LXR linux/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
  54void
  55nfs4_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);
 110out_exp:
 111        nfs_expire_unreferenced_delegations(clp);
 112out:
 113        dprintk("%s: done\n", __func__);
 114}
 115
 116void
 117nfs4_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
 133void
 134nfs4_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 */
 144