/*
   *  fs/nfs/nfs4renewd.c
   *
   *  Copyright (c) 2002 The Regents of the University of Michigan.
   *  All rights reserved.
   *
   *  Kendrick Smith <kmsmith@umich.edu>
   *
   *  Redistribution and use in source and binary forms, with or without
   *  modification, are permitted provided that the following conditions
   *  are met:
   *
   *  1. Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   *  2. Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   *  3. Neither the name of the University nor the names of its
   *     contributors may be used to endorse or promote products derived
   *     from this software without specific prior written permission.
   *
   *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
   *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
   *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * Implementation of the NFSv4 "renew daemon", which wakes up periodically to
   * send a RENEW, to keep state alive on the server.  The daemon is implemented
   * as an rpc_task, not a real kernel thread, so it always runs in rpciod's
   * context.  There is one renewd per nfs_server.
   *

   */

  #include <linux/mm.h>
  #include <linux/pagemap.h>
  #include <linux/sunrpc/sched.h>
  #include <linux/sunrpc/clnt.h>
  
  #include <linux/nfs.h>
  #include <linux/nfs4.h>
  #include <linux/nfs_fs.h>

  #include "nfs4_fs.h"

  #include "delegation.h"

  #define NFSDBG_FACILITY		NFSDBG_STATE

  
  void

  nfs4_renew_state(struct work_struct *work)

  {

  	const struct nfs4_state_maintenance_ops *ops;

  	struct nfs_client *clp =
  		container_of(work, struct nfs_client, cl_renewd.work);

  	const struct cred *cred;

  	long lease;

  	unsigned long last, now;

  	unsigned renew_flags = 0;

  	ops = clp->cl_mvops->state_renewal_ops;

  	dprintk("%s: start
  ", __func__);

  	if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))

  		goto out;

  	lease = clp->cl_lease_time;
  	last = clp->cl_last_renewal;
  	now = jiffies;

  	/* Are we close to a lease timeout? */

  	if (time_after(now, last + lease/3))
  		renew_flags |= NFS4_RENEW_TIMEOUT;
  	if (nfs_delegations_present(clp))
  		renew_flags |= NFS4_RENEW_DELEGATION_CB;
  
  	if (renew_flags != 0) {

  		cred = ops->get_state_renewal_cred(clp);

  		if (cred == NULL) {

  			if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {

  				set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
  				goto out;
  			}

  			nfs_expire_all_delegations(clp);

  		} else {

  			int ret;

  			/* Queue an asynchronous RENEW. */

  			ret = ops->sched_state_renewal(clp, cred, renew_flags);

  			put_cred(cred);

  			switch (ret) {
  			default:
  				goto out_exp;
  			case -EAGAIN:
  			case -ENOMEM:
  				break;
  			}

  		}

  	} else {

  		dprintk("%s: failed to call renewd. Reason: lease not expired 
  ",

  				__func__);

  	}
  	nfs4_schedule_state_renewal(clp);
  out_exp:

  	nfs_expire_unreferenced_delegations(clp);

  out:

  	dprintk("%s: done
  ", __func__);

  }

  void

  nfs4_schedule_state_renewal(struct nfs_client *clp)

  {
  	long timeout;
  
  	spin_lock(&clp->cl_lock);
  	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
  		- (long)jiffies;
  	if (timeout < 5 * HZ)
  		timeout = 5 * HZ;
  	dprintk("%s: requeueing work. Lease period = %ld
  ",

  			__func__, (timeout + HZ - 1) / HZ);

  	mod_delayed_work(system_wq, &clp->cl_renewd, timeout);

  	set_bit(NFS_CS_RENEWD, &clp->cl_res_state);

  	spin_unlock(&clp->cl_lock);
  }
  
  void

  nfs4_kill_renewd(struct nfs_client *clp)

  {

  	cancel_delayed_work_sync(&clp->cl_renewd);

  }

  /**
   * nfs4_set_lease_period - Sets the lease period on a nfs_client
   *
   * @clp: pointer to nfs_client
   * @lease: new value for lease period

   */
  void nfs4_set_lease_period(struct nfs_client *clp,

  		unsigned long lease)

  {
  	spin_lock(&clp->cl_lock);
  	clp->cl_lease_time = lease;

  	spin_unlock(&clp->cl_lock);

  
  	/* Cap maximum reconnect timeout at 1/2 lease period */

  	rpc_set_connect_timeout(clp->cl_rpcclient, lease, lease >> 1);

  }

  /*
   * Local variables:
   *   c-basic-offset: 8
   * End:
   */