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_PROC
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
64	ops = clp->cl_mvops->state_renewal_ops;
65	dprintk("%s: start\n", __func__);
66	/* Are there any active superblocks? */
67	if (list_empty(&clp->cl_superblocks))
68		goto out;
69	spin_lock(&clp->cl_lock);
70	lease = clp->cl_lease_time;
71	last = clp->cl_last_renewal;
72	now = jiffies;
73	/* Are we close to a lease timeout? */
74	if (time_after(now, last + lease/3)) {
75		cred = ops->get_state_renewal_cred_locked(clp);
76		spin_unlock(&clp->cl_lock);
77		if (cred == NULL) {
78			if (list_empty(&clp->cl_delegations)) {
79				set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
80				goto out;
81			}
82			nfs_expire_all_delegations(clp);
83		} else {
84			/* Queue an asynchronous RENEW. */
85			ops->sched_state_renewal(clp, cred);
86			put_rpccred(cred);
87			goto out_exp;
88		}
89	} else {
90		dprintk("%s: failed to call renewd. Reason: lease not expired \n",
91				__func__);
92		spin_unlock(&clp->cl_lock);
93	}
94	nfs4_schedule_state_renewal(clp);
95out_exp:
96	nfs_expire_unreferenced_delegations(clp);
97out:
98	dprintk("%s: done\n", __func__);
99}
100
101void
102nfs4_schedule_state_renewal(struct nfs_client *clp)
103{
104	long timeout;
105
106	spin_lock(&clp->cl_lock);
107	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
108		- (long)jiffies;
109	if (timeout < 5 * HZ)
110		timeout = 5 * HZ;
111	dprintk("%s: requeueing work. Lease period = %ld\n",
112			__func__, (timeout + HZ - 1) / HZ);
113	cancel_delayed_work(&clp->cl_renewd);
114	schedule_delayed_work(&clp->cl_renewd, timeout);
115	set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
116	spin_unlock(&clp->cl_lock);
117}
118
119void
120nfs4_kill_renewd(struct nfs_client *clp)
121{
122	cancel_delayed_work_sync(&clp->cl_renewd);
123}
124
125/*
126 * Local variables:
127 *   c-basic-offset: 8
128 * End:
129 */
130