fs/nfs/nfs4renewd.c

   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 #include "nfs4_fs.h"
  57
  58 #define NFSDBG_FACILITY NFSDBG_PROC
  59
  60 void
  61 nfs4_renew_state(void *data)
  62 {
  63         struct nfs4_client *clp = (struct nfs4_client *)data;
  64         long lease, timeout;
  65         unsigned long last, now;
  66
  67         down_read(&clp->cl_sem);
  68         dprintk("%s: start\n", __FUNCTION__);
  69         /* Are there any active superblocks? */
  70         if (list_empty(&clp->cl_superblocks))
  71                 goto out;
  72         spin_lock(&clp->cl_lock);
  73         lease = clp->cl_lease_time;
  74         last = clp->cl_last_renewal;
  75         now = jiffies;
  76         timeout = (2 * lease) / 3 + (long)last - (long)now;
  77         /* Are we close to a lease timeout? */
  78         if (time_after(now, last + lease/3)) {
  79                 spin_unlock(&clp->cl_lock);
  80                 /* Queue an asynchronous RENEW. */
  81                 nfs4_proc_async_renew(clp);
  82                 timeout = (2 * lease) / 3;
  83                 spin_lock(&clp->cl_lock);
  84         } else
  85                 dprintk("%s: failed to call renewd. Reason: lease not expired \n",
  86                                 __FUNCTION__);
  87         if (timeout < 5 * HZ)    /* safeguard */
  88                 timeout = 5 * HZ;
  89         dprintk("%s: requeueing work. Lease period = %ld\n",
  90                         __FUNCTION__, (timeout + HZ - 1) / HZ);
  91         cancel_delayed_work(&clp->cl_renewd);
  92         schedule_delayed_work(&clp->cl_renewd, timeout);
  93         spin_unlock(&clp->cl_lock);
  94 out:
  95         up_read(&clp->cl_sem);
  96         dprintk("%s: done\n", __FUNCTION__);
  97 }
  98
  99 /* Must be called with clp->cl_sem locked for writes */
 100 void
 101 nfs4_schedule_state_renewal(struct nfs4_client *clp)
 102 {
 103         long timeout;
 104
 105         spin_lock(&clp->cl_lock);
 106         timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
 107                 - (long)jiffies;
 108         if (timeout < 5 * HZ)
 109                 timeout = 5 * HZ;
 110         dprintk("%s: requeueing work. Lease period = %ld\n",
 111                         __FUNCTION__, (timeout + HZ - 1) / HZ);
 112         cancel_delayed_work(&clp->cl_renewd);
 113         schedule_delayed_work(&clp->cl_renewd, timeout);
 114         spin_unlock(&clp->cl_lock);
 115 }
 116
 117 void
 118 nfs4_renewd_prepare_shutdown(struct nfs_server *server)
 119 {
 120         struct nfs4_client *clp = server->nfs4_state;
 121
 122         if (!clp)
 123                 return;
 124         flush_scheduled_work();
 125         down_write(&clp->cl_sem);
 126         if (!list_empty(&server->nfs4_siblings))
 127                 list_del_init(&server->nfs4_siblings);
 128         up_write(&clp->cl_sem);
 129 }
 130
 131 /* Must be called with clp->cl_sem locked for writes */
 132 void
 133 nfs4_kill_renewd(struct nfs4_client *clp)
 134 {
 135         down_read(&clp->cl_sem);
 136         if (!list_empty(&clp->cl_superblocks)) {
 137                 up_read(&clp->cl_sem);
 138                 return;
 139         }
 140         cancel_delayed_work(&clp->cl_renewd);
 141         up_read(&clp->cl_sem);
 142         flush_scheduled_work();
 143 }
 144
 145 /*
 146  * Local variables:
 147  *   c-basic-offset: 8
 148  * End:
 149  */