[net-next-2.6.git] / fs / nfs / nfs4renewd.c

/*
 *  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.
 *
 * TODO: If the send queue gets backlogged (e.g., if the server goes down),
 * we will keep filling the queue with periodic RENEW requests.  We need a
 * mechanism for ensuring that if renewd successfully sends off a request,
 * then it only wakes up when the request is finished.  Maybe use the
 * child task framework of the RPC layer?
 */

#include <linux/sched.h>
#include <linux/smp_lock.h>
#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"

#define NFSDBG_FACILITY	NFSDBG_PROC

void
nfs4_renew_state(void *data)
{
	struct nfs4_client *clp = (struct nfs4_client *)data;
	long lease, timeout;
	unsigned long last, now;

	down_read(&clp->cl_sem);
	dprintk("%s: start\n", __FUNCTION__);
	/* Are there any active superblocks? */
	if (list_empty(&clp->cl_superblocks))
		goto out; 
	spin_lock(&clp->cl_lock);
	lease = clp->cl_lease_time;
	last = clp->cl_last_renewal;
	now = jiffies;
	timeout = (2 * lease) / 3 + (long)last - (long)now;
	/* Are we close to a lease timeout? */
	if (time_after(now, last + lease/3)) {
		spin_unlock(&clp->cl_lock);
		/* Queue an asynchronous RENEW. */
		nfs4_proc_async_renew(clp);
		timeout = (2 * lease) / 3;
		spin_lock(&clp->cl_lock);
	} else
		dprintk("%s: failed to call renewd. Reason: lease not expired \n",
				__FUNCTION__);
	if (timeout < 5 * HZ)    /* safeguard */
		timeout = 5 * HZ;
	dprintk("%s: requeueing work. Lease period = %ld\n",
			__FUNCTION__, (timeout + HZ - 1) / HZ);
	cancel_delayed_work(&clp->cl_renewd);
	schedule_delayed_work(&clp->cl_renewd, timeout);
	spin_unlock(&clp->cl_lock);
out:
	up_read(&clp->cl_sem);
	dprintk("%s: done\n", __FUNCTION__);
}

/* Must be called with clp->cl_sem locked for writes */
void
nfs4_schedule_state_renewal(struct nfs4_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\n",
			__FUNCTION__, (timeout + HZ - 1) / HZ);
	cancel_delayed_work(&clp->cl_renewd);
	schedule_delayed_work(&clp->cl_renewd, timeout);
	spin_unlock(&clp->cl_lock);
}

void
nfs4_renewd_prepare_shutdown(struct nfs_server *server)
{
	struct nfs4_client *clp = server->nfs4_state;

	if (!clp)
		return;
	flush_scheduled_work();
	down_write(&clp->cl_sem);
	if (!list_empty(&server->nfs4_siblings))
		list_del_init(&server->nfs4_siblings);
	up_write(&clp->cl_sem);
}

/* Must be called with clp->cl_sem locked for writes */
void
nfs4_kill_renewd(struct nfs4_client *clp)
{
	down_read(&clp->cl_sem);
	if (!list_empty(&clp->cl_superblocks)) {
		up_read(&clp->cl_sem);
		return;
	}
	cancel_delayed_work(&clp->cl_renewd);
	up_read(&clp->cl_sem);
	flush_scheduled_work();
}

/*
 * Local variables:
 *   c-basic-offset: 8
 * End:
 */
Commit	Line	Data
1da177e4 LT	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/sched.h>
	47	#include <linux/smp_lock.h>
	48	#include <linux/mm.h>
	49	#include <linux/pagemap.h>
	50	#include <linux/sunrpc/sched.h>
	51	#include <linux/sunrpc/clnt.h>
	52
	53	#include <linux/nfs.h>
	54	#include <linux/nfs4.h>
	55	#include <linux/nfs_fs.h>
4ce79717	56	#include "nfs4_fs.h"
1da177e4 LT	57
	58	#define NFSDBG_FACILITY NFSDBG_PROC
	59
	60	void
	61	nfs4_renew_state(void *data)
	62	{
	63	struct nfs4_client clp = (struct nfs4_client )data;
	64	long lease, timeout;
	65	unsigned long last, now;
	66
	67	down_read(&clp->cl_sem);
	68	dprintk("%s: start\n", __FUNCTION__);
	69	/* Are there any active superblocks? */
	70	if (list_empty(&clp->cl_superblocks))
	71	goto out;
	72	spin_lock(&clp->cl_lock);
	73	lease = clp->cl_lease_time;
	74	last = clp->cl_last_renewal;
	75	now = jiffies;
	76	timeout = (2 * lease) / 3 + (long)last - (long)now;
	77	/* Are we close to a lease timeout? */
	78	if (time_after(now, last + lease/3)) {
	79	spin_unlock(&clp->cl_lock);
	80	/* Queue an asynchronous RENEW. */
	81	nfs4_proc_async_renew(clp);
	82	timeout = (2 * lease) / 3;
	83	spin_lock(&clp->cl_lock);
	84	} else
	85	dprintk("%s: failed to call renewd. Reason: lease not expired \n",
	86	__FUNCTION__);
	87	if (timeout < 5 * HZ) /* safeguard */
	88	timeout = 5 * HZ;
	89	dprintk("%s: requeueing work. Lease period = %ld\n",
	90	__FUNCTION__, (timeout + HZ - 1) / HZ);
	91	cancel_delayed_work(&clp->cl_renewd);
	92	schedule_delayed_work(&clp->cl_renewd, timeout);
	93	spin_unlock(&clp->cl_lock);
	94	out:
	95	up_read(&clp->cl_sem);
	96	dprintk("%s: done\n", __FUNCTION__);
	97	}
	98
	99	/* Must be called with clp->cl_sem locked for writes */
	100	void
	101	nfs4_schedule_state_renewal(struct nfs4_client *clp)
	102	{
	103	long timeout;
	104
	105	spin_lock(&clp->cl_lock);
	106	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
	107	- (long)jiffies;
	108	if (timeout < 5 * HZ)
	109	timeout = 5 * HZ;
	110	dprintk("%s: requeueing work. Lease period = %ld\n",
	111	__FUNCTION__, (timeout + HZ - 1) / HZ);
	112	cancel_delayed_work(&clp->cl_renewd);
	113	schedule_delayed_work(&clp->cl_renewd, timeout);
	114	spin_unlock(&clp->cl_lock);
	115	}
	116
	117	void
	118	nfs4_renewd_prepare_shutdown(struct nfs_server *server)
	119	{
	120	struct nfs4_client *clp = server->nfs4_state;
121
122	if (!clp)
123	return;
124	flush_scheduled_work();
125	down_write(&clp->cl_sem);
126	if (!list_empty(&server->nfs4_siblings))
127	list_del_init(&server->nfs4_siblings);
128	up_write(&clp->cl_sem);
129	}
130
131	/* Must be called with clp->cl_sem locked for writes */
132	void
133	nfs4_kill_renewd(struct nfs4_client *clp)
134	{
135	down_read(&clp->cl_sem);
136	if (!list_empty(&clp->cl_superblocks)) {
137	up_read(&clp->cl_sem);
138	return;
139	}
140	cancel_delayed_work(&clp->cl_renewd);
141	up_read(&clp->cl_sem);
142	flush_scheduled_work();
143	}
144
145	/*
146	* Local variables:
147	* c-basic-offset: 8
148	* End:
149	*/