[PATCH] knfsd: add a callback for when last rpc thread finishes
[linux-2.6.git] / fs / nfsd / nfssvc.c
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/module.h>
12
13 #include <linux/time.h>
14 #include <linux/errno.h>
15 #include <linux/nfs.h>
16 #include <linux/in.h>
17 #include <linux/uio.h>
18 #include <linux/unistd.h>
19 #include <linux/slab.h>
20 #include <linux/smp.h>
21 #include <linux/smp_lock.h>
22 #include <linux/fs_struct.h>
23
24 #include <linux/sunrpc/types.h>
25 #include <linux/sunrpc/stats.h>
26 #include <linux/sunrpc/svc.h>
27 #include <linux/sunrpc/svcsock.h>
28 #include <linux/sunrpc/cache.h>
29 #include <linux/nfsd/nfsd.h>
30 #include <linux/nfsd/stats.h>
31 #include <linux/nfsd/cache.h>
32 #include <linux/nfsd/syscall.h>
33 #include <linux/lockd/bind.h>
34 #include <linux/nfsacl.h>
35
36 #define NFSDDBG_FACILITY        NFSDDBG_SVC
37
38 /* these signals will be delivered to an nfsd thread 
39  * when handling a request
40  */
41 #define ALLOWED_SIGS    (sigmask(SIGKILL))
42 /* these signals will be delivered to an nfsd thread
43  * when not handling a request. i.e. when waiting
44  */
45 #define SHUTDOWN_SIGS   (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
46 /* if the last thread dies with SIGHUP, then the exports table is
47  * left unchanged ( like 2.4-{0-9} ).  Any other signal will clear
48  * the exports table (like 2.2).
49  */
50 #define SIG_NOCLEAN     SIGHUP
51
52 extern struct svc_program       nfsd_program;
53 static void                     nfsd(struct svc_rqst *rqstp);
54 struct timeval                  nfssvc_boot;
55        struct svc_serv          *nfsd_serv;
56 static atomic_t                 nfsd_busy;
57 static unsigned long            nfsd_last_call;
58 static DEFINE_SPINLOCK(nfsd_call_lock);
59
60 struct nfsd_list {
61         struct list_head        list;
62         struct task_struct      *task;
63 };
64 static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);
65
66 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
67 static struct svc_stat  nfsd_acl_svcstats;
68 static struct svc_version *     nfsd_acl_version[] = {
69         [2] = &nfsd_acl_version2,
70         [3] = &nfsd_acl_version3,
71 };
72
73 #define NFSD_ACL_MINVERS            2
74 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
75 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
76
77 static struct svc_program       nfsd_acl_program = {
78         .pg_prog                = NFS_ACL_PROGRAM,
79         .pg_nvers               = NFSD_ACL_NRVERS,
80         .pg_vers                = nfsd_acl_versions,
81         .pg_name                = "nfsd",
82         .pg_class               = "nfsd",
83         .pg_stats               = &nfsd_acl_svcstats,
84         .pg_authenticate        = &svc_set_client,
85 };
86
87 static struct svc_stat  nfsd_acl_svcstats = {
88         .program        = &nfsd_acl_program,
89 };
90 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
91
92 static struct svc_version *     nfsd_version[] = {
93         [2] = &nfsd_version2,
94 #if defined(CONFIG_NFSD_V3)
95         [3] = &nfsd_version3,
96 #endif
97 #if defined(CONFIG_NFSD_V4)
98         [4] = &nfsd_version4,
99 #endif
100 };
101
102 #define NFSD_MINVERS            2
103 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
104 static struct svc_version *nfsd_versions[NFSD_NRVERS];
105
106 struct svc_program              nfsd_program = {
107 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
108         .pg_next                = &nfsd_acl_program,
109 #endif
110         .pg_prog                = NFS_PROGRAM,          /* program number */
111         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
112         .pg_vers                = nfsd_versions,        /* version table */
113         .pg_name                = "nfsd",               /* program name */
114         .pg_class               = "nfsd",               /* authentication class */
115         .pg_stats               = &nfsd_svcstats,       /* version table */
116         .pg_authenticate        = &svc_set_client,      /* export authentication */
117
118 };
119
120 /*
121  * Maximum number of nfsd processes
122  */
123 #define NFSD_MAXSERVS           8192
124
125 int nfsd_nrthreads(void)
126 {
127         if (nfsd_serv == NULL)
128                 return 0;
129         else
130                 return nfsd_serv->sv_nrthreads;
131 }
132
133 static int killsig;     /* signal that was used to kill last nfsd */
134 static void nfsd_last_thread(struct svc_serv *serv)
135 {
136         /* When last nfsd thread exits we need to do some clean-up */
137         nfsd_serv = NULL;
138         nfsd_racache_shutdown();
139         nfs4_state_shutdown();
140
141         printk(KERN_WARNING "nfsd: last server has exited\n");
142         if (killsig != SIG_NOCLEAN) {
143                 printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
144                 nfsd_export_flush();
145         }
146 }
147 int
148 nfsd_svc(unsigned short port, int nrservs)
149 {
150         int     error;
151         int     found_one, i;
152         struct list_head *victim;
153         
154         lock_kernel();
155         dprintk("nfsd: creating service: vers 0x%x\n",
156                 nfsd_versbits);
157         error = -EINVAL;
158         if (nrservs <= 0)
159                 nrservs = 0;
160         if (nrservs > NFSD_MAXSERVS)
161                 nrservs = NFSD_MAXSERVS;
162         
163         /* Readahead param cache - will no-op if it already exists */
164         error = nfsd_racache_init(2*nrservs);
165         if (error<0)
166                 goto out;
167         error = nfs4_state_start();
168         if (error<0)
169                 goto out;
170         if (!nfsd_serv) {
171                 /*
172                  * Use the nfsd_ctlbits to define which
173                  * versions that will be advertised.
174                  * If nfsd_ctlbits doesn't list any version,
175                  * export them all.
176                  */
177                 found_one = 0;
178
179                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
180                         if (NFSCTL_VERISSET(nfsd_versbits, i)) {
181                                 nfsd_program.pg_vers[i] = nfsd_version[i];
182                                 found_one = 1;
183                         } else
184                                 nfsd_program.pg_vers[i] = NULL;
185                 }
186
187                 if (!found_one) {
188                         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
189                                 nfsd_program.pg_vers[i] = nfsd_version[i];
190                 }
191
192
193 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
194                 found_one = 0;
195
196                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) {
197                         if (NFSCTL_VERISSET(nfsd_versbits, i)) {
198                                 nfsd_acl_program.pg_vers[i] =
199                                         nfsd_acl_version[i];
200                                 found_one = 1;
201                         } else
202                                 nfsd_acl_program.pg_vers[i] = NULL;
203                 }
204
205                 if (!found_one) {
206                         for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
207                                 nfsd_acl_program.pg_vers[i] =
208                                         nfsd_acl_version[i];
209                 }
210 #endif
211
212                 atomic_set(&nfsd_busy, 0);
213                 error = -ENOMEM;
214                 nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE,
215                                        nfsd_last_thread);
216                 if (nfsd_serv == NULL)
217                         goto out;
218                 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
219                 if (error < 0)
220                         goto failure;
221
222 #ifdef CONFIG_NFSD_TCP
223                 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
224                 if (error < 0)
225                         goto failure;
226 #endif
227                 do_gettimeofday(&nfssvc_boot);          /* record boot time */
228         } else
229                 nfsd_serv->sv_nrthreads++;
230         nrservs -= (nfsd_serv->sv_nrthreads-1);
231         while (nrservs > 0) {
232                 nrservs--;
233                 __module_get(THIS_MODULE);
234                 error = svc_create_thread(nfsd, nfsd_serv);
235                 if (error < 0) {
236                         module_put(THIS_MODULE);
237                         break;
238                 }
239         }
240         victim = nfsd_list.next;
241         while (nrservs < 0 && victim != &nfsd_list) {
242                 struct nfsd_list *nl =
243                         list_entry(victim,struct nfsd_list, list);
244                 victim = victim->next;
245                 send_sig(SIG_NOCLEAN, nl->task, 1);
246                 nrservs++;
247         }
248  failure:
249         svc_destroy(nfsd_serv);         /* Release server */
250  out:
251         unlock_kernel();
252         return error;
253 }
254
255 static inline void
256 update_thread_usage(int busy_threads)
257 {
258         unsigned long prev_call;
259         unsigned long diff;
260         int decile;
261
262         spin_lock(&nfsd_call_lock);
263         prev_call = nfsd_last_call;
264         nfsd_last_call = jiffies;
265         decile = busy_threads*10/nfsdstats.th_cnt;
266         if (decile>0 && decile <= 10) {
267                 diff = nfsd_last_call - prev_call;
268                 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
269                         nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
270                 if (decile == 10)
271                         nfsdstats.th_fullcnt++;
272         }
273         spin_unlock(&nfsd_call_lock);
274 }
275
276 /*
277  * This is the NFS server kernel thread
278  */
279 static void
280 nfsd(struct svc_rqst *rqstp)
281 {
282         struct svc_serv *serv = rqstp->rq_server;
283         struct fs_struct *fsp;
284         int             err;
285         struct nfsd_list me;
286         sigset_t shutdown_mask, allowed_mask;
287
288         /* Lock module and set up kernel thread */
289         lock_kernel();
290         daemonize("nfsd");
291
292         /* After daemonize() this kernel thread shares current->fs
293          * with the init process. We need to create files with a
294          * umask of 0 instead of init's umask. */
295         fsp = copy_fs_struct(current->fs);
296         if (!fsp) {
297                 printk("Unable to start nfsd thread: out of memory\n");
298                 goto out;
299         }
300         exit_fs(current);
301         current->fs = fsp;
302         current->fs->umask = 0;
303
304         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
305         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
306
307         nfsdstats.th_cnt++;
308
309         lockd_up();                             /* start lockd */
310
311         me.task = current;
312         list_add(&me.list, &nfsd_list);
313
314         unlock_kernel();
315
316         /*
317          * We want less throttling in balance_dirty_pages() so that nfs to
318          * localhost doesn't cause nfsd to lock up due to all the client's
319          * dirty pages.
320          */
321         current->flags |= PF_LESS_THROTTLE;
322
323         /*
324          * The main request loop
325          */
326         for (;;) {
327                 /* Block all but the shutdown signals */
328                 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
329
330                 /*
331                  * Find a socket with data available and call its
332                  * recvfrom routine.
333                  */
334                 while ((err = svc_recv(serv, rqstp,
335                                        60*60*HZ)) == -EAGAIN)
336                         ;
337                 if (err < 0)
338                         break;
339                 update_thread_usage(atomic_read(&nfsd_busy));
340                 atomic_inc(&nfsd_busy);
341
342                 /* Lock the export hash tables for reading. */
343                 exp_readlock();
344
345                 /* Process request with signals blocked.  */
346                 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
347
348                 svc_process(serv, rqstp);
349
350                 /* Unlock export hash tables */
351                 exp_readunlock();
352                 update_thread_usage(atomic_read(&nfsd_busy));
353                 atomic_dec(&nfsd_busy);
354         }
355
356         if (err != -EINTR) {
357                 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
358         } else {
359                 unsigned int    signo;
360
361                 for (signo = 1; signo <= _NSIG; signo++)
362                         if (sigismember(&current->pending.signal, signo) &&
363                             !sigismember(&current->blocked, signo))
364                                 break;
365                 killsig = signo;
366         }
367         /* Clear signals before calling lockd_down() and svc_exit_thread() */
368         flush_signals(current);
369
370         lock_kernel();
371
372         /* Release lockd */
373         lockd_down();
374         list_del(&me.list);
375         nfsdstats.th_cnt --;
376
377 out:
378         /* Release the thread */
379         svc_exit_thread(rqstp);
380
381         /* Release module */
382         unlock_kernel();
383         module_put_and_exit(0);
384 }
385
386 int
387 nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)
388 {
389         struct svc_procedure    *proc;
390         kxdrproc_t              xdr;
391         u32                     nfserr;
392         u32                     *nfserrp;
393
394         dprintk("nfsd_dispatch: vers %d proc %d\n",
395                                 rqstp->rq_vers, rqstp->rq_proc);
396         proc = rqstp->rq_procinfo;
397
398         /* Check whether we have this call in the cache. */
399         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
400         case RC_INTR:
401         case RC_DROPIT:
402                 return 0;
403         case RC_REPLY:
404                 return 1;
405         case RC_DOIT:;
406                 /* do it */
407         }
408
409         /* Decode arguments */
410         xdr = proc->pc_decode;
411         if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base,
412                         rqstp->rq_argp)) {
413                 dprintk("nfsd: failed to decode arguments!\n");
414                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
415                 *statp = rpc_garbage_args;
416                 return 1;
417         }
418
419         /* need to grab the location to store the status, as
420          * nfsv4 does some encoding while processing 
421          */
422         nfserrp = rqstp->rq_res.head[0].iov_base
423                 + rqstp->rq_res.head[0].iov_len;
424         rqstp->rq_res.head[0].iov_len += sizeof(u32);
425
426         /* Now call the procedure handler, and encode NFS status. */
427         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
428         if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
429                 nfserr = nfserr_dropit;
430         if (nfserr == nfserr_dropit) {
431                 dprintk("nfsd: Dropping request due to malloc failure!\n");
432                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
433                 return 0;
434         }
435
436         if (rqstp->rq_proc != 0)
437                 *nfserrp++ = nfserr;
438
439         /* Encode result.
440          * For NFSv2, additional info is never returned in case of an error.
441          */
442         if (!(nfserr && rqstp->rq_vers == 2)) {
443                 xdr = proc->pc_encode;
444                 if (xdr && !xdr(rqstp, nfserrp,
445                                 rqstp->rq_resp)) {
446                         /* Failed to encode result. Release cache entry */
447                         dprintk("nfsd: failed to encode result!\n");
448                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
449                         *statp = rpc_system_err;
450                         return 1;
451                 }
452         }
453
454         /* Store reply in cache. */
455         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
456         return 1;
457 }