nfsd: make NFSv4 lease time per net

Lease time is a part of NFSv4 state engine, which is constructed per network
namespace.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index f5ab74a..09d909a 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -909,7 +909,8 @@
  */
 static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
 {
-	return nfsd4_write_time(file, buf, size, &nfsd4_lease);
+	struct nfsd_net *nn = net_generic(&init_net, nfsd_net_id);
+	return nfsd4_write_time(file, buf, size, &nn->nfsd4_lease);
 }
 
 /**
@@ -1060,6 +1061,7 @@
 static __net_init int nfsd_init_net(struct net *net)
 {
 	int retval;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
 	retval = nfsd_export_init(net);
 	if (retval)
@@ -1067,6 +1069,7 @@
 	retval = nfsd_idmap_init(net);
 	if (retval)
 		goto out_idmap_error;
+	nn->nfsd4_lease = 90;	/* default lease time */
 	return 0;
 
 out_idmap_error: