NFS: show retransmit settings when displaying mount options

Sometimes it's important to know the exact RPC retransmit settings the
kernel is using for an NFS mount point.  Add this facility to the NFS
client's show_options method.

Test plan:
Set various retransmit settings via the mount command, and check that the
settings are reflected in /proc/mounts.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -396,6 +396,9 @@ nfs_create_client(struct nfs_server *server, const struct nfs_mount_data *data)
 
 	nfs_init_timeout_values(&timeparms, proto, data->timeo, data->retrans);
 
+	server->retrans_timeo = timeparms.to_initval;
+	server->retrans_count = timeparms.to_retries;
+
 	/* create transport and client */
 	xprt = xprt_create_proto(proto, &server->addr, &timeparms);
 	if (IS_ERR(xprt)) {
@@ -629,6 +632,8 @@ static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 			proto = buf;
 	}
 	seq_printf(m, ",proto=%s", proto);
+	seq_printf(m, ",timeo=%lu", 10U * nfss->retrans_timeo / HZ);
+	seq_printf(m, ",retrans=%u", nfss->retrans_count);
 	seq_puts(m, ",addr=");
 	seq_escape(m, nfss->hostname, " \t\n\\");
 	return 0;
@@ -1800,6 +1805,9 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,
 
 	nfs_init_timeout_values(&timeparms, data->proto, data->timeo, data->retrans);
 
+	server->retrans_timeo = timeparms.to_initval;
+	server->retrans_count = timeparms.to_retries;
+
 	clp = nfs4_get_client(&server->addr.sin_addr);
 	if (!clp) {
 		dprintk("%s: failed to create NFS4 client.\n", __FUNCTION__);

include/linux/nfs_fs_sb.h

@@ -26,6 +26,8 @@ struct nfs_server {
 	unsigned int		acregmax;
 	unsigned int		acdirmin;
 	unsigned int		acdirmax;
+	unsigned long		retrans_timeo;	/* retransmit timeout */
+	unsigned int		retrans_count;	/* number of retransmit tries */
 	unsigned int		namelen;
 	char *			hostname;	/* remote hostname */
 	struct nfs_fh		fh;