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 * 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/mm.h>
  47#include <linux/pagemap.h>
  48#include <linux/sunrpc/sched.h>
  49#include <linux/sunrpc/clnt.h>
  50
  51#include <linux/nfs.h>
  52#include <linux/nfs4.h>
  53#include <linux/nfs_fs.h>
  54#include "nfs4_fs.h"
  55#include "delegation.h"
  56
  57#define NFSDBG_FACILITY NFSDBG_PROC
  58
  59void
  60nfs4_renew_state(struct work_struct *work)
  61{
  62        struct nfs4_state_maintenance_ops *ops;
  63        struct nfs_client *clp =
  64                container_of(work, struct nfs_client, cl_renewd.work);
  65        struct rpc_cred *cred;
  66        long lease, timeout;
  67        unsigned long last, now;
  68
  69        ops = nfs4_state_renewal_ops[clp->cl_minorversion];
  70        dprintk("%s: start\n", __func__);
  71        /* Are there any active superblocks? */
  72        if (list_empty(&clp->cl_superblocks))
  73                goto out;
  74        spin_lock(&clp->cl_lock);
  75        lease = clp->cl_lease_time;
  76        last = clp->cl_last_renewal;
  77        now = jiffies;
  78        timeout = (2 * lease) / 3 + (long)last - (long)now;
  79        /* Are we close to a lease timeout? */
  80        if (time_after(now, last + lease/3)) {
  81                cred = ops->get_state_renewal_cred_locked(clp);
  82                spin_unlock(&clp->cl_lock);
  83                if (cred == NULL) {
  84                        if (list_empty(&clp->cl_delegations)) {
  85                                set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
  86                                goto out;
  87                        }
  88                        nfs_expire_all_delegations(clp);
  89                } else {
  90                        /* Queue an asynchronous RENEW. */
  91                        ops->sched_state_renewal(clp, cred);
  92                        put_rpccred(cred);
  93                }
  94                timeout = (2 * lease) / 3;
  95                spin_lock(&clp->cl_lock);
  96        } else
  97                dprintk("%s: failed to call renewd. Reason: lease not expired \n",
  98                                __func__);
  99        if (timeout < 5 * HZ)    /* safeguard */
 100                timeout = 5 * HZ;
 101        dprintk("%s: requeueing work. Lease period = %ld\n",
 102                        __func__, (timeout + HZ - 1) / HZ);
 103        cancel_delayed_work(&clp->cl_renewd);
 104        schedule_delayed_work(&clp->cl_renewd, timeout);
 105        spin_unlock(&clp->cl_lock);
 106        nfs_expire_unreferenced_delegations(clp);
 107out:
 108        dprintk("%s: done\n", __func__);
 109}
 110
 111void
 112nfs4_schedule_state_renewal(struct nfs_client *clp)
 113{
 114        long timeout;
 115
 116        spin_lock(&clp->cl_lock);
 117        timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
 118                - (long)jiffies;
 119        if (timeout < 5 * HZ)
 120                timeout = 5 * HZ;
 121        dprintk("%s: requeueing work. Lease period = %ld\n",
 122                        __func__, (timeout + HZ - 1) / HZ);
 123        cancel_delayed_work(&clp->cl_renewd);
 124        schedule_delayed_work(&clp->cl_renewd, timeout);
 125        set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
 126        spin_unlock(&clp->cl_lock);
 127}
 128
 129void
 130nfs4_kill_renewd(struct nfs_client *clp)
 131{
 132        cancel_delayed_work_sync(&clp->cl_renewd);
 133}
 134
 135/*
 136 * Local variables:
 137 *   c-basic-offset: 8
 138 * End:
 139 */
 140