release/src-rt-6.x.4708/linux/linux-2.6.36/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  */
  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
  54 void
  55 nfs4_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);
  95 out_exp:
  96         nfs_expire_unreferenced_delegations(clp);
  97 out:
  98         dprintk("%s: done\n", __func__);
  99 }
 100
 101 void
 102 nfs4_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
 119 void
 120 nfs4_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  */