1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * net/sunrpc/cache.c |
4 | * |
5 | * Generic code for various authentication-related caches |
6 | * used by sunrpc clients and servers. |
7 | * |
8 | * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> |
9 | */ |
10 | |
11 | #include <linux/types.h> |
12 | #include <linux/fs.h> |
13 | #include <linux/file.h> |
14 | #include <linux/slab.h> |
15 | #include <linux/signal.h> |
16 | #include <linux/sched.h> |
17 | #include <linux/kmod.h> |
18 | #include <linux/list.h> |
19 | #include <linux/module.h> |
20 | #include <linux/ctype.h> |
21 | #include <linux/string_helpers.h> |
22 | #include <linux/uaccess.h> |
23 | #include <linux/poll.h> |
24 | #include <linux/seq_file.h> |
25 | #include <linux/proc_fs.h> |
26 | #include <linux/net.h> |
27 | #include <linux/workqueue.h> |
28 | #include <linux/mutex.h> |
29 | #include <linux/pagemap.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 | #include <linux/sunrpc/rpc_pipe_fs.h> |
35 | #include <trace/events/sunrpc.h> |
36 | |
37 | #include "netns.h" |
38 | #include "fail.h" |
39 | |
40 | #define RPCDBG_FACILITY RPCDBG_CACHE |
41 | |
42 | static bool cache_defer_req(struct cache_req *req, struct cache_head *item); |
43 | static void cache_revisit_request(struct cache_head *item); |
44 | |
45 | static void cache_init(struct cache_head *h, struct cache_detail *detail) |
46 | { |
47 | time64_t now = seconds_since_boot(); |
48 | INIT_HLIST_NODE(h: &h->cache_list); |
49 | h->flags = 0; |
50 | kref_init(kref: &h->ref); |
51 | h->expiry_time = now + CACHE_NEW_EXPIRY; |
52 | if (now <= detail->flush_time) |
53 | /* ensure it isn't already expired */ |
54 | now = detail->flush_time + 1; |
55 | h->last_refresh = now; |
56 | } |
57 | |
58 | static void cache_fresh_unlocked(struct cache_head *head, |
59 | struct cache_detail *detail); |
60 | |
61 | static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail, |
62 | struct cache_head *key, |
63 | int hash) |
64 | { |
65 | struct hlist_head *head = &detail->hash_table[hash]; |
66 | struct cache_head *tmp; |
67 | |
68 | rcu_read_lock(); |
69 | hlist_for_each_entry_rcu(tmp, head, cache_list) { |
70 | if (!detail->match(tmp, key)) |
71 | continue; |
72 | if (test_bit(CACHE_VALID, &tmp->flags) && |
73 | cache_is_expired(detail, h: tmp)) |
74 | continue; |
75 | tmp = cache_get_rcu(h: tmp); |
76 | rcu_read_unlock(); |
77 | return tmp; |
78 | } |
79 | rcu_read_unlock(); |
80 | return NULL; |
81 | } |
82 | |
83 | static void sunrpc_begin_cache_remove_entry(struct cache_head *ch, |
84 | struct cache_detail *cd) |
85 | { |
86 | /* Must be called under cd->hash_lock */ |
87 | hlist_del_init_rcu(n: &ch->cache_list); |
88 | set_bit(nr: CACHE_CLEANED, addr: &ch->flags); |
89 | cd->entries --; |
90 | } |
91 | |
92 | static void sunrpc_end_cache_remove_entry(struct cache_head *ch, |
93 | struct cache_detail *cd) |
94 | { |
95 | cache_fresh_unlocked(head: ch, detail: cd); |
96 | cache_put(h: ch, cd); |
97 | } |
98 | |
99 | static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail, |
100 | struct cache_head *key, |
101 | int hash) |
102 | { |
103 | struct cache_head *new, *tmp, *freeme = NULL; |
104 | struct hlist_head *head = &detail->hash_table[hash]; |
105 | |
106 | new = detail->alloc(); |
107 | if (!new) |
108 | return NULL; |
109 | /* must fully initialise 'new', else |
110 | * we might get lose if we need to |
111 | * cache_put it soon. |
112 | */ |
113 | cache_init(h: new, detail); |
114 | detail->init(new, key); |
115 | |
116 | spin_lock(lock: &detail->hash_lock); |
117 | |
118 | /* check if entry appeared while we slept */ |
119 | hlist_for_each_entry_rcu(tmp, head, cache_list, |
120 | lockdep_is_held(&detail->hash_lock)) { |
121 | if (!detail->match(tmp, key)) |
122 | continue; |
123 | if (test_bit(CACHE_VALID, &tmp->flags) && |
124 | cache_is_expired(detail, h: tmp)) { |
125 | sunrpc_begin_cache_remove_entry(ch: tmp, cd: detail); |
126 | trace_cache_entry_expired(cd: detail, h: tmp); |
127 | freeme = tmp; |
128 | break; |
129 | } |
130 | cache_get(h: tmp); |
131 | spin_unlock(lock: &detail->hash_lock); |
132 | cache_put(h: new, cd: detail); |
133 | return tmp; |
134 | } |
135 | |
136 | hlist_add_head_rcu(n: &new->cache_list, h: head); |
137 | detail->entries++; |
138 | cache_get(h: new); |
139 | spin_unlock(lock: &detail->hash_lock); |
140 | |
141 | if (freeme) |
142 | sunrpc_end_cache_remove_entry(ch: freeme, cd: detail); |
143 | return new; |
144 | } |
145 | |
146 | struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail, |
147 | struct cache_head *key, int hash) |
148 | { |
149 | struct cache_head *ret; |
150 | |
151 | ret = sunrpc_cache_find_rcu(detail, key, hash); |
152 | if (ret) |
153 | return ret; |
154 | /* Didn't find anything, insert an empty entry */ |
155 | return sunrpc_cache_add_entry(detail, key, hash); |
156 | } |
157 | EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu); |
158 | |
159 | static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch); |
160 | |
161 | static void cache_fresh_locked(struct cache_head *head, time64_t expiry, |
162 | struct cache_detail *detail) |
163 | { |
164 | time64_t now = seconds_since_boot(); |
165 | if (now <= detail->flush_time) |
166 | /* ensure it isn't immediately treated as expired */ |
167 | now = detail->flush_time + 1; |
168 | head->expiry_time = expiry; |
169 | head->last_refresh = now; |
170 | smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */ |
171 | set_bit(nr: CACHE_VALID, addr: &head->flags); |
172 | } |
173 | |
174 | static void cache_fresh_unlocked(struct cache_head *head, |
175 | struct cache_detail *detail) |
176 | { |
177 | if (test_and_clear_bit(nr: CACHE_PENDING, addr: &head->flags)) { |
178 | cache_revisit_request(item: head); |
179 | cache_dequeue(detail, ch: head); |
180 | } |
181 | } |
182 | |
183 | static void cache_make_negative(struct cache_detail *detail, |
184 | struct cache_head *h) |
185 | { |
186 | set_bit(nr: CACHE_NEGATIVE, addr: &h->flags); |
187 | trace_cache_entry_make_negative(cd: detail, h); |
188 | } |
189 | |
190 | static void cache_entry_update(struct cache_detail *detail, |
191 | struct cache_head *h, |
192 | struct cache_head *new) |
193 | { |
194 | if (!test_bit(CACHE_NEGATIVE, &new->flags)) { |
195 | detail->update(h, new); |
196 | trace_cache_entry_update(cd: detail, h); |
197 | } else { |
198 | cache_make_negative(detail, h); |
199 | } |
200 | } |
201 | |
202 | struct cache_head *sunrpc_cache_update(struct cache_detail *detail, |
203 | struct cache_head *new, struct cache_head *old, int hash) |
204 | { |
205 | /* The 'old' entry is to be replaced by 'new'. |
206 | * If 'old' is not VALID, we update it directly, |
207 | * otherwise we need to replace it |
208 | */ |
209 | struct cache_head *tmp; |
210 | |
211 | if (!test_bit(CACHE_VALID, &old->flags)) { |
212 | spin_lock(lock: &detail->hash_lock); |
213 | if (!test_bit(CACHE_VALID, &old->flags)) { |
214 | cache_entry_update(detail, h: old, new); |
215 | cache_fresh_locked(head: old, expiry: new->expiry_time, detail); |
216 | spin_unlock(lock: &detail->hash_lock); |
217 | cache_fresh_unlocked(head: old, detail); |
218 | return old; |
219 | } |
220 | spin_unlock(lock: &detail->hash_lock); |
221 | } |
222 | /* We need to insert a new entry */ |
223 | tmp = detail->alloc(); |
224 | if (!tmp) { |
225 | cache_put(h: old, cd: detail); |
226 | return NULL; |
227 | } |
228 | cache_init(h: tmp, detail); |
229 | detail->init(tmp, old); |
230 | |
231 | spin_lock(lock: &detail->hash_lock); |
232 | cache_entry_update(detail, h: tmp, new); |
233 | hlist_add_head(n: &tmp->cache_list, h: &detail->hash_table[hash]); |
234 | detail->entries++; |
235 | cache_get(h: tmp); |
236 | cache_fresh_locked(head: tmp, expiry: new->expiry_time, detail); |
237 | cache_fresh_locked(head: old, expiry: 0, detail); |
238 | spin_unlock(lock: &detail->hash_lock); |
239 | cache_fresh_unlocked(head: tmp, detail); |
240 | cache_fresh_unlocked(head: old, detail); |
241 | cache_put(h: old, cd: detail); |
242 | return tmp; |
243 | } |
244 | EXPORT_SYMBOL_GPL(sunrpc_cache_update); |
245 | |
246 | static inline int cache_is_valid(struct cache_head *h) |
247 | { |
248 | if (!test_bit(CACHE_VALID, &h->flags)) |
249 | return -EAGAIN; |
250 | else { |
251 | /* entry is valid */ |
252 | if (test_bit(CACHE_NEGATIVE, &h->flags)) |
253 | return -ENOENT; |
254 | else { |
255 | /* |
256 | * In combination with write barrier in |
257 | * sunrpc_cache_update, ensures that anyone |
258 | * using the cache entry after this sees the |
259 | * updated contents: |
260 | */ |
261 | smp_rmb(); |
262 | return 0; |
263 | } |
264 | } |
265 | } |
266 | |
267 | static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h) |
268 | { |
269 | int rv; |
270 | |
271 | spin_lock(lock: &detail->hash_lock); |
272 | rv = cache_is_valid(h); |
273 | if (rv == -EAGAIN) { |
274 | cache_make_negative(detail, h); |
275 | cache_fresh_locked(head: h, expiry: seconds_since_boot()+CACHE_NEW_EXPIRY, |
276 | detail); |
277 | rv = -ENOENT; |
278 | } |
279 | spin_unlock(lock: &detail->hash_lock); |
280 | cache_fresh_unlocked(head: h, detail); |
281 | return rv; |
282 | } |
283 | |
284 | /* |
285 | * This is the generic cache management routine for all |
286 | * the authentication caches. |
287 | * It checks the currency of a cache item and will (later) |
288 | * initiate an upcall to fill it if needed. |
289 | * |
290 | * |
291 | * Returns 0 if the cache_head can be used, or cache_puts it and returns |
292 | * -EAGAIN if upcall is pending and request has been queued |
293 | * -ETIMEDOUT if upcall failed or request could not be queue or |
294 | * upcall completed but item is still invalid (implying that |
295 | * the cache item has been replaced with a newer one). |
296 | * -ENOENT if cache entry was negative |
297 | */ |
298 | int cache_check(struct cache_detail *detail, |
299 | struct cache_head *h, struct cache_req *rqstp) |
300 | { |
301 | int rv; |
302 | time64_t refresh_age, age; |
303 | |
304 | /* First decide return status as best we can */ |
305 | rv = cache_is_valid(h); |
306 | |
307 | /* now see if we want to start an upcall */ |
308 | refresh_age = (h->expiry_time - h->last_refresh); |
309 | age = seconds_since_boot() - h->last_refresh; |
310 | |
311 | if (rqstp == NULL) { |
312 | if (rv == -EAGAIN) |
313 | rv = -ENOENT; |
314 | } else if (rv == -EAGAIN || |
315 | (h->expiry_time != 0 && age > refresh_age/2)) { |
316 | dprintk("RPC: Want update, refage=%lld, age=%lld\n" , |
317 | refresh_age, age); |
318 | switch (detail->cache_upcall(detail, h)) { |
319 | case -EINVAL: |
320 | rv = try_to_negate_entry(detail, h); |
321 | break; |
322 | case -EAGAIN: |
323 | cache_fresh_unlocked(head: h, detail); |
324 | break; |
325 | } |
326 | } |
327 | |
328 | if (rv == -EAGAIN) { |
329 | if (!cache_defer_req(req: rqstp, item: h)) { |
330 | /* |
331 | * Request was not deferred; handle it as best |
332 | * we can ourselves: |
333 | */ |
334 | rv = cache_is_valid(h); |
335 | if (rv == -EAGAIN) |
336 | rv = -ETIMEDOUT; |
337 | } |
338 | } |
339 | if (rv) |
340 | cache_put(h, cd: detail); |
341 | return rv; |
342 | } |
343 | EXPORT_SYMBOL_GPL(cache_check); |
344 | |
345 | /* |
346 | * caches need to be periodically cleaned. |
347 | * For this we maintain a list of cache_detail and |
348 | * a current pointer into that list and into the table |
349 | * for that entry. |
350 | * |
351 | * Each time cache_clean is called it finds the next non-empty entry |
352 | * in the current table and walks the list in that entry |
353 | * looking for entries that can be removed. |
354 | * |
355 | * An entry gets removed if: |
356 | * - The expiry is before current time |
357 | * - The last_refresh time is before the flush_time for that cache |
358 | * |
359 | * later we might drop old entries with non-NEVER expiry if that table |
360 | * is getting 'full' for some definition of 'full' |
361 | * |
362 | * The question of "how often to scan a table" is an interesting one |
363 | * and is answered in part by the use of the "nextcheck" field in the |
364 | * cache_detail. |
365 | * When a scan of a table begins, the nextcheck field is set to a time |
366 | * that is well into the future. |
367 | * While scanning, if an expiry time is found that is earlier than the |
368 | * current nextcheck time, nextcheck is set to that expiry time. |
369 | * If the flush_time is ever set to a time earlier than the nextcheck |
370 | * time, the nextcheck time is then set to that flush_time. |
371 | * |
372 | * A table is then only scanned if the current time is at least |
373 | * the nextcheck time. |
374 | * |
375 | */ |
376 | |
377 | static LIST_HEAD(cache_list); |
378 | static DEFINE_SPINLOCK(cache_list_lock); |
379 | static struct cache_detail *current_detail; |
380 | static int current_index; |
381 | |
382 | static void do_cache_clean(struct work_struct *work); |
383 | static struct delayed_work cache_cleaner; |
384 | |
385 | void sunrpc_init_cache_detail(struct cache_detail *cd) |
386 | { |
387 | spin_lock_init(&cd->hash_lock); |
388 | INIT_LIST_HEAD(list: &cd->queue); |
389 | spin_lock(lock: &cache_list_lock); |
390 | cd->nextcheck = 0; |
391 | cd->entries = 0; |
392 | atomic_set(v: &cd->writers, i: 0); |
393 | cd->last_close = 0; |
394 | cd->last_warn = -1; |
395 | list_add(new: &cd->others, head: &cache_list); |
396 | spin_unlock(lock: &cache_list_lock); |
397 | |
398 | /* start the cleaning process */ |
399 | queue_delayed_work(wq: system_power_efficient_wq, dwork: &cache_cleaner, delay: 0); |
400 | } |
401 | EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail); |
402 | |
403 | void sunrpc_destroy_cache_detail(struct cache_detail *cd) |
404 | { |
405 | cache_purge(detail: cd); |
406 | spin_lock(lock: &cache_list_lock); |
407 | spin_lock(lock: &cd->hash_lock); |
408 | if (current_detail == cd) |
409 | current_detail = NULL; |
410 | list_del_init(entry: &cd->others); |
411 | spin_unlock(lock: &cd->hash_lock); |
412 | spin_unlock(lock: &cache_list_lock); |
413 | if (list_empty(head: &cache_list)) { |
414 | /* module must be being unloaded so its safe to kill the worker */ |
415 | cancel_delayed_work_sync(dwork: &cache_cleaner); |
416 | } |
417 | } |
418 | EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail); |
419 | |
420 | /* clean cache tries to find something to clean |
421 | * and cleans it. |
422 | * It returns 1 if it cleaned something, |
423 | * 0 if it didn't find anything this time |
424 | * -1 if it fell off the end of the list. |
425 | */ |
426 | static int cache_clean(void) |
427 | { |
428 | int rv = 0; |
429 | struct list_head *next; |
430 | |
431 | spin_lock(lock: &cache_list_lock); |
432 | |
433 | /* find a suitable table if we don't already have one */ |
434 | while (current_detail == NULL || |
435 | current_index >= current_detail->hash_size) { |
436 | if (current_detail) |
437 | next = current_detail->others.next; |
438 | else |
439 | next = cache_list.next; |
440 | if (next == &cache_list) { |
441 | current_detail = NULL; |
442 | spin_unlock(lock: &cache_list_lock); |
443 | return -1; |
444 | } |
445 | current_detail = list_entry(next, struct cache_detail, others); |
446 | if (current_detail->nextcheck > seconds_since_boot()) |
447 | current_index = current_detail->hash_size; |
448 | else { |
449 | current_index = 0; |
450 | current_detail->nextcheck = seconds_since_boot()+30*60; |
451 | } |
452 | } |
453 | |
454 | /* find a non-empty bucket in the table */ |
455 | while (current_detail && |
456 | current_index < current_detail->hash_size && |
457 | hlist_empty(h: ¤t_detail->hash_table[current_index])) |
458 | current_index++; |
459 | |
460 | /* find a cleanable entry in the bucket and clean it, or set to next bucket */ |
461 | |
462 | if (current_detail && current_index < current_detail->hash_size) { |
463 | struct cache_head *ch = NULL; |
464 | struct cache_detail *d; |
465 | struct hlist_head *head; |
466 | struct hlist_node *tmp; |
467 | |
468 | spin_lock(lock: ¤t_detail->hash_lock); |
469 | |
470 | /* Ok, now to clean this strand */ |
471 | |
472 | head = ¤t_detail->hash_table[current_index]; |
473 | hlist_for_each_entry_safe(ch, tmp, head, cache_list) { |
474 | if (current_detail->nextcheck > ch->expiry_time) |
475 | current_detail->nextcheck = ch->expiry_time+1; |
476 | if (!cache_is_expired(detail: current_detail, h: ch)) |
477 | continue; |
478 | |
479 | sunrpc_begin_cache_remove_entry(ch, cd: current_detail); |
480 | trace_cache_entry_expired(cd: current_detail, h: ch); |
481 | rv = 1; |
482 | break; |
483 | } |
484 | |
485 | spin_unlock(lock: ¤t_detail->hash_lock); |
486 | d = current_detail; |
487 | if (!ch) |
488 | current_index ++; |
489 | spin_unlock(lock: &cache_list_lock); |
490 | if (ch) |
491 | sunrpc_end_cache_remove_entry(ch, cd: d); |
492 | } else |
493 | spin_unlock(lock: &cache_list_lock); |
494 | |
495 | return rv; |
496 | } |
497 | |
498 | /* |
499 | * We want to regularly clean the cache, so we need to schedule some work ... |
500 | */ |
501 | static void do_cache_clean(struct work_struct *work) |
502 | { |
503 | int delay; |
504 | |
505 | if (list_empty(head: &cache_list)) |
506 | return; |
507 | |
508 | if (cache_clean() == -1) |
509 | delay = round_jiffies_relative(j: 30*HZ); |
510 | else |
511 | delay = 5; |
512 | |
513 | queue_delayed_work(wq: system_power_efficient_wq, dwork: &cache_cleaner, delay); |
514 | } |
515 | |
516 | |
517 | /* |
518 | * Clean all caches promptly. This just calls cache_clean |
519 | * repeatedly until we are sure that every cache has had a chance to |
520 | * be fully cleaned |
521 | */ |
522 | void cache_flush(void) |
523 | { |
524 | while (cache_clean() != -1) |
525 | cond_resched(); |
526 | while (cache_clean() != -1) |
527 | cond_resched(); |
528 | } |
529 | EXPORT_SYMBOL_GPL(cache_flush); |
530 | |
531 | void cache_purge(struct cache_detail *detail) |
532 | { |
533 | struct cache_head *ch = NULL; |
534 | struct hlist_head *head = NULL; |
535 | int i = 0; |
536 | |
537 | spin_lock(lock: &detail->hash_lock); |
538 | if (!detail->entries) { |
539 | spin_unlock(lock: &detail->hash_lock); |
540 | return; |
541 | } |
542 | |
543 | dprintk("RPC: %d entries in %s cache\n" , detail->entries, detail->name); |
544 | for (i = 0; i < detail->hash_size; i++) { |
545 | head = &detail->hash_table[i]; |
546 | while (!hlist_empty(h: head)) { |
547 | ch = hlist_entry(head->first, struct cache_head, |
548 | cache_list); |
549 | sunrpc_begin_cache_remove_entry(ch, cd: detail); |
550 | spin_unlock(lock: &detail->hash_lock); |
551 | sunrpc_end_cache_remove_entry(ch, cd: detail); |
552 | spin_lock(lock: &detail->hash_lock); |
553 | } |
554 | } |
555 | spin_unlock(lock: &detail->hash_lock); |
556 | } |
557 | EXPORT_SYMBOL_GPL(cache_purge); |
558 | |
559 | |
560 | /* |
561 | * Deferral and Revisiting of Requests. |
562 | * |
563 | * If a cache lookup finds a pending entry, we |
564 | * need to defer the request and revisit it later. |
565 | * All deferred requests are stored in a hash table, |
566 | * indexed by "struct cache_head *". |
567 | * As it may be wasteful to store a whole request |
568 | * structure, we allow the request to provide a |
569 | * deferred form, which must contain a |
570 | * 'struct cache_deferred_req' |
571 | * This cache_deferred_req contains a method to allow |
572 | * it to be revisited when cache info is available |
573 | */ |
574 | |
575 | #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head)) |
576 | #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE) |
577 | |
578 | #define DFR_MAX 300 /* ??? */ |
579 | |
580 | static DEFINE_SPINLOCK(cache_defer_lock); |
581 | static LIST_HEAD(cache_defer_list); |
582 | static struct hlist_head cache_defer_hash[DFR_HASHSIZE]; |
583 | static int cache_defer_cnt; |
584 | |
585 | static void __unhash_deferred_req(struct cache_deferred_req *dreq) |
586 | { |
587 | hlist_del_init(n: &dreq->hash); |
588 | if (!list_empty(head: &dreq->recent)) { |
589 | list_del_init(entry: &dreq->recent); |
590 | cache_defer_cnt--; |
591 | } |
592 | } |
593 | |
594 | static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item) |
595 | { |
596 | int hash = DFR_HASH(item); |
597 | |
598 | INIT_LIST_HEAD(list: &dreq->recent); |
599 | hlist_add_head(n: &dreq->hash, h: &cache_defer_hash[hash]); |
600 | } |
601 | |
602 | static void setup_deferral(struct cache_deferred_req *dreq, |
603 | struct cache_head *item, |
604 | int count_me) |
605 | { |
606 | |
607 | dreq->item = item; |
608 | |
609 | spin_lock(lock: &cache_defer_lock); |
610 | |
611 | __hash_deferred_req(dreq, item); |
612 | |
613 | if (count_me) { |
614 | cache_defer_cnt++; |
615 | list_add(new: &dreq->recent, head: &cache_defer_list); |
616 | } |
617 | |
618 | spin_unlock(lock: &cache_defer_lock); |
619 | |
620 | } |
621 | |
622 | struct thread_deferred_req { |
623 | struct cache_deferred_req handle; |
624 | struct completion completion; |
625 | }; |
626 | |
627 | static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many) |
628 | { |
629 | struct thread_deferred_req *dr = |
630 | container_of(dreq, struct thread_deferred_req, handle); |
631 | complete(&dr->completion); |
632 | } |
633 | |
634 | static void cache_wait_req(struct cache_req *req, struct cache_head *item) |
635 | { |
636 | struct thread_deferred_req sleeper; |
637 | struct cache_deferred_req *dreq = &sleeper.handle; |
638 | |
639 | sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion); |
640 | dreq->revisit = cache_restart_thread; |
641 | |
642 | setup_deferral(dreq, item, count_me: 0); |
643 | |
644 | if (!test_bit(CACHE_PENDING, &item->flags) || |
645 | wait_for_completion_interruptible_timeout( |
646 | x: &sleeper.completion, timeout: req->thread_wait) <= 0) { |
647 | /* The completion wasn't completed, so we need |
648 | * to clean up |
649 | */ |
650 | spin_lock(lock: &cache_defer_lock); |
651 | if (!hlist_unhashed(h: &sleeper.handle.hash)) { |
652 | __unhash_deferred_req(dreq: &sleeper.handle); |
653 | spin_unlock(lock: &cache_defer_lock); |
654 | } else { |
655 | /* cache_revisit_request already removed |
656 | * this from the hash table, but hasn't |
657 | * called ->revisit yet. It will very soon |
658 | * and we need to wait for it. |
659 | */ |
660 | spin_unlock(lock: &cache_defer_lock); |
661 | wait_for_completion(&sleeper.completion); |
662 | } |
663 | } |
664 | } |
665 | |
666 | static void cache_limit_defers(void) |
667 | { |
668 | /* Make sure we haven't exceed the limit of allowed deferred |
669 | * requests. |
670 | */ |
671 | struct cache_deferred_req *discard = NULL; |
672 | |
673 | if (cache_defer_cnt <= DFR_MAX) |
674 | return; |
675 | |
676 | spin_lock(lock: &cache_defer_lock); |
677 | |
678 | /* Consider removing either the first or the last */ |
679 | if (cache_defer_cnt > DFR_MAX) { |
680 | if (get_random_u32_below(ceil: 2)) |
681 | discard = list_entry(cache_defer_list.next, |
682 | struct cache_deferred_req, recent); |
683 | else |
684 | discard = list_entry(cache_defer_list.prev, |
685 | struct cache_deferred_req, recent); |
686 | __unhash_deferred_req(dreq: discard); |
687 | } |
688 | spin_unlock(lock: &cache_defer_lock); |
689 | if (discard) |
690 | discard->revisit(discard, 1); |
691 | } |
692 | |
693 | #if IS_ENABLED(CONFIG_FAIL_SUNRPC) |
694 | static inline bool cache_defer_immediately(void) |
695 | { |
696 | return !fail_sunrpc.ignore_cache_wait && |
697 | should_fail(attr: &fail_sunrpc.attr, size: 1); |
698 | } |
699 | #else |
700 | static inline bool cache_defer_immediately(void) |
701 | { |
702 | return false; |
703 | } |
704 | #endif |
705 | |
706 | /* Return true if and only if a deferred request is queued. */ |
707 | static bool cache_defer_req(struct cache_req *req, struct cache_head *item) |
708 | { |
709 | struct cache_deferred_req *dreq; |
710 | |
711 | if (!cache_defer_immediately()) { |
712 | cache_wait_req(req, item); |
713 | if (!test_bit(CACHE_PENDING, &item->flags)) |
714 | return false; |
715 | } |
716 | |
717 | dreq = req->defer(req); |
718 | if (dreq == NULL) |
719 | return false; |
720 | setup_deferral(dreq, item, count_me: 1); |
721 | if (!test_bit(CACHE_PENDING, &item->flags)) |
722 | /* Bit could have been cleared before we managed to |
723 | * set up the deferral, so need to revisit just in case |
724 | */ |
725 | cache_revisit_request(item); |
726 | |
727 | cache_limit_defers(); |
728 | return true; |
729 | } |
730 | |
731 | static void cache_revisit_request(struct cache_head *item) |
732 | { |
733 | struct cache_deferred_req *dreq; |
734 | struct list_head pending; |
735 | struct hlist_node *tmp; |
736 | int hash = DFR_HASH(item); |
737 | |
738 | INIT_LIST_HEAD(list: &pending); |
739 | spin_lock(lock: &cache_defer_lock); |
740 | |
741 | hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash) |
742 | if (dreq->item == item) { |
743 | __unhash_deferred_req(dreq); |
744 | list_add(new: &dreq->recent, head: &pending); |
745 | } |
746 | |
747 | spin_unlock(lock: &cache_defer_lock); |
748 | |
749 | while (!list_empty(head: &pending)) { |
750 | dreq = list_entry(pending.next, struct cache_deferred_req, recent); |
751 | list_del_init(entry: &dreq->recent); |
752 | dreq->revisit(dreq, 0); |
753 | } |
754 | } |
755 | |
756 | void cache_clean_deferred(void *owner) |
757 | { |
758 | struct cache_deferred_req *dreq, *tmp; |
759 | struct list_head pending; |
760 | |
761 | |
762 | INIT_LIST_HEAD(list: &pending); |
763 | spin_lock(lock: &cache_defer_lock); |
764 | |
765 | list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) { |
766 | if (dreq->owner == owner) { |
767 | __unhash_deferred_req(dreq); |
768 | list_add(new: &dreq->recent, head: &pending); |
769 | } |
770 | } |
771 | spin_unlock(lock: &cache_defer_lock); |
772 | |
773 | while (!list_empty(head: &pending)) { |
774 | dreq = list_entry(pending.next, struct cache_deferred_req, recent); |
775 | list_del_init(entry: &dreq->recent); |
776 | dreq->revisit(dreq, 1); |
777 | } |
778 | } |
779 | |
780 | /* |
781 | * communicate with user-space |
782 | * |
783 | * We have a magic /proc file - /proc/net/rpc/<cachename>/channel. |
784 | * On read, you get a full request, or block. |
785 | * On write, an update request is processed. |
786 | * Poll works if anything to read, and always allows write. |
787 | * |
788 | * Implemented by linked list of requests. Each open file has |
789 | * a ->private that also exists in this list. New requests are added |
790 | * to the end and may wakeup and preceding readers. |
791 | * New readers are added to the head. If, on read, an item is found with |
792 | * CACHE_UPCALLING clear, we free it from the list. |
793 | * |
794 | */ |
795 | |
796 | static DEFINE_SPINLOCK(queue_lock); |
797 | |
798 | struct cache_queue { |
799 | struct list_head list; |
800 | int reader; /* if 0, then request */ |
801 | }; |
802 | struct cache_request { |
803 | struct cache_queue q; |
804 | struct cache_head *item; |
805 | char * buf; |
806 | int len; |
807 | int readers; |
808 | }; |
809 | struct cache_reader { |
810 | struct cache_queue q; |
811 | int offset; /* if non-0, we have a refcnt on next request */ |
812 | }; |
813 | |
814 | static int cache_request(struct cache_detail *detail, |
815 | struct cache_request *crq) |
816 | { |
817 | char *bp = crq->buf; |
818 | int len = PAGE_SIZE; |
819 | |
820 | detail->cache_request(detail, crq->item, &bp, &len); |
821 | if (len < 0) |
822 | return -E2BIG; |
823 | return PAGE_SIZE - len; |
824 | } |
825 | |
826 | static ssize_t cache_read(struct file *filp, char __user *buf, size_t count, |
827 | loff_t *ppos, struct cache_detail *cd) |
828 | { |
829 | struct cache_reader *rp = filp->private_data; |
830 | struct cache_request *rq; |
831 | struct inode *inode = file_inode(f: filp); |
832 | int err; |
833 | |
834 | if (count == 0) |
835 | return 0; |
836 | |
837 | inode_lock(inode); /* protect against multiple concurrent |
838 | * readers on this file */ |
839 | again: |
840 | spin_lock(lock: &queue_lock); |
841 | /* need to find next request */ |
842 | while (rp->q.list.next != &cd->queue && |
843 | list_entry(rp->q.list.next, struct cache_queue, list) |
844 | ->reader) { |
845 | struct list_head *next = rp->q.list.next; |
846 | list_move(list: &rp->q.list, head: next); |
847 | } |
848 | if (rp->q.list.next == &cd->queue) { |
849 | spin_unlock(lock: &queue_lock); |
850 | inode_unlock(inode); |
851 | WARN_ON_ONCE(rp->offset); |
852 | return 0; |
853 | } |
854 | rq = container_of(rp->q.list.next, struct cache_request, q.list); |
855 | WARN_ON_ONCE(rq->q.reader); |
856 | if (rp->offset == 0) |
857 | rq->readers++; |
858 | spin_unlock(lock: &queue_lock); |
859 | |
860 | if (rq->len == 0) { |
861 | err = cache_request(detail: cd, crq: rq); |
862 | if (err < 0) |
863 | goto out; |
864 | rq->len = err; |
865 | } |
866 | |
867 | if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { |
868 | err = -EAGAIN; |
869 | spin_lock(lock: &queue_lock); |
870 | list_move(list: &rp->q.list, head: &rq->q.list); |
871 | spin_unlock(lock: &queue_lock); |
872 | } else { |
873 | if (rp->offset + count > rq->len) |
874 | count = rq->len - rp->offset; |
875 | err = -EFAULT; |
876 | if (copy_to_user(to: buf, from: rq->buf + rp->offset, n: count)) |
877 | goto out; |
878 | rp->offset += count; |
879 | if (rp->offset >= rq->len) { |
880 | rp->offset = 0; |
881 | spin_lock(lock: &queue_lock); |
882 | list_move(list: &rp->q.list, head: &rq->q.list); |
883 | spin_unlock(lock: &queue_lock); |
884 | } |
885 | err = 0; |
886 | } |
887 | out: |
888 | if (rp->offset == 0) { |
889 | /* need to release rq */ |
890 | spin_lock(lock: &queue_lock); |
891 | rq->readers--; |
892 | if (rq->readers == 0 && |
893 | !test_bit(CACHE_PENDING, &rq->item->flags)) { |
894 | list_del(entry: &rq->q.list); |
895 | spin_unlock(lock: &queue_lock); |
896 | cache_put(h: rq->item, cd); |
897 | kfree(objp: rq->buf); |
898 | kfree(objp: rq); |
899 | } else |
900 | spin_unlock(lock: &queue_lock); |
901 | } |
902 | if (err == -EAGAIN) |
903 | goto again; |
904 | inode_unlock(inode); |
905 | return err ? err : count; |
906 | } |
907 | |
908 | static ssize_t cache_do_downcall(char *kaddr, const char __user *buf, |
909 | size_t count, struct cache_detail *cd) |
910 | { |
911 | ssize_t ret; |
912 | |
913 | if (count == 0) |
914 | return -EINVAL; |
915 | if (copy_from_user(to: kaddr, from: buf, n: count)) |
916 | return -EFAULT; |
917 | kaddr[count] = '\0'; |
918 | ret = cd->cache_parse(cd, kaddr, count); |
919 | if (!ret) |
920 | ret = count; |
921 | return ret; |
922 | } |
923 | |
924 | static ssize_t cache_downcall(struct address_space *mapping, |
925 | const char __user *buf, |
926 | size_t count, struct cache_detail *cd) |
927 | { |
928 | char *write_buf; |
929 | ssize_t ret = -ENOMEM; |
930 | |
931 | if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */ |
932 | ret = -EINVAL; |
933 | goto out; |
934 | } |
935 | |
936 | write_buf = kvmalloc(size: count + 1, GFP_KERNEL); |
937 | if (!write_buf) |
938 | goto out; |
939 | |
940 | ret = cache_do_downcall(kaddr: write_buf, buf, count, cd); |
941 | kvfree(addr: write_buf); |
942 | out: |
943 | return ret; |
944 | } |
945 | |
946 | static ssize_t cache_write(struct file *filp, const char __user *buf, |
947 | size_t count, loff_t *ppos, |
948 | struct cache_detail *cd) |
949 | { |
950 | struct address_space *mapping = filp->f_mapping; |
951 | struct inode *inode = file_inode(f: filp); |
952 | ssize_t ret = -EINVAL; |
953 | |
954 | if (!cd->cache_parse) |
955 | goto out; |
956 | |
957 | inode_lock(inode); |
958 | ret = cache_downcall(mapping, buf, count, cd); |
959 | inode_unlock(inode); |
960 | out: |
961 | return ret; |
962 | } |
963 | |
964 | static DECLARE_WAIT_QUEUE_HEAD(queue_wait); |
965 | |
966 | static __poll_t cache_poll(struct file *filp, poll_table *wait, |
967 | struct cache_detail *cd) |
968 | { |
969 | __poll_t mask; |
970 | struct cache_reader *rp = filp->private_data; |
971 | struct cache_queue *cq; |
972 | |
973 | poll_wait(filp, wait_address: &queue_wait, p: wait); |
974 | |
975 | /* alway allow write */ |
976 | mask = EPOLLOUT | EPOLLWRNORM; |
977 | |
978 | if (!rp) |
979 | return mask; |
980 | |
981 | spin_lock(lock: &queue_lock); |
982 | |
983 | for (cq= &rp->q; &cq->list != &cd->queue; |
984 | cq = list_entry(cq->list.next, struct cache_queue, list)) |
985 | if (!cq->reader) { |
986 | mask |= EPOLLIN | EPOLLRDNORM; |
987 | break; |
988 | } |
989 | spin_unlock(lock: &queue_lock); |
990 | return mask; |
991 | } |
992 | |
993 | static int cache_ioctl(struct inode *ino, struct file *filp, |
994 | unsigned int cmd, unsigned long arg, |
995 | struct cache_detail *cd) |
996 | { |
997 | int len = 0; |
998 | struct cache_reader *rp = filp->private_data; |
999 | struct cache_queue *cq; |
1000 | |
1001 | if (cmd != FIONREAD || !rp) |
1002 | return -EINVAL; |
1003 | |
1004 | spin_lock(lock: &queue_lock); |
1005 | |
1006 | /* only find the length remaining in current request, |
1007 | * or the length of the next request |
1008 | */ |
1009 | for (cq= &rp->q; &cq->list != &cd->queue; |
1010 | cq = list_entry(cq->list.next, struct cache_queue, list)) |
1011 | if (!cq->reader) { |
1012 | struct cache_request *cr = |
1013 | container_of(cq, struct cache_request, q); |
1014 | len = cr->len - rp->offset; |
1015 | break; |
1016 | } |
1017 | spin_unlock(lock: &queue_lock); |
1018 | |
1019 | return put_user(len, (int __user *)arg); |
1020 | } |
1021 | |
1022 | static int cache_open(struct inode *inode, struct file *filp, |
1023 | struct cache_detail *cd) |
1024 | { |
1025 | struct cache_reader *rp = NULL; |
1026 | |
1027 | if (!cd || !try_module_get(module: cd->owner)) |
1028 | return -EACCES; |
1029 | nonseekable_open(inode, filp); |
1030 | if (filp->f_mode & FMODE_READ) { |
1031 | rp = kmalloc(size: sizeof(*rp), GFP_KERNEL); |
1032 | if (!rp) { |
1033 | module_put(module: cd->owner); |
1034 | return -ENOMEM; |
1035 | } |
1036 | rp->offset = 0; |
1037 | rp->q.reader = 1; |
1038 | |
1039 | spin_lock(lock: &queue_lock); |
1040 | list_add(new: &rp->q.list, head: &cd->queue); |
1041 | spin_unlock(lock: &queue_lock); |
1042 | } |
1043 | if (filp->f_mode & FMODE_WRITE) |
1044 | atomic_inc(v: &cd->writers); |
1045 | filp->private_data = rp; |
1046 | return 0; |
1047 | } |
1048 | |
1049 | static int cache_release(struct inode *inode, struct file *filp, |
1050 | struct cache_detail *cd) |
1051 | { |
1052 | struct cache_reader *rp = filp->private_data; |
1053 | |
1054 | if (rp) { |
1055 | spin_lock(lock: &queue_lock); |
1056 | if (rp->offset) { |
1057 | struct cache_queue *cq; |
1058 | for (cq= &rp->q; &cq->list != &cd->queue; |
1059 | cq = list_entry(cq->list.next, struct cache_queue, list)) |
1060 | if (!cq->reader) { |
1061 | container_of(cq, struct cache_request, q) |
1062 | ->readers--; |
1063 | break; |
1064 | } |
1065 | rp->offset = 0; |
1066 | } |
1067 | list_del(entry: &rp->q.list); |
1068 | spin_unlock(lock: &queue_lock); |
1069 | |
1070 | filp->private_data = NULL; |
1071 | kfree(objp: rp); |
1072 | |
1073 | } |
1074 | if (filp->f_mode & FMODE_WRITE) { |
1075 | atomic_dec(v: &cd->writers); |
1076 | cd->last_close = seconds_since_boot(); |
1077 | } |
1078 | module_put(module: cd->owner); |
1079 | return 0; |
1080 | } |
1081 | |
1082 | |
1083 | |
1084 | static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch) |
1085 | { |
1086 | struct cache_queue *cq, *tmp; |
1087 | struct cache_request *cr; |
1088 | struct list_head dequeued; |
1089 | |
1090 | INIT_LIST_HEAD(list: &dequeued); |
1091 | spin_lock(lock: &queue_lock); |
1092 | list_for_each_entry_safe(cq, tmp, &detail->queue, list) |
1093 | if (!cq->reader) { |
1094 | cr = container_of(cq, struct cache_request, q); |
1095 | if (cr->item != ch) |
1096 | continue; |
1097 | if (test_bit(CACHE_PENDING, &ch->flags)) |
1098 | /* Lost a race and it is pending again */ |
1099 | break; |
1100 | if (cr->readers != 0) |
1101 | continue; |
1102 | list_move(list: &cr->q.list, head: &dequeued); |
1103 | } |
1104 | spin_unlock(lock: &queue_lock); |
1105 | while (!list_empty(head: &dequeued)) { |
1106 | cr = list_entry(dequeued.next, struct cache_request, q.list); |
1107 | list_del(entry: &cr->q.list); |
1108 | cache_put(h: cr->item, cd: detail); |
1109 | kfree(objp: cr->buf); |
1110 | kfree(objp: cr); |
1111 | } |
1112 | } |
1113 | |
1114 | /* |
1115 | * Support routines for text-based upcalls. |
1116 | * Fields are separated by spaces. |
1117 | * Fields are either mangled to quote space tab newline slosh with slosh |
1118 | * or a hexified with a leading \x |
1119 | * Record is terminated with newline. |
1120 | * |
1121 | */ |
1122 | |
1123 | void qword_add(char **bpp, int *lp, char *str) |
1124 | { |
1125 | char *bp = *bpp; |
1126 | int len = *lp; |
1127 | int ret; |
1128 | |
1129 | if (len < 0) return; |
1130 | |
1131 | ret = string_escape_str(src: str, dst: bp, sz: len, ESCAPE_OCTAL, only: "\\ \n\t" ); |
1132 | if (ret >= len) { |
1133 | bp += len; |
1134 | len = -1; |
1135 | } else { |
1136 | bp += ret; |
1137 | len -= ret; |
1138 | *bp++ = ' '; |
1139 | len--; |
1140 | } |
1141 | *bpp = bp; |
1142 | *lp = len; |
1143 | } |
1144 | EXPORT_SYMBOL_GPL(qword_add); |
1145 | |
1146 | void qword_addhex(char **bpp, int *lp, char *buf, int blen) |
1147 | { |
1148 | char *bp = *bpp; |
1149 | int len = *lp; |
1150 | |
1151 | if (len < 0) return; |
1152 | |
1153 | if (len > 2) { |
1154 | *bp++ = '\\'; |
1155 | *bp++ = 'x'; |
1156 | len -= 2; |
1157 | while (blen && len >= 2) { |
1158 | bp = hex_byte_pack(buf: bp, byte: *buf++); |
1159 | len -= 2; |
1160 | blen--; |
1161 | } |
1162 | } |
1163 | if (blen || len<1) len = -1; |
1164 | else { |
1165 | *bp++ = ' '; |
1166 | len--; |
1167 | } |
1168 | *bpp = bp; |
1169 | *lp = len; |
1170 | } |
1171 | EXPORT_SYMBOL_GPL(qword_addhex); |
1172 | |
1173 | static void warn_no_listener(struct cache_detail *detail) |
1174 | { |
1175 | if (detail->last_warn != detail->last_close) { |
1176 | detail->last_warn = detail->last_close; |
1177 | if (detail->warn_no_listener) |
1178 | detail->warn_no_listener(detail, detail->last_close != 0); |
1179 | } |
1180 | } |
1181 | |
1182 | static bool cache_listeners_exist(struct cache_detail *detail) |
1183 | { |
1184 | if (atomic_read(v: &detail->writers)) |
1185 | return true; |
1186 | if (detail->last_close == 0) |
1187 | /* This cache was never opened */ |
1188 | return false; |
1189 | if (detail->last_close < seconds_since_boot() - 30) |
1190 | /* |
1191 | * We allow for the possibility that someone might |
1192 | * restart a userspace daemon without restarting the |
1193 | * server; but after 30 seconds, we give up. |
1194 | */ |
1195 | return false; |
1196 | return true; |
1197 | } |
1198 | |
1199 | /* |
1200 | * register an upcall request to user-space and queue it up for read() by the |
1201 | * upcall daemon. |
1202 | * |
1203 | * Each request is at most one page long. |
1204 | */ |
1205 | static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h) |
1206 | { |
1207 | char *buf; |
1208 | struct cache_request *crq; |
1209 | int ret = 0; |
1210 | |
1211 | if (test_bit(CACHE_CLEANED, &h->flags)) |
1212 | /* Too late to make an upcall */ |
1213 | return -EAGAIN; |
1214 | |
1215 | buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
1216 | if (!buf) |
1217 | return -EAGAIN; |
1218 | |
1219 | crq = kmalloc(size: sizeof (*crq), GFP_KERNEL); |
1220 | if (!crq) { |
1221 | kfree(objp: buf); |
1222 | return -EAGAIN; |
1223 | } |
1224 | |
1225 | crq->q.reader = 0; |
1226 | crq->buf = buf; |
1227 | crq->len = 0; |
1228 | crq->readers = 0; |
1229 | spin_lock(lock: &queue_lock); |
1230 | if (test_bit(CACHE_PENDING, &h->flags)) { |
1231 | crq->item = cache_get(h); |
1232 | list_add_tail(new: &crq->q.list, head: &detail->queue); |
1233 | trace_cache_entry_upcall(cd: detail, h); |
1234 | } else |
1235 | /* Lost a race, no longer PENDING, so don't enqueue */ |
1236 | ret = -EAGAIN; |
1237 | spin_unlock(lock: &queue_lock); |
1238 | wake_up(&queue_wait); |
1239 | if (ret == -EAGAIN) { |
1240 | kfree(objp: buf); |
1241 | kfree(objp: crq); |
1242 | } |
1243 | return ret; |
1244 | } |
1245 | |
1246 | int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h) |
1247 | { |
1248 | if (test_and_set_bit(nr: CACHE_PENDING, addr: &h->flags)) |
1249 | return 0; |
1250 | return cache_pipe_upcall(detail, h); |
1251 | } |
1252 | EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall); |
1253 | |
1254 | int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail, |
1255 | struct cache_head *h) |
1256 | { |
1257 | if (!cache_listeners_exist(detail)) { |
1258 | warn_no_listener(detail); |
1259 | trace_cache_entry_no_listener(cd: detail, h); |
1260 | return -EINVAL; |
1261 | } |
1262 | return sunrpc_cache_pipe_upcall(detail, h); |
1263 | } |
1264 | EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout); |
1265 | |
1266 | /* |
1267 | * parse a message from user-space and pass it |
1268 | * to an appropriate cache |
1269 | * Messages are, like requests, separated into fields by |
1270 | * spaces and dequotes as \xHEXSTRING or embedded \nnn octal |
1271 | * |
1272 | * Message is |
1273 | * reply cachename expiry key ... content.... |
1274 | * |
1275 | * key and content are both parsed by cache |
1276 | */ |
1277 | |
1278 | int qword_get(char **bpp, char *dest, int bufsize) |
1279 | { |
1280 | /* return bytes copied, or -1 on error */ |
1281 | char *bp = *bpp; |
1282 | int len = 0; |
1283 | |
1284 | while (*bp == ' ') bp++; |
1285 | |
1286 | if (bp[0] == '\\' && bp[1] == 'x') { |
1287 | /* HEX STRING */ |
1288 | bp += 2; |
1289 | while (len < bufsize - 1) { |
1290 | int h, l; |
1291 | |
1292 | h = hex_to_bin(ch: bp[0]); |
1293 | if (h < 0) |
1294 | break; |
1295 | |
1296 | l = hex_to_bin(ch: bp[1]); |
1297 | if (l < 0) |
1298 | break; |
1299 | |
1300 | *dest++ = (h << 4) | l; |
1301 | bp += 2; |
1302 | len++; |
1303 | } |
1304 | } else { |
1305 | /* text with \nnn octal quoting */ |
1306 | while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { |
1307 | if (*bp == '\\' && |
1308 | isodigit(c: bp[1]) && (bp[1] <= '3') && |
1309 | isodigit(c: bp[2]) && |
1310 | isodigit(c: bp[3])) { |
1311 | int byte = (*++bp -'0'); |
1312 | bp++; |
1313 | byte = (byte << 3) | (*bp++ - '0'); |
1314 | byte = (byte << 3) | (*bp++ - '0'); |
1315 | *dest++ = byte; |
1316 | len++; |
1317 | } else { |
1318 | *dest++ = *bp++; |
1319 | len++; |
1320 | } |
1321 | } |
1322 | } |
1323 | |
1324 | if (*bp != ' ' && *bp != '\n' && *bp != '\0') |
1325 | return -1; |
1326 | while (*bp == ' ') bp++; |
1327 | *bpp = bp; |
1328 | *dest = '\0'; |
1329 | return len; |
1330 | } |
1331 | EXPORT_SYMBOL_GPL(qword_get); |
1332 | |
1333 | |
1334 | /* |
1335 | * support /proc/net/rpc/$CACHENAME/content |
1336 | * as a seqfile. |
1337 | * We call ->cache_show passing NULL for the item to |
1338 | * get a header, then pass each real item in the cache |
1339 | */ |
1340 | |
1341 | static void *__cache_seq_start(struct seq_file *m, loff_t *pos) |
1342 | { |
1343 | loff_t n = *pos; |
1344 | unsigned int hash, entry; |
1345 | struct cache_head *ch; |
1346 | struct cache_detail *cd = m->private; |
1347 | |
1348 | if (!n--) |
1349 | return SEQ_START_TOKEN; |
1350 | hash = n >> 32; |
1351 | entry = n & ((1LL<<32) - 1); |
1352 | |
1353 | hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list) |
1354 | if (!entry--) |
1355 | return ch; |
1356 | n &= ~((1LL<<32) - 1); |
1357 | do { |
1358 | hash++; |
1359 | n += 1LL<<32; |
1360 | } while(hash < cd->hash_size && |
1361 | hlist_empty(h: &cd->hash_table[hash])); |
1362 | if (hash >= cd->hash_size) |
1363 | return NULL; |
1364 | *pos = n+1; |
1365 | return hlist_entry_safe(rcu_dereference_raw( |
1366 | hlist_first_rcu(&cd->hash_table[hash])), |
1367 | struct cache_head, cache_list); |
1368 | } |
1369 | |
1370 | static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos) |
1371 | { |
1372 | struct cache_head *ch = p; |
1373 | int hash = (*pos >> 32); |
1374 | struct cache_detail *cd = m->private; |
1375 | |
1376 | if (p == SEQ_START_TOKEN) |
1377 | hash = 0; |
1378 | else if (ch->cache_list.next == NULL) { |
1379 | hash++; |
1380 | *pos += 1LL<<32; |
1381 | } else { |
1382 | ++*pos; |
1383 | return hlist_entry_safe(rcu_dereference_raw( |
1384 | hlist_next_rcu(&ch->cache_list)), |
1385 | struct cache_head, cache_list); |
1386 | } |
1387 | *pos &= ~((1LL<<32) - 1); |
1388 | while (hash < cd->hash_size && |
1389 | hlist_empty(h: &cd->hash_table[hash])) { |
1390 | hash++; |
1391 | *pos += 1LL<<32; |
1392 | } |
1393 | if (hash >= cd->hash_size) |
1394 | return NULL; |
1395 | ++*pos; |
1396 | return hlist_entry_safe(rcu_dereference_raw( |
1397 | hlist_first_rcu(&cd->hash_table[hash])), |
1398 | struct cache_head, cache_list); |
1399 | } |
1400 | |
1401 | void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos) |
1402 | __acquires(RCU) |
1403 | { |
1404 | rcu_read_lock(); |
1405 | return __cache_seq_start(m, pos); |
1406 | } |
1407 | EXPORT_SYMBOL_GPL(cache_seq_start_rcu); |
1408 | |
1409 | void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos) |
1410 | { |
1411 | return cache_seq_next(m: file, p, pos); |
1412 | } |
1413 | EXPORT_SYMBOL_GPL(cache_seq_next_rcu); |
1414 | |
1415 | void cache_seq_stop_rcu(struct seq_file *m, void *p) |
1416 | __releases(RCU) |
1417 | { |
1418 | rcu_read_unlock(); |
1419 | } |
1420 | EXPORT_SYMBOL_GPL(cache_seq_stop_rcu); |
1421 | |
1422 | static int c_show(struct seq_file *m, void *p) |
1423 | { |
1424 | struct cache_head *cp = p; |
1425 | struct cache_detail *cd = m->private; |
1426 | |
1427 | if (p == SEQ_START_TOKEN) |
1428 | return cd->cache_show(m, cd, NULL); |
1429 | |
1430 | ifdebug(CACHE) |
1431 | seq_printf(m, fmt: "# expiry=%lld refcnt=%d flags=%lx\n" , |
1432 | convert_to_wallclock(sinceboot: cp->expiry_time), |
1433 | kref_read(kref: &cp->ref), cp->flags); |
1434 | cache_get(h: cp); |
1435 | if (cache_check(cd, cp, NULL)) |
1436 | /* cache_check does a cache_put on failure */ |
1437 | seq_puts(m, s: "# " ); |
1438 | else { |
1439 | if (cache_is_expired(detail: cd, h: cp)) |
1440 | seq_puts(m, s: "# " ); |
1441 | cache_put(h: cp, cd); |
1442 | } |
1443 | |
1444 | return cd->cache_show(m, cd, cp); |
1445 | } |
1446 | |
1447 | static const struct seq_operations cache_content_op = { |
1448 | .start = cache_seq_start_rcu, |
1449 | .next = cache_seq_next_rcu, |
1450 | .stop = cache_seq_stop_rcu, |
1451 | .show = c_show, |
1452 | }; |
1453 | |
1454 | static int content_open(struct inode *inode, struct file *file, |
1455 | struct cache_detail *cd) |
1456 | { |
1457 | struct seq_file *seq; |
1458 | int err; |
1459 | |
1460 | if (!cd || !try_module_get(module: cd->owner)) |
1461 | return -EACCES; |
1462 | |
1463 | err = seq_open(file, &cache_content_op); |
1464 | if (err) { |
1465 | module_put(module: cd->owner); |
1466 | return err; |
1467 | } |
1468 | |
1469 | seq = file->private_data; |
1470 | seq->private = cd; |
1471 | return 0; |
1472 | } |
1473 | |
1474 | static int content_release(struct inode *inode, struct file *file, |
1475 | struct cache_detail *cd) |
1476 | { |
1477 | int ret = seq_release(inode, file); |
1478 | module_put(module: cd->owner); |
1479 | return ret; |
1480 | } |
1481 | |
1482 | static int open_flush(struct inode *inode, struct file *file, |
1483 | struct cache_detail *cd) |
1484 | { |
1485 | if (!cd || !try_module_get(module: cd->owner)) |
1486 | return -EACCES; |
1487 | return nonseekable_open(inode, filp: file); |
1488 | } |
1489 | |
1490 | static int release_flush(struct inode *inode, struct file *file, |
1491 | struct cache_detail *cd) |
1492 | { |
1493 | module_put(module: cd->owner); |
1494 | return 0; |
1495 | } |
1496 | |
1497 | static ssize_t read_flush(struct file *file, char __user *buf, |
1498 | size_t count, loff_t *ppos, |
1499 | struct cache_detail *cd) |
1500 | { |
1501 | char tbuf[22]; |
1502 | size_t len; |
1503 | |
1504 | len = snprintf(buf: tbuf, size: sizeof(tbuf), fmt: "%llu\n" , |
1505 | convert_to_wallclock(sinceboot: cd->flush_time)); |
1506 | return simple_read_from_buffer(to: buf, count, ppos, from: tbuf, available: len); |
1507 | } |
1508 | |
1509 | static ssize_t write_flush(struct file *file, const char __user *buf, |
1510 | size_t count, loff_t *ppos, |
1511 | struct cache_detail *cd) |
1512 | { |
1513 | char tbuf[20]; |
1514 | char *ep; |
1515 | time64_t now; |
1516 | |
1517 | if (*ppos || count > sizeof(tbuf)-1) |
1518 | return -EINVAL; |
1519 | if (copy_from_user(to: tbuf, from: buf, n: count)) |
1520 | return -EFAULT; |
1521 | tbuf[count] = 0; |
1522 | simple_strtoul(tbuf, &ep, 0); |
1523 | if (*ep && *ep != '\n') |
1524 | return -EINVAL; |
1525 | /* Note that while we check that 'buf' holds a valid number, |
1526 | * we always ignore the value and just flush everything. |
1527 | * Making use of the number leads to races. |
1528 | */ |
1529 | |
1530 | now = seconds_since_boot(); |
1531 | /* Always flush everything, so behave like cache_purge() |
1532 | * Do this by advancing flush_time to the current time, |
1533 | * or by one second if it has already reached the current time. |
1534 | * Newly added cache entries will always have ->last_refresh greater |
1535 | * that ->flush_time, so they don't get flushed prematurely. |
1536 | */ |
1537 | |
1538 | if (cd->flush_time >= now) |
1539 | now = cd->flush_time + 1; |
1540 | |
1541 | cd->flush_time = now; |
1542 | cd->nextcheck = now; |
1543 | cache_flush(); |
1544 | |
1545 | if (cd->flush) |
1546 | cd->flush(); |
1547 | |
1548 | *ppos += count; |
1549 | return count; |
1550 | } |
1551 | |
1552 | static ssize_t cache_read_procfs(struct file *filp, char __user *buf, |
1553 | size_t count, loff_t *ppos) |
1554 | { |
1555 | struct cache_detail *cd = pde_data(inode: file_inode(f: filp)); |
1556 | |
1557 | return cache_read(filp, buf, count, ppos, cd); |
1558 | } |
1559 | |
1560 | static ssize_t cache_write_procfs(struct file *filp, const char __user *buf, |
1561 | size_t count, loff_t *ppos) |
1562 | { |
1563 | struct cache_detail *cd = pde_data(inode: file_inode(f: filp)); |
1564 | |
1565 | return cache_write(filp, buf, count, ppos, cd); |
1566 | } |
1567 | |
1568 | static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait) |
1569 | { |
1570 | struct cache_detail *cd = pde_data(inode: file_inode(f: filp)); |
1571 | |
1572 | return cache_poll(filp, wait, cd); |
1573 | } |
1574 | |
1575 | static long cache_ioctl_procfs(struct file *filp, |
1576 | unsigned int cmd, unsigned long arg) |
1577 | { |
1578 | struct inode *inode = file_inode(f: filp); |
1579 | struct cache_detail *cd = pde_data(inode); |
1580 | |
1581 | return cache_ioctl(ino: inode, filp, cmd, arg, cd); |
1582 | } |
1583 | |
1584 | static int cache_open_procfs(struct inode *inode, struct file *filp) |
1585 | { |
1586 | struct cache_detail *cd = pde_data(inode); |
1587 | |
1588 | return cache_open(inode, filp, cd); |
1589 | } |
1590 | |
1591 | static int cache_release_procfs(struct inode *inode, struct file *filp) |
1592 | { |
1593 | struct cache_detail *cd = pde_data(inode); |
1594 | |
1595 | return cache_release(inode, filp, cd); |
1596 | } |
1597 | |
1598 | static const struct proc_ops cache_channel_proc_ops = { |
1599 | .proc_lseek = no_llseek, |
1600 | .proc_read = cache_read_procfs, |
1601 | .proc_write = cache_write_procfs, |
1602 | .proc_poll = cache_poll_procfs, |
1603 | .proc_ioctl = cache_ioctl_procfs, /* for FIONREAD */ |
1604 | .proc_open = cache_open_procfs, |
1605 | .proc_release = cache_release_procfs, |
1606 | }; |
1607 | |
1608 | static int content_open_procfs(struct inode *inode, struct file *filp) |
1609 | { |
1610 | struct cache_detail *cd = pde_data(inode); |
1611 | |
1612 | return content_open(inode, file: filp, cd); |
1613 | } |
1614 | |
1615 | static int content_release_procfs(struct inode *inode, struct file *filp) |
1616 | { |
1617 | struct cache_detail *cd = pde_data(inode); |
1618 | |
1619 | return content_release(inode, file: filp, cd); |
1620 | } |
1621 | |
1622 | static const struct proc_ops content_proc_ops = { |
1623 | .proc_open = content_open_procfs, |
1624 | .proc_read = seq_read, |
1625 | .proc_lseek = seq_lseek, |
1626 | .proc_release = content_release_procfs, |
1627 | }; |
1628 | |
1629 | static int open_flush_procfs(struct inode *inode, struct file *filp) |
1630 | { |
1631 | struct cache_detail *cd = pde_data(inode); |
1632 | |
1633 | return open_flush(inode, file: filp, cd); |
1634 | } |
1635 | |
1636 | static int release_flush_procfs(struct inode *inode, struct file *filp) |
1637 | { |
1638 | struct cache_detail *cd = pde_data(inode); |
1639 | |
1640 | return release_flush(inode, file: filp, cd); |
1641 | } |
1642 | |
1643 | static ssize_t read_flush_procfs(struct file *filp, char __user *buf, |
1644 | size_t count, loff_t *ppos) |
1645 | { |
1646 | struct cache_detail *cd = pde_data(inode: file_inode(f: filp)); |
1647 | |
1648 | return read_flush(file: filp, buf, count, ppos, cd); |
1649 | } |
1650 | |
1651 | static ssize_t write_flush_procfs(struct file *filp, |
1652 | const char __user *buf, |
1653 | size_t count, loff_t *ppos) |
1654 | { |
1655 | struct cache_detail *cd = pde_data(inode: file_inode(f: filp)); |
1656 | |
1657 | return write_flush(file: filp, buf, count, ppos, cd); |
1658 | } |
1659 | |
1660 | static const struct proc_ops cache_flush_proc_ops = { |
1661 | .proc_open = open_flush_procfs, |
1662 | .proc_read = read_flush_procfs, |
1663 | .proc_write = write_flush_procfs, |
1664 | .proc_release = release_flush_procfs, |
1665 | .proc_lseek = no_llseek, |
1666 | }; |
1667 | |
1668 | static void remove_cache_proc_entries(struct cache_detail *cd) |
1669 | { |
1670 | if (cd->procfs) { |
1671 | proc_remove(cd->procfs); |
1672 | cd->procfs = NULL; |
1673 | } |
1674 | } |
1675 | |
1676 | #ifdef CONFIG_PROC_FS |
1677 | static int create_cache_proc_entries(struct cache_detail *cd, struct net *net) |
1678 | { |
1679 | struct proc_dir_entry *p; |
1680 | struct sunrpc_net *sn; |
1681 | |
1682 | sn = net_generic(net, id: sunrpc_net_id); |
1683 | cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc); |
1684 | if (cd->procfs == NULL) |
1685 | goto out_nomem; |
1686 | |
1687 | p = proc_create_data("flush" , S_IFREG | 0600, |
1688 | cd->procfs, &cache_flush_proc_ops, cd); |
1689 | if (p == NULL) |
1690 | goto out_nomem; |
1691 | |
1692 | if (cd->cache_request || cd->cache_parse) { |
1693 | p = proc_create_data("channel" , S_IFREG | 0600, cd->procfs, |
1694 | &cache_channel_proc_ops, cd); |
1695 | if (p == NULL) |
1696 | goto out_nomem; |
1697 | } |
1698 | if (cd->cache_show) { |
1699 | p = proc_create_data("content" , S_IFREG | 0400, cd->procfs, |
1700 | &content_proc_ops, cd); |
1701 | if (p == NULL) |
1702 | goto out_nomem; |
1703 | } |
1704 | return 0; |
1705 | out_nomem: |
1706 | remove_cache_proc_entries(cd); |
1707 | return -ENOMEM; |
1708 | } |
1709 | #else /* CONFIG_PROC_FS */ |
1710 | static int create_cache_proc_entries(struct cache_detail *cd, struct net *net) |
1711 | { |
1712 | return 0; |
1713 | } |
1714 | #endif |
1715 | |
1716 | void __init cache_initialize(void) |
1717 | { |
1718 | INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean); |
1719 | } |
1720 | |
1721 | int cache_register_net(struct cache_detail *cd, struct net *net) |
1722 | { |
1723 | int ret; |
1724 | |
1725 | sunrpc_init_cache_detail(cd); |
1726 | ret = create_cache_proc_entries(cd, net); |
1727 | if (ret) |
1728 | sunrpc_destroy_cache_detail(cd); |
1729 | return ret; |
1730 | } |
1731 | EXPORT_SYMBOL_GPL(cache_register_net); |
1732 | |
1733 | void cache_unregister_net(struct cache_detail *cd, struct net *net) |
1734 | { |
1735 | remove_cache_proc_entries(cd); |
1736 | sunrpc_destroy_cache_detail(cd); |
1737 | } |
1738 | EXPORT_SYMBOL_GPL(cache_unregister_net); |
1739 | |
1740 | struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net) |
1741 | { |
1742 | struct cache_detail *cd; |
1743 | int i; |
1744 | |
1745 | cd = kmemdup(p: tmpl, size: sizeof(struct cache_detail), GFP_KERNEL); |
1746 | if (cd == NULL) |
1747 | return ERR_PTR(error: -ENOMEM); |
1748 | |
1749 | cd->hash_table = kcalloc(n: cd->hash_size, size: sizeof(struct hlist_head), |
1750 | GFP_KERNEL); |
1751 | if (cd->hash_table == NULL) { |
1752 | kfree(objp: cd); |
1753 | return ERR_PTR(error: -ENOMEM); |
1754 | } |
1755 | |
1756 | for (i = 0; i < cd->hash_size; i++) |
1757 | INIT_HLIST_HEAD(&cd->hash_table[i]); |
1758 | cd->net = net; |
1759 | return cd; |
1760 | } |
1761 | EXPORT_SYMBOL_GPL(cache_create_net); |
1762 | |
1763 | void cache_destroy_net(struct cache_detail *cd, struct net *net) |
1764 | { |
1765 | kfree(objp: cd->hash_table); |
1766 | kfree(objp: cd); |
1767 | } |
1768 | EXPORT_SYMBOL_GPL(cache_destroy_net); |
1769 | |
1770 | static ssize_t cache_read_pipefs(struct file *filp, char __user *buf, |
1771 | size_t count, loff_t *ppos) |
1772 | { |
1773 | struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private; |
1774 | |
1775 | return cache_read(filp, buf, count, ppos, cd); |
1776 | } |
1777 | |
1778 | static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf, |
1779 | size_t count, loff_t *ppos) |
1780 | { |
1781 | struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private; |
1782 | |
1783 | return cache_write(filp, buf, count, ppos, cd); |
1784 | } |
1785 | |
1786 | static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait) |
1787 | { |
1788 | struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private; |
1789 | |
1790 | return cache_poll(filp, wait, cd); |
1791 | } |
1792 | |
1793 | static long cache_ioctl_pipefs(struct file *filp, |
1794 | unsigned int cmd, unsigned long arg) |
1795 | { |
1796 | struct inode *inode = file_inode(f: filp); |
1797 | struct cache_detail *cd = RPC_I(inode)->private; |
1798 | |
1799 | return cache_ioctl(ino: inode, filp, cmd, arg, cd); |
1800 | } |
1801 | |
1802 | static int cache_open_pipefs(struct inode *inode, struct file *filp) |
1803 | { |
1804 | struct cache_detail *cd = RPC_I(inode)->private; |
1805 | |
1806 | return cache_open(inode, filp, cd); |
1807 | } |
1808 | |
1809 | static int cache_release_pipefs(struct inode *inode, struct file *filp) |
1810 | { |
1811 | struct cache_detail *cd = RPC_I(inode)->private; |
1812 | |
1813 | return cache_release(inode, filp, cd); |
1814 | } |
1815 | |
1816 | const struct file_operations cache_file_operations_pipefs = { |
1817 | .owner = THIS_MODULE, |
1818 | .llseek = no_llseek, |
1819 | .read = cache_read_pipefs, |
1820 | .write = cache_write_pipefs, |
1821 | .poll = cache_poll_pipefs, |
1822 | .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */ |
1823 | .open = cache_open_pipefs, |
1824 | .release = cache_release_pipefs, |
1825 | }; |
1826 | |
1827 | static int content_open_pipefs(struct inode *inode, struct file *filp) |
1828 | { |
1829 | struct cache_detail *cd = RPC_I(inode)->private; |
1830 | |
1831 | return content_open(inode, file: filp, cd); |
1832 | } |
1833 | |
1834 | static int content_release_pipefs(struct inode *inode, struct file *filp) |
1835 | { |
1836 | struct cache_detail *cd = RPC_I(inode)->private; |
1837 | |
1838 | return content_release(inode, file: filp, cd); |
1839 | } |
1840 | |
1841 | const struct file_operations content_file_operations_pipefs = { |
1842 | .open = content_open_pipefs, |
1843 | .read = seq_read, |
1844 | .llseek = seq_lseek, |
1845 | .release = content_release_pipefs, |
1846 | }; |
1847 | |
1848 | static int open_flush_pipefs(struct inode *inode, struct file *filp) |
1849 | { |
1850 | struct cache_detail *cd = RPC_I(inode)->private; |
1851 | |
1852 | return open_flush(inode, file: filp, cd); |
1853 | } |
1854 | |
1855 | static int release_flush_pipefs(struct inode *inode, struct file *filp) |
1856 | { |
1857 | struct cache_detail *cd = RPC_I(inode)->private; |
1858 | |
1859 | return release_flush(inode, file: filp, cd); |
1860 | } |
1861 | |
1862 | static ssize_t read_flush_pipefs(struct file *filp, char __user *buf, |
1863 | size_t count, loff_t *ppos) |
1864 | { |
1865 | struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private; |
1866 | |
1867 | return read_flush(file: filp, buf, count, ppos, cd); |
1868 | } |
1869 | |
1870 | static ssize_t write_flush_pipefs(struct file *filp, |
1871 | const char __user *buf, |
1872 | size_t count, loff_t *ppos) |
1873 | { |
1874 | struct cache_detail *cd = RPC_I(inode: file_inode(f: filp))->private; |
1875 | |
1876 | return write_flush(file: filp, buf, count, ppos, cd); |
1877 | } |
1878 | |
1879 | const struct file_operations cache_flush_operations_pipefs = { |
1880 | .open = open_flush_pipefs, |
1881 | .read = read_flush_pipefs, |
1882 | .write = write_flush_pipefs, |
1883 | .release = release_flush_pipefs, |
1884 | .llseek = no_llseek, |
1885 | }; |
1886 | |
1887 | int sunrpc_cache_register_pipefs(struct dentry *parent, |
1888 | const char *name, umode_t umode, |
1889 | struct cache_detail *cd) |
1890 | { |
1891 | struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd); |
1892 | if (IS_ERR(ptr: dir)) |
1893 | return PTR_ERR(ptr: dir); |
1894 | cd->pipefs = dir; |
1895 | return 0; |
1896 | } |
1897 | EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs); |
1898 | |
1899 | void sunrpc_cache_unregister_pipefs(struct cache_detail *cd) |
1900 | { |
1901 | if (cd->pipefs) { |
1902 | rpc_remove_cache_dir(cd->pipefs); |
1903 | cd->pipefs = NULL; |
1904 | } |
1905 | } |
1906 | EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs); |
1907 | |
1908 | void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h) |
1909 | { |
1910 | spin_lock(lock: &cd->hash_lock); |
1911 | if (!hlist_unhashed(h: &h->cache_list)){ |
1912 | sunrpc_begin_cache_remove_entry(ch: h, cd); |
1913 | spin_unlock(lock: &cd->hash_lock); |
1914 | sunrpc_end_cache_remove_entry(ch: h, cd); |
1915 | } else |
1916 | spin_unlock(lock: &cd->hash_lock); |
1917 | } |
1918 | EXPORT_SYMBOL_GPL(sunrpc_cache_unhash); |
1919 | |