[net-next-2.6.git] / fs / nfsd / nfssvc.c

/*
 * linux/fs/nfsd/nfssvc.c
 *
 * Central processing for nfsd.
 *
 * Authors:	Olaf Kirch (okir@monad.swb.de)
 *
 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/config.h>
#include <linux/module.h>

#include <linux/time.h>
#include <linux/errno.h>
#include <linux/nfs.h>
#include <linux/in.h>
#include <linux/uio.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/fs_struct.h>

#include <linux/sunrpc/types.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/cache.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/stats.h>
#include <linux/nfsd/cache.h>
#include <linux/lockd/bind.h>

#define NFSDDBG_FACILITY	NFSDDBG_SVC

/* these signals will be delivered to an nfsd thread 
 * when handling a request
 */
#define ALLOWED_SIGS	(sigmask(SIGKILL))
/* these signals will be delivered to an nfsd thread
 * when not handling a request. i.e. when waiting
 */
#define SHUTDOWN_SIGS	(sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
/* if the last thread dies with SIGHUP, then the exports table is
 * left unchanged ( like 2.4-{0-9} ).  Any other signal will clear
 * the exports table (like 2.2).
 */
#define	SIG_NOCLEAN	SIGHUP

extern struct svc_program	nfsd_program;
static void			nfsd(struct svc_rqst *rqstp);
struct timeval			nfssvc_boot;
static struct svc_serv 		*nfsd_serv;
static atomic_t			nfsd_busy;
static unsigned long		nfsd_last_call;
static DEFINE_SPINLOCK(nfsd_call_lock);

struct nfsd_list {
	struct list_head 	list;
	struct task_struct	*task;
};
static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);

/*
 * Maximum number of nfsd processes
 */
#define	NFSD_MAXSERVS		8192

int nfsd_nrthreads(void)
{
	if (nfsd_serv == NULL)
		return 0;
	else
		return nfsd_serv->sv_nrthreads;
}

int
nfsd_svc(unsigned short port, int nrservs)
{
	int	error;
	int	none_left;	
	struct list_head *victim;
	
	lock_kernel();
	dprintk("nfsd: creating service\n");
	error = -EINVAL;
	if (nrservs <= 0)
		nrservs = 0;
	if (nrservs > NFSD_MAXSERVS)
		nrservs = NFSD_MAXSERVS;
	
	/* Readahead param cache - will no-op if it already exists */
	error =	nfsd_racache_init(2*nrservs);
	if (error<0)
		goto out;
	error = nfs4_state_init();
	if (error<0)
		goto out;
	if (!nfsd_serv) {
		atomic_set(&nfsd_busy, 0);
		error = -ENOMEM;
		nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE);
		if (nfsd_serv == NULL)
			goto out;
		error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
		if (error < 0)
			goto failure;

#ifdef CONFIG_NFSD_TCP
		error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
		if (error < 0)
			goto failure;
#endif
		do_gettimeofday(&nfssvc_boot);		/* record boot time */
	} else
		nfsd_serv->sv_nrthreads++;
	nrservs -= (nfsd_serv->sv_nrthreads-1);
	while (nrservs > 0) {
		nrservs--;
		__module_get(THIS_MODULE);
		error = svc_create_thread(nfsd, nfsd_serv);
		if (error < 0) {
			module_put(THIS_MODULE);
			break;
		}
	}
	victim = nfsd_list.next;
	while (nrservs < 0 && victim != &nfsd_list) {
		struct nfsd_list *nl =
			list_entry(victim,struct nfsd_list, list);
		victim = victim->next;
		send_sig(SIG_NOCLEAN, nl->task, 1);
		nrservs++;
	}
 failure:
	none_left = (nfsd_serv->sv_nrthreads == 1);
	svc_destroy(nfsd_serv);		/* Release server */
	if (none_left) {
		nfsd_serv = NULL;
		nfsd_racache_shutdown();
		nfs4_state_shutdown();
	}
 out:
	unlock_kernel();
	return error;
}

static inline void
update_thread_usage(int busy_threads)
{
	unsigned long prev_call;
	unsigned long diff;
	int decile;

	spin_lock(&nfsd_call_lock);
	prev_call = nfsd_last_call;
	nfsd_last_call = jiffies;
	decile = busy_threads*10/nfsdstats.th_cnt;
	if (decile>0 && decile <= 10) {
		diff = nfsd_last_call - prev_call;
		if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
			nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
		if (decile == 10)
			nfsdstats.th_fullcnt++;
	}
	spin_unlock(&nfsd_call_lock);
}

/*
 * This is the NFS server kernel thread
 */
static void
nfsd(struct svc_rqst *rqstp)
{
	struct svc_serv	*serv = rqstp->rq_server;
	struct fs_struct *fsp;
	int		err;
	struct nfsd_list me;
	sigset_t shutdown_mask, allowed_mask;

	/* Lock module and set up kernel thread */
	lock_kernel();
	daemonize("nfsd");

	/* After daemonize() this kernel thread shares current->fs
	 * with the init process. We need to create files with a
	 * umask of 0 instead of init's umask. */
	fsp = copy_fs_struct(current->fs);
	if (!fsp) {
		printk("Unable to start nfsd thread: out of memory\n");
		goto out;
	}
	exit_fs(current);
	current->fs = fsp;
	current->fs->umask = 0;

	siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
	siginitsetinv(&allowed_mask, ALLOWED_SIGS);

	nfsdstats.th_cnt++;

	lockd_up();				/* start lockd */

	me.task = current;
	list_add(&me.list, &nfsd_list);

	unlock_kernel();

	/*
	 * We want less throttling in balance_dirty_pages() so that nfs to
	 * localhost doesn't cause nfsd to lock up due to all the client's
	 * dirty pages.
	 */
	current->flags |= PF_LESS_THROTTLE;

	/*
	 * The main request loop
	 */
	for (;;) {
		/* Block all but the shutdown signals */
		sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);

		/*
		 * Find a socket with data available and call its
		 * recvfrom routine.
		 */
		while ((err = svc_recv(serv, rqstp,
				       60*60*HZ)) == -EAGAIN)
			;
		if (err < 0)
			break;
		update_thread_usage(atomic_read(&nfsd_busy));
		atomic_inc(&nfsd_busy);

		/* Lock the export hash tables for reading. */
		exp_readlock();

		/* Process request with signals blocked.  */
		sigprocmask(SIG_SETMASK, &allowed_mask, NULL);

		svc_process(serv, rqstp);

		/* Unlock export hash tables */
		exp_readunlock();
		update_thread_usage(atomic_read(&nfsd_busy));
		atomic_dec(&nfsd_busy);
	}

	if (err != -EINTR) {
		printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
	} else {
		unsigned int	signo;

		for (signo = 1; signo <= _NSIG; signo++)
			if (sigismember(&current->pending.signal, signo) &&
			    !sigismember(&current->blocked, signo))
				break;
		err = signo;
	}

	lock_kernel();

	/* Release lockd */
	lockd_down();

	/* Check if this is last thread */
	if (serv->sv_nrthreads==1) {
		
		printk(KERN_WARNING "nfsd: last server has exited\n");
		if (err != SIG_NOCLEAN) {
			printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
			nfsd_export_flush();
		}
		nfsd_serv = NULL;
	        nfsd_racache_shutdown();	/* release read-ahead cache */
		nfs4_state_shutdown();
	}
	list_del(&me.list);
	nfsdstats.th_cnt --;

out:
	/* Release the thread */
	svc_exit_thread(rqstp);

	/* Release module */
	module_put_and_exit(0);
}

int
nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)
{
	struct svc_procedure	*proc;
	kxdrproc_t		xdr;
	u32			nfserr;
	u32			*nfserrp;

	dprintk("nfsd_dispatch: vers %d proc %d\n",
				rqstp->rq_vers, rqstp->rq_proc);
	proc = rqstp->rq_procinfo;

	/* Check whether we have this call in the cache. */
	switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
	case RC_INTR:
	case RC_DROPIT:
		return 0;
	case RC_REPLY:
		return 1;
	case RC_DOIT:;
		/* do it */
	}

	/* Decode arguments */
	xdr = proc->pc_decode;
	if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base,
			rqstp->rq_argp)) {
		dprintk("nfsd: failed to decode arguments!\n");
		nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
		*statp = rpc_garbage_args;
		return 1;
	}

	/* need to grab the location to store the status, as
	 * nfsv4 does some encoding while processing 
	 */
	nfserrp = rqstp->rq_res.head[0].iov_base
		+ rqstp->rq_res.head[0].iov_len;
	rqstp->rq_res.head[0].iov_len += sizeof(u32);

	/* Now call the procedure handler, and encode NFS status. */
	nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
	if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
		nfserr = nfserr_dropit;
	if (nfserr == nfserr_dropit) {
		dprintk("nfsd: Dropping request due to malloc failure!\n");
		nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
		return 0;
	}

	if (rqstp->rq_proc != 0)
		*nfserrp++ = nfserr;

	/* Encode result.
	 * For NFSv2, additional info is never returned in case of an error.
	 */
	if (!(nfserr && rqstp->rq_vers == 2)) {
		xdr = proc->pc_encode;
		if (xdr && !xdr(rqstp, nfserrp,
				rqstp->rq_resp)) {
			/* Failed to encode result. Release cache entry */
			dprintk("nfsd: failed to encode result!\n");
			nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
			*statp = rpc_system_err;
			return 1;
		}
	}

	/* Store reply in cache. */
	nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
	return 1;
}

extern struct svc_version nfsd_version2, nfsd_version3, nfsd_version4;

static struct svc_version *	nfsd_version[] = {
	[2] = &nfsd_version2,
#if defined(CONFIG_NFSD_V3)
	[3] = &nfsd_version3,
#endif
#if defined(CONFIG_NFSD_V4)
	[4] = &nfsd_version4,
#endif
};

#define NFSD_NRVERS		(sizeof(nfsd_version)/sizeof(nfsd_version[0]))
struct svc_program		nfsd_program = {
	.pg_prog		= NFS_PROGRAM,		/* program number */
	.pg_nvers		= NFSD_NRVERS,		/* nr of entries in nfsd_version */
	.pg_vers		= nfsd_version,		/* version table */
	.pg_name		= "nfsd",		/* program name */
	.pg_class		= "nfsd",		/* authentication class */
	.pg_stats		= &nfsd_svcstats,	/* version table */
	.pg_authenticate	= &svc_set_client,	/* export authentication */

};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfsd/nfssvc.c
	3	*
	4	* Central processing for nfsd.
	5	*
	6	* Authors: Olaf Kirch (okir@monad.swb.de)
	7	*
	8	* Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
	9	*/
	10
	11	#include <linux/config.h>
	12	#include <linux/module.h>
	13
	14	#include <linux/time.h>
	15	#include <linux/errno.h>
	16	#include <linux/nfs.h>
	17	#include <linux/in.h>
	18	#include <linux/uio.h>
	19	#include <linux/unistd.h>
	20	#include <linux/slab.h>
	21	#include <linux/smp.h>
	22	#include <linux/smp_lock.h>
	23	#include <linux/fs_struct.h>
	24
	25	#include <linux/sunrpc/types.h>
	26	#include <linux/sunrpc/stats.h>
	27	#include <linux/sunrpc/svc.h>
	28	#include <linux/sunrpc/svcsock.h>
	29	#include <linux/sunrpc/cache.h>
	30	#include <linux/nfsd/nfsd.h>
	31	#include <linux/nfsd/stats.h>
	32	#include <linux/nfsd/cache.h>
	33	#include <linux/lockd/bind.h>
	34
	35	#define NFSDDBG_FACILITY NFSDDBG_SVC
	36
	37	/* these signals will be delivered to an nfsd thread
	38	* when handling a request
	39	*/
	40	#define ALLOWED_SIGS (sigmask(SIGKILL))
	41	/* these signals will be delivered to an nfsd thread
	42	* when not handling a request. i.e. when waiting
	43	*/
	44	#define SHUTDOWN_SIGS (sigmask(SIGKILL) \| sigmask(SIGHUP) \| sigmask(SIGINT) \| sigmask(SIGQUIT))
	45	/* if the last thread dies with SIGHUP, then the exports table is
	46	* left unchanged ( like 2.4-{0-9} ). Any other signal will clear
	47	* the exports table (like 2.2).
	48	*/
	49	#define SIG_NOCLEAN SIGHUP
	50
	51	extern struct svc_program nfsd_program;
	52	static void nfsd(struct svc_rqst *rqstp);
	53	struct timeval nfssvc_boot;
	54	static struct svc_serv *nfsd_serv;
	55	static atomic_t nfsd_busy;
	56	static unsigned long nfsd_last_call;
	57	static DEFINE_SPINLOCK(nfsd_call_lock);
	58
	59	struct nfsd_list {
	60	struct list_head list;
	61	struct task_struct *task;
	62	};
	63	static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);
	64
65	/*
66	* Maximum number of nfsd processes
67	*/
68	#define NFSD_MAXSERVS 8192
69
70	int nfsd_nrthreads(void)
71	{
72	if (nfsd_serv == NULL)
73	return 0;
74	else
75	return nfsd_serv->sv_nrthreads;
76	}
77
78	int
79	nfsd_svc(unsigned short port, int nrservs)
80	{
81	int error;
82	int none_left;
83	struct list_head *victim;
84
85	lock_kernel();
86	dprintk("nfsd: creating service\n");
87	error = -EINVAL;
88	if (nrservs <= 0)
89	nrservs = 0;
90	if (nrservs > NFSD_MAXSERVS)
91	nrservs = NFSD_MAXSERVS;
92
93	/* Readahead param cache - will no-op if it already exists */
94	error = nfsd_racache_init(2*nrservs);
95	if (error<0)
96	goto out;
97	error = nfs4_state_init();
98	if (error<0)
99	goto out;
100	if (!nfsd_serv) {
101	atomic_set(&nfsd_busy, 0);
102	error = -ENOMEM;
103	nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE);
104	if (nfsd_serv == NULL)
105	goto out;
106	error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
107	if (error < 0)
108	goto failure;
109
110	#ifdef CONFIG_NFSD_TCP
111	error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
112	if (error < 0)
113	goto failure;
114	#endif
115	do_gettimeofday(&nfssvc_boot); /* record boot time */
116	} else
117	nfsd_serv->sv_nrthreads++;
118	nrservs -= (nfsd_serv->sv_nrthreads-1);
119	while (nrservs > 0) {
120	nrservs--;
121	__module_get(THIS_MODULE);
122	error = svc_create_thread(nfsd, nfsd_serv);
123	if (error < 0) {
124	module_put(THIS_MODULE);
125	break;
126	}
127	}
128	victim = nfsd_list.next;
129	while (nrservs < 0 && victim != &nfsd_list) {
130	struct nfsd_list *nl =
131	list_entry(victim,struct nfsd_list, list);
132	victim = victim->next;
133	send_sig(SIG_NOCLEAN, nl->task, 1);
134	nrservs++;
135	}
136	failure:
137	none_left = (nfsd_serv->sv_nrthreads == 1);
138	svc_destroy(nfsd_serv); /* Release server */
139	if (none_left) {
140	nfsd_serv = NULL;
141	nfsd_racache_shutdown();
142	nfs4_state_shutdown();
143	}
144	out:
145	unlock_kernel();
146	return error;
147	}
148
149	static inline void
150	update_thread_usage(int busy_threads)
151	{
152	unsigned long prev_call;
153	unsigned long diff;
154	int decile;
155
156	spin_lock(&nfsd_call_lock);
157	prev_call = nfsd_last_call;
158	nfsd_last_call = jiffies;
159	decile = busy_threads*10/nfsdstats.th_cnt;
160	if (decile>0 && decile <= 10) {
161	diff = nfsd_last_call - prev_call;
162	if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
163	nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
164	if (decile == 10)
165	nfsdstats.th_fullcnt++;
166	}
167	spin_unlock(&nfsd_call_lock);
168	}
169
170	/*
171	* This is the NFS server kernel thread
172	*/
173	static void
174	nfsd(struct svc_rqst *rqstp)
175	{
176	struct svc_serv *serv = rqstp->rq_server;
177	struct fs_struct *fsp;
178	int err;
179	struct nfsd_list me;
180	sigset_t shutdown_mask, allowed_mask;
181
182	/* Lock module and set up kernel thread */
183	lock_kernel();
184	daemonize("nfsd");
185
186	/* After daemonize() this kernel thread shares current->fs
187	* with the init process. We need to create files with a
188	* umask of 0 instead of init's umask. */
189	fsp = copy_fs_struct(current->fs);
190	if (!fsp) {
191	printk("Unable to start nfsd thread: out of memory\n");
192	goto out;
193	}
194	exit_fs(current);
195	current->fs = fsp;
196	current->fs->umask = 0;
197
198	siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
199	siginitsetinv(&allowed_mask, ALLOWED_SIGS);
200
201	nfsdstats.th_cnt++;
202
203	lockd_up(); /* start lockd */
204
205	me.task = current;
206	list_add(&me.list, &nfsd_list);
207
208	unlock_kernel();
209
210	/*
211	* We want less throttling in balance_dirty_pages() so that nfs to
212	* localhost doesn't cause nfsd to lock up due to all the client's
213	* dirty pages.
214	*/
215	current->flags \|= PF_LESS_THROTTLE;
216
217	/*
218	* The main request loop
219	*/
220	for (;;) {
221	/* Block all but the shutdown signals */
222	sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
223
224	/*
225	* Find a socket with data available and call its
226	* recvfrom routine.
227	*/
228	while ((err = svc_recv(serv, rqstp,
229	6060HZ)) == -EAGAIN)
230	;
231	if (err < 0)
232	break;
233	update_thread_usage(atomic_read(&nfsd_busy));
234	atomic_inc(&nfsd_busy);
235
236	/* Lock the export hash tables for reading. */
237	exp_readlock();
238
239	/* Process request with signals blocked. */
240	sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
241
242	svc_process(serv, rqstp);
243
244	/* Unlock export hash tables */
245	exp_readunlock();
246	update_thread_usage(atomic_read(&nfsd_busy));
247	atomic_dec(&nfsd_busy);
248	}
249
250	if (err != -EINTR) {
251	printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
252	} else {
253	unsigned int signo;
254
255	for (signo = 1; signo <= _NSIG; signo++)
256	if (sigismember(&current->pending.signal, signo) &&
257	!sigismember(&current->blocked, signo))
258	break;
259	err = signo;
260	}
261
262	lock_kernel();
263
264	/* Release lockd */
265	lockd_down();
266
267	/* Check if this is last thread */
268	if (serv->sv_nrthreads==1) {
269
270	printk(KERN_WARNING "nfsd: last server has exited\n");
271	if (err != SIG_NOCLEAN) {
272	printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
273	nfsd_export_flush();
274	}
275	nfsd_serv = NULL;
276	nfsd_racache_shutdown(); /* release read-ahead cache */
277	nfs4_state_shutdown();
278	}
279	list_del(&me.list);
280	nfsdstats.th_cnt --;
281
282	out:
283	/* Release the thread */
284	svc_exit_thread(rqstp);
285
286	/* Release module */
287	module_put_and_exit(0);
288	}
289
290	int
291	nfsd_dispatch(struct svc_rqst rqstp, u32 statp)
292	{
293	struct svc_procedure *proc;
294	kxdrproc_t xdr;
295	u32 nfserr;
296	u32 *nfserrp;
297
298	dprintk("nfsd_dispatch: vers %d proc %d\n",
299	rqstp->rq_vers, rqstp->rq_proc);
300	proc = rqstp->rq_procinfo;
301
302	/* Check whether we have this call in the cache. */
303	switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
304	case RC_INTR:
305	case RC_DROPIT:
306	return 0;
307	case RC_REPLY:
308	return 1;
309	case RC_DOIT:;
310	/* do it */
311	}
312
313	/* Decode arguments */
314	xdr = proc->pc_decode;
315	if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base,
316	rqstp->rq_argp)) {
317	dprintk("nfsd: failed to decode arguments!\n");
318	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
319	*statp = rpc_garbage_args;
320	return 1;
321	}
322
323	/* need to grab the location to store the status, as
324	* nfsv4 does some encoding while processing
325	*/
326	nfserrp = rqstp->rq_res.head[0].iov_base
327	+ rqstp->rq_res.head[0].iov_len;
328	rqstp->rq_res.head[0].iov_len += sizeof(u32);
329
330	/* Now call the procedure handler, and encode NFS status. */
331	nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
332	if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
333	nfserr = nfserr_dropit;
334	if (nfserr == nfserr_dropit) {
335	dprintk("nfsd: Dropping request due to malloc failure!\n");
336	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
337	return 0;
338	}
339
340	if (rqstp->rq_proc != 0)
341	*nfserrp++ = nfserr;
342
343	/* Encode result.
344	* For NFSv2, additional info is never returned in case of an error.
345	*/
346	if (!(nfserr && rqstp->rq_vers == 2)) {
347	xdr = proc->pc_encode;
348	if (xdr && !xdr(rqstp, nfserrp,
349	rqstp->rq_resp)) {
350	/* Failed to encode result. Release cache entry */
351	dprintk("nfsd: failed to encode result!\n");
352	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
353	*statp = rpc_system_err;
354	return 1;
355	}
356	}
357
358	/* Store reply in cache. */
359	nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
360	return 1;
361	}
362
363	extern struct svc_version nfsd_version2, nfsd_version3, nfsd_version4;
364
365	static struct svc_version * nfsd_version[] = {
366	[2] = &nfsd_version2,
367	#if defined(CONFIG_NFSD_V3)
368	[3] = &nfsd_version3,
369	#endif
370	#if defined(CONFIG_NFSD_V4)
371	[4] = &nfsd_version4,
372	#endif
373	};
374
375	#define NFSD_NRVERS (sizeof(nfsd_version)/sizeof(nfsd_version[0]))
376	struct svc_program nfsd_program = {
377	.pg_prog = NFS_PROGRAM, /* program number */
378	.pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */
379	.pg_vers = nfsd_version, /* version table */
380	.pg_name = "nfsd", /* program name */
381	.pg_class = "nfsd", /* authentication class */
382	.pg_stats = &nfsd_svcstats, /* version table */
383	.pg_authenticate = &svc_set_client, /* export authentication */
384
385	};