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 nfs_client *clp =
  63                container_of(work, struct nfs_client, cl_renewd.work);
  64        struct rpc_cred *cred;
  65        long lease, timeout;
  66        unsigned long last, now;
  67
  68        down_read(&clp->cl_sem);
  69        dprintk("%s: start\n", __func__);
  70        /* Are there any active superblocks? */
  71        if (list_empty(&clp->cl_superblocks))
  72                goto out;
  73        spin_lock(&clp->cl_lock);
  74        lease = clp->cl_lease_time;
  75        last = clp->cl_last_renewal;
  76        now = jiffies;
  77        timeout = (2 * lease) / 3 + (long)last - (long)now;
  78        /* Are we close to a lease timeout? */
  79        if (time_after(now, last + lease/3)) {
  80                cred = nfs4_get_renew_cred(clp);
  81                if (cred == NULL) {
  82                        set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
  83                        spin_unlock(&clp->cl_lock);
  84                        nfs_expire_all_delegations(clp);
  85                        goto out;
  86                }
  87                spin_unlock(&clp->cl_lock);
  88                /* Queue an asynchronous RENEW. */
  89                nfs4_proc_async_renew(clp, cred);
  90                put_rpccred(cred);
  91                timeout = (2 * lease) / 3;
  92                spin_lock(&clp->cl_lock);
  93        } else
  94                dprintk("%s: failed to call renewd. Reason: lease not expired \n",
  95                                __func__);
  96        if (timeout < 5 * HZ)    /* safeguard */
  97                timeout = 5 * HZ;
  98        dprintk("%s: requeueing work. Lease period = %ld\n",
  99                        __func__, (timeout + HZ - 1) / HZ);
 100        cancel_delayed_work(&clp->cl_renewd);
 101        schedule_delayed_work(&clp->cl_renewd, timeout);
 102        spin_unlock(&clp->cl_lock);
 103out:
 104        up_read(&clp->cl_sem);
 105        dprintk("%s: done\n", __func__);
 106}
 107
 108/* Must be called with clp->cl_sem locked for writes */
 109void
 110nfs4_schedule_state_renewal(struct nfs_client *clp)
 111{
 112        long timeout;
 113
 114        spin_lock(&clp->cl_lock);
 115        timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
 116                - (long)jiffies;
 117        if (timeout < 5 * HZ)
 118                timeout = 5 * HZ;
 119        dprintk("%s: requeueing work. Lease period = %ld\n",
 120                        __func__, (timeout + HZ - 1) / HZ);
 121        cancel_delayed_work(&clp->cl_renewd);
 122        schedule_delayed_work(&clp->cl_renewd, timeout);
 123        set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
 124        spin_unlock(&clp->cl_lock);
 125}
 126
 127void
 128nfs4_renewd_prepare_shutdown(struct nfs_server *server)
 129{
 130        cancel_delayed_work(&server->nfs_client->cl_renewd);
 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