4 * Generic code for various authentication-related caches
5 * used by sunrpc clients and servers.
7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
9 * Released under terms in GPL version 2. See COPYING.
13 #include <linux/types.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 <linux/string_helpers.h>
24 #include <linux/uaccess.h>
25 #include <linux/poll.h>
26 #include <linux/seq_file.h>
27 #include <linux/proc_fs.h>
28 #include <linux/net.h>
29 #include <linux/workqueue.h>
30 #include <linux/mutex.h>
31 #include <linux/pagemap.h>
32 #include <asm/ioctls.h>
33 #include <linux/sunrpc/types.h>
34 #include <linux/sunrpc/cache.h>
35 #include <linux/sunrpc/stats.h>
36 #include <linux/sunrpc/rpc_pipe_fs.h>
39 #define RPCDBG_FACILITY RPCDBG_CACHE
41 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
42 static void cache_revisit_request(struct cache_head *item);
44 static void cache_init(struct cache_head *h, struct cache_detail *detail)
46 time_t now = seconds_since_boot();
47 INIT_HLIST_NODE(&h->cache_list);
50 h->expiry_time = now + CACHE_NEW_EXPIRY;
51 if (now <= detail->flush_time)
52 /* ensure it isn't already expired */
53 now = detail->flush_time + 1;
54 h->last_refresh = now;
57 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
58 struct cache_head *key, int hash)
60 struct cache_head *new = NULL, *freeme = NULL, *tmp = NULL;
61 struct hlist_head *head;
63 head = &detail->hash_table[hash];
65 read_lock(&detail->hash_lock);
67 hlist_for_each_entry(tmp, head, cache_list) {
68 if (detail->match(tmp, key)) {
69 if (cache_is_expired(detail, tmp))
70 /* This entry is expired, we will discard it. */
73 read_unlock(&detail->hash_lock);
77 read_unlock(&detail->hash_lock);
78 /* Didn't find anything, insert an empty entry */
80 new = detail->alloc();
83 /* must fully initialise 'new', else
84 * we might get lose if we need to
87 cache_init(new, detail);
88 detail->init(new, key);
90 write_lock(&detail->hash_lock);
92 /* check if entry appeared while we slept */
93 hlist_for_each_entry(tmp, head, cache_list) {
94 if (detail->match(tmp, key)) {
95 if (cache_is_expired(detail, tmp)) {
96 hlist_del_init(&tmp->cache_list);
102 write_unlock(&detail->hash_lock);
103 cache_put(new, detail);
108 hlist_add_head(&new->cache_list, head);
111 write_unlock(&detail->hash_lock);
114 cache_put(freeme, detail);
117 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
120 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
122 static void cache_fresh_locked(struct cache_head *head, time_t expiry,
123 struct cache_detail *detail)
125 time_t now = seconds_since_boot();
126 if (now <= detail->flush_time)
127 /* ensure it isn't immediately treated as expired */
128 now = detail->flush_time + 1;
129 head->expiry_time = expiry;
130 head->last_refresh = now;
131 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
132 set_bit(CACHE_VALID, &head->flags);
135 static void cache_fresh_unlocked(struct cache_head *head,
136 struct cache_detail *detail)
138 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
139 cache_revisit_request(head);
140 cache_dequeue(detail, head);
144 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
145 struct cache_head *new, struct cache_head *old, int hash)
147 /* The 'old' entry is to be replaced by 'new'.
148 * If 'old' is not VALID, we update it directly,
149 * otherwise we need to replace it
151 struct cache_head *tmp;
153 if (!test_bit(CACHE_VALID, &old->flags)) {
154 write_lock(&detail->hash_lock);
155 if (!test_bit(CACHE_VALID, &old->flags)) {
156 if (test_bit(CACHE_NEGATIVE, &new->flags))
157 set_bit(CACHE_NEGATIVE, &old->flags);
159 detail->update(old, new);
160 cache_fresh_locked(old, new->expiry_time, detail);
161 write_unlock(&detail->hash_lock);
162 cache_fresh_unlocked(old, detail);
165 write_unlock(&detail->hash_lock);
167 /* We need to insert a new entry */
168 tmp = detail->alloc();
170 cache_put(old, detail);
173 cache_init(tmp, detail);
174 detail->init(tmp, old);
176 write_lock(&detail->hash_lock);
177 if (test_bit(CACHE_NEGATIVE, &new->flags))
178 set_bit(CACHE_NEGATIVE, &tmp->flags);
180 detail->update(tmp, new);
181 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
184 cache_fresh_locked(tmp, new->expiry_time, detail);
185 cache_fresh_locked(old, 0, detail);
186 write_unlock(&detail->hash_lock);
187 cache_fresh_unlocked(tmp, detail);
188 cache_fresh_unlocked(old, detail);
189 cache_put(old, detail);
192 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
194 static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
196 if (cd->cache_upcall)
197 return cd->cache_upcall(cd, h);
198 return sunrpc_cache_pipe_upcall(cd, h);
201 static inline int cache_is_valid(struct cache_head *h)
203 if (!test_bit(CACHE_VALID, &h->flags))
207 if (test_bit(CACHE_NEGATIVE, &h->flags))
211 * In combination with write barrier in
212 * sunrpc_cache_update, ensures that anyone
213 * using the cache entry after this sees the
222 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
226 write_lock(&detail->hash_lock);
227 rv = cache_is_valid(h);
229 set_bit(CACHE_NEGATIVE, &h->flags);
230 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
234 write_unlock(&detail->hash_lock);
235 cache_fresh_unlocked(h, detail);
240 * This is the generic cache management routine for all
241 * the authentication caches.
242 * It checks the currency of a cache item and will (later)
243 * initiate an upcall to fill it if needed.
246 * Returns 0 if the cache_head can be used, or cache_puts it and returns
247 * -EAGAIN if upcall is pending and request has been queued
248 * -ETIMEDOUT if upcall failed or request could not be queue or
249 * upcall completed but item is still invalid (implying that
250 * the cache item has been replaced with a newer one).
251 * -ENOENT if cache entry was negative
253 int cache_check(struct cache_detail *detail,
254 struct cache_head *h, struct cache_req *rqstp)
257 long refresh_age, age;
259 /* First decide return status as best we can */
260 rv = cache_is_valid(h);
262 /* now see if we want to start an upcall */
263 refresh_age = (h->expiry_time - h->last_refresh);
264 age = seconds_since_boot() - h->last_refresh;
269 } else if (rv == -EAGAIN ||
270 (h->expiry_time != 0 && age > refresh_age/2)) {
271 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
273 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
274 switch (cache_make_upcall(detail, h)) {
276 rv = try_to_negate_entry(detail, h);
279 cache_fresh_unlocked(h, detail);
286 if (!cache_defer_req(rqstp, h)) {
288 * Request was not deferred; handle it as best
291 rv = cache_is_valid(h);
297 cache_put(h, detail);
300 EXPORT_SYMBOL_GPL(cache_check);
303 * caches need to be periodically cleaned.
304 * For this we maintain a list of cache_detail and
305 * a current pointer into that list and into the table
308 * Each time cache_clean is called it finds the next non-empty entry
309 * in the current table and walks the list in that entry
310 * looking for entries that can be removed.
312 * An entry gets removed if:
313 * - The expiry is before current time
314 * - The last_refresh time is before the flush_time for that cache
316 * later we might drop old entries with non-NEVER expiry if that table
317 * is getting 'full' for some definition of 'full'
319 * The question of "how often to scan a table" is an interesting one
320 * and is answered in part by the use of the "nextcheck" field in the
322 * When a scan of a table begins, the nextcheck field is set to a time
323 * that is well into the future.
324 * While scanning, if an expiry time is found that is earlier than the
325 * current nextcheck time, nextcheck is set to that expiry time.
326 * If the flush_time is ever set to a time earlier than the nextcheck
327 * time, the nextcheck time is then set to that flush_time.
329 * A table is then only scanned if the current time is at least
330 * the nextcheck time.
334 static LIST_HEAD(cache_list);
335 static DEFINE_SPINLOCK(cache_list_lock);
336 static struct cache_detail *current_detail;
337 static int current_index;
339 static void do_cache_clean(struct work_struct *work);
340 static struct delayed_work cache_cleaner;
342 void sunrpc_init_cache_detail(struct cache_detail *cd)
344 rwlock_init(&cd->hash_lock);
345 INIT_LIST_HEAD(&cd->queue);
346 spin_lock(&cache_list_lock);
349 atomic_set(&cd->readers, 0);
352 list_add(&cd->others, &cache_list);
353 spin_unlock(&cache_list_lock);
355 /* start the cleaning process */
356 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
358 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
360 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
363 spin_lock(&cache_list_lock);
364 write_lock(&cd->hash_lock);
366 write_unlock(&cd->hash_lock);
367 spin_unlock(&cache_list_lock);
370 if (current_detail == cd)
371 current_detail = NULL;
372 list_del_init(&cd->others);
373 write_unlock(&cd->hash_lock);
374 spin_unlock(&cache_list_lock);
375 if (list_empty(&cache_list)) {
376 /* module must be being unloaded so its safe to kill the worker */
377 cancel_delayed_work_sync(&cache_cleaner);
381 printk(KERN_ERR "RPC: failed to unregister %s cache\n", cd->name);
383 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
385 /* clean cache tries to find something to clean
387 * It returns 1 if it cleaned something,
388 * 0 if it didn't find anything this time
389 * -1 if it fell off the end of the list.
391 static int cache_clean(void)
394 struct list_head *next;
396 spin_lock(&cache_list_lock);
398 /* find a suitable table if we don't already have one */
399 while (current_detail == NULL ||
400 current_index >= current_detail->hash_size) {
402 next = current_detail->others.next;
404 next = cache_list.next;
405 if (next == &cache_list) {
406 current_detail = NULL;
407 spin_unlock(&cache_list_lock);
410 current_detail = list_entry(next, struct cache_detail, others);
411 if (current_detail->nextcheck > seconds_since_boot())
412 current_index = current_detail->hash_size;
415 current_detail->nextcheck = seconds_since_boot()+30*60;
419 /* find a non-empty bucket in the table */
420 while (current_detail &&
421 current_index < current_detail->hash_size &&
422 hlist_empty(¤t_detail->hash_table[current_index]))
425 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
427 if (current_detail && current_index < current_detail->hash_size) {
428 struct cache_head *ch = NULL;
429 struct cache_detail *d;
430 struct hlist_head *head;
431 struct hlist_node *tmp;
433 write_lock(¤t_detail->hash_lock);
435 /* Ok, now to clean this strand */
437 head = ¤t_detail->hash_table[current_index];
438 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
439 if (current_detail->nextcheck > ch->expiry_time)
440 current_detail->nextcheck = ch->expiry_time+1;
441 if (!cache_is_expired(current_detail, ch))
444 hlist_del_init(&ch->cache_list);
445 current_detail->entries--;
450 write_unlock(¤t_detail->hash_lock);
454 spin_unlock(&cache_list_lock);
456 set_bit(CACHE_CLEANED, &ch->flags);
457 cache_fresh_unlocked(ch, d);
461 spin_unlock(&cache_list_lock);
467 * We want to regularly clean the cache, so we need to schedule some work ...
469 static void do_cache_clean(struct work_struct *work)
472 if (cache_clean() == -1)
473 delay = round_jiffies_relative(30*HZ);
475 if (list_empty(&cache_list))
479 queue_delayed_work(system_power_efficient_wq,
480 &cache_cleaner, delay);
485 * Clean all caches promptly. This just calls cache_clean
486 * repeatedly until we are sure that every cache has had a chance to
489 void cache_flush(void)
491 while (cache_clean() != -1)
493 while (cache_clean() != -1)
496 EXPORT_SYMBOL_GPL(cache_flush);
498 void cache_purge(struct cache_detail *detail)
500 time_t now = seconds_since_boot();
501 if (detail->flush_time >= now)
502 now = detail->flush_time + 1;
503 /* 'now' is the maximum value any 'last_refresh' can have */
504 detail->flush_time = now;
505 detail->nextcheck = seconds_since_boot();
508 EXPORT_SYMBOL_GPL(cache_purge);
512 * Deferral and Revisiting of Requests.
514 * If a cache lookup finds a pending entry, we
515 * need to defer the request and revisit it later.
516 * All deferred requests are stored in a hash table,
517 * indexed by "struct cache_head *".
518 * As it may be wasteful to store a whole request
519 * structure, we allow the request to provide a
520 * deferred form, which must contain a
521 * 'struct cache_deferred_req'
522 * This cache_deferred_req contains a method to allow
523 * it to be revisited when cache info is available
526 #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
527 #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
529 #define DFR_MAX 300 /* ??? */
531 static DEFINE_SPINLOCK(cache_defer_lock);
532 static LIST_HEAD(cache_defer_list);
533 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
534 static int cache_defer_cnt;
536 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
538 hlist_del_init(&dreq->hash);
539 if (!list_empty(&dreq->recent)) {
540 list_del_init(&dreq->recent);
545 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
547 int hash = DFR_HASH(item);
549 INIT_LIST_HEAD(&dreq->recent);
550 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
553 static void setup_deferral(struct cache_deferred_req *dreq,
554 struct cache_head *item,
560 spin_lock(&cache_defer_lock);
562 __hash_deferred_req(dreq, item);
566 list_add(&dreq->recent, &cache_defer_list);
569 spin_unlock(&cache_defer_lock);
573 struct thread_deferred_req {
574 struct cache_deferred_req handle;
575 struct completion completion;
578 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
580 struct thread_deferred_req *dr =
581 container_of(dreq, struct thread_deferred_req, handle);
582 complete(&dr->completion);
585 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
587 struct thread_deferred_req sleeper;
588 struct cache_deferred_req *dreq = &sleeper.handle;
590 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
591 dreq->revisit = cache_restart_thread;
593 setup_deferral(dreq, item, 0);
595 if (!test_bit(CACHE_PENDING, &item->flags) ||
596 wait_for_completion_interruptible_timeout(
597 &sleeper.completion, req->thread_wait) <= 0) {
598 /* The completion wasn't completed, so we need
601 spin_lock(&cache_defer_lock);
602 if (!hlist_unhashed(&sleeper.handle.hash)) {
603 __unhash_deferred_req(&sleeper.handle);
604 spin_unlock(&cache_defer_lock);
606 /* cache_revisit_request already removed
607 * this from the hash table, but hasn't
608 * called ->revisit yet. It will very soon
609 * and we need to wait for it.
611 spin_unlock(&cache_defer_lock);
612 wait_for_completion(&sleeper.completion);
617 static void cache_limit_defers(void)
619 /* Make sure we haven't exceed the limit of allowed deferred
622 struct cache_deferred_req *discard = NULL;
624 if (cache_defer_cnt <= DFR_MAX)
627 spin_lock(&cache_defer_lock);
629 /* Consider removing either the first or the last */
630 if (cache_defer_cnt > DFR_MAX) {
631 if (prandom_u32() & 1)
632 discard = list_entry(cache_defer_list.next,
633 struct cache_deferred_req, recent);
635 discard = list_entry(cache_defer_list.prev,
636 struct cache_deferred_req, recent);
637 __unhash_deferred_req(discard);
639 spin_unlock(&cache_defer_lock);
641 discard->revisit(discard, 1);
644 /* Return true if and only if a deferred request is queued. */
645 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
647 struct cache_deferred_req *dreq;
649 if (req->thread_wait) {
650 cache_wait_req(req, item);
651 if (!test_bit(CACHE_PENDING, &item->flags))
654 dreq = req->defer(req);
657 setup_deferral(dreq, item, 1);
658 if (!test_bit(CACHE_PENDING, &item->flags))
659 /* Bit could have been cleared before we managed to
660 * set up the deferral, so need to revisit just in case
662 cache_revisit_request(item);
664 cache_limit_defers();
668 static void cache_revisit_request(struct cache_head *item)
670 struct cache_deferred_req *dreq;
671 struct list_head pending;
672 struct hlist_node *tmp;
673 int hash = DFR_HASH(item);
675 INIT_LIST_HEAD(&pending);
676 spin_lock(&cache_defer_lock);
678 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
679 if (dreq->item == item) {
680 __unhash_deferred_req(dreq);
681 list_add(&dreq->recent, &pending);
684 spin_unlock(&cache_defer_lock);
686 while (!list_empty(&pending)) {
687 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
688 list_del_init(&dreq->recent);
689 dreq->revisit(dreq, 0);
693 void cache_clean_deferred(void *owner)
695 struct cache_deferred_req *dreq, *tmp;
696 struct list_head pending;
699 INIT_LIST_HEAD(&pending);
700 spin_lock(&cache_defer_lock);
702 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
703 if (dreq->owner == owner) {
704 __unhash_deferred_req(dreq);
705 list_add(&dreq->recent, &pending);
708 spin_unlock(&cache_defer_lock);
710 while (!list_empty(&pending)) {
711 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
712 list_del_init(&dreq->recent);
713 dreq->revisit(dreq, 1);
718 * communicate with user-space
720 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
721 * On read, you get a full request, or block.
722 * On write, an update request is processed.
723 * Poll works if anything to read, and always allows write.
725 * Implemented by linked list of requests. Each open file has
726 * a ->private that also exists in this list. New requests are added
727 * to the end and may wakeup and preceding readers.
728 * New readers are added to the head. If, on read, an item is found with
729 * CACHE_UPCALLING clear, we free it from the list.
733 static DEFINE_SPINLOCK(queue_lock);
734 static DEFINE_MUTEX(queue_io_mutex);
737 struct list_head list;
738 int reader; /* if 0, then request */
740 struct cache_request {
741 struct cache_queue q;
742 struct cache_head *item;
747 struct cache_reader {
748 struct cache_queue q;
749 int offset; /* if non-0, we have a refcnt on next request */
752 static int cache_request(struct cache_detail *detail,
753 struct cache_request *crq)
758 detail->cache_request(detail, crq->item, &bp, &len);
761 return PAGE_SIZE - len;
764 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
765 loff_t *ppos, struct cache_detail *cd)
767 struct cache_reader *rp = filp->private_data;
768 struct cache_request *rq;
769 struct inode *inode = file_inode(filp);
775 inode_lock(inode); /* protect against multiple concurrent
776 * readers on this file */
778 spin_lock(&queue_lock);
779 /* need to find next request */
780 while (rp->q.list.next != &cd->queue &&
781 list_entry(rp->q.list.next, struct cache_queue, list)
783 struct list_head *next = rp->q.list.next;
784 list_move(&rp->q.list, next);
786 if (rp->q.list.next == &cd->queue) {
787 spin_unlock(&queue_lock);
789 WARN_ON_ONCE(rp->offset);
792 rq = container_of(rp->q.list.next, struct cache_request, q.list);
793 WARN_ON_ONCE(rq->q.reader);
796 spin_unlock(&queue_lock);
799 err = cache_request(cd, rq);
805 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
807 spin_lock(&queue_lock);
808 list_move(&rp->q.list, &rq->q.list);
809 spin_unlock(&queue_lock);
811 if (rp->offset + count > rq->len)
812 count = rq->len - rp->offset;
814 if (copy_to_user(buf, rq->buf + rp->offset, count))
817 if (rp->offset >= rq->len) {
819 spin_lock(&queue_lock);
820 list_move(&rp->q.list, &rq->q.list);
821 spin_unlock(&queue_lock);
826 if (rp->offset == 0) {
827 /* need to release rq */
828 spin_lock(&queue_lock);
830 if (rq->readers == 0 &&
831 !test_bit(CACHE_PENDING, &rq->item->flags)) {
832 list_del(&rq->q.list);
833 spin_unlock(&queue_lock);
834 cache_put(rq->item, cd);
838 spin_unlock(&queue_lock);
843 return err ? err : count;
846 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
847 size_t count, struct cache_detail *cd)
853 if (copy_from_user(kaddr, buf, count))
856 ret = cd->cache_parse(cd, kaddr, count);
862 static ssize_t cache_slow_downcall(const char __user *buf,
863 size_t count, struct cache_detail *cd)
865 static char write_buf[8192]; /* protected by queue_io_mutex */
866 ssize_t ret = -EINVAL;
868 if (count >= sizeof(write_buf))
870 mutex_lock(&queue_io_mutex);
871 ret = cache_do_downcall(write_buf, buf, count, cd);
872 mutex_unlock(&queue_io_mutex);
877 static ssize_t cache_downcall(struct address_space *mapping,
878 const char __user *buf,
879 size_t count, struct cache_detail *cd)
883 ssize_t ret = -ENOMEM;
885 if (count >= PAGE_SIZE)
888 page = find_or_create_page(mapping, 0, GFP_KERNEL);
893 ret = cache_do_downcall(kaddr, buf, count, cd);
899 return cache_slow_downcall(buf, count, cd);
902 static ssize_t cache_write(struct file *filp, const char __user *buf,
903 size_t count, loff_t *ppos,
904 struct cache_detail *cd)
906 struct address_space *mapping = filp->f_mapping;
907 struct inode *inode = file_inode(filp);
908 ssize_t ret = -EINVAL;
910 if (!cd->cache_parse)
914 ret = cache_downcall(mapping, buf, count, cd);
920 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
922 static unsigned int cache_poll(struct file *filp, poll_table *wait,
923 struct cache_detail *cd)
926 struct cache_reader *rp = filp->private_data;
927 struct cache_queue *cq;
929 poll_wait(filp, &queue_wait, wait);
931 /* alway allow write */
932 mask = POLLOUT | POLLWRNORM;
937 spin_lock(&queue_lock);
939 for (cq= &rp->q; &cq->list != &cd->queue;
940 cq = list_entry(cq->list.next, struct cache_queue, list))
942 mask |= POLLIN | POLLRDNORM;
945 spin_unlock(&queue_lock);
949 static int cache_ioctl(struct inode *ino, struct file *filp,
950 unsigned int cmd, unsigned long arg,
951 struct cache_detail *cd)
954 struct cache_reader *rp = filp->private_data;
955 struct cache_queue *cq;
957 if (cmd != FIONREAD || !rp)
960 spin_lock(&queue_lock);
962 /* only find the length remaining in current request,
963 * or the length of the next request
965 for (cq= &rp->q; &cq->list != &cd->queue;
966 cq = list_entry(cq->list.next, struct cache_queue, list))
968 struct cache_request *cr =
969 container_of(cq, struct cache_request, q);
970 len = cr->len - rp->offset;
973 spin_unlock(&queue_lock);
975 return put_user(len, (int __user *)arg);
978 static int cache_open(struct inode *inode, struct file *filp,
979 struct cache_detail *cd)
981 struct cache_reader *rp = NULL;
983 if (!cd || !try_module_get(cd->owner))
985 nonseekable_open(inode, filp);
986 if (filp->f_mode & FMODE_READ) {
987 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
989 module_put(cd->owner);
994 atomic_inc(&cd->readers);
995 spin_lock(&queue_lock);
996 list_add(&rp->q.list, &cd->queue);
997 spin_unlock(&queue_lock);
999 filp->private_data = rp;
1003 static int cache_release(struct inode *inode, struct file *filp,
1004 struct cache_detail *cd)
1006 struct cache_reader *rp = filp->private_data;
1009 spin_lock(&queue_lock);
1011 struct cache_queue *cq;
1012 for (cq= &rp->q; &cq->list != &cd->queue;
1013 cq = list_entry(cq->list.next, struct cache_queue, list))
1015 container_of(cq, struct cache_request, q)
1021 list_del(&rp->q.list);
1022 spin_unlock(&queue_lock);
1024 filp->private_data = NULL;
1027 cd->last_close = seconds_since_boot();
1028 atomic_dec(&cd->readers);
1030 module_put(cd->owner);
1036 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1038 struct cache_queue *cq, *tmp;
1039 struct cache_request *cr;
1040 struct list_head dequeued;
1042 INIT_LIST_HEAD(&dequeued);
1043 spin_lock(&queue_lock);
1044 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1046 cr = container_of(cq, struct cache_request, q);
1049 if (test_bit(CACHE_PENDING, &ch->flags))
1050 /* Lost a race and it is pending again */
1052 if (cr->readers != 0)
1054 list_move(&cr->q.list, &dequeued);
1056 spin_unlock(&queue_lock);
1057 while (!list_empty(&dequeued)) {
1058 cr = list_entry(dequeued.next, struct cache_request, q.list);
1059 list_del(&cr->q.list);
1060 cache_put(cr->item, detail);
1067 * Support routines for text-based upcalls.
1068 * Fields are separated by spaces.
1069 * Fields are either mangled to quote space tab newline slosh with slosh
1070 * or a hexified with a leading \x
1071 * Record is terminated with newline.
1075 void qword_add(char **bpp, int *lp, char *str)
1081 if (len < 0) return;
1083 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1096 EXPORT_SYMBOL_GPL(qword_add);
1098 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1103 if (len < 0) return;
1109 while (blen && len >= 2) {
1110 bp = hex_byte_pack(bp, *buf++);
1115 if (blen || len<1) len = -1;
1123 EXPORT_SYMBOL_GPL(qword_addhex);
1125 static void warn_no_listener(struct cache_detail *detail)
1127 if (detail->last_warn != detail->last_close) {
1128 detail->last_warn = detail->last_close;
1129 if (detail->warn_no_listener)
1130 detail->warn_no_listener(detail, detail->last_close != 0);
1134 static bool cache_listeners_exist(struct cache_detail *detail)
1136 if (atomic_read(&detail->readers))
1138 if (detail->last_close == 0)
1139 /* This cache was never opened */
1141 if (detail->last_close < seconds_since_boot() - 30)
1143 * We allow for the possibility that someone might
1144 * restart a userspace daemon without restarting the
1145 * server; but after 30 seconds, we give up.
1152 * register an upcall request to user-space and queue it up for read() by the
1155 * Each request is at most one page long.
1157 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1161 struct cache_request *crq;
1164 if (!detail->cache_request)
1167 if (!cache_listeners_exist(detail)) {
1168 warn_no_listener(detail);
1171 if (test_bit(CACHE_CLEANED, &h->flags))
1172 /* Too late to make an upcall */
1175 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1179 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1189 spin_lock(&queue_lock);
1190 if (test_bit(CACHE_PENDING, &h->flags)) {
1191 crq->item = cache_get(h);
1192 list_add_tail(&crq->q.list, &detail->queue);
1194 /* Lost a race, no longer PENDING, so don't enqueue */
1196 spin_unlock(&queue_lock);
1197 wake_up(&queue_wait);
1198 if (ret == -EAGAIN) {
1204 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1207 * parse a message from user-space and pass it
1208 * to an appropriate cache
1209 * Messages are, like requests, separated into fields by
1210 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1213 * reply cachename expiry key ... content....
1215 * key and content are both parsed by cache
1218 int qword_get(char **bpp, char *dest, int bufsize)
1220 /* return bytes copied, or -1 on error */
1224 while (*bp == ' ') bp++;
1226 if (bp[0] == '\\' && bp[1] == 'x') {
1229 while (len < bufsize - 1) {
1232 h = hex_to_bin(bp[0]);
1236 l = hex_to_bin(bp[1]);
1240 *dest++ = (h << 4) | l;
1245 /* text with \nnn octal quoting */
1246 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1248 isodigit(bp[1]) && (bp[1] <= '3') &&
1251 int byte = (*++bp -'0');
1253 byte = (byte << 3) | (*bp++ - '0');
1254 byte = (byte << 3) | (*bp++ - '0');
1264 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1266 while (*bp == ' ') bp++;
1271 EXPORT_SYMBOL_GPL(qword_get);
1275 * support /proc/sunrpc/cache/$CACHENAME/content
1277 * We call ->cache_show passing NULL for the item to
1278 * get a header, then pass each real item in the cache
1281 void *cache_seq_start(struct seq_file *m, loff_t *pos)
1282 __acquires(cd->hash_lock)
1285 unsigned int hash, entry;
1286 struct cache_head *ch;
1287 struct cache_detail *cd = m->private;
1289 read_lock(&cd->hash_lock);
1291 return SEQ_START_TOKEN;
1293 entry = n & ((1LL<<32) - 1);
1295 hlist_for_each_entry(ch, &cd->hash_table[hash], cache_list)
1298 n &= ~((1LL<<32) - 1);
1302 } while(hash < cd->hash_size &&
1303 hlist_empty(&cd->hash_table[hash]));
1304 if (hash >= cd->hash_size)
1307 return hlist_entry_safe(cd->hash_table[hash].first,
1308 struct cache_head, cache_list);
1310 EXPORT_SYMBOL_GPL(cache_seq_start);
1312 void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1314 struct cache_head *ch = p;
1315 int hash = (*pos >> 32);
1316 struct cache_detail *cd = m->private;
1318 if (p == SEQ_START_TOKEN)
1320 else if (ch->cache_list.next == NULL) {
1325 return hlist_entry_safe(ch->cache_list.next,
1326 struct cache_head, cache_list);
1328 *pos &= ~((1LL<<32) - 1);
1329 while (hash < cd->hash_size &&
1330 hlist_empty(&cd->hash_table[hash])) {
1334 if (hash >= cd->hash_size)
1337 return hlist_entry_safe(cd->hash_table[hash].first,
1338 struct cache_head, cache_list);
1340 EXPORT_SYMBOL_GPL(cache_seq_next);
1342 void cache_seq_stop(struct seq_file *m, void *p)
1343 __releases(cd->hash_lock)
1345 struct cache_detail *cd = m->private;
1346 read_unlock(&cd->hash_lock);
1348 EXPORT_SYMBOL_GPL(cache_seq_stop);
1350 static int c_show(struct seq_file *m, void *p)
1352 struct cache_head *cp = p;
1353 struct cache_detail *cd = m->private;
1355 if (p == SEQ_START_TOKEN)
1356 return cd->cache_show(m, cd, NULL);
1359 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1360 convert_to_wallclock(cp->expiry_time),
1361 kref_read(&cp->ref), cp->flags);
1363 if (cache_check(cd, cp, NULL))
1364 /* cache_check does a cache_put on failure */
1365 seq_printf(m, "# ");
1367 if (cache_is_expired(cd, cp))
1368 seq_printf(m, "# ");
1372 return cd->cache_show(m, cd, cp);
1375 static const struct seq_operations cache_content_op = {
1376 .start = cache_seq_start,
1377 .next = cache_seq_next,
1378 .stop = cache_seq_stop,
1382 static int content_open(struct inode *inode, struct file *file,
1383 struct cache_detail *cd)
1385 struct seq_file *seq;
1388 if (!cd || !try_module_get(cd->owner))
1391 err = seq_open(file, &cache_content_op);
1393 module_put(cd->owner);
1397 seq = file->private_data;
1402 static int content_release(struct inode *inode, struct file *file,
1403 struct cache_detail *cd)
1405 int ret = seq_release(inode, file);
1406 module_put(cd->owner);
1410 static int open_flush(struct inode *inode, struct file *file,
1411 struct cache_detail *cd)
1413 if (!cd || !try_module_get(cd->owner))
1415 return nonseekable_open(inode, file);
1418 static int release_flush(struct inode *inode, struct file *file,
1419 struct cache_detail *cd)
1421 module_put(cd->owner);
1425 static ssize_t read_flush(struct file *file, char __user *buf,
1426 size_t count, loff_t *ppos,
1427 struct cache_detail *cd)
1430 unsigned long p = *ppos;
1433 snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
1440 if (copy_to_user(buf, (void*)(tbuf+p), len))
1446 static ssize_t write_flush(struct file *file, const char __user *buf,
1447 size_t count, loff_t *ppos,
1448 struct cache_detail *cd)
1454 if (*ppos || count > sizeof(tbuf)-1)
1456 if (copy_from_user(tbuf, buf, count))
1459 simple_strtoul(tbuf, &ep, 0);
1460 if (*ep && *ep != '\n')
1464 then = get_expiry(&bp);
1465 now = seconds_since_boot();
1466 cd->nextcheck = now;
1467 /* Can only set flush_time to 1 second beyond "now", or
1468 * possibly 1 second beyond flushtime. This is because
1469 * flush_time never goes backwards so it mustn't get too far
1473 /* Want to flush everything, so behave like cache_purge() */
1474 if (cd->flush_time >= now)
1475 now = cd->flush_time + 1;
1479 cd->flush_time = then;
1486 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1487 size_t count, loff_t *ppos)
1489 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1491 return cache_read(filp, buf, count, ppos, cd);
1494 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1495 size_t count, loff_t *ppos)
1497 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1499 return cache_write(filp, buf, count, ppos, cd);
1502 static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1504 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1506 return cache_poll(filp, wait, cd);
1509 static long cache_ioctl_procfs(struct file *filp,
1510 unsigned int cmd, unsigned long arg)
1512 struct inode *inode = file_inode(filp);
1513 struct cache_detail *cd = PDE_DATA(inode);
1515 return cache_ioctl(inode, filp, cmd, arg, cd);
1518 static int cache_open_procfs(struct inode *inode, struct file *filp)
1520 struct cache_detail *cd = PDE_DATA(inode);
1522 return cache_open(inode, filp, cd);
1525 static int cache_release_procfs(struct inode *inode, struct file *filp)
1527 struct cache_detail *cd = PDE_DATA(inode);
1529 return cache_release(inode, filp, cd);
1532 static const struct file_operations cache_file_operations_procfs = {
1533 .owner = THIS_MODULE,
1534 .llseek = no_llseek,
1535 .read = cache_read_procfs,
1536 .write = cache_write_procfs,
1537 .poll = cache_poll_procfs,
1538 .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1539 .open = cache_open_procfs,
1540 .release = cache_release_procfs,
1543 static int content_open_procfs(struct inode *inode, struct file *filp)
1545 struct cache_detail *cd = PDE_DATA(inode);
1547 return content_open(inode, filp, cd);
1550 static int content_release_procfs(struct inode *inode, struct file *filp)
1552 struct cache_detail *cd = PDE_DATA(inode);
1554 return content_release(inode, filp, cd);
1557 static const struct file_operations content_file_operations_procfs = {
1558 .open = content_open_procfs,
1560 .llseek = seq_lseek,
1561 .release = content_release_procfs,
1564 static int open_flush_procfs(struct inode *inode, struct file *filp)
1566 struct cache_detail *cd = PDE_DATA(inode);
1568 return open_flush(inode, filp, cd);
1571 static int release_flush_procfs(struct inode *inode, struct file *filp)
1573 struct cache_detail *cd = PDE_DATA(inode);
1575 return release_flush(inode, filp, cd);
1578 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1579 size_t count, loff_t *ppos)
1581 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1583 return read_flush(filp, buf, count, ppos, cd);
1586 static ssize_t write_flush_procfs(struct file *filp,
1587 const char __user *buf,
1588 size_t count, loff_t *ppos)
1590 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1592 return write_flush(filp, buf, count, ppos, cd);
1595 static const struct file_operations cache_flush_operations_procfs = {
1596 .open = open_flush_procfs,
1597 .read = read_flush_procfs,
1598 .write = write_flush_procfs,
1599 .release = release_flush_procfs,
1600 .llseek = no_llseek,
1603 static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1605 struct sunrpc_net *sn;
1607 if (cd->u.procfs.proc_ent == NULL)
1609 if (cd->u.procfs.flush_ent)
1610 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1611 if (cd->u.procfs.channel_ent)
1612 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1613 if (cd->u.procfs.content_ent)
1614 remove_proc_entry("content", cd->u.procfs.proc_ent);
1615 cd->u.procfs.proc_ent = NULL;
1616 sn = net_generic(net, sunrpc_net_id);
1617 remove_proc_entry(cd->name, sn->proc_net_rpc);
1620 #ifdef CONFIG_PROC_FS
1621 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1623 struct proc_dir_entry *p;
1624 struct sunrpc_net *sn;
1626 sn = net_generic(net, sunrpc_net_id);
1627 cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1628 if (cd->u.procfs.proc_ent == NULL)
1630 cd->u.procfs.channel_ent = NULL;
1631 cd->u.procfs.content_ent = NULL;
1633 p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1634 cd->u.procfs.proc_ent,
1635 &cache_flush_operations_procfs, cd);
1636 cd->u.procfs.flush_ent = p;
1640 if (cd->cache_request || cd->cache_parse) {
1641 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1642 cd->u.procfs.proc_ent,
1643 &cache_file_operations_procfs, cd);
1644 cd->u.procfs.channel_ent = p;
1648 if (cd->cache_show) {
1649 p = proc_create_data("content", S_IFREG|S_IRUSR,
1650 cd->u.procfs.proc_ent,
1651 &content_file_operations_procfs, cd);
1652 cd->u.procfs.content_ent = p;
1658 remove_cache_proc_entries(cd, net);
1661 #else /* CONFIG_PROC_FS */
1662 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1668 void __init cache_initialize(void)
1670 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1673 int cache_register_net(struct cache_detail *cd, struct net *net)
1677 sunrpc_init_cache_detail(cd);
1678 ret = create_cache_proc_entries(cd, net);
1680 sunrpc_destroy_cache_detail(cd);
1683 EXPORT_SYMBOL_GPL(cache_register_net);
1685 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1687 remove_cache_proc_entries(cd, net);
1688 sunrpc_destroy_cache_detail(cd);
1690 EXPORT_SYMBOL_GPL(cache_unregister_net);
1692 struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
1694 struct cache_detail *cd;
1697 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1699 return ERR_PTR(-ENOMEM);
1701 cd->hash_table = kzalloc(cd->hash_size * sizeof(struct hlist_head),
1703 if (cd->hash_table == NULL) {
1705 return ERR_PTR(-ENOMEM);
1708 for (i = 0; i < cd->hash_size; i++)
1709 INIT_HLIST_HEAD(&cd->hash_table[i]);
1713 EXPORT_SYMBOL_GPL(cache_create_net);
1715 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1717 kfree(cd->hash_table);
1720 EXPORT_SYMBOL_GPL(cache_destroy_net);
1722 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1723 size_t count, loff_t *ppos)
1725 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1727 return cache_read(filp, buf, count, ppos, cd);
1730 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1731 size_t count, loff_t *ppos)
1733 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1735 return cache_write(filp, buf, count, ppos, cd);
1738 static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1740 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1742 return cache_poll(filp, wait, cd);
1745 static long cache_ioctl_pipefs(struct file *filp,
1746 unsigned int cmd, unsigned long arg)
1748 struct inode *inode = file_inode(filp);
1749 struct cache_detail *cd = RPC_I(inode)->private;
1751 return cache_ioctl(inode, filp, cmd, arg, cd);
1754 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1756 struct cache_detail *cd = RPC_I(inode)->private;
1758 return cache_open(inode, filp, cd);
1761 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1763 struct cache_detail *cd = RPC_I(inode)->private;
1765 return cache_release(inode, filp, cd);
1768 const struct file_operations cache_file_operations_pipefs = {
1769 .owner = THIS_MODULE,
1770 .llseek = no_llseek,
1771 .read = cache_read_pipefs,
1772 .write = cache_write_pipefs,
1773 .poll = cache_poll_pipefs,
1774 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1775 .open = cache_open_pipefs,
1776 .release = cache_release_pipefs,
1779 static int content_open_pipefs(struct inode *inode, struct file *filp)
1781 struct cache_detail *cd = RPC_I(inode)->private;
1783 return content_open(inode, filp, cd);
1786 static int content_release_pipefs(struct inode *inode, struct file *filp)
1788 struct cache_detail *cd = RPC_I(inode)->private;
1790 return content_release(inode, filp, cd);
1793 const struct file_operations content_file_operations_pipefs = {
1794 .open = content_open_pipefs,
1796 .llseek = seq_lseek,
1797 .release = content_release_pipefs,
1800 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1802 struct cache_detail *cd = RPC_I(inode)->private;
1804 return open_flush(inode, filp, cd);
1807 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1809 struct cache_detail *cd = RPC_I(inode)->private;
1811 return release_flush(inode, filp, cd);
1814 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1815 size_t count, loff_t *ppos)
1817 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1819 return read_flush(filp, buf, count, ppos, cd);
1822 static ssize_t write_flush_pipefs(struct file *filp,
1823 const char __user *buf,
1824 size_t count, loff_t *ppos)
1826 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1828 return write_flush(filp, buf, count, ppos, cd);
1831 const struct file_operations cache_flush_operations_pipefs = {
1832 .open = open_flush_pipefs,
1833 .read = read_flush_pipefs,
1834 .write = write_flush_pipefs,
1835 .release = release_flush_pipefs,
1836 .llseek = no_llseek,
1839 int sunrpc_cache_register_pipefs(struct dentry *parent,
1840 const char *name, umode_t umode,
1841 struct cache_detail *cd)
1843 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1845 return PTR_ERR(dir);
1846 cd->u.pipefs.dir = dir;
1849 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1851 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1853 rpc_remove_cache_dir(cd->u.pipefs.dir);
1854 cd->u.pipefs.dir = NULL;
1856 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);