Linux Kernel  3.7.1
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nfs4renewd.c
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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 <[email protected]>
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 
54 void
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 
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  }
90  } else {
91  /* Queue an asynchronous RENEW. */
92  ops->sched_state_renewal(clp, cred, renew_flags);
93  put_rpccred(cred);
94  goto out_exp;
95  }
96  } else {
97  dprintk("%s: failed to call renewd. Reason: lease not expired \n",
98  __func__);
99  spin_unlock(&clp->cl_lock);
100  }
102 out_exp:
104 out:
105  dprintk("%s: done\n", __func__);
106 }
107 
108 void
110 {
111  long timeout;
112 
113  spin_lock(&clp->cl_lock);
114  timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
115  - (long)jiffies;
116  if (timeout < 5 * HZ)
117  timeout = 5 * HZ;
118  dprintk("%s: requeueing work. Lease period = %ld\n",
119  __func__, (timeout + HZ - 1) / HZ);
120  mod_delayed_work(system_wq, &clp->cl_renewd, timeout);
122  spin_unlock(&clp->cl_lock);
123 }
124 
125 void
127 {
128  cancel_delayed_work_sync(&clp->cl_renewd);
129 }
130 
131 /*
132  * Local variables:
133  * c-basic-offset: 8
134  * End:
135  */