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 * TODO: If the send queue gets backlogged (e.g., if the server goes down),
40 * we will keep filling the queue with periodic RENEW requests.  We need a
41 * mechanism for ensuring that if renewd successfully sends off a request,
42 * then it only wakes up when the request is finished.  Maybe use the
43 * child task framework of the RPC layer?
44 */
45
46#include <linux/mm.h>
47#include <linux/pagemap.h>
48#include <linux/sunrpc/sched.h>
49#include <linux/sunrpc/clnt.h>
50
51#include <linux/nfs.h>
52#include <linux/nfs4.h>
53#include <linux/nfs_fs.h>
54#include "nfs4_fs.h"
55#include "delegation.h"
56
57#define NFSDBG_FACILITY	NFSDBG_PROC
58
59void
60nfs4_renew_state(struct work_struct *work)
61{
62	struct nfs_client *clp =
63		container_of(work, struct nfs_client, cl_renewd.work);
64	struct rpc_cred *cred;
65	long lease, timeout;
66	unsigned long last, now;
67
68	down_read(&clp->cl_sem);
69	dprintk("%s: start\n", __FUNCTION__);
70	/* Are there any active superblocks? */
71	if (list_empty(&clp->cl_superblocks))
72		goto out;
73	spin_lock(&clp->cl_lock);
74	lease = clp->cl_lease_time;
75	last = clp->cl_last_renewal;
76	now = jiffies;
77	timeout = (2 * lease) / 3 + (long)last - (long)now;
78	/* Are we close to a lease timeout? */
79	if (time_after(now, last + lease/3)) {
80		cred = nfs4_get_renew_cred(clp);
81		if (cred == NULL) {
82			set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
83			spin_unlock(&clp->cl_lock);
84			nfs_expire_all_delegations(clp);
85			goto out;
86		}
87		spin_unlock(&clp->cl_lock);
88		/* Queue an asynchronous RENEW. */
89		nfs4_proc_async_renew(clp, cred);
90		put_rpccred(cred);
91		timeout = (2 * lease) / 3;
92		spin_lock(&clp->cl_lock);
93	} else
94		dprintk("%s: failed to call renewd. Reason: lease not expired \n",
95				__FUNCTION__);
96	if (timeout < 5 * HZ)    /* safeguard */
97		timeout = 5 * HZ;
98	dprintk("%s: requeueing work. Lease period = %ld\n",
99			__FUNCTION__, (timeout + HZ - 1) / HZ);
100	cancel_delayed_work(&clp->cl_renewd);
101	schedule_delayed_work(&clp->cl_renewd, timeout);
102	spin_unlock(&clp->cl_lock);
103out:
104	up_read(&clp->cl_sem);
105	dprintk("%s: done\n", __FUNCTION__);
106}
107
108/* Must be called with clp->cl_sem locked for writes */
109void
110nfs4_schedule_state_renewal(struct nfs_client *clp)
111{
112	long timeout;
113
114	spin_lock(&clp->cl_lock);
115	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
116		- (long)jiffies;
117	if (timeout < 5 * HZ)
118		timeout = 5 * HZ;
119	dprintk("%s: requeueing work. Lease period = %ld\n",
120			__FUNCTION__, (timeout + HZ - 1) / HZ);
121	cancel_delayed_work(&clp->cl_renewd);
122	schedule_delayed_work(&clp->cl_renewd, timeout);
123	set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
124	spin_unlock(&clp->cl_lock);
125}
126
127void
128nfs4_renewd_prepare_shutdown(struct nfs_server *server)
129{
130	flush_scheduled_work();
131}
132
133void
134nfs4_kill_renewd(struct nfs_client *clp)
135{
136	down_read(&clp->cl_sem);
137	cancel_delayed_work(&clp->cl_renewd);
138	up_read(&clp->cl_sem);
139	flush_scheduled_work();
140}
141
142/*
143 * Local variables:
144 *   c-basic-offset: 8
145 * End:
146 */
147