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	struct rpc_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	spin_lock(&clp->cl_lock);
72	lease = clp->cl_lease_time;
73	last = clp->cl_last_renewal;
74	now = jiffies;
75	/* Are we close to a lease timeout? */
76	if (time_after(now, last + lease/3))
77		renew_flags |= NFS4_RENEW_TIMEOUT;
78	if (nfs_delegations_present(clp))
79		renew_flags |= NFS4_RENEW_DELEGATION_CB;
80
81	if (renew_flags != 0) {
82		cred = ops->get_state_renewal_cred_locked(clp);
83		spin_unlock(&clp->cl_lock);
84		if (cred == NULL) {
85			if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {
86				set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
87				goto out;
88			}
89			nfs_expire_all_delegations(clp);
90		} else {
91			int ret;
92
93			/* Queue an asynchronous RENEW. */
94			ret = ops->sched_state_renewal(clp, cred, renew_flags);
95			put_rpccred(cred);
96			switch (ret) {
97			default:
98				goto out_exp;
99			case -EAGAIN:
100			case -ENOMEM:
101				break;
102			}
103		}
104	} else {
105		dprintk("%s: failed to call renewd. Reason: lease not expired \n",
106				__func__);
107		spin_unlock(&clp->cl_lock);
108	}
109	nfs4_schedule_state_renewal(clp);
110out_exp:
111	nfs_expire_unreferenced_delegations(clp);
112out:
113	dprintk("%s: done\n", __func__);
114}
115
116void
117nfs4_schedule_state_renewal(struct nfs_client *clp)
118{
119	long timeout;
120
121	spin_lock(&clp->cl_lock);
122	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
123		- (long)jiffies;
124	if (timeout < 5 * HZ)
125		timeout = 5 * HZ;
126	dprintk("%s: requeueing work. Lease period = %ld\n",
127			__func__, (timeout + HZ - 1) / HZ);
128	mod_delayed_work(system_wq, &clp->cl_renewd, timeout);
129	set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
130	spin_unlock(&clp->cl_lock);
131}
132
133void
134nfs4_kill_renewd(struct nfs_client *clp)
135{
136	cancel_delayed_work_sync(&clp->cl_renewd);
137}
138
139/*
140 * Local variables:
141 *   c-basic-offset: 8
142 * End:
143 */
144