[linux-2.6-block.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"
#include "delegation.h"

#define NFSDBG_FACILITY	NFSDBG_PROC

void
nfs4_renew_state(void *data)
{
	struct nfs4_client *clp = (struct nfs4_client *)data;
	struct rpc_cred *cred;
	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)) {
		cred = nfs4_get_renew_cred(clp);
		if (cred == NULL) {
			set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
			spin_unlock(&clp->cl_lock);
			nfs_expire_all_delegations(clp);
			goto out;
		}
		spin_unlock(&clp->cl_lock);
		/* Queue an asynchronous RENEW. */
		nfs4_proc_async_renew(clp, cred);
		put_rpccred(cred);
		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"
58d9714a	57	#include "delegation.h"
1da177e4 LT	58
	59	#define NFSDBG_FACILITY NFSDBG_PROC
	60
	61	void
	62	nfs4_renew_state(void *data)
	63	{
	64	struct nfs4_client clp = (struct nfs4_client )data;
b4454fe1	65	struct rpc_cred *cred;
1da177e4 LT	66	long lease, timeout;
	67	unsigned long last, now;
	68
	69	down_read(&clp->cl_sem);
	70	dprintk("%s: start\n", __FUNCTION__);
	71	/* Are there any active superblocks? */
	72	if (list_empty(&clp->cl_superblocks))
58d9714a	73	goto out;
1da177e4 LT	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)) {
b4454fe1 TM	81	cred = nfs4_get_renew_cred(clp);
b4454fe1 TM	82	if (cred == NULL) {
58d9714a TM	83	set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
	84	spin_unlock(&clp->cl_lock);
	85	nfs_expire_all_delegations(clp);
	86	goto out;
	87	}
1da177e4 LT	88	spin_unlock(&clp->cl_lock);
1da177e4 LT	89	/* Queue an asynchronous RENEW. */
b4454fe1 TM	90	nfs4_proc_async_renew(clp, cred);
b4454fe1 TM	91	put_rpccred(cred);
1da177e4 LT	92	timeout = (2 * lease) / 3;
	93	spin_lock(&clp->cl_lock);
	94	} else
	95	dprintk("%s: failed to call renewd. Reason: lease not expired \n",
	96	__FUNCTION__);
	97	if (timeout < 5 * HZ) /* safeguard */
	98	timeout = 5 * HZ;
	99	dprintk("%s: requeueing work. Lease period = %ld\n",
	100	__FUNCTION__, (timeout + HZ - 1) / HZ);
	101	cancel_delayed_work(&clp->cl_renewd);
	102	schedule_delayed_work(&clp->cl_renewd, timeout);
	103	spin_unlock(&clp->cl_lock);
	104	out:
	105	up_read(&clp->cl_sem);
	106	dprintk("%s: done\n", __FUNCTION__);
	107	}
	108
	109	/* Must be called with clp->cl_sem locked for writes */
	110	void
	111	nfs4_schedule_state_renewal(struct nfs4_client *clp)
	112	{
	113	long timeout;
	114
	115	spin_lock(&clp->cl_lock);
	116	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
	117	- (long)jiffies;
	118	if (timeout < 5 * HZ)
	119	timeout = 5 * HZ;
	120	dprintk("%s: requeueing work. Lease period = %ld\n",
	121	__FUNCTION__, (timeout + HZ - 1) / HZ);
	122	cancel_delayed_work(&clp->cl_renewd);
	123	schedule_delayed_work(&clp->cl_renewd, timeout);
	124	spin_unlock(&clp->cl_lock);
	125	}
	126
	127	void
	128	nfs4_renewd_prepare_shutdown(struct nfs_server *server)
	129	{
	130	struct nfs4_client *clp = server->nfs4_state;
	131
	132	if (!clp)
	133	return;
	134	flush_scheduled_work();
	135	down_write(&clp->cl_sem);
	136	if (!list_empty(&server->nfs4_siblings))
	137	list_del_init(&server->nfs4_siblings);
	138	up_write(&clp->cl_sem);
	139	}
	140
	141	/* Must be called with clp->cl_sem locked for writes */
	142	void
	143	nfs4_kill_renewd(struct nfs4_client *clp)
	144	{
	145	down_read(&clp->cl_sem);
	146	if (!list_empty(&clp->cl_superblocks)) {
	147	up_read(&clp->cl_sem);
	148	return;
	149	}
	150	cancel_delayed_work(&clp->cl_renewd);
	151	up_read(&clp->cl_sem);
	152	flush_scheduled_work();
	153	}
	154
	155	/*
156	* Local variables:
157	* c-basic-offset: 8
158	* End:
159	*/