blob: b5f2786251b95368f4bccda69290683e1c3f0b28 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080029#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#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
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -080037static int cache_defer_req(struct cache_req *req, struct cache_head *item);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static void cache_revisit_request(struct cache_head *item);
39
Adrian Bunk74cae612006-03-27 01:15:10 -080040static void cache_init(struct cache_head *h)
Linus Torvalds1da177e2005-04-16 15:20:36 -070041{
42 time_t now = get_seconds();
43 h->next = NULL;
44 h->flags = 0;
NeilBrownbaab9352006-03-27 01:15:09 -080045 kref_init(&h->ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 h->expiry_time = now + CACHE_NEW_EXPIRY;
47 h->last_refresh = now;
48}
49
NeilBrown15a5f6b2006-03-27 01:15:02 -080050struct 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;
Neil Brown2f349312006-08-05 12:14:29 -070074 /* must fully initialise 'new', else
75 * we might get lose if we need to
76 * cache_put it soon.
77 */
NeilBrown15a5f6b2006-03-27 01:15:02 -080078 cache_init(new);
Neil Brown2f349312006-08-05 12:14:29 -070079 detail->init(new, key);
NeilBrown15a5f6b2006-03-27 01:15:02 -080080
81 write_lock(&detail->hash_lock);
82
83 /* check if entry appeared while we slept */
84 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
85 struct cache_head *tmp = *hp;
86 if (detail->match(tmp, key)) {
87 cache_get(tmp);
88 write_unlock(&detail->hash_lock);
NeilBrownbaab9352006-03-27 01:15:09 -080089 cache_put(new, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -080090 return tmp;
91 }
92 }
NeilBrown15a5f6b2006-03-27 01:15:02 -080093 new->next = *head;
94 *head = new;
95 detail->entries++;
96 cache_get(new);
97 write_unlock(&detail->hash_lock);
98
99 return new;
100}
101EXPORT_SYMBOL(sunrpc_cache_lookup);
102
NeilBrownebd0cb12006-03-27 01:15:08 -0800103
104static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
105
106static int cache_fresh_locked(struct cache_head *head, time_t expiry)
107{
108 head->expiry_time = expiry;
109 head->last_refresh = get_seconds();
110 return !test_and_set_bit(CACHE_VALID, &head->flags);
111}
112
113static void cache_fresh_unlocked(struct cache_head *head,
114 struct cache_detail *detail, int new)
115{
116 if (new)
117 cache_revisit_request(head);
118 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
119 cache_revisit_request(head);
120 queue_loose(detail, head);
121 }
122}
123
NeilBrown15a5f6b2006-03-27 01:15:02 -0800124struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
125 struct cache_head *new, struct cache_head *old, int hash)
126{
127 /* The 'old' entry is to be replaced by 'new'.
128 * If 'old' is not VALID, we update it directly,
129 * otherwise we need to replace it
130 */
131 struct cache_head **head;
132 struct cache_head *tmp;
NeilBrownebd0cb12006-03-27 01:15:08 -0800133 int is_new;
NeilBrown15a5f6b2006-03-27 01:15:02 -0800134
135 if (!test_bit(CACHE_VALID, &old->flags)) {
136 write_lock(&detail->hash_lock);
137 if (!test_bit(CACHE_VALID, &old->flags)) {
138 if (test_bit(CACHE_NEGATIVE, &new->flags))
139 set_bit(CACHE_NEGATIVE, &old->flags);
140 else
141 detail->update(old, new);
NeilBrownebd0cb12006-03-27 01:15:08 -0800142 is_new = cache_fresh_locked(old, new->expiry_time);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800143 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800144 cache_fresh_unlocked(old, detail, is_new);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800145 return old;
146 }
147 write_unlock(&detail->hash_lock);
148 }
149 /* We need to insert a new entry */
150 tmp = detail->alloc();
151 if (!tmp) {
NeilBrownbaab9352006-03-27 01:15:09 -0800152 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800153 return NULL;
154 }
155 cache_init(tmp);
156 detail->init(tmp, old);
157 head = &detail->hash_table[hash];
158
159 write_lock(&detail->hash_lock);
160 if (test_bit(CACHE_NEGATIVE, &new->flags))
161 set_bit(CACHE_NEGATIVE, &tmp->flags);
162 else
163 detail->update(tmp, new);
164 tmp->next = *head;
165 *head = tmp;
NeilBrownf2d39582006-05-22 22:35:25 -0700166 detail->entries++;
NeilBrown15a5f6b2006-03-27 01:15:02 -0800167 cache_get(tmp);
NeilBrownebd0cb12006-03-27 01:15:08 -0800168 is_new = cache_fresh_locked(tmp, new->expiry_time);
169 cache_fresh_locked(old, 0);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800170 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800171 cache_fresh_unlocked(tmp, detail, is_new);
172 cache_fresh_unlocked(old, detail, 0);
NeilBrownbaab9352006-03-27 01:15:09 -0800173 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800174 return tmp;
175}
176EXPORT_SYMBOL(sunrpc_cache_update);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
178static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
179/*
180 * This is the generic cache management routine for all
181 * the authentication caches.
182 * It checks the currency of a cache item and will (later)
183 * initiate an upcall to fill it if needed.
184 *
185 *
186 * Returns 0 if the cache_head can be used, or cache_puts it and returns
187 * -EAGAIN if upcall is pending,
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800188 * -ETIMEDOUT if upcall failed and should be retried,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 * -ENOENT if cache entry was negative
190 */
191int cache_check(struct cache_detail *detail,
192 struct cache_head *h, struct cache_req *rqstp)
193{
194 int rv;
195 long refresh_age, age;
196
197 /* First decide return status as best we can */
198 if (!test_bit(CACHE_VALID, &h->flags) ||
199 h->expiry_time < get_seconds())
200 rv = -EAGAIN;
201 else if (detail->flush_time > h->last_refresh)
202 rv = -EAGAIN;
203 else {
204 /* entry is valid */
205 if (test_bit(CACHE_NEGATIVE, &h->flags))
206 rv = -ENOENT;
207 else rv = 0;
208 }
209
210 /* now see if we want to start an upcall */
211 refresh_age = (h->expiry_time - h->last_refresh);
212 age = get_seconds() - h->last_refresh;
213
214 if (rqstp == NULL) {
215 if (rv == -EAGAIN)
216 rv = -ENOENT;
217 } else if (rv == -EAGAIN || age > refresh_age/2) {
Chuck Lever46121cf2007-01-31 12:14:08 -0500218 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
219 refresh_age, age);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
221 switch (cache_make_upcall(detail, h)) {
222 case -EINVAL:
223 clear_bit(CACHE_PENDING, &h->flags);
224 if (rv == -EAGAIN) {
225 set_bit(CACHE_NEGATIVE, &h->flags);
NeilBrownebd0cb12006-03-27 01:15:08 -0800226 cache_fresh_unlocked(h, detail,
227 cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 rv = -ENOENT;
229 }
230 break;
231
232 case -EAGAIN:
233 clear_bit(CACHE_PENDING, &h->flags);
234 cache_revisit_request(h);
235 break;
236 }
237 }
238 }
239
240 if (rv == -EAGAIN)
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800241 if (cache_defer_req(rqstp, h) != 0)
242 rv = -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
NeilBrown4013ede2006-03-27 01:15:07 -0800244 if (rv)
NeilBrownbaab9352006-03-27 01:15:09 -0800245 cache_put(h, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 return rv;
247}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400248EXPORT_SYMBOL(cache_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250/*
251 * caches need to be periodically cleaned.
252 * For this we maintain a list of cache_detail and
253 * a current pointer into that list and into the table
254 * for that entry.
255 *
256 * Each time clean_cache is called it finds the next non-empty entry
257 * in the current table and walks the list in that entry
258 * looking for entries that can be removed.
259 *
260 * An entry gets removed if:
261 * - The expiry is before current time
262 * - The last_refresh time is before the flush_time for that cache
263 *
264 * later we might drop old entries with non-NEVER expiry if that table
265 * is getting 'full' for some definition of 'full'
266 *
267 * The question of "how often to scan a table" is an interesting one
268 * and is answered in part by the use of the "nextcheck" field in the
269 * cache_detail.
270 * When a scan of a table begins, the nextcheck field is set to a time
271 * that is well into the future.
272 * While scanning, if an expiry time is found that is earlier than the
273 * current nextcheck time, nextcheck is set to that expiry time.
274 * If the flush_time is ever set to a time earlier than the nextcheck
275 * time, the nextcheck time is then set to that flush_time.
276 *
277 * A table is then only scanned if the current time is at least
278 * the nextcheck time.
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800279 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 */
281
282static LIST_HEAD(cache_list);
283static DEFINE_SPINLOCK(cache_list_lock);
284static struct cache_detail *current_detail;
285static int current_index;
286
Arjan van de Venda7071d2007-02-12 00:55:36 -0800287static const struct file_operations cache_file_operations;
288static const struct file_operations content_file_operations;
289static const struct file_operations cache_flush_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
David Howells65f27f32006-11-22 14:55:48 +0000291static void do_cache_clean(struct work_struct *work);
292static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500294static void remove_cache_proc_entries(struct cache_detail *cd)
295{
296 if (cd->proc_ent == NULL)
297 return;
298 if (cd->flush_ent)
299 remove_proc_entry("flush", cd->proc_ent);
300 if (cd->channel_ent)
301 remove_proc_entry("channel", cd->proc_ent);
302 if (cd->content_ent)
303 remove_proc_entry("content", cd->proc_ent);
304 cd->proc_ent = NULL;
305 remove_proc_entry(cd->name, proc_net_rpc);
306}
307
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500308#ifdef CONFIG_PROC_FS
309static int create_cache_proc_entries(struct cache_detail *cd)
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500310{
311 struct proc_dir_entry *p;
312
313 cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
314 if (cd->proc_ent == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500315 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500316 cd->proc_ent->owner = cd->owner;
317 cd->channel_ent = cd->content_ent = NULL;
318
Wang Chen2ce8f042008-02-28 14:00:59 -0800319 p = proc_create("flush", S_IFREG|S_IRUSR|S_IWUSR,
320 cd->proc_ent, &cache_flush_operations);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500321 cd->flush_ent = p;
322 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500323 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500324 p->owner = cd->owner;
325 p->data = cd;
326
327 if (cd->cache_request || cd->cache_parse) {
Wang Chen2ce8f042008-02-28 14:00:59 -0800328 p = proc_create("channel", S_IFREG|S_IRUSR|S_IWUSR,
329 cd->proc_ent, &cache_file_operations);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500330 cd->channel_ent = p;
331 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500332 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500333 p->owner = cd->owner;
334 p->data = cd;
335 }
336 if (cd->cache_show) {
Wang Chen2ce8f042008-02-28 14:00:59 -0800337 p = proc_create("content", S_IFREG|S_IRUSR|S_IWUSR,
338 cd->proc_ent, &content_file_operations);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500339 cd->content_ent = p;
340 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500341 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500342 p->owner = cd->owner;
343 p->data = cd;
344 }
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500345 return 0;
346out_nomem:
347 remove_cache_proc_entries(cd);
348 return -ENOMEM;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500349}
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500350#else /* CONFIG_PROC_FS */
351static int create_cache_proc_entries(struct cache_detail *cd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352{
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500353 return 0;
354}
355#endif
356
357int cache_register(struct cache_detail *cd)
358{
359 int ret;
360
361 ret = create_cache_proc_entries(cd);
362 if (ret)
363 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 rwlock_init(&cd->hash_lock);
365 INIT_LIST_HEAD(&cd->queue);
366 spin_lock(&cache_list_lock);
367 cd->nextcheck = 0;
368 cd->entries = 0;
369 atomic_set(&cd->readers, 0);
370 cd->last_close = 0;
371 cd->last_warn = -1;
372 list_add(&cd->others, &cache_list);
373 spin_unlock(&cache_list_lock);
374
375 /* start the cleaning process */
David Howells52bad642006-11-22 14:54:01 +0000376 schedule_delayed_work(&cache_cleaner, 0);
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500377 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400379EXPORT_SYMBOL(cache_register);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500381void cache_unregister(struct cache_detail *cd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382{
383 cache_purge(cd);
384 spin_lock(&cache_list_lock);
385 write_lock(&cd->hash_lock);
386 if (cd->entries || atomic_read(&cd->inuse)) {
387 write_unlock(&cd->hash_lock);
388 spin_unlock(&cache_list_lock);
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500389 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 }
391 if (current_detail == cd)
392 current_detail = NULL;
393 list_del_init(&cd->others);
394 write_unlock(&cd->hash_lock);
395 spin_unlock(&cache_list_lock);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500396 remove_cache_proc_entries(cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 if (list_empty(&cache_list)) {
398 /* module must be being unloaded so its safe to kill the worker */
Trond Myklebust4011cd92007-08-07 15:33:01 -0400399 cancel_delayed_work_sync(&cache_cleaner);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 }
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500401 return;
402out:
403 printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400405EXPORT_SYMBOL(cache_unregister);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406
407/* clean cache tries to find something to clean
408 * and cleans it.
409 * It returns 1 if it cleaned something,
410 * 0 if it didn't find anything this time
411 * -1 if it fell off the end of the list.
412 */
413static int cache_clean(void)
414{
415 int rv = 0;
416 struct list_head *next;
417
418 spin_lock(&cache_list_lock);
419
420 /* find a suitable table if we don't already have one */
421 while (current_detail == NULL ||
422 current_index >= current_detail->hash_size) {
423 if (current_detail)
424 next = current_detail->others.next;
425 else
426 next = cache_list.next;
427 if (next == &cache_list) {
428 current_detail = NULL;
429 spin_unlock(&cache_list_lock);
430 return -1;
431 }
432 current_detail = list_entry(next, struct cache_detail, others);
433 if (current_detail->nextcheck > get_seconds())
434 current_index = current_detail->hash_size;
435 else {
436 current_index = 0;
437 current_detail->nextcheck = get_seconds()+30*60;
438 }
439 }
440
441 /* find a non-empty bucket in the table */
442 while (current_detail &&
443 current_index < current_detail->hash_size &&
444 current_detail->hash_table[current_index] == NULL)
445 current_index++;
446
447 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800448
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 if (current_detail && current_index < current_detail->hash_size) {
450 struct cache_head *ch, **cp;
451 struct cache_detail *d;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800452
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 write_lock(&current_detail->hash_lock);
454
455 /* Ok, now to clean this strand */
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800456
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 cp = & current_detail->hash_table[current_index];
458 ch = *cp;
459 for (; ch; cp= & ch->next, ch= *cp) {
460 if (current_detail->nextcheck > ch->expiry_time)
461 current_detail->nextcheck = ch->expiry_time+1;
462 if (ch->expiry_time >= get_seconds()
463 && ch->last_refresh >= current_detail->flush_time
464 )
465 continue;
466 if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
467 queue_loose(current_detail, ch);
468
NeilBrownbaab9352006-03-27 01:15:09 -0800469 if (atomic_read(&ch->ref.refcount) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 break;
471 }
472 if (ch) {
473 *cp = ch->next;
474 ch->next = NULL;
475 current_detail->entries--;
476 rv = 1;
477 }
478 write_unlock(&current_detail->hash_lock);
479 d = current_detail;
480 if (!ch)
481 current_index ++;
482 spin_unlock(&cache_list_lock);
483 if (ch)
NeilBrownbaab9352006-03-27 01:15:09 -0800484 cache_put(ch, d);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 } else
486 spin_unlock(&cache_list_lock);
487
488 return rv;
489}
490
491/*
492 * We want to regularly clean the cache, so we need to schedule some work ...
493 */
David Howells65f27f32006-11-22 14:55:48 +0000494static void do_cache_clean(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
496 int delay = 5;
497 if (cache_clean() == -1)
498 delay = 30*HZ;
499
500 if (list_empty(&cache_list))
501 delay = 0;
502
503 if (delay)
504 schedule_delayed_work(&cache_cleaner, delay);
505}
506
507
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800508/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 * Clean all caches promptly. This just calls cache_clean
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800510 * repeatedly until we are sure that every cache has had a chance to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 * be fully cleaned
512 */
513void cache_flush(void)
514{
515 while (cache_clean() != -1)
516 cond_resched();
517 while (cache_clean() != -1)
518 cond_resched();
519}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400520EXPORT_SYMBOL(cache_flush);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521
522void cache_purge(struct cache_detail *detail)
523{
524 detail->flush_time = LONG_MAX;
525 detail->nextcheck = get_seconds();
526 cache_flush();
527 detail->flush_time = 1;
528}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400529EXPORT_SYMBOL(cache_purge);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
531
532/*
533 * Deferral and Revisiting of Requests.
534 *
535 * If a cache lookup finds a pending entry, we
536 * need to defer the request and revisit it later.
537 * All deferred requests are stored in a hash table,
538 * indexed by "struct cache_head *".
539 * As it may be wasteful to store a whole request
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800540 * structure, we allow the request to provide a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 * deferred form, which must contain a
542 * 'struct cache_deferred_req'
543 * This cache_deferred_req contains a method to allow
544 * it to be revisited when cache info is available
545 */
546
547#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
548#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
549
550#define DFR_MAX 300 /* ??? */
551
552static DEFINE_SPINLOCK(cache_defer_lock);
553static LIST_HEAD(cache_defer_list);
554static struct list_head cache_defer_hash[DFR_HASHSIZE];
555static int cache_defer_cnt;
556
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800557static int cache_defer_req(struct cache_req *req, struct cache_head *item)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558{
559 struct cache_deferred_req *dreq;
560 int hash = DFR_HASH(item);
561
J.Bruce Fields01f3bd12006-12-13 00:35:26 -0800562 if (cache_defer_cnt >= DFR_MAX) {
563 /* too much in the cache, randomly drop this one,
564 * or continue and drop the oldest below
565 */
566 if (net_random()&1)
567 return -ETIMEDOUT;
568 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 dreq = req->defer(req);
570 if (dreq == NULL)
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800571 return -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572
573 dreq->item = item;
574 dreq->recv_time = get_seconds();
575
576 spin_lock(&cache_defer_lock);
577
578 list_add(&dreq->recent, &cache_defer_list);
579
580 if (cache_defer_hash[hash].next == NULL)
581 INIT_LIST_HEAD(&cache_defer_hash[hash]);
582 list_add(&dreq->hash, &cache_defer_hash[hash]);
583
584 /* it is in, now maybe clean up */
585 dreq = NULL;
586 if (++cache_defer_cnt > DFR_MAX) {
J.Bruce Fields01f3bd12006-12-13 00:35:26 -0800587 dreq = list_entry(cache_defer_list.prev,
588 struct cache_deferred_req, recent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 list_del(&dreq->recent);
590 list_del(&dreq->hash);
591 cache_defer_cnt--;
592 }
593 spin_unlock(&cache_defer_lock);
594
595 if (dreq) {
596 /* there was one too many */
597 dreq->revisit(dreq, 1);
598 }
NeilBrown4013ede2006-03-27 01:15:07 -0800599 if (!test_bit(CACHE_PENDING, &item->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 /* must have just been validated... */
601 cache_revisit_request(item);
602 }
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800603 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604}
605
606static void cache_revisit_request(struct cache_head *item)
607{
608 struct cache_deferred_req *dreq;
609 struct list_head pending;
610
611 struct list_head *lp;
612 int hash = DFR_HASH(item);
613
614 INIT_LIST_HEAD(&pending);
615 spin_lock(&cache_defer_lock);
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800616
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 lp = cache_defer_hash[hash].next;
618 if (lp) {
619 while (lp != &cache_defer_hash[hash]) {
620 dreq = list_entry(lp, struct cache_deferred_req, hash);
621 lp = lp->next;
622 if (dreq->item == item) {
623 list_del(&dreq->hash);
624 list_move(&dreq->recent, &pending);
625 cache_defer_cnt--;
626 }
627 }
628 }
629 spin_unlock(&cache_defer_lock);
630
631 while (!list_empty(&pending)) {
632 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
633 list_del_init(&dreq->recent);
634 dreq->revisit(dreq, 0);
635 }
636}
637
638void cache_clean_deferred(void *owner)
639{
640 struct cache_deferred_req *dreq, *tmp;
641 struct list_head pending;
642
643
644 INIT_LIST_HEAD(&pending);
645 spin_lock(&cache_defer_lock);
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800646
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
648 if (dreq->owner == owner) {
649 list_del(&dreq->hash);
650 list_move(&dreq->recent, &pending);
651 cache_defer_cnt--;
652 }
653 }
654 spin_unlock(&cache_defer_lock);
655
656 while (!list_empty(&pending)) {
657 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
658 list_del_init(&dreq->recent);
659 dreq->revisit(dreq, 1);
660 }
661}
662
663/*
664 * communicate with user-space
665 *
J. Bruce Fieldsa490c682007-11-06 14:15:19 -0500666 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
667 * On read, you get a full request, or block.
668 * On write, an update request is processed.
669 * Poll works if anything to read, and always allows write.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800671 * Implemented by linked list of requests. Each open file has
J. Bruce Fieldsa490c682007-11-06 14:15:19 -0500672 * a ->private that also exists in this list. New requests are added
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 * to the end and may wakeup and preceding readers.
674 * New readers are added to the head. If, on read, an item is found with
675 * CACHE_UPCALLING clear, we free it from the list.
676 *
677 */
678
679static DEFINE_SPINLOCK(queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800680static DEFINE_MUTEX(queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
682struct cache_queue {
683 struct list_head list;
684 int reader; /* if 0, then request */
685};
686struct cache_request {
687 struct cache_queue q;
688 struct cache_head *item;
689 char * buf;
690 int len;
691 int readers;
692};
693struct cache_reader {
694 struct cache_queue q;
695 int offset; /* if non-0, we have a refcnt on next request */
696};
697
698static ssize_t
699cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
700{
701 struct cache_reader *rp = filp->private_data;
702 struct cache_request *rq;
Josef Sipek303b46b2006-12-08 02:37:42 -0800703 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 int err;
705
706 if (count == 0)
707 return 0;
708
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800709 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 * readers on this file */
711 again:
712 spin_lock(&queue_lock);
713 /* need to find next request */
714 while (rp->q.list.next != &cd->queue &&
715 list_entry(rp->q.list.next, struct cache_queue, list)
716 ->reader) {
717 struct list_head *next = rp->q.list.next;
718 list_move(&rp->q.list, next);
719 }
720 if (rp->q.list.next == &cd->queue) {
721 spin_unlock(&queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800722 mutex_unlock(&queue_io_mutex);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800723 BUG_ON(rp->offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 return 0;
725 }
726 rq = container_of(rp->q.list.next, struct cache_request, q.list);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800727 BUG_ON(rq->q.reader);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 if (rp->offset == 0)
729 rq->readers++;
730 spin_unlock(&queue_lock);
731
732 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
733 err = -EAGAIN;
734 spin_lock(&queue_lock);
735 list_move(&rp->q.list, &rq->q.list);
736 spin_unlock(&queue_lock);
737 } else {
738 if (rp->offset + count > rq->len)
739 count = rq->len - rp->offset;
740 err = -EFAULT;
741 if (copy_to_user(buf, rq->buf + rp->offset, count))
742 goto out;
743 rp->offset += count;
744 if (rp->offset >= rq->len) {
745 rp->offset = 0;
746 spin_lock(&queue_lock);
747 list_move(&rp->q.list, &rq->q.list);
748 spin_unlock(&queue_lock);
749 }
750 err = 0;
751 }
752 out:
753 if (rp->offset == 0) {
754 /* need to release rq */
755 spin_lock(&queue_lock);
756 rq->readers--;
757 if (rq->readers == 0 &&
758 !test_bit(CACHE_PENDING, &rq->item->flags)) {
759 list_del(&rq->q.list);
760 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800761 cache_put(rq->item, cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 kfree(rq->buf);
763 kfree(rq);
764 } else
765 spin_unlock(&queue_lock);
766 }
767 if (err == -EAGAIN)
768 goto again;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800769 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 return err ? err : count;
771}
772
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800773static char write_buf[8192]; /* protected by queue_io_mutex */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774
775static ssize_t
776cache_write(struct file *filp, const char __user *buf, size_t count,
777 loff_t *ppos)
778{
779 int err;
Josef Sipek303b46b2006-12-08 02:37:42 -0800780 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781
782 if (count == 0)
783 return 0;
784 if (count >= sizeof(write_buf))
785 return -EINVAL;
786
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800787 mutex_lock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788
789 if (copy_from_user(write_buf, buf, count)) {
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800790 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 return -EFAULT;
792 }
793 write_buf[count] = '\0';
794 if (cd->cache_parse)
795 err = cd->cache_parse(cd, write_buf, count);
796 else
797 err = -EINVAL;
798
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800799 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 return err ? err : count;
801}
802
803static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
804
805static unsigned int
806cache_poll(struct file *filp, poll_table *wait)
807{
808 unsigned int mask;
809 struct cache_reader *rp = filp->private_data;
810 struct cache_queue *cq;
Josef Sipek303b46b2006-12-08 02:37:42 -0800811 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812
813 poll_wait(filp, &queue_wait, wait);
814
815 /* alway allow write */
816 mask = POLL_OUT | POLLWRNORM;
817
818 if (!rp)
819 return mask;
820
821 spin_lock(&queue_lock);
822
823 for (cq= &rp->q; &cq->list != &cd->queue;
824 cq = list_entry(cq->list.next, struct cache_queue, list))
825 if (!cq->reader) {
826 mask |= POLLIN | POLLRDNORM;
827 break;
828 }
829 spin_unlock(&queue_lock);
830 return mask;
831}
832
833static int
834cache_ioctl(struct inode *ino, struct file *filp,
835 unsigned int cmd, unsigned long arg)
836{
837 int len = 0;
838 struct cache_reader *rp = filp->private_data;
839 struct cache_queue *cq;
840 struct cache_detail *cd = PDE(ino)->data;
841
842 if (cmd != FIONREAD || !rp)
843 return -EINVAL;
844
845 spin_lock(&queue_lock);
846
847 /* only find the length remaining in current request,
848 * or the length of the next request
849 */
850 for (cq= &rp->q; &cq->list != &cd->queue;
851 cq = list_entry(cq->list.next, struct cache_queue, list))
852 if (!cq->reader) {
853 struct cache_request *cr =
854 container_of(cq, struct cache_request, q);
855 len = cr->len - rp->offset;
856 break;
857 }
858 spin_unlock(&queue_lock);
859
860 return put_user(len, (int __user *)arg);
861}
862
863static int
864cache_open(struct inode *inode, struct file *filp)
865{
866 struct cache_reader *rp = NULL;
867
868 nonseekable_open(inode, filp);
869 if (filp->f_mode & FMODE_READ) {
870 struct cache_detail *cd = PDE(inode)->data;
871
872 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
873 if (!rp)
874 return -ENOMEM;
875 rp->offset = 0;
876 rp->q.reader = 1;
877 atomic_inc(&cd->readers);
878 spin_lock(&queue_lock);
879 list_add(&rp->q.list, &cd->queue);
880 spin_unlock(&queue_lock);
881 }
882 filp->private_data = rp;
883 return 0;
884}
885
886static int
887cache_release(struct inode *inode, struct file *filp)
888{
889 struct cache_reader *rp = filp->private_data;
890 struct cache_detail *cd = PDE(inode)->data;
891
892 if (rp) {
893 spin_lock(&queue_lock);
894 if (rp->offset) {
895 struct cache_queue *cq;
896 for (cq= &rp->q; &cq->list != &cd->queue;
897 cq = list_entry(cq->list.next, struct cache_queue, list))
898 if (!cq->reader) {
899 container_of(cq, struct cache_request, q)
900 ->readers--;
901 break;
902 }
903 rp->offset = 0;
904 }
905 list_del(&rp->q.list);
906 spin_unlock(&queue_lock);
907
908 filp->private_data = NULL;
909 kfree(rp);
910
911 cd->last_close = get_seconds();
912 atomic_dec(&cd->readers);
913 }
914 return 0;
915}
916
917
918
Arjan van de Venda7071d2007-02-12 00:55:36 -0800919static const struct file_operations cache_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 .owner = THIS_MODULE,
921 .llseek = no_llseek,
922 .read = cache_read,
923 .write = cache_write,
924 .poll = cache_poll,
925 .ioctl = cache_ioctl, /* for FIONREAD */
926 .open = cache_open,
927 .release = cache_release,
928};
929
930
931static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
932{
933 struct cache_queue *cq;
934 spin_lock(&queue_lock);
935 list_for_each_entry(cq, &detail->queue, list)
936 if (!cq->reader) {
937 struct cache_request *cr = container_of(cq, struct cache_request, q);
938 if (cr->item != ch)
939 continue;
940 if (cr->readers != 0)
NeilBrown4013ede2006-03-27 01:15:07 -0800941 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 list_del(&cr->q.list);
943 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800944 cache_put(cr->item, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 kfree(cr->buf);
946 kfree(cr);
947 return;
948 }
949 spin_unlock(&queue_lock);
950}
951
952/*
953 * Support routines for text-based upcalls.
954 * Fields are separated by spaces.
955 * Fields are either mangled to quote space tab newline slosh with slosh
956 * or a hexified with a leading \x
957 * Record is terminated with newline.
958 *
959 */
960
961void qword_add(char **bpp, int *lp, char *str)
962{
963 char *bp = *bpp;
964 int len = *lp;
965 char c;
966
967 if (len < 0) return;
968
969 while ((c=*str++) && len)
970 switch(c) {
971 case ' ':
972 case '\t':
973 case '\n':
974 case '\\':
975 if (len >= 4) {
976 *bp++ = '\\';
977 *bp++ = '0' + ((c & 0300)>>6);
978 *bp++ = '0' + ((c & 0070)>>3);
979 *bp++ = '0' + ((c & 0007)>>0);
980 }
981 len -= 4;
982 break;
983 default:
984 *bp++ = c;
985 len--;
986 }
987 if (c || len <1) len = -1;
988 else {
989 *bp++ = ' ';
990 len--;
991 }
992 *bpp = bp;
993 *lp = len;
994}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400995EXPORT_SYMBOL(qword_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996
997void qword_addhex(char **bpp, int *lp, char *buf, int blen)
998{
999 char *bp = *bpp;
1000 int len = *lp;
1001
1002 if (len < 0) return;
1003
1004 if (len > 2) {
1005 *bp++ = '\\';
1006 *bp++ = 'x';
1007 len -= 2;
1008 while (blen && len >= 2) {
1009 unsigned char c = *buf++;
1010 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
1011 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
1012 len -= 2;
1013 blen--;
1014 }
1015 }
1016 if (blen || len<1) len = -1;
1017 else {
1018 *bp++ = ' ';
1019 len--;
1020 }
1021 *bpp = bp;
1022 *lp = len;
1023}
Trond Myklebustd2f7e792007-07-14 15:39:58 -04001024EXPORT_SYMBOL(qword_addhex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025
1026static void warn_no_listener(struct cache_detail *detail)
1027{
1028 if (detail->last_warn != detail->last_close) {
1029 detail->last_warn = detail->last_close;
1030 if (detail->warn_no_listener)
1031 detail->warn_no_listener(detail);
1032 }
1033}
1034
1035/*
1036 * register an upcall request to user-space.
1037 * Each request is at most one page long.
1038 */
1039static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
1040{
1041
1042 char *buf;
1043 struct cache_request *crq;
1044 char *bp;
1045 int len;
1046
1047 if (detail->cache_request == NULL)
1048 return -EINVAL;
1049
1050 if (atomic_read(&detail->readers) == 0 &&
1051 detail->last_close < get_seconds() - 30) {
1052 warn_no_listener(detail);
1053 return -EINVAL;
1054 }
1055
1056 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1057 if (!buf)
1058 return -EAGAIN;
1059
1060 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1061 if (!crq) {
1062 kfree(buf);
1063 return -EAGAIN;
1064 }
1065
1066 bp = buf; len = PAGE_SIZE;
1067
1068 detail->cache_request(detail, h, &bp, &len);
1069
1070 if (len < 0) {
1071 kfree(buf);
1072 kfree(crq);
1073 return -EAGAIN;
1074 }
1075 crq->q.reader = 0;
1076 crq->item = cache_get(h);
1077 crq->buf = buf;
1078 crq->len = PAGE_SIZE - len;
1079 crq->readers = 0;
1080 spin_lock(&queue_lock);
1081 list_add_tail(&crq->q.list, &detail->queue);
1082 spin_unlock(&queue_lock);
1083 wake_up(&queue_wait);
1084 return 0;
1085}
1086
1087/*
1088 * parse a message from user-space and pass it
1089 * to an appropriate cache
1090 * Messages are, like requests, separated into fields by
1091 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1092 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001093 * Message is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 * reply cachename expiry key ... content....
1095 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001096 * key and content are both parsed by cache
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 */
1098
1099#define isodigit(c) (isdigit(c) && c <= '7')
1100int qword_get(char **bpp, char *dest, int bufsize)
1101{
1102 /* return bytes copied, or -1 on error */
1103 char *bp = *bpp;
1104 int len = 0;
1105
1106 while (*bp == ' ') bp++;
1107
1108 if (bp[0] == '\\' && bp[1] == 'x') {
1109 /* HEX STRING */
1110 bp += 2;
1111 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) {
1112 int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1113 bp++;
1114 byte <<= 4;
1115 byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1116 *dest++ = byte;
1117 bp++;
1118 len++;
1119 }
1120 } else {
1121 /* text with \nnn octal quoting */
1122 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1123 if (*bp == '\\' &&
1124 isodigit(bp[1]) && (bp[1] <= '3') &&
1125 isodigit(bp[2]) &&
1126 isodigit(bp[3])) {
1127 int byte = (*++bp -'0');
1128 bp++;
1129 byte = (byte << 3) | (*bp++ - '0');
1130 byte = (byte << 3) | (*bp++ - '0');
1131 *dest++ = byte;
1132 len++;
1133 } else {
1134 *dest++ = *bp++;
1135 len++;
1136 }
1137 }
1138 }
1139
1140 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1141 return -1;
1142 while (*bp == ' ') bp++;
1143 *bpp = bp;
1144 *dest = '\0';
1145 return len;
1146}
Trond Myklebustd2f7e792007-07-14 15:39:58 -04001147EXPORT_SYMBOL(qword_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148
1149
1150/*
1151 * support /proc/sunrpc/cache/$CACHENAME/content
1152 * as a seqfile.
1153 * We call ->cache_show passing NULL for the item to
1154 * get a header, then pass each real item in the cache
1155 */
1156
1157struct handle {
1158 struct cache_detail *cd;
1159};
1160
1161static void *c_start(struct seq_file *m, loff_t *pos)
Eric Dumazet9a429c42008-01-01 21:58:02 -08001162 __acquires(cd->hash_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163{
1164 loff_t n = *pos;
1165 unsigned hash, entry;
1166 struct cache_head *ch;
1167 struct cache_detail *cd = ((struct handle*)m->private)->cd;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001168
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169
1170 read_lock(&cd->hash_lock);
1171 if (!n--)
1172 return SEQ_START_TOKEN;
1173 hash = n >> 32;
1174 entry = n & ((1LL<<32) - 1);
1175
1176 for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1177 if (!entry--)
1178 return ch;
1179 n &= ~((1LL<<32) - 1);
1180 do {
1181 hash++;
1182 n += 1LL<<32;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001183 } while(hash < cd->hash_size &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 cd->hash_table[hash]==NULL);
1185 if (hash >= cd->hash_size)
1186 return NULL;
1187 *pos = n+1;
1188 return cd->hash_table[hash];
1189}
1190
1191static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1192{
1193 struct cache_head *ch = p;
1194 int hash = (*pos >> 32);
1195 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1196
1197 if (p == SEQ_START_TOKEN)
1198 hash = 0;
1199 else if (ch->next == NULL) {
1200 hash++;
1201 *pos += 1LL<<32;
1202 } else {
1203 ++*pos;
1204 return ch->next;
1205 }
1206 *pos &= ~((1LL<<32) - 1);
1207 while (hash < cd->hash_size &&
1208 cd->hash_table[hash] == NULL) {
1209 hash++;
1210 *pos += 1LL<<32;
1211 }
1212 if (hash >= cd->hash_size)
1213 return NULL;
1214 ++*pos;
1215 return cd->hash_table[hash];
1216}
1217
1218static void c_stop(struct seq_file *m, void *p)
Eric Dumazet9a429c42008-01-01 21:58:02 -08001219 __releases(cd->hash_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220{
1221 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1222 read_unlock(&cd->hash_lock);
1223}
1224
1225static int c_show(struct seq_file *m, void *p)
1226{
1227 struct cache_head *cp = p;
1228 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1229
1230 if (p == SEQ_START_TOKEN)
1231 return cd->cache_show(m, cd, NULL);
1232
1233 ifdebug(CACHE)
NeilBrown4013ede2006-03-27 01:15:07 -08001234 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
NeilBrownbaab9352006-03-27 01:15:09 -08001235 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 cache_get(cp);
1237 if (cache_check(cd, cp, NULL))
1238 /* cache_check does a cache_put on failure */
1239 seq_printf(m, "# ");
1240 else
1241 cache_put(cp, cd);
1242
1243 return cd->cache_show(m, cd, cp);
1244}
1245
Philippe De Muyter56b3d972007-07-10 23:07:31 -07001246static const struct seq_operations cache_content_op = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 .start = c_start,
1248 .next = c_next,
1249 .stop = c_stop,
1250 .show = c_show,
1251};
1252
1253static int content_open(struct inode *inode, struct file *file)
1254{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 struct handle *han;
1256 struct cache_detail *cd = PDE(inode)->data;
1257
Pavel Emelyanovec931032007-10-10 02:31:07 -07001258 han = __seq_open_private(file, &cache_content_op, sizeof(*han));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 if (han == NULL)
1260 return -ENOMEM;
1261
1262 han->cd = cd;
Pavel Emelyanovec931032007-10-10 02:31:07 -07001263 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265
Arjan van de Venda7071d2007-02-12 00:55:36 -08001266static const struct file_operations content_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 .open = content_open,
1268 .read = seq_read,
1269 .llseek = seq_lseek,
Martin Peschke14690fc2007-04-26 01:03:43 -07001270 .release = seq_release_private,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271};
1272
1273static ssize_t read_flush(struct file *file, char __user *buf,
1274 size_t count, loff_t *ppos)
1275{
Josef Sipek303b46b2006-12-08 02:37:42 -08001276 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 char tbuf[20];
1278 unsigned long p = *ppos;
Chuck Lever01b29692007-10-26 13:31:20 -04001279 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280
1281 sprintf(tbuf, "%lu\n", cd->flush_time);
1282 len = strlen(tbuf);
1283 if (p >= len)
1284 return 0;
1285 len -= p;
Chuck Lever01b29692007-10-26 13:31:20 -04001286 if (len > count)
1287 len = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 if (copy_to_user(buf, (void*)(tbuf+p), len))
Chuck Lever01b29692007-10-26 13:31:20 -04001289 return -EFAULT;
1290 *ppos += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 return len;
1292}
1293
1294static ssize_t write_flush(struct file * file, const char __user * buf,
1295 size_t count, loff_t *ppos)
1296{
Josef Sipek303b46b2006-12-08 02:37:42 -08001297 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298 char tbuf[20];
1299 char *ep;
1300 long flushtime;
1301 if (*ppos || count > sizeof(tbuf)-1)
1302 return -EINVAL;
1303 if (copy_from_user(tbuf, buf, count))
1304 return -EFAULT;
1305 tbuf[count] = 0;
1306 flushtime = simple_strtoul(tbuf, &ep, 0);
1307 if (*ep && *ep != '\n')
1308 return -EINVAL;
1309
1310 cd->flush_time = flushtime;
1311 cd->nextcheck = get_seconds();
1312 cache_flush();
1313
1314 *ppos += count;
1315 return count;
1316}
1317
Arjan van de Venda7071d2007-02-12 00:55:36 -08001318static const struct file_operations cache_flush_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 .open = nonseekable_open,
1320 .read = read_flush,
1321 .write = write_flush,
1322};