1/*
2 *  fs/nfs/nfs4renewd.c
3 *
4 *  Copyright (c) 2002 The Regents of the University of Michigan.
5 *  All rights reserved.
6 *
7 *  Kendrick Smith <kmsmith@umich.edu>
8 *
9 *  Redistribution and use in source and binary forms, with or without
10 *  modification, are permitted provided that the following conditions
11 *  are met:
12 *
13 *  1. Redistributions of source code must retain the above copyright
14 *     notice, this list of conditions and the following disclaimer.
15 *  2. Redistributions in binary form must reproduce the above copyright
16 *     notice, this list of conditions and the following disclaimer in the
17 *     documentation and/or other materials provided with the distribution.
18 *  3. Neither the name of the University nor the names of its
19 *     contributors may be used to endorse or promote products derived
20 *     from this software without specific prior written permission.
21 *
22 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
23 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
25 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
29 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
30 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
31 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
32 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 *
34 * Implementation of the NFSv4 "renew daemon", which wakes up periodically to
35 * send a RENEW, to keep state alive on the server.  The daemon is implemented
36 * as an rpc_task, not a real kernel thread, so it always runs in rpciod's
37 * context.  There is one renewd per nfs_server.
38 *
39 */
40
41#include <linux/mm.h>
42#include <linux/pagemap.h>
43#include <linux/sunrpc/sched.h>
44#include <linux/sunrpc/clnt.h>
45
46#include <linux/nfs.h>
47#include <linux/nfs4.h>
48#include <linux/nfs_fs.h>
49#include "nfs4_fs.h"
50#include "delegation.h"
51
52#define NFSDBG_FACILITY		NFSDBG_STATE
53
54void
55nfs4_renew_state(struct work_struct *work)
56{
57	const struct nfs4_state_maintenance_ops *ops;
58	struct nfs_client *clp =
59		container_of(work, struct nfs_client, cl_renewd.work);
60	const struct cred *cred;
61	long lease;
62	unsigned long last, now;
63	unsigned renew_flags = 0;
64
65	ops = clp->cl_mvops->state_renewal_ops;
66	dprintk("%s: start\n", __func__);
67
68	if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))
69		goto out;
70
71	lease = clp->cl_lease_time;
72	last = clp->cl_last_renewal;
73	now = jiffies;
74	/* Are we close to a lease timeout? */
75	if (time_after(now, last + lease/3))
76		renew_flags |= NFS4_RENEW_TIMEOUT;
77	if (nfs_delegations_present(clp))
78		renew_flags |= NFS4_RENEW_DELEGATION_CB;
79
80	if (renew_flags != 0) {
81		cred = ops->get_state_renewal_cred(clp);
82		if (cred == NULL) {
83			if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {
84				set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
85				goto out;
86			}
87			nfs_expire_all_delegations(clp);
88		} else {
89			int ret;
90
91			/* Queue an asynchronous RENEW. */
92			ret = ops->sched_state_renewal(clp, cred, renew_flags);
93			put_cred(cred);
94			switch (ret) {
95			default:
96				goto out_exp;
97			case -EAGAIN:
98			case -ENOMEM:
99				break;
100			}
101		}
102	} else {
103		dprintk("%s: failed to call renewd. Reason: lease not expired \n",
104				__func__);
105	}
106	nfs4_schedule_state_renewal(clp);
107out_exp:
108	nfs_expire_unreferenced_delegations(clp);
109out:
110	dprintk("%s: done\n", __func__);
111}
112
113void
114nfs4_schedule_state_renewal(struct nfs_client *clp)
115{
116	long timeout;
117
118	spin_lock(&clp->cl_lock);
119	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
120		- (long)jiffies;
121	if (timeout < 5 * HZ)
122		timeout = 5 * HZ;
123	dprintk("%s: requeueing work. Lease period = %ld\n",
124			__func__, (timeout + HZ - 1) / HZ);
125	mod_delayed_work(system_wq, &clp->cl_renewd, timeout);
126	set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
127	spin_unlock(&clp->cl_lock);
128}
129
130void
131nfs4_kill_renewd(struct nfs_client *clp)
132{
133	cancel_delayed_work_sync(&clp->cl_renewd);
134}
135
136/**
137 * nfs4_set_lease_period - Sets the lease period on a nfs_client
138 *
139 * @clp: pointer to nfs_client
140 * @lease: new value for lease period
141 */
142void nfs4_set_lease_period(struct nfs_client *clp,
143		unsigned long lease)
144{
145	spin_lock(&clp->cl_lock);
146	clp->cl_lease_time = lease;
147	spin_unlock(&clp->cl_lock);
148
149	/* Cap maximum reconnect timeout at 1/2 lease period */
150	rpc_set_connect_timeout(clp->cl_rpcclient, lease, lease >> 1);
151}
152