve Dickson <SteveD@redhat.com>]

Neil Brown wrote:
> On Friday July 18, neilb@suse.de wrote:
>> This is done over an unconnected socket so ICMP errors don't come back
>> (I think) so the timeout is all that clnt_call gets to know there is
>> an error... I wonder what would happen if we just changed that to be a
>> connected socket...
> 
> Yep, that was a good idea.
> The patch below causes a connected socket to be used when talking to
> portmap over UDP.  That means that we get ICMP errors back.
> And if we handle the errors correctly, we avoid the timeout.
> 
> With this added to all my other current patches, attempting to mount
> when udp/portmap is blocked succeeds in 90 seconds rather than 112
> seconds, and the 90 seconds is all in the mount system call.
> 
> If the kernel used connected UDP ports to talk to portmap, it might
> benefit too (didn't I see some emails about connected UDP ports in
> net/sunrpc recently - I'm afraid I didn't pay much attention).
> 
> NeilBrown
> 
> 
> From: NeilBrown <neilb@suse.de>
> 
> Use a connected port when talking to portmap via UDP.
> 
> This allows us to get ICMP errors reported back so we can avoid
> timeouts.  Also catch the error (RPC_CANTRECV) properly in getport.
> 
> Signed-off-by: NeilBrown <neilb@suse.de>
> 
> diff --git a/utils/mount/network.c b/utils/mount/network.c
> index 75354a7..ff50512 100644
> --- a/utils/mount/network.c
> +++ b/utils/mount/network.c
> @@ -447,7 +447,7 @@ static unsigned short getport(struct sockaddr_in *saddr,
>  	bind_saddr = *saddr;
>  	bind_saddr.sin_port = htons(PMAPPORT);
>  
> -	socket = get_socket(&bind_saddr, proto, PMAP_TIMEOUT, FALSE, FALSE);
> +	socket = get_socket(&bind_saddr, proto, PMAP_TIMEOUT, FALSE, TRUE);
>  	if (socket == RPC_ANYSOCK) {
>  		if (proto == IPPROTO_TCP &&
>  		    rpc_createerr.cf_error.re_errno == ETIMEDOUT)
> @@ -536,6 +536,7 @@ static int probe_port(clnt_addr_t *server, const unsigned long *versions,
>  		}
>  		if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED &&
>  		    rpc_createerr.cf_stat != RPC_TIMEDOUT &&
> +		    rpc_createerr.cf_stat != RPC_CANTRECV &&
>  		    rpc_createerr.cf_stat != RPC_PROGVERSMISMATCH)
>  			goto out_bad;
>  
> @@ -544,7 +545,8 @@ static int probe_port(clnt_addr_t *server, const unsigned long *versions,
>  				continue;
>  			p_prot = protos;
>  		}
> -		if (rpc_createerr.cf_stat == RPC_TIMEDOUT)
> +		if (rpc_createerr.cf_stat == RPC_TIMEDOUT ||
> +		    rpc_createerr.cf_stat == RPC_CANTRECV)
>  			goto out_bad;
>  
>  		if (vers || !*++p_vers)

Committed....

steved.