[PATCH] fs/nfsd/export.c,net/sunrpc/cache.c: make needlessly global code static
[linux-2.6.git] / net / sunrpc / cache.c
1 /*
2  * net/sunrpc/cache.c
3  *
4  * Generic code for various authentication-related caches
5  * used by sunrpc clients and servers.
6  *
7  * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
8  *
9  * Released under terms in GPL version 2.  See COPYING.
10  *
11  */
12
13 #include <linux/types.h>
14 #include <linux/fs.h>
15 #include <linux/file.h>
16 #include <linux/slab.h>
17 #include <linux/signal.h>
18 #include <linux/sched.h>
19 #include <linux/kmod.h>
20 #include <linux/list.h>
21 #include <linux/module.h>
22 #include <linux/ctype.h>
23 #include <asm/uaccess.h>
24 #include <linux/poll.h>
25 #include <linux/seq_file.h>
26 #include <linux/proc_fs.h>
27 #include <linux/net.h>
28 #include <linux/workqueue.h>
29 #include <linux/mutex.h>
30 #include <asm/ioctls.h>
31 #include <linux/sunrpc/types.h>
32 #include <linux/sunrpc/cache.h>
33 #include <linux/sunrpc/stats.h>
34
35 #define  RPCDBG_FACILITY RPCDBG_CACHE
36
37 static void cache_defer_req(struct cache_req *req, struct cache_head *item);
38 static void cache_revisit_request(struct cache_head *item);
39
40 static void cache_init(struct cache_head *h)
41 {
42         time_t now = get_seconds();
43         h->next = NULL;
44         h->flags = 0;
45         kref_init(&h->ref);
46         h->expiry_time = now + CACHE_NEW_EXPIRY;
47         h->last_refresh = now;
48 }
49
50 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
51                                        struct cache_head *key, int hash)
52 {
53         struct cache_head **head,  **hp;
54         struct cache_head *new = NULL;
55
56         head = &detail->hash_table[hash];
57
58         read_lock(&detail->hash_lock);
59
60         for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
61                 struct cache_head *tmp = *hp;
62                 if (detail->match(tmp, key)) {
63                         cache_get(tmp);
64                         read_unlock(&detail->hash_lock);
65                         return tmp;
66                 }
67         }
68         read_unlock(&detail->hash_lock);
69         /* Didn't find anything, insert an empty entry */
70
71         new = detail->alloc();
72         if (!new)
73                 return NULL;
74         cache_init(new);
75
76         write_lock(&detail->hash_lock);
77
78         /* check if entry appeared while we slept */
79         for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
80                 struct cache_head *tmp = *hp;
81                 if (detail->match(tmp, key)) {
82                         cache_get(tmp);
83                         write_unlock(&detail->hash_lock);
84                         cache_put(new, detail);
85                         return tmp;
86                 }
87         }
88         detail->init(new, key);
89         new->next = *head;
90         *head = new;
91         detail->entries++;
92         cache_get(new);
93         write_unlock(&detail->hash_lock);
94
95         return new;
96 }
97 EXPORT_SYMBOL(sunrpc_cache_lookup);
98
99
100 static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
101
102 static int cache_fresh_locked(struct cache_head *head, time_t expiry)
103 {
104         head->expiry_time = expiry;
105         head->last_refresh = get_seconds();
106         return !test_and_set_bit(CACHE_VALID, &head->flags);
107 }
108
109 static void cache_fresh_unlocked(struct cache_head *head,
110                         struct cache_detail *detail, int new)
111 {
112         if (new)
113                 cache_revisit_request(head);
114         if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
115                 cache_revisit_request(head);
116                 queue_loose(detail, head);
117         }
118 }
119
120 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
121                                        struct cache_head *new, struct cache_head *old, int hash)
122 {
123         /* The 'old' entry is to be replaced by 'new'.
124          * If 'old' is not VALID, we update it directly,
125          * otherwise we need to replace it
126          */
127         struct cache_head **head;
128         struct cache_head *tmp;
129         int is_new;
130
131         if (!test_bit(CACHE_VALID, &old->flags)) {
132                 write_lock(&detail->hash_lock);
133                 if (!test_bit(CACHE_VALID, &old->flags)) {
134                         if (test_bit(CACHE_NEGATIVE, &new->flags))
135                                 set_bit(CACHE_NEGATIVE, &old->flags);
136                         else
137                                 detail->update(old, new);
138                         is_new = cache_fresh_locked(old, new->expiry_time);
139                         write_unlock(&detail->hash_lock);
140                         cache_fresh_unlocked(old, detail, is_new);
141                         return old;
142                 }
143                 write_unlock(&detail->hash_lock);
144         }
145         /* We need to insert a new entry */
146         tmp = detail->alloc();
147         if (!tmp) {
148                 cache_put(old, detail);
149                 return NULL;
150         }
151         cache_init(tmp);
152         detail->init(tmp, old);
153         head = &detail->hash_table[hash];
154
155         write_lock(&detail->hash_lock);
156         if (test_bit(CACHE_NEGATIVE, &new->flags))
157                 set_bit(CACHE_NEGATIVE, &tmp->flags);
158         else
159                 detail->update(tmp, new);
160         tmp->next = *head;
161         *head = tmp;
162         cache_get(tmp);
163         is_new = cache_fresh_locked(tmp, new->expiry_time);
164         cache_fresh_locked(old, 0);
165         write_unlock(&detail->hash_lock);
166         cache_fresh_unlocked(tmp, detail, is_new);
167         cache_fresh_unlocked(old, detail, 0);
168         cache_put(old, detail);
169         return tmp;
170 }
171 EXPORT_SYMBOL(sunrpc_cache_update);
172
173 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
174 /*
175  * This is the generic cache management routine for all
176  * the authentication caches.
177  * It checks the currency of a cache item and will (later)
178  * initiate an upcall to fill it if needed.
179  *
180  *
181  * Returns 0 if the cache_head can be used, or cache_puts it and returns
182  * -EAGAIN if upcall is pending,
183  * -ENOENT if cache entry was negative
184  */
185 int cache_check(struct cache_detail *detail,
186                     struct cache_head *h, struct cache_req *rqstp)
187 {
188         int rv;
189         long refresh_age, age;
190
191         /* First decide return status as best we can */
192         if (!test_bit(CACHE_VALID, &h->flags) ||
193             h->expiry_time < get_seconds())
194                 rv = -EAGAIN;
195         else if (detail->flush_time > h->last_refresh)
196                 rv = -EAGAIN;
197         else {
198                 /* entry is valid */
199                 if (test_bit(CACHE_NEGATIVE, &h->flags))
200                         rv = -ENOENT;
201                 else rv = 0;
202         }
203
204         /* now see if we want to start an upcall */
205         refresh_age = (h->expiry_time - h->last_refresh);
206         age = get_seconds() - h->last_refresh;
207
208         if (rqstp == NULL) {
209                 if (rv == -EAGAIN)
210                         rv = -ENOENT;
211         } else if (rv == -EAGAIN || age > refresh_age/2) {
212                 dprintk("Want update, refage=%ld, age=%ld\n", refresh_age, age);
213                 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
214                         switch (cache_make_upcall(detail, h)) {
215                         case -EINVAL:
216                                 clear_bit(CACHE_PENDING, &h->flags);
217                                 if (rv == -EAGAIN) {
218                                         set_bit(CACHE_NEGATIVE, &h->flags);
219                                         cache_fresh_unlocked(h, detail,
220                                              cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
221                                         rv = -ENOENT;
222                                 }
223                                 break;
224
225                         case -EAGAIN:
226                                 clear_bit(CACHE_PENDING, &h->flags);
227                                 cache_revisit_request(h);
228                                 break;
229                         }
230                 }
231         }
232
233         if (rv == -EAGAIN)
234                 cache_defer_req(rqstp, h);
235
236         if (rv)
237                 cache_put(h, detail);
238         return rv;
239 }
240
241 /*
242  * caches need to be periodically cleaned.
243  * For this we maintain a list of cache_detail and
244  * a current pointer into that list and into the table
245  * for that entry.
246  *
247  * Each time clean_cache is called it finds the next non-empty entry
248  * in the current table and walks the list in that entry
249  * looking for entries that can be removed.
250  *
251  * An entry gets removed if:
252  * - The expiry is before current time
253  * - The last_refresh time is before the flush_time for that cache
254  *
255  * later we might drop old entries with non-NEVER expiry if that table
256  * is getting 'full' for some definition of 'full'
257  *
258  * The question of "how often to scan a table" is an interesting one
259  * and is answered in part by the use of the "nextcheck" field in the
260  * cache_detail.
261  * When a scan of a table begins, the nextcheck field is set to a time
262  * that is well into the future.
263  * While scanning, if an expiry time is found that is earlier than the
264  * current nextcheck time, nextcheck is set to that expiry time.
265  * If the flush_time is ever set to a time earlier than the nextcheck
266  * time, the nextcheck time is then set to that flush_time.
267  *
268  * A table is then only scanned if the current time is at least
269  * the nextcheck time.
270  * 
271  */
272
273 static LIST_HEAD(cache_list);
274 static DEFINE_SPINLOCK(cache_list_lock);
275 static struct cache_detail *current_detail;
276 static int current_index;
277
278 static struct file_operations cache_file_operations;
279 static struct file_operations content_file_operations;
280 static struct file_operations cache_flush_operations;
281
282 static void do_cache_clean(void *data);
283 static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL);
284
285 void cache_register(struct cache_detail *cd)
286 {
287         cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
288         if (cd->proc_ent) {
289                 struct proc_dir_entry *p;
290                 cd->proc_ent->owner = cd->owner;
291                 cd->channel_ent = cd->content_ent = NULL;
292                 
293                 p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR,
294                                       cd->proc_ent);
295                 cd->flush_ent =  p;
296                 if (p) {
297                         p->proc_fops = &cache_flush_operations;
298                         p->owner = cd->owner;
299                         p->data = cd;
300                 }
301  
302                 if (cd->cache_request || cd->cache_parse) {
303                         p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR,
304                                               cd->proc_ent);
305                         cd->channel_ent = p;
306                         if (p) {
307                                 p->proc_fops = &cache_file_operations;
308                                 p->owner = cd->owner;
309                                 p->data = cd;
310                         }
311                 }
312                 if (cd->cache_show) {
313                         p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR,
314                                               cd->proc_ent);
315                         cd->content_ent = p;
316                         if (p) {
317                                 p->proc_fops = &content_file_operations;
318                                 p->owner = cd->owner;
319                                 p->data = cd;
320                         }
321                 }
322         }
323         rwlock_init(&cd->hash_lock);
324         INIT_LIST_HEAD(&cd->queue);
325         spin_lock(&cache_list_lock);
326         cd->nextcheck = 0;
327         cd->entries = 0;
328         atomic_set(&cd->readers, 0);
329         cd->last_close = 0;
330         cd->last_warn = -1;
331         list_add(&cd->others, &cache_list);
332         spin_unlock(&cache_list_lock);
333
334         /* start the cleaning process */
335         schedule_work(&cache_cleaner);
336 }
337
338 int cache_unregister(struct cache_detail *cd)
339 {
340         cache_purge(cd);
341         spin_lock(&cache_list_lock);
342         write_lock(&cd->hash_lock);
343         if (cd->entries || atomic_read(&cd->inuse)) {
344                 write_unlock(&cd->hash_lock);
345                 spin_unlock(&cache_list_lock);
346                 return -EBUSY;
347         }
348         if (current_detail == cd)
349                 current_detail = NULL;
350         list_del_init(&cd->others);
351         write_unlock(&cd->hash_lock);
352         spin_unlock(&cache_list_lock);
353         if (cd->proc_ent) {
354                 if (cd->flush_ent)
355                         remove_proc_entry("flush", cd->proc_ent);
356                 if (cd->channel_ent)
357                         remove_proc_entry("channel", cd->proc_ent);
358                 if (cd->content_ent)
359                         remove_proc_entry("content", cd->proc_ent);
360
361                 cd->proc_ent = NULL;
362                 remove_proc_entry(cd->name, proc_net_rpc);
363         }
364         if (list_empty(&cache_list)) {
365                 /* module must be being unloaded so its safe to kill the worker */
366                 cancel_delayed_work(&cache_cleaner);
367                 flush_scheduled_work();
368         }
369         return 0;
370 }
371
372 /* clean cache tries to find something to clean
373  * and cleans it.
374  * It returns 1 if it cleaned something,
375  *            0 if it didn't find anything this time
376  *           -1 if it fell off the end of the list.
377  */
378 static int cache_clean(void)
379 {
380         int rv = 0;
381         struct list_head *next;
382
383         spin_lock(&cache_list_lock);
384
385         /* find a suitable table if we don't already have one */
386         while (current_detail == NULL ||
387             current_index >= current_detail->hash_size) {
388                 if (current_detail)
389                         next = current_detail->others.next;
390                 else
391                         next = cache_list.next;
392                 if (next == &cache_list) {
393                         current_detail = NULL;
394                         spin_unlock(&cache_list_lock);
395                         return -1;
396                 }
397                 current_detail = list_entry(next, struct cache_detail, others);
398                 if (current_detail->nextcheck > get_seconds())
399                         current_index = current_detail->hash_size;
400                 else {
401                         current_index = 0;
402                         current_detail->nextcheck = get_seconds()+30*60;
403                 }
404         }
405
406         /* find a non-empty bucket in the table */
407         while (current_detail &&
408                current_index < current_detail->hash_size &&
409                current_detail->hash_table[current_index] == NULL)
410                 current_index++;
411
412         /* find a cleanable entry in the bucket and clean it, or set to next bucket */
413         
414         if (current_detail && current_index < current_detail->hash_size) {
415                 struct cache_head *ch, **cp;
416                 struct cache_detail *d;
417                 
418                 write_lock(&current_detail->hash_lock);
419
420                 /* Ok, now to clean this strand */
421                         
422                 cp = & current_detail->hash_table[current_index];
423                 ch = *cp;
424                 for (; ch; cp= & ch->next, ch= *cp) {
425                         if (current_detail->nextcheck > ch->expiry_time)
426                                 current_detail->nextcheck = ch->expiry_time+1;
427                         if (ch->expiry_time >= get_seconds()
428                             && ch->last_refresh >= current_detail->flush_time
429                                 )
430                                 continue;
431                         if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
432                                 queue_loose(current_detail, ch);
433
434                         if (atomic_read(&ch->ref.refcount) == 1)
435                                 break;
436                 }
437                 if (ch) {
438                         *cp = ch->next;
439                         ch->next = NULL;
440                         current_detail->entries--;
441                         rv = 1;
442                 }
443                 write_unlock(&current_detail->hash_lock);
444                 d = current_detail;
445                 if (!ch)
446                         current_index ++;
447                 spin_unlock(&cache_list_lock);
448                 if (ch)
449                         cache_put(ch, d);
450         } else
451                 spin_unlock(&cache_list_lock);
452
453         return rv;
454 }
455
456 /*
457  * We want to regularly clean the cache, so we need to schedule some work ...
458  */
459 static void do_cache_clean(void *data)
460 {
461         int delay = 5;
462         if (cache_clean() == -1)
463                 delay = 30*HZ;
464
465         if (list_empty(&cache_list))
466                 delay = 0;
467
468         if (delay)
469                 schedule_delayed_work(&cache_cleaner, delay);
470 }
471
472
473 /* 
474  * Clean all caches promptly.  This just calls cache_clean
475  * repeatedly until we are sure that every cache has had a chance to 
476  * be fully cleaned
477  */
478 void cache_flush(void)
479 {
480         while (cache_clean() != -1)
481                 cond_resched();
482         while (cache_clean() != -1)
483                 cond_resched();
484 }
485
486 void cache_purge(struct cache_detail *detail)
487 {
488         detail->flush_time = LONG_MAX;
489         detail->nextcheck = get_seconds();
490         cache_flush();
491         detail->flush_time = 1;
492 }
493
494
495
496 /*
497  * Deferral and Revisiting of Requests.
498  *
499  * If a cache lookup finds a pending entry, we
500  * need to defer the request and revisit it later.
501  * All deferred requests are stored in a hash table,
502  * indexed by "struct cache_head *".
503  * As it may be wasteful to store a whole request
504  * structure, we allow the request to provide a 
505  * deferred form, which must contain a
506  * 'struct cache_deferred_req'
507  * This cache_deferred_req contains a method to allow
508  * it to be revisited when cache info is available
509  */
510
511 #define DFR_HASHSIZE    (PAGE_SIZE/sizeof(struct list_head))
512 #define DFR_HASH(item)  ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
513
514 #define DFR_MAX 300     /* ??? */
515
516 static DEFINE_SPINLOCK(cache_defer_lock);
517 static LIST_HEAD(cache_defer_list);
518 static struct list_head cache_defer_hash[DFR_HASHSIZE];
519 static int cache_defer_cnt;
520
521 static void cache_defer_req(struct cache_req *req, struct cache_head *item)
522 {
523         struct cache_deferred_req *dreq;
524         int hash = DFR_HASH(item);
525
526         dreq = req->defer(req);
527         if (dreq == NULL)
528                 return;
529
530         dreq->item = item;
531         dreq->recv_time = get_seconds();
532
533         spin_lock(&cache_defer_lock);
534
535         list_add(&dreq->recent, &cache_defer_list);
536
537         if (cache_defer_hash[hash].next == NULL)
538                 INIT_LIST_HEAD(&cache_defer_hash[hash]);
539         list_add(&dreq->hash, &cache_defer_hash[hash]);
540
541         /* it is in, now maybe clean up */
542         dreq = NULL;
543         if (++cache_defer_cnt > DFR_MAX) {
544                 /* too much in the cache, randomly drop
545                  * first or last
546                  */
547                 if (net_random()&1) 
548                         dreq = list_entry(cache_defer_list.next,
549                                           struct cache_deferred_req,
550                                           recent);
551                 else
552                         dreq = list_entry(cache_defer_list.prev,
553                                           struct cache_deferred_req,
554                                           recent);
555                 list_del(&dreq->recent);
556                 list_del(&dreq->hash);
557                 cache_defer_cnt--;
558         }
559         spin_unlock(&cache_defer_lock);
560
561         if (dreq) {
562                 /* there was one too many */
563                 dreq->revisit(dreq, 1);
564         }
565         if (!test_bit(CACHE_PENDING, &item->flags)) {
566                 /* must have just been validated... */
567                 cache_revisit_request(item);
568         }
569 }
570
571 static void cache_revisit_request(struct cache_head *item)
572 {
573         struct cache_deferred_req *dreq;
574         struct list_head pending;
575
576         struct list_head *lp;
577         int hash = DFR_HASH(item);
578
579         INIT_LIST_HEAD(&pending);
580         spin_lock(&cache_defer_lock);
581         
582         lp = cache_defer_hash[hash].next;
583         if (lp) {
584                 while (lp != &cache_defer_hash[hash]) {
585                         dreq = list_entry(lp, struct cache_deferred_req, hash);
586                         lp = lp->next;
587                         if (dreq->item == item) {
588                                 list_del(&dreq->hash);
589                                 list_move(&dreq->recent, &pending);
590                                 cache_defer_cnt--;
591                         }
592                 }
593         }
594         spin_unlock(&cache_defer_lock);
595
596         while (!list_empty(&pending)) {
597                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
598                 list_del_init(&dreq->recent);
599                 dreq->revisit(dreq, 0);
600         }
601 }
602
603 void cache_clean_deferred(void *owner)
604 {
605         struct cache_deferred_req *dreq, *tmp;
606         struct list_head pending;
607
608
609         INIT_LIST_HEAD(&pending);
610         spin_lock(&cache_defer_lock);
611         
612         list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
613                 if (dreq->owner == owner) {
614                         list_del(&dreq->hash);
615                         list_move(&dreq->recent, &pending);
616                         cache_defer_cnt--;
617                 }
618         }
619         spin_unlock(&cache_defer_lock);
620
621         while (!list_empty(&pending)) {
622                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
623                 list_del_init(&dreq->recent);
624                 dreq->revisit(dreq, 1);
625         }
626 }
627
628 /*
629  * communicate with user-space
630  *
631  * We have a magic /proc file - /proc/sunrpc/cache
632  * On read, you get a full request, or block
633  * On write, an update request is processed
634  * Poll works if anything to read, and always allows write
635  *
636  * Implemented by linked list of requests.  Each open file has 
637  * a ->private that also exists in this list.  New request are added
638  * to the end and may wakeup and preceding readers.
639  * New readers are added to the head.  If, on read, an item is found with
640  * CACHE_UPCALLING clear, we free it from the list.
641  *
642  */
643
644 static DEFINE_SPINLOCK(queue_lock);
645 static DEFINE_MUTEX(queue_io_mutex);
646
647 struct cache_queue {
648         struct list_head        list;
649         int                     reader; /* if 0, then request */
650 };
651 struct cache_request {
652         struct cache_queue      q;
653         struct cache_head       *item;
654         char                    * buf;
655         int                     len;
656         int                     readers;
657 };
658 struct cache_reader {
659         struct cache_queue      q;
660         int                     offset; /* if non-0, we have a refcnt on next request */
661 };
662
663 static ssize_t
664 cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
665 {
666         struct cache_reader *rp = filp->private_data;
667         struct cache_request *rq;
668         struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
669         int err;
670
671         if (count == 0)
672                 return 0;
673
674         mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
675                               * readers on this file */
676  again:
677         spin_lock(&queue_lock);
678         /* need to find next request */
679         while (rp->q.list.next != &cd->queue &&
680                list_entry(rp->q.list.next, struct cache_queue, list)
681                ->reader) {
682                 struct list_head *next = rp->q.list.next;
683                 list_move(&rp->q.list, next);
684         }
685         if (rp->q.list.next == &cd->queue) {
686                 spin_unlock(&queue_lock);
687                 mutex_unlock(&queue_io_mutex);
688                 BUG_ON(rp->offset);
689                 return 0;
690         }
691         rq = container_of(rp->q.list.next, struct cache_request, q.list);
692         BUG_ON(rq->q.reader);
693         if (rp->offset == 0)
694                 rq->readers++;
695         spin_unlock(&queue_lock);
696
697         if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
698                 err = -EAGAIN;
699                 spin_lock(&queue_lock);
700                 list_move(&rp->q.list, &rq->q.list);
701                 spin_unlock(&queue_lock);
702         } else {
703                 if (rp->offset + count > rq->len)
704                         count = rq->len - rp->offset;
705                 err = -EFAULT;
706                 if (copy_to_user(buf, rq->buf + rp->offset, count))
707                         goto out;
708                 rp->offset += count;
709                 if (rp->offset >= rq->len) {
710                         rp->offset = 0;
711                         spin_lock(&queue_lock);
712                         list_move(&rp->q.list, &rq->q.list);
713                         spin_unlock(&queue_lock);
714                 }
715                 err = 0;
716         }
717  out:
718         if (rp->offset == 0) {
719                 /* need to release rq */
720                 spin_lock(&queue_lock);
721                 rq->readers--;
722                 if (rq->readers == 0 &&
723                     !test_bit(CACHE_PENDING, &rq->item->flags)) {
724                         list_del(&rq->q.list);
725                         spin_unlock(&queue_lock);
726                         cache_put(rq->item, cd);
727                         kfree(rq->buf);
728                         kfree(rq);
729                 } else
730                         spin_unlock(&queue_lock);
731         }
732         if (err == -EAGAIN)
733                 goto again;
734         mutex_unlock(&queue_io_mutex);
735         return err ? err :  count;
736 }
737
738 static char write_buf[8192]; /* protected by queue_io_mutex */
739
740 static ssize_t
741 cache_write(struct file *filp, const char __user *buf, size_t count,
742             loff_t *ppos)
743 {
744         int err;
745         struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
746
747         if (count == 0)
748                 return 0;
749         if (count >= sizeof(write_buf))
750                 return -EINVAL;
751
752         mutex_lock(&queue_io_mutex);
753
754         if (copy_from_user(write_buf, buf, count)) {
755                 mutex_unlock(&queue_io_mutex);
756                 return -EFAULT;
757         }
758         write_buf[count] = '\0';
759         if (cd->cache_parse)
760                 err = cd->cache_parse(cd, write_buf, count);
761         else
762                 err = -EINVAL;
763
764         mutex_unlock(&queue_io_mutex);
765         return err ? err : count;
766 }
767
768 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
769
770 static unsigned int
771 cache_poll(struct file *filp, poll_table *wait)
772 {
773         unsigned int mask;
774         struct cache_reader *rp = filp->private_data;
775         struct cache_queue *cq;
776         struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
777
778         poll_wait(filp, &queue_wait, wait);
779
780         /* alway allow write */
781         mask = POLL_OUT | POLLWRNORM;
782
783         if (!rp)
784                 return mask;
785
786         spin_lock(&queue_lock);
787
788         for (cq= &rp->q; &cq->list != &cd->queue;
789              cq = list_entry(cq->list.next, struct cache_queue, list))
790                 if (!cq->reader) {
791                         mask |= POLLIN | POLLRDNORM;
792                         break;
793                 }
794         spin_unlock(&queue_lock);
795         return mask;
796 }
797
798 static int
799 cache_ioctl(struct inode *ino, struct file *filp,
800             unsigned int cmd, unsigned long arg)
801 {
802         int len = 0;
803         struct cache_reader *rp = filp->private_data;
804         struct cache_queue *cq;
805         struct cache_detail *cd = PDE(ino)->data;
806
807         if (cmd != FIONREAD || !rp)
808                 return -EINVAL;
809
810         spin_lock(&queue_lock);
811
812         /* only find the length remaining in current request,
813          * or the length of the next request
814          */
815         for (cq= &rp->q; &cq->list != &cd->queue;
816              cq = list_entry(cq->list.next, struct cache_queue, list))
817                 if (!cq->reader) {
818                         struct cache_request *cr =
819                                 container_of(cq, struct cache_request, q);
820                         len = cr->len - rp->offset;
821                         break;
822                 }
823         spin_unlock(&queue_lock);
824
825         return put_user(len, (int __user *)arg);
826 }
827
828 static int
829 cache_open(struct inode *inode, struct file *filp)
830 {
831         struct cache_reader *rp = NULL;
832
833         nonseekable_open(inode, filp);
834         if (filp->f_mode & FMODE_READ) {
835                 struct cache_detail *cd = PDE(inode)->data;
836
837                 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
838                 if (!rp)
839                         return -ENOMEM;
840                 rp->offset = 0;
841                 rp->q.reader = 1;
842                 atomic_inc(&cd->readers);
843                 spin_lock(&queue_lock);
844                 list_add(&rp->q.list, &cd->queue);
845                 spin_unlock(&queue_lock);
846         }
847         filp->private_data = rp;
848         return 0;
849 }
850
851 static int
852 cache_release(struct inode *inode, struct file *filp)
853 {
854         struct cache_reader *rp = filp->private_data;
855         struct cache_detail *cd = PDE(inode)->data;
856
857         if (rp) {
858                 spin_lock(&queue_lock);
859                 if (rp->offset) {
860                         struct cache_queue *cq;
861                         for (cq= &rp->q; &cq->list != &cd->queue;
862                              cq = list_entry(cq->list.next, struct cache_queue, list))
863                                 if (!cq->reader) {
864                                         container_of(cq, struct cache_request, q)
865                                                 ->readers--;
866                                         break;
867                                 }
868                         rp->offset = 0;
869                 }
870                 list_del(&rp->q.list);
871                 spin_unlock(&queue_lock);
872
873                 filp->private_data = NULL;
874                 kfree(rp);
875
876                 cd->last_close = get_seconds();
877                 atomic_dec(&cd->readers);
878         }
879         return 0;
880 }
881
882
883
884 static struct file_operations cache_file_operations = {
885         .owner          = THIS_MODULE,
886         .llseek         = no_llseek,
887         .read           = cache_read,
888         .write          = cache_write,
889         .poll           = cache_poll,
890         .ioctl          = cache_ioctl, /* for FIONREAD */
891         .open           = cache_open,
892         .release        = cache_release,
893 };
894
895
896 static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
897 {
898         struct cache_queue *cq;
899         spin_lock(&queue_lock);
900         list_for_each_entry(cq, &detail->queue, list)
901                 if (!cq->reader) {
902                         struct cache_request *cr = container_of(cq, struct cache_request, q);
903                         if (cr->item != ch)
904                                 continue;
905                         if (cr->readers != 0)
906                                 continue;
907                         list_del(&cr->q.list);
908                         spin_unlock(&queue_lock);
909                         cache_put(cr->item, detail);
910                         kfree(cr->buf);
911                         kfree(cr);
912                         return;
913                 }
914         spin_unlock(&queue_lock);
915 }
916
917 /*
918  * Support routines for text-based upcalls.
919  * Fields are separated by spaces.
920  * Fields are either mangled to quote space tab newline slosh with slosh
921  * or a hexified with a leading \x
922  * Record is terminated with newline.
923  *
924  */
925
926 void qword_add(char **bpp, int *lp, char *str)
927 {
928         char *bp = *bpp;
929         int len = *lp;
930         char c;
931
932         if (len < 0) return;
933
934         while ((c=*str++) && len)
935                 switch(c) {
936                 case ' ':
937                 case '\t':
938                 case '\n':
939                 case '\\':
940                         if (len >= 4) {
941                                 *bp++ = '\\';
942                                 *bp++ = '0' + ((c & 0300)>>6);
943                                 *bp++ = '0' + ((c & 0070)>>3);
944                                 *bp++ = '0' + ((c & 0007)>>0);
945                         }
946                         len -= 4;
947                         break;
948                 default:
949                         *bp++ = c;
950                         len--;
951                 }
952         if (c || len <1) len = -1;
953         else {
954                 *bp++ = ' ';
955                 len--;
956         }
957         *bpp = bp;
958         *lp = len;
959 }
960
961 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
962 {
963         char *bp = *bpp;
964         int len = *lp;
965
966         if (len < 0) return;
967
968         if (len > 2) {
969                 *bp++ = '\\';
970                 *bp++ = 'x';
971                 len -= 2;
972                 while (blen && len >= 2) {
973                         unsigned char c = *buf++;
974                         *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
975                         *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
976                         len -= 2;
977                         blen--;
978                 }
979         }
980         if (blen || len<1) len = -1;
981         else {
982                 *bp++ = ' ';
983                 len--;
984         }
985         *bpp = bp;
986         *lp = len;
987 }
988
989 static void warn_no_listener(struct cache_detail *detail)
990 {
991         if (detail->last_warn != detail->last_close) {
992                 detail->last_warn = detail->last_close;
993                 if (detail->warn_no_listener)
994                         detail->warn_no_listener(detail);
995         }
996 }
997
998 /*
999  * register an upcall request to user-space.
1000  * Each request is at most one page long.
1001  */
1002 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
1003 {
1004
1005         char *buf;
1006         struct cache_request *crq;
1007         char *bp;
1008         int len;
1009
1010         if (detail->cache_request == NULL)
1011                 return -EINVAL;
1012
1013         if (atomic_read(&detail->readers) == 0 &&
1014             detail->last_close < get_seconds() - 30) {
1015                         warn_no_listener(detail);
1016                         return -EINVAL;
1017         }
1018
1019         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1020         if (!buf)
1021                 return -EAGAIN;
1022
1023         crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1024         if (!crq) {
1025                 kfree(buf);
1026                 return -EAGAIN;
1027         }
1028
1029         bp = buf; len = PAGE_SIZE;
1030
1031         detail->cache_request(detail, h, &bp, &len);
1032
1033         if (len < 0) {
1034                 kfree(buf);
1035                 kfree(crq);
1036                 return -EAGAIN;
1037         }
1038         crq->q.reader = 0;
1039         crq->item = cache_get(h);
1040         crq->buf = buf;
1041         crq->len = PAGE_SIZE - len;
1042         crq->readers = 0;
1043         spin_lock(&queue_lock);
1044         list_add_tail(&crq->q.list, &detail->queue);
1045         spin_unlock(&queue_lock);
1046         wake_up(&queue_wait);
1047         return 0;
1048 }
1049
1050 /*
1051  * parse a message from user-space and pass it
1052  * to an appropriate cache
1053  * Messages are, like requests, separated into fields by
1054  * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1055  *
1056  * Message is 
1057  *   reply cachename expiry key ... content....
1058  *
1059  * key and content are both parsed by cache 
1060  */
1061
1062 #define isodigit(c) (isdigit(c) && c <= '7')
1063 int qword_get(char **bpp, char *dest, int bufsize)
1064 {
1065         /* return bytes copied, or -1 on error */
1066         char *bp = *bpp;
1067         int len = 0;
1068
1069         while (*bp == ' ') bp++;
1070
1071         if (bp[0] == '\\' && bp[1] == 'x') {
1072                 /* HEX STRING */
1073                 bp += 2;
1074                 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) {
1075                         int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1076                         bp++;
1077                         byte <<= 4;
1078                         byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1079                         *dest++ = byte;
1080                         bp++;
1081                         len++;
1082                 }
1083         } else {
1084                 /* text with \nnn octal quoting */
1085                 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1086                         if (*bp == '\\' &&
1087                             isodigit(bp[1]) && (bp[1] <= '3') &&
1088                             isodigit(bp[2]) &&
1089                             isodigit(bp[3])) {
1090                                 int byte = (*++bp -'0');
1091                                 bp++;
1092                                 byte = (byte << 3) | (*bp++ - '0');
1093                                 byte = (byte << 3) | (*bp++ - '0');
1094                                 *dest++ = byte;
1095                                 len++;
1096                         } else {
1097                                 *dest++ = *bp++;
1098                                 len++;
1099                         }
1100                 }
1101         }
1102
1103         if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1104                 return -1;
1105         while (*bp == ' ') bp++;
1106         *bpp = bp;
1107         *dest = '\0';
1108         return len;
1109 }
1110
1111
1112 /*
1113  * support /proc/sunrpc/cache/$CACHENAME/content
1114  * as a seqfile.
1115  * We call ->cache_show passing NULL for the item to
1116  * get a header, then pass each real item in the cache
1117  */
1118
1119 struct handle {
1120         struct cache_detail *cd;
1121 };
1122
1123 static void *c_start(struct seq_file *m, loff_t *pos)
1124 {
1125         loff_t n = *pos;
1126         unsigned hash, entry;
1127         struct cache_head *ch;
1128         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1129         
1130
1131         read_lock(&cd->hash_lock);
1132         if (!n--)
1133                 return SEQ_START_TOKEN;
1134         hash = n >> 32;
1135         entry = n & ((1LL<<32) - 1);
1136
1137         for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1138                 if (!entry--)
1139                         return ch;
1140         n &= ~((1LL<<32) - 1);
1141         do {
1142                 hash++;
1143                 n += 1LL<<32;
1144         } while(hash < cd->hash_size && 
1145                 cd->hash_table[hash]==NULL);
1146         if (hash >= cd->hash_size)
1147                 return NULL;
1148         *pos = n+1;
1149         return cd->hash_table[hash];
1150 }
1151
1152 static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1153 {
1154         struct cache_head *ch = p;
1155         int hash = (*pos >> 32);
1156         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1157
1158         if (p == SEQ_START_TOKEN)
1159                 hash = 0;
1160         else if (ch->next == NULL) {
1161                 hash++;
1162                 *pos += 1LL<<32;
1163         } else {
1164                 ++*pos;
1165                 return ch->next;
1166         }
1167         *pos &= ~((1LL<<32) - 1);
1168         while (hash < cd->hash_size &&
1169                cd->hash_table[hash] == NULL) {
1170                 hash++;
1171                 *pos += 1LL<<32;
1172         }
1173         if (hash >= cd->hash_size)
1174                 return NULL;
1175         ++*pos;
1176         return cd->hash_table[hash];
1177 }
1178
1179 static void c_stop(struct seq_file *m, void *p)
1180 {
1181         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1182         read_unlock(&cd->hash_lock);
1183 }
1184
1185 static int c_show(struct seq_file *m, void *p)
1186 {
1187         struct cache_head *cp = p;
1188         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1189
1190         if (p == SEQ_START_TOKEN)
1191                 return cd->cache_show(m, cd, NULL);
1192
1193         ifdebug(CACHE)
1194                 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1195                            cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
1196         cache_get(cp);
1197         if (cache_check(cd, cp, NULL))
1198                 /* cache_check does a cache_put on failure */
1199                 seq_printf(m, "# ");
1200         else
1201                 cache_put(cp, cd);
1202
1203         return cd->cache_show(m, cd, cp);
1204 }
1205
1206 static struct seq_operations cache_content_op = {
1207         .start  = c_start,
1208         .next   = c_next,
1209         .stop   = c_stop,
1210         .show   = c_show,
1211 };
1212
1213 static int content_open(struct inode *inode, struct file *file)
1214 {
1215         int res;
1216         struct handle *han;
1217         struct cache_detail *cd = PDE(inode)->data;
1218
1219         han = kmalloc(sizeof(*han), GFP_KERNEL);
1220         if (han == NULL)
1221                 return -ENOMEM;
1222
1223         han->cd = cd;
1224
1225         res = seq_open(file, &cache_content_op);
1226         if (res)
1227                 kfree(han);
1228         else
1229                 ((struct seq_file *)file->private_data)->private = han;
1230
1231         return res;
1232 }
1233 static int content_release(struct inode *inode, struct file *file)
1234 {
1235         struct seq_file *m = (struct seq_file *)file->private_data;
1236         struct handle *han = m->private;
1237         kfree(han);
1238         m->private = NULL;
1239         return seq_release(inode, file);
1240 }
1241
1242 static struct file_operations content_file_operations = {
1243         .open           = content_open,
1244         .read           = seq_read,
1245         .llseek         = seq_lseek,
1246         .release        = content_release,
1247 };
1248
1249 static ssize_t read_flush(struct file *file, char __user *buf,
1250                             size_t count, loff_t *ppos)
1251 {
1252         struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
1253         char tbuf[20];
1254         unsigned long p = *ppos;
1255         int len;
1256
1257         sprintf(tbuf, "%lu\n", cd->flush_time);
1258         len = strlen(tbuf);
1259         if (p >= len)
1260                 return 0;
1261         len -= p;
1262         if (len > count) len = count;
1263         if (copy_to_user(buf, (void*)(tbuf+p), len))
1264                 len = -EFAULT;
1265         else
1266                 *ppos += len;
1267         return len;
1268 }
1269
1270 static ssize_t write_flush(struct file * file, const char __user * buf,
1271                              size_t count, loff_t *ppos)
1272 {
1273         struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
1274         char tbuf[20];
1275         char *ep;
1276         long flushtime;
1277         if (*ppos || count > sizeof(tbuf)-1)
1278                 return -EINVAL;
1279         if (copy_from_user(tbuf, buf, count))
1280                 return -EFAULT;
1281         tbuf[count] = 0;
1282         flushtime = simple_strtoul(tbuf, &ep, 0);
1283         if (*ep && *ep != '\n')
1284                 return -EINVAL;
1285
1286         cd->flush_time = flushtime;
1287         cd->nextcheck = get_seconds();
1288         cache_flush();
1289
1290         *ppos += count;
1291         return count;
1292 }
1293
1294 static struct file_operations cache_flush_operations = {
1295         .open           = nonseekable_open,
1296         .read           = read_flush,
1297         .write          = write_flush,
1298 };