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1da177e4 LT |
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/sched.h> | |
47 | #include <linux/smp_lock.h> | |
48 | #include <linux/mm.h> | |
49 | #include <linux/pagemap.h> | |
50 | #include <linux/sunrpc/sched.h> | |
51 | #include <linux/sunrpc/clnt.h> | |
52 | ||
53 | #include <linux/nfs.h> | |
54 | #include <linux/nfs4.h> | |
55 | #include <linux/nfs_fs.h> | |
56 | ||
57 | #define NFSDBG_FACILITY NFSDBG_PROC | |
58 | ||
59 | void | |
60 | nfs4_renew_state(void *data) | |
61 | { | |
62 | struct nfs4_client *clp = (struct nfs4_client *)data; | |
63 | long lease, timeout; | |
64 | unsigned long last, now; | |
65 | ||
66 | down_read(&clp->cl_sem); | |
67 | dprintk("%s: start\n", __FUNCTION__); | |
68 | /* Are there any active superblocks? */ | |
69 | if (list_empty(&clp->cl_superblocks)) | |
70 | goto out; | |
71 | spin_lock(&clp->cl_lock); | |
72 | lease = clp->cl_lease_time; | |
73 | last = clp->cl_last_renewal; | |
74 | now = jiffies; | |
75 | timeout = (2 * lease) / 3 + (long)last - (long)now; | |
76 | /* Are we close to a lease timeout? */ | |
77 | if (time_after(now, last + lease/3)) { | |
78 | spin_unlock(&clp->cl_lock); | |
79 | /* Queue an asynchronous RENEW. */ | |
80 | nfs4_proc_async_renew(clp); | |
81 | timeout = (2 * lease) / 3; | |
82 | spin_lock(&clp->cl_lock); | |
83 | } else | |
84 | dprintk("%s: failed to call renewd. Reason: lease not expired \n", | |
85 | __FUNCTION__); | |
86 | if (timeout < 5 * HZ) /* safeguard */ | |
87 | timeout = 5 * HZ; | |
88 | dprintk("%s: requeueing work. Lease period = %ld\n", | |
89 | __FUNCTION__, (timeout + HZ - 1) / HZ); | |
90 | cancel_delayed_work(&clp->cl_renewd); | |
91 | schedule_delayed_work(&clp->cl_renewd, timeout); | |
92 | spin_unlock(&clp->cl_lock); | |
93 | out: | |
94 | up_read(&clp->cl_sem); | |
95 | dprintk("%s: done\n", __FUNCTION__); | |
96 | } | |
97 | ||
98 | /* Must be called with clp->cl_sem locked for writes */ | |
99 | void | |
100 | nfs4_schedule_state_renewal(struct nfs4_client *clp) | |
101 | { | |
102 | long timeout; | |
103 | ||
104 | spin_lock(&clp->cl_lock); | |
105 | timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal | |
106 | - (long)jiffies; | |
107 | if (timeout < 5 * HZ) | |
108 | timeout = 5 * HZ; | |
109 | dprintk("%s: requeueing work. Lease period = %ld\n", | |
110 | __FUNCTION__, (timeout + HZ - 1) / HZ); | |
111 | cancel_delayed_work(&clp->cl_renewd); | |
112 | schedule_delayed_work(&clp->cl_renewd, timeout); | |
113 | spin_unlock(&clp->cl_lock); | |
114 | } | |
115 | ||
116 | void | |
117 | nfs4_renewd_prepare_shutdown(struct nfs_server *server) | |
118 | { | |
119 | struct nfs4_client *clp = server->nfs4_state; | |
120 | ||
121 | if (!clp) | |
122 | return; | |
123 | flush_scheduled_work(); | |
124 | down_write(&clp->cl_sem); | |
125 | if (!list_empty(&server->nfs4_siblings)) | |
126 | list_del_init(&server->nfs4_siblings); | |
127 | up_write(&clp->cl_sem); | |
128 | } | |
129 | ||
130 | /* Must be called with clp->cl_sem locked for writes */ | |
131 | void | |
132 | nfs4_kill_renewd(struct nfs4_client *clp) | |
133 | { | |
134 | down_read(&clp->cl_sem); | |
135 | if (!list_empty(&clp->cl_superblocks)) { | |
136 | up_read(&clp->cl_sem); | |
137 | return; | |
138 | } | |
139 | cancel_delayed_work(&clp->cl_renewd); | |
140 | up_read(&clp->cl_sem); | |
141 | flush_scheduled_work(); | |
142 | } | |
143 | ||
144 | /* | |
145 | * Local variables: | |
146 | * c-basic-offset: 8 | |
147 | * End: | |
148 | */ |