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_STATE
  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         unsigned renew_flags = 0;
  64
  65         ops = clp->cl_mvops->state_renewal_ops;
  66         dprintk("%s: start\n", __func__);
  67
  68         if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))
  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                         }
  89                         nfs_expire_all_delegations(clp);
  90                 } else {
  91                         int ret;
  92
  93                         /* Queue an asynchronous RENEW. */
  94                         ret = ops->sched_state_renewal(clp, cred, renew_flags);
  95                         put_rpccred(cred);
  96                         switch (ret) {
  97                         default:
  98                                 goto out_exp;
  99                         case -EAGAIN:
 100                         case -ENOMEM:
 101                                 break;
 102                         }
 103                 }
 104         } else {
 105                 dprintk("%s: failed to call renewd. Reason: lease not expired \n",
 106                                 __func__);
 107                 spin_unlock(&clp->cl_lock);
 108         }
 109         nfs4_schedule_state_renewal(clp);
 110 out_exp:
 111         nfs_expire_unreferenced_delegations(clp);
 112 out:
 113         dprintk("%s: done\n", __func__);
 114 }
 115
 116 void
 117 nfs4_schedule_state_renewal(struct nfs_client *clp)
 118 {
 119         long timeout;
 120
 121         spin_lock(&clp->cl_lock);
 122         timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
 123                 - (long)jiffies;
 124         if (timeout < 5 * HZ)
 125                 timeout = 5 * HZ;
 126         dprintk("%s: requeueing work. Lease period = %ld\n",
 127                         __func__, (timeout + HZ - 1) / HZ);
 128         mod_delayed_work(system_wq, &clp->cl_renewd, timeout);
 129         set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
 130         spin_unlock(&clp->cl_lock);
 131 }
 132
 133 void
 134 nfs4_kill_renewd(struct nfs_client *clp)
 135 {
 136         cancel_delayed_work_sync(&clp->cl_renewd);
 137 }
 138
 139 /*
 140  * Local variables:
 141  *   c-basic-offset: 8
 142  * End:
 143  */