1 /* 2 * net/sunrpc/cache.c 3 * 4 * Generic code for various authentication-related caches 5 * used by sunrpc clients and servers. 6 * 7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> 8 * 9 * Released under terms in GPL version 2. See COPYING. 10 * 11 */ 12 13 #include <linux/types.h> 14 #include <linux/fs.h> 15 #include <linux/file.h> 16 #include <linux/slab.h> 17 #include <linux/signal.h> 18 #include <linux/sched.h> 19 #include <linux/kmod.h> 20 #include <linux/list.h> 21 #include <linux/module.h> 22 #include <linux/ctype.h> 23 #include <asm/uaccess.h> 24 #include <linux/poll.h> 25 #include <linux/seq_file.h> 26 #include <linux/proc_fs.h> 27 #include <linux/net.h> 28 #include <linux/workqueue.h> 29 #include <linux/mutex.h> 30 #include <asm/ioctls.h> 31 #include <linux/sunrpc/types.h> 32 #include <linux/sunrpc/cache.h> 33 #include <linux/sunrpc/stats.h> 34 35 #define RPCDBG_FACILITY RPCDBG_CACHE 36 37 static int cache_defer_req(struct cache_req *req, struct cache_head *item); 38 static void cache_revisit_request(struct cache_head *item); 39 40 static void cache_init(struct cache_head *h) 41 { 42 time_t now = get_seconds(); 43 h->next = NULL; 44 h->flags = 0; 45 kref_init(&h->ref); 46 h->expiry_time = now + CACHE_NEW_EXPIRY; 47 h->last_refresh = now; 48 } 49 50 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, 51 struct cache_head *key, int hash) 52 { 53 struct cache_head **head, **hp; 54 struct cache_head *new = NULL; 55 56 head = &detail->hash_table[hash]; 57 58 read_lock(&detail->hash_lock); 59 60 for (hp=head; *hp != NULL ; hp = &(*hp)->next) { 61 struct cache_head *tmp = *hp; 62 if (detail->match(tmp, key)) { 63 cache_get(tmp); 64 read_unlock(&detail->hash_lock); 65 return tmp; 66 } 67 } 68 read_unlock(&detail->hash_lock); 69 /* Didn't find anything, insert an empty entry */ 70 71 new = detail->alloc(); 72 if (!new) 73 return NULL; 74 /* must fully initialise 'new', else 75 * we might get lose if we need to 76 * cache_put it soon. 77 */ 78 cache_init(new); 79 detail->init(new, key); 80 81 write_lock(&detail->hash_lock); 82 83 /* check if entry appeared while we slept */ 84 for (hp=head; *hp != NULL ; hp = &(*hp)->next) { 85 struct cache_head *tmp = *hp; 86 if (detail->match(tmp, key)) { 87 cache_get(tmp); 88 write_unlock(&detail->hash_lock); 89 cache_put(new, detail); 90 return tmp; 91 } 92 } 93 new->next = *head; 94 *head = new; 95 detail->entries++; 96 cache_get(new); 97 write_unlock(&detail->hash_lock); 98 99 return new; 100 } 101 EXPORT_SYMBOL(sunrpc_cache_lookup); 102 103 104 static void queue_loose(struct cache_detail *detail, struct cache_head *ch); 105 106 static int cache_fresh_locked(struct cache_head *head, time_t expiry) 107 { 108 head->expiry_time = expiry; 109 head->last_refresh = get_seconds(); 110 return !test_and_set_bit(CACHE_VALID, &head->flags); 111 } 112 113 static void cache_fresh_unlocked(struct cache_head *head, 114 struct cache_detail *detail, int new) 115 { 116 if (new) 117 cache_revisit_request(head); 118 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { 119 cache_revisit_request(head); 120 queue_loose(detail, head); 121 } 122 } 123 124 struct cache_head *sunrpc_cache_update(struct cache_detail *detail, 125 struct cache_head *new, struct cache_head *old, int hash) 126 { 127 /* The 'old' entry is to be replaced by 'new'. 128 * If 'old' is not VALID, we update it directly, 129 * otherwise we need to replace it 130 */ 131 struct cache_head **head; 132 struct cache_head *tmp; 133 int is_new; 134 135 if (!test_bit(CACHE_VALID, &old->flags)) { 136 write_lock(&detail->hash_lock); 137 if (!test_bit(CACHE_VALID, &old->flags)) { 138 if (test_bit(CACHE_NEGATIVE, &new->flags)) 139 set_bit(CACHE_NEGATIVE, &old->flags); 140 else 141 detail->update(old, new); 142 is_new = cache_fresh_locked(old, new->expiry_time); 143 write_unlock(&detail->hash_lock); 144 cache_fresh_unlocked(old, detail, is_new); 145 return old; 146 } 147 write_unlock(&detail->hash_lock); 148 } 149 /* We need to insert a new entry */ 150 tmp = detail->alloc(); 151 if (!tmp) { 152 cache_put(old, detail); 153 return NULL; 154 } 155 cache_init(tmp); 156 detail->init(tmp, old); 157 head = &detail->hash_table[hash]; 158 159 write_lock(&detail->hash_lock); 160 if (test_bit(CACHE_NEGATIVE, &new->flags)) 161 set_bit(CACHE_NEGATIVE, &tmp->flags); 162 else 163 detail->update(tmp, new); 164 tmp->next = *head; 165 *head = tmp; 166 detail->entries++; 167 cache_get(tmp); 168 is_new = cache_fresh_locked(tmp, new->expiry_time); 169 cache_fresh_locked(old, 0); 170 write_unlock(&detail->hash_lock); 171 cache_fresh_unlocked(tmp, detail, is_new); 172 cache_fresh_unlocked(old, detail, 0); 173 cache_put(old, detail); 174 return tmp; 175 } 176 EXPORT_SYMBOL(sunrpc_cache_update); 177 178 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h); 179 /* 180 * This is the generic cache management routine for all 181 * the authentication caches. 182 * It checks the currency of a cache item and will (later) 183 * initiate an upcall to fill it if needed. 184 * 185 * 186 * Returns 0 if the cache_head can be used, or cache_puts it and returns 187 * -EAGAIN if upcall is pending, 188 * -ETIMEDOUT if upcall failed and should be retried, 189 * -ENOENT if cache entry was negative 190 */ 191 int cache_check(struct cache_detail *detail, 192 struct cache_head *h, struct cache_req *rqstp) 193 { 194 int rv; 195 long refresh_age, age; 196 197 /* First decide return status as best we can */ 198 if (!test_bit(CACHE_VALID, &h->flags) || 199 h->expiry_time < get_seconds()) 200 rv = -EAGAIN; 201 else if (detail->flush_time > h->last_refresh) 202 rv = -EAGAIN; 203 else { 204 /* entry is valid */ 205 if (test_bit(CACHE_NEGATIVE, &h->flags)) 206 rv = -ENOENT; 207 else rv = 0; 208 } 209 210 /* now see if we want to start an upcall */ 211 refresh_age = (h->expiry_time - h->last_refresh); 212 age = get_seconds() - h->last_refresh; 213 214 if (rqstp == NULL) { 215 if (rv == -EAGAIN) 216 rv = -ENOENT; 217 } else if (rv == -EAGAIN || age > refresh_age/2) { 218 dprintk("RPC: Want update, refage=%ld, age=%ld\n", 219 refresh_age, age); 220 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { 221 switch (cache_make_upcall(detail, h)) { 222 case -EINVAL: 223 clear_bit(CACHE_PENDING, &h->flags); 224 if (rv == -EAGAIN) { 225 set_bit(CACHE_NEGATIVE, &h->flags); 226 cache_fresh_unlocked(h, detail, 227 cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY)); 228 rv = -ENOENT; 229 } 230 break; 231 232 case -EAGAIN: 233 clear_bit(CACHE_PENDING, &h->flags); 234 cache_revisit_request(h); 235 break; 236 } 237 } 238 } 239 240 if (rv == -EAGAIN) 241 if (cache_defer_req(rqstp, h) != 0) 242 rv = -ETIMEDOUT; 243 244 if (rv) 245 cache_put(h, detail); 246 return rv; 247 } 248 EXPORT_SYMBOL(cache_check); 249 250 /* 251 * caches need to be periodically cleaned. 252 * For this we maintain a list of cache_detail and 253 * a current pointer into that list and into the table 254 * for that entry. 255 * 256 * Each time clean_cache is called it finds the next non-empty entry 257 * in the current table and walks the list in that entry 258 * looking for entries that can be removed. 259 * 260 * An entry gets removed if: 261 * - The expiry is before current time 262 * - The last_refresh time is before the flush_time for that cache 263 * 264 * later we might drop old entries with non-NEVER expiry if that table 265 * is getting 'full' for some definition of 'full' 266 * 267 * The question of "how often to scan a table" is an interesting one 268 * and is answered in part by the use of the "nextcheck" field in the 269 * cache_detail. 270 * When a scan of a table begins, the nextcheck field is set to a time 271 * that is well into the future. 272 * While scanning, if an expiry time is found that is earlier than the 273 * current nextcheck time, nextcheck is set to that expiry time. 274 * If the flush_time is ever set to a time earlier than the nextcheck 275 * time, the nextcheck time is then set to that flush_time. 276 * 277 * A table is then only scanned if the current time is at least 278 * the nextcheck time. 279 * 280 */ 281 282 static LIST_HEAD(cache_list); 283 static DEFINE_SPINLOCK(cache_list_lock); 284 static struct cache_detail *current_detail; 285 static int current_index; 286 287 static const struct file_operations cache_file_operations; 288 static const struct file_operations content_file_operations; 289 static const struct file_operations cache_flush_operations; 290 291 static void do_cache_clean(struct work_struct *work); 292 static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean); 293 294 static void remove_cache_proc_entries(struct cache_detail *cd) 295 { 296 if (cd->proc_ent == NULL) 297 return; 298 if (cd->flush_ent) 299 remove_proc_entry("flush", cd->proc_ent); 300 if (cd->channel_ent) 301 remove_proc_entry("channel", cd->proc_ent); 302 if (cd->content_ent) 303 remove_proc_entry("content", cd->proc_ent); 304 cd->proc_ent = NULL; 305 remove_proc_entry(cd->name, proc_net_rpc); 306 } 307 308 #ifdef CONFIG_PROC_FS 309 static int create_cache_proc_entries(struct cache_detail *cd) 310 { 311 struct proc_dir_entry *p; 312 313 cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc); 314 if (cd->proc_ent == NULL) 315 goto out_nomem; 316 cd->proc_ent->owner = cd->owner; 317 cd->channel_ent = cd->content_ent = NULL; 318 319 p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR, cd->proc_ent); 320 cd->flush_ent = p; 321 if (p == NULL) 322 goto out_nomem; 323 p->proc_fops = &cache_flush_operations; 324 p->owner = cd->owner; 325 p->data = cd; 326 327 if (cd->cache_request || cd->cache_parse) { 328 p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR, 329 cd->proc_ent); 330 cd->channel_ent = p; 331 if (p == NULL) 332 goto out_nomem; 333 p->proc_fops = &cache_file_operations; 334 p->owner = cd->owner; 335 p->data = cd; 336 } 337 if (cd->cache_show) { 338 p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR, 339 cd->proc_ent); 340 cd->content_ent = p; 341 if (p == NULL) 342 goto out_nomem; 343 p->proc_fops = &content_file_operations; 344 p->owner = cd->owner; 345 p->data = cd; 346 } 347 return 0; 348 out_nomem: 349 remove_cache_proc_entries(cd); 350 return -ENOMEM; 351 } 352 #else /* CONFIG_PROC_FS */ 353 static int create_cache_proc_entries(struct cache_detail *cd) 354 { 355 return 0; 356 } 357 #endif 358 359 int cache_register(struct cache_detail *cd) 360 { 361 int ret; 362 363 ret = create_cache_proc_entries(cd); 364 if (ret) 365 return ret; 366 rwlock_init(&cd->hash_lock); 367 INIT_LIST_HEAD(&cd->queue); 368 spin_lock(&cache_list_lock); 369 cd->nextcheck = 0; 370 cd->entries = 0; 371 atomic_set(&cd->readers, 0); 372 cd->last_close = 0; 373 cd->last_warn = -1; 374 list_add(&cd->others, &cache_list); 375 spin_unlock(&cache_list_lock); 376 377 /* start the cleaning process */ 378 schedule_delayed_work(&cache_cleaner, 0); 379 return 0; 380 } 381 EXPORT_SYMBOL(cache_register); 382 383 void cache_unregister(struct cache_detail *cd) 384 { 385 cache_purge(cd); 386 spin_lock(&cache_list_lock); 387 write_lock(&cd->hash_lock); 388 if (cd->entries || atomic_read(&cd->inuse)) { 389 write_unlock(&cd->hash_lock); 390 spin_unlock(&cache_list_lock); 391 goto out; 392 } 393 if (current_detail == cd) 394 current_detail = NULL; 395 list_del_init(&cd->others); 396 write_unlock(&cd->hash_lock); 397 spin_unlock(&cache_list_lock); 398 remove_cache_proc_entries(cd); 399 if (list_empty(&cache_list)) { 400 /* module must be being unloaded so its safe to kill the worker */ 401 cancel_delayed_work_sync(&cache_cleaner); 402 } 403 return; 404 out: 405 printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name); 406 } 407 EXPORT_SYMBOL(cache_unregister); 408 409 /* clean cache tries to find something to clean 410 * and cleans it. 411 * It returns 1 if it cleaned something, 412 * 0 if it didn't find anything this time 413 * -1 if it fell off the end of the list. 414 */ 415 static int cache_clean(void) 416 { 417 int rv = 0; 418 struct list_head *next; 419 420 spin_lock(&cache_list_lock); 421 422 /* find a suitable table if we don't already have one */ 423 while (current_detail == NULL || 424 current_index >= current_detail->hash_size) { 425 if (current_detail) 426 next = current_detail->others.next; 427 else 428 next = cache_list.next; 429 if (next == &cache_list) { 430 current_detail = NULL; 431 spin_unlock(&cache_list_lock); 432 return -1; 433 } 434 current_detail = list_entry(next, struct cache_detail, others); 435 if (current_detail->nextcheck > get_seconds()) 436 current_index = current_detail->hash_size; 437 else { 438 current_index = 0; 439 current_detail->nextcheck = get_seconds()+30*60; 440 } 441 } 442 443 /* find a non-empty bucket in the table */ 444 while (current_detail && 445 current_index < current_detail->hash_size && 446 current_detail->hash_table[current_index] == NULL) 447 current_index++; 448 449 /* find a cleanable entry in the bucket and clean it, or set to next bucket */ 450 451 if (current_detail && current_index < current_detail->hash_size) { 452 struct cache_head *ch, **cp; 453 struct cache_detail *d; 454 455 write_lock(¤t_detail->hash_lock); 456 457 /* Ok, now to clean this strand */ 458 459 cp = & current_detail->hash_table[current_index]; 460 ch = *cp; 461 for (; ch; cp= & ch->next, ch= *cp) { 462 if (current_detail->nextcheck > ch->expiry_time) 463 current_detail->nextcheck = ch->expiry_time+1; 464 if (ch->expiry_time >= get_seconds() 465 && ch->last_refresh >= current_detail->flush_time 466 ) 467 continue; 468 if (test_and_clear_bit(CACHE_PENDING, &ch->flags)) 469 queue_loose(current_detail, ch); 470 471 if (atomic_read(&ch->ref.refcount) == 1) 472 break; 473 } 474 if (ch) { 475 *cp = ch->next; 476 ch->next = NULL; 477 current_detail->entries--; 478 rv = 1; 479 } 480 write_unlock(¤t_detail->hash_lock); 481 d = current_detail; 482 if (!ch) 483 current_index ++; 484 spin_unlock(&cache_list_lock); 485 if (ch) 486 cache_put(ch, d); 487 } else 488 spin_unlock(&cache_list_lock); 489 490 return rv; 491 } 492 493 /* 494 * We want to regularly clean the cache, so we need to schedule some work ... 495 */ 496 static void do_cache_clean(struct work_struct *work) 497 { 498 int delay = 5; 499 if (cache_clean() == -1) 500 delay = 30*HZ; 501 502 if (list_empty(&cache_list)) 503 delay = 0; 504 505 if (delay) 506 schedule_delayed_work(&cache_cleaner, delay); 507 } 508 509 510 /* 511 * Clean all caches promptly. This just calls cache_clean 512 * repeatedly until we are sure that every cache has had a chance to 513 * be fully cleaned 514 */ 515 void cache_flush(void) 516 { 517 while (cache_clean() != -1) 518 cond_resched(); 519 while (cache_clean() != -1) 520 cond_resched(); 521 } 522 EXPORT_SYMBOL(cache_flush); 523 524 void cache_purge(struct cache_detail *detail) 525 { 526 detail->flush_time = LONG_MAX; 527 detail->nextcheck = get_seconds(); 528 cache_flush(); 529 detail->flush_time = 1; 530 } 531 EXPORT_SYMBOL(cache_purge); 532 533 534 /* 535 * Deferral and Revisiting of Requests. 536 * 537 * If a cache lookup finds a pending entry, we 538 * need to defer the request and revisit it later. 539 * All deferred requests are stored in a hash table, 540 * indexed by "struct cache_head *". 541 * As it may be wasteful to store a whole request 542 * structure, we allow the request to provide a 543 * deferred form, which must contain a 544 * 'struct cache_deferred_req' 545 * This cache_deferred_req contains a method to allow 546 * it to be revisited when cache info is available 547 */ 548 549 #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head)) 550 #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE) 551 552 #define DFR_MAX 300 /* ??? */ 553 554 static DEFINE_SPINLOCK(cache_defer_lock); 555 static LIST_HEAD(cache_defer_list); 556 static struct list_head cache_defer_hash[DFR_HASHSIZE]; 557 static int cache_defer_cnt; 558 559 static int cache_defer_req(struct cache_req *req, struct cache_head *item) 560 { 561 struct cache_deferred_req *dreq; 562 int hash = DFR_HASH(item); 563 564 if (cache_defer_cnt >= DFR_MAX) { 565 /* too much in the cache, randomly drop this one, 566 * or continue and drop the oldest below 567 */ 568 if (net_random()&1) 569 return -ETIMEDOUT; 570 } 571 dreq = req->defer(req); 572 if (dreq == NULL) 573 return -ETIMEDOUT; 574 575 dreq->item = item; 576 dreq->recv_time = get_seconds(); 577 578 spin_lock(&cache_defer_lock); 579 580 list_add(&dreq->recent, &cache_defer_list); 581 582 if (cache_defer_hash[hash].next == NULL) 583 INIT_LIST_HEAD(&cache_defer_hash[hash]); 584 list_add(&dreq->hash, &cache_defer_hash[hash]); 585 586 /* it is in, now maybe clean up */ 587 dreq = NULL; 588 if (++cache_defer_cnt > DFR_MAX) { 589 dreq = list_entry(cache_defer_list.prev, 590 struct cache_deferred_req, recent); 591 list_del(&dreq->recent); 592 list_del(&dreq->hash); 593 cache_defer_cnt--; 594 } 595 spin_unlock(&cache_defer_lock); 596 597 if (dreq) { 598 /* there was one too many */ 599 dreq->revisit(dreq, 1); 600 } 601 if (!test_bit(CACHE_PENDING, &item->flags)) { 602 /* must have just been validated... */ 603 cache_revisit_request(item); 604 } 605 return 0; 606 } 607 608 static void cache_revisit_request(struct cache_head *item) 609 { 610 struct cache_deferred_req *dreq; 611 struct list_head pending; 612 613 struct list_head *lp; 614 int hash = DFR_HASH(item); 615 616 INIT_LIST_HEAD(&pending); 617 spin_lock(&cache_defer_lock); 618 619 lp = cache_defer_hash[hash].next; 620 if (lp) { 621 while (lp != &cache_defer_hash[hash]) { 622 dreq = list_entry(lp, struct cache_deferred_req, hash); 623 lp = lp->next; 624 if (dreq->item == item) { 625 list_del(&dreq->hash); 626 list_move(&dreq->recent, &pending); 627 cache_defer_cnt--; 628 } 629 } 630 } 631 spin_unlock(&cache_defer_lock); 632 633 while (!list_empty(&pending)) { 634 dreq = list_entry(pending.next, struct cache_deferred_req, recent); 635 list_del_init(&dreq->recent); 636 dreq->revisit(dreq, 0); 637 } 638 } 639 640 void cache_clean_deferred(void *owner) 641 { 642 struct cache_deferred_req *dreq, *tmp; 643 struct list_head pending; 644 645 646 INIT_LIST_HEAD(&pending); 647 spin_lock(&cache_defer_lock); 648 649 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) { 650 if (dreq->owner == owner) { 651 list_del(&dreq->hash); 652 list_move(&dreq->recent, &pending); 653 cache_defer_cnt--; 654 } 655 } 656 spin_unlock(&cache_defer_lock); 657 658 while (!list_empty(&pending)) { 659 dreq = list_entry(pending.next, struct cache_deferred_req, recent); 660 list_del_init(&dreq->recent); 661 dreq->revisit(dreq, 1); 662 } 663 } 664 665 /* 666 * communicate with user-space 667 * 668 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel. 669 * On read, you get a full request, or block. 670 * On write, an update request is processed. 671 * Poll works if anything to read, and always allows write. 672 * 673 * Implemented by linked list of requests. Each open file has 674 * a ->private that also exists in this list. New requests are added 675 * to the end and may wakeup and preceding readers. 676 * New readers are added to the head. If, on read, an item is found with 677 * CACHE_UPCALLING clear, we free it from the list. 678 * 679 */ 680 681 static DEFINE_SPINLOCK(queue_lock); 682 static DEFINE_MUTEX(queue_io_mutex); 683 684 struct cache_queue { 685 struct list_head list; 686 int reader; /* if 0, then request */ 687 }; 688 struct cache_request { 689 struct cache_queue q; 690 struct cache_head *item; 691 char * buf; 692 int len; 693 int readers; 694 }; 695 struct cache_reader { 696 struct cache_queue q; 697 int offset; /* if non-0, we have a refcnt on next request */ 698 }; 699 700 static ssize_t 701 cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) 702 { 703 struct cache_reader *rp = filp->private_data; 704 struct cache_request *rq; 705 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; 706 int err; 707 708 if (count == 0) 709 return 0; 710 711 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent 712 * readers on this file */ 713 again: 714 spin_lock(&queue_lock); 715 /* need to find next request */ 716 while (rp->q.list.next != &cd->queue && 717 list_entry(rp->q.list.next, struct cache_queue, list) 718 ->reader) { 719 struct list_head *next = rp->q.list.next; 720 list_move(&rp->q.list, next); 721 } 722 if (rp->q.list.next == &cd->queue) { 723 spin_unlock(&queue_lock); 724 mutex_unlock(&queue_io_mutex); 725 BUG_ON(rp->offset); 726 return 0; 727 } 728 rq = container_of(rp->q.list.next, struct cache_request, q.list); 729 BUG_ON(rq->q.reader); 730 if (rp->offset == 0) 731 rq->readers++; 732 spin_unlock(&queue_lock); 733 734 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { 735 err = -EAGAIN; 736 spin_lock(&queue_lock); 737 list_move(&rp->q.list, &rq->q.list); 738 spin_unlock(&queue_lock); 739 } else { 740 if (rp->offset + count > rq->len) 741 count = rq->len - rp->offset; 742 err = -EFAULT; 743 if (copy_to_user(buf, rq->buf + rp->offset, count)) 744 goto out; 745 rp->offset += count; 746 if (rp->offset >= rq->len) { 747 rp->offset = 0; 748 spin_lock(&queue_lock); 749 list_move(&rp->q.list, &rq->q.list); 750 spin_unlock(&queue_lock); 751 } 752 err = 0; 753 } 754 out: 755 if (rp->offset == 0) { 756 /* need to release rq */ 757 spin_lock(&queue_lock); 758 rq->readers--; 759 if (rq->readers == 0 && 760 !test_bit(CACHE_PENDING, &rq->item->flags)) { 761 list_del(&rq->q.list); 762 spin_unlock(&queue_lock); 763 cache_put(rq->item, cd); 764 kfree(rq->buf); 765 kfree(rq); 766 } else 767 spin_unlock(&queue_lock); 768 } 769 if (err == -EAGAIN) 770 goto again; 771 mutex_unlock(&queue_io_mutex); 772 return err ? err : count; 773 } 774 775 static char write_buf[8192]; /* protected by queue_io_mutex */ 776 777 static ssize_t 778 cache_write(struct file *filp, const char __user *buf, size_t count, 779 loff_t *ppos) 780 { 781 int err; 782 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; 783 784 if (count == 0) 785 return 0; 786 if (count >= sizeof(write_buf)) 787 return -EINVAL; 788 789 mutex_lock(&queue_io_mutex); 790 791 if (copy_from_user(write_buf, buf, count)) { 792 mutex_unlock(&queue_io_mutex); 793 return -EFAULT; 794 } 795 write_buf[count] = '\0'; 796 if (cd->cache_parse) 797 err = cd->cache_parse(cd, write_buf, count); 798 else 799 err = -EINVAL; 800 801 mutex_unlock(&queue_io_mutex); 802 return err ? err : count; 803 } 804 805 static DECLARE_WAIT_QUEUE_HEAD(queue_wait); 806 807 static unsigned int 808 cache_poll(struct file *filp, poll_table *wait) 809 { 810 unsigned int mask; 811 struct cache_reader *rp = filp->private_data; 812 struct cache_queue *cq; 813 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; 814 815 poll_wait(filp, &queue_wait, wait); 816 817 /* alway allow write */ 818 mask = POLL_OUT | POLLWRNORM; 819 820 if (!rp) 821 return mask; 822 823 spin_lock(&queue_lock); 824 825 for (cq= &rp->q; &cq->list != &cd->queue; 826 cq = list_entry(cq->list.next, struct cache_queue, list)) 827 if (!cq->reader) { 828 mask |= POLLIN | POLLRDNORM; 829 break; 830 } 831 spin_unlock(&queue_lock); 832 return mask; 833 } 834 835 static int 836 cache_ioctl(struct inode *ino, struct file *filp, 837 unsigned int cmd, unsigned long arg) 838 { 839 int len = 0; 840 struct cache_reader *rp = filp->private_data; 841 struct cache_queue *cq; 842 struct cache_detail *cd = PDE(ino)->data; 843 844 if (cmd != FIONREAD || !rp) 845 return -EINVAL; 846 847 spin_lock(&queue_lock); 848 849 /* only find the length remaining in current request, 850 * or the length of the next request 851 */ 852 for (cq= &rp->q; &cq->list != &cd->queue; 853 cq = list_entry(cq->list.next, struct cache_queue, list)) 854 if (!cq->reader) { 855 struct cache_request *cr = 856 container_of(cq, struct cache_request, q); 857 len = cr->len - rp->offset; 858 break; 859 } 860 spin_unlock(&queue_lock); 861 862 return put_user(len, (int __user *)arg); 863 } 864 865 static int 866 cache_open(struct inode *inode, struct file *filp) 867 { 868 struct cache_reader *rp = NULL; 869 870 nonseekable_open(inode, filp); 871 if (filp->f_mode & FMODE_READ) { 872 struct cache_detail *cd = PDE(inode)->data; 873 874 rp = kmalloc(sizeof(*rp), GFP_KERNEL); 875 if (!rp) 876 return -ENOMEM; 877 rp->offset = 0; 878 rp->q.reader = 1; 879 atomic_inc(&cd->readers); 880 spin_lock(&queue_lock); 881 list_add(&rp->q.list, &cd->queue); 882 spin_unlock(&queue_lock); 883 } 884 filp->private_data = rp; 885 return 0; 886 } 887 888 static int 889 cache_release(struct inode *inode, struct file *filp) 890 { 891 struct cache_reader *rp = filp->private_data; 892 struct cache_detail *cd = PDE(inode)->data; 893 894 if (rp) { 895 spin_lock(&queue_lock); 896 if (rp->offset) { 897 struct cache_queue *cq; 898 for (cq= &rp->q; &cq->list != &cd->queue; 899 cq = list_entry(cq->list.next, struct cache_queue, list)) 900 if (!cq->reader) { 901 container_of(cq, struct cache_request, q) 902 ->readers--; 903 break; 904 } 905 rp->offset = 0; 906 } 907 list_del(&rp->q.list); 908 spin_unlock(&queue_lock); 909 910 filp->private_data = NULL; 911 kfree(rp); 912 913 cd->last_close = get_seconds(); 914 atomic_dec(&cd->readers); 915 } 916 return 0; 917 } 918 919 920 921 static const struct file_operations cache_file_operations = { 922 .owner = THIS_MODULE, 923 .llseek = no_llseek, 924 .read = cache_read, 925 .write = cache_write, 926 .poll = cache_poll, 927 .ioctl = cache_ioctl, /* for FIONREAD */ 928 .open = cache_open, 929 .release = cache_release, 930 }; 931 932 933 static void queue_loose(struct cache_detail *detail, struct cache_head *ch) 934 { 935 struct cache_queue *cq; 936 spin_lock(&queue_lock); 937 list_for_each_entry(cq, &detail->queue, list) 938 if (!cq->reader) { 939 struct cache_request *cr = container_of(cq, struct cache_request, q); 940 if (cr->item != ch) 941 continue; 942 if (cr->readers != 0) 943 continue; 944 list_del(&cr->q.list); 945 spin_unlock(&queue_lock); 946 cache_put(cr->item, detail); 947 kfree(cr->buf); 948 kfree(cr); 949 return; 950 } 951 spin_unlock(&queue_lock); 952 } 953 954 /* 955 * Support routines for text-based upcalls. 956 * Fields are separated by spaces. 957 * Fields are either mangled to quote space tab newline slosh with slosh 958 * or a hexified with a leading \x 959 * Record is terminated with newline. 960 * 961 */ 962 963 void qword_add(char **bpp, int *lp, char *str) 964 { 965 char *bp = *bpp; 966 int len = *lp; 967 char c; 968 969 if (len < 0) return; 970 971 while ((c=*str++) && len) 972 switch(c) { 973 case ' ': 974 case '\t': 975 case '\n': 976 case '\\': 977 if (len >= 4) { 978 *bp++ = '\\'; 979 *bp++ = '0' + ((c & 0300)>>6); 980 *bp++ = '0' + ((c & 0070)>>3); 981 *bp++ = '0' + ((c & 0007)>>0); 982 } 983 len -= 4; 984 break; 985 default: 986 *bp++ = c; 987 len--; 988 } 989 if (c || len <1) len = -1; 990 else { 991 *bp++ = ' '; 992 len--; 993 } 994 *bpp = bp; 995 *lp = len; 996 } 997 EXPORT_SYMBOL(qword_add); 998 999 void qword_addhex(char **bpp, int *lp, char *buf, int blen) 1000 { 1001 char *bp = *bpp; 1002 int len = *lp; 1003 1004 if (len < 0) return; 1005 1006 if (len > 2) { 1007 *bp++ = '\\'; 1008 *bp++ = 'x'; 1009 len -= 2; 1010 while (blen && len >= 2) { 1011 unsigned char c = *buf++; 1012 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); 1013 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); 1014 len -= 2; 1015 blen--; 1016 } 1017 } 1018 if (blen || len<1) len = -1; 1019 else { 1020 *bp++ = ' '; 1021 len--; 1022 } 1023 *bpp = bp; 1024 *lp = len; 1025 } 1026 EXPORT_SYMBOL(qword_addhex); 1027 1028 static void warn_no_listener(struct cache_detail *detail) 1029 { 1030 if (detail->last_warn != detail->last_close) { 1031 detail->last_warn = detail->last_close; 1032 if (detail->warn_no_listener) 1033 detail->warn_no_listener(detail); 1034 } 1035 } 1036 1037 /* 1038 * register an upcall request to user-space. 1039 * Each request is at most one page long. 1040 */ 1041 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h) 1042 { 1043 1044 char *buf; 1045 struct cache_request *crq; 1046 char *bp; 1047 int len; 1048 1049 if (detail->cache_request == NULL) 1050 return -EINVAL; 1051 1052 if (atomic_read(&detail->readers) == 0 && 1053 detail->last_close < get_seconds() - 30) { 1054 warn_no_listener(detail); 1055 return -EINVAL; 1056 } 1057 1058 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 1059 if (!buf) 1060 return -EAGAIN; 1061 1062 crq = kmalloc(sizeof (*crq), GFP_KERNEL); 1063 if (!crq) { 1064 kfree(buf); 1065 return -EAGAIN; 1066 } 1067 1068 bp = buf; len = PAGE_SIZE; 1069 1070 detail->cache_request(detail, h, &bp, &len); 1071 1072 if (len < 0) { 1073 kfree(buf); 1074 kfree(crq); 1075 return -EAGAIN; 1076 } 1077 crq->q.reader = 0; 1078 crq->item = cache_get(h); 1079 crq->buf = buf; 1080 crq->len = PAGE_SIZE - len; 1081 crq->readers = 0; 1082 spin_lock(&queue_lock); 1083 list_add_tail(&crq->q.list, &detail->queue); 1084 spin_unlock(&queue_lock); 1085 wake_up(&queue_wait); 1086 return 0; 1087 } 1088 1089 /* 1090 * parse a message from user-space and pass it 1091 * to an appropriate cache 1092 * Messages are, like requests, separated into fields by 1093 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal 1094 * 1095 * Message is 1096 * reply cachename expiry key ... content.... 1097 * 1098 * key and content are both parsed by cache 1099 */ 1100 1101 #define isodigit(c) (isdigit(c) && c <= '7') 1102 int qword_get(char **bpp, char *dest, int bufsize) 1103 { 1104 /* return bytes copied, or -1 on error */ 1105 char *bp = *bpp; 1106 int len = 0; 1107 1108 while (*bp == ' ') bp++; 1109 1110 if (bp[0] == '\\' && bp[1] == 'x') { 1111 /* HEX STRING */ 1112 bp += 2; 1113 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) { 1114 int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; 1115 bp++; 1116 byte <<= 4; 1117 byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; 1118 *dest++ = byte; 1119 bp++; 1120 len++; 1121 } 1122 } else { 1123 /* text with \nnn octal quoting */ 1124 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { 1125 if (*bp == '\\' && 1126 isodigit(bp[1]) && (bp[1] <= '3') && 1127 isodigit(bp[2]) && 1128 isodigit(bp[3])) { 1129 int byte = (*++bp -'0'); 1130 bp++; 1131 byte = (byte << 3) | (*bp++ - '0'); 1132 byte = (byte << 3) | (*bp++ - '0'); 1133 *dest++ = byte; 1134 len++; 1135 } else { 1136 *dest++ = *bp++; 1137 len++; 1138 } 1139 } 1140 } 1141 1142 if (*bp != ' ' && *bp != '\n' && *bp != '\0') 1143 return -1; 1144 while (*bp == ' ') bp++; 1145 *bpp = bp; 1146 *dest = '\0'; 1147 return len; 1148 } 1149 EXPORT_SYMBOL(qword_get); 1150 1151 1152 /* 1153 * support /proc/sunrpc/cache/$CACHENAME/content 1154 * as a seqfile. 1155 * We call ->cache_show passing NULL for the item to 1156 * get a header, then pass each real item in the cache 1157 */ 1158 1159 struct handle { 1160 struct cache_detail *cd; 1161 }; 1162 1163 static void *c_start(struct seq_file *m, loff_t *pos) 1164 __acquires(cd->hash_lock) 1165 { 1166 loff_t n = *pos; 1167 unsigned hash, entry; 1168 struct cache_head *ch; 1169 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1170 1171 1172 read_lock(&cd->hash_lock); 1173 if (!n--) 1174 return SEQ_START_TOKEN; 1175 hash = n >> 32; 1176 entry = n & ((1LL<<32) - 1); 1177 1178 for (ch=cd->hash_table[hash]; ch; ch=ch->next) 1179 if (!entry--) 1180 return ch; 1181 n &= ~((1LL<<32) - 1); 1182 do { 1183 hash++; 1184 n += 1LL<<32; 1185 } while(hash < cd->hash_size && 1186 cd->hash_table[hash]==NULL); 1187 if (hash >= cd->hash_size) 1188 return NULL; 1189 *pos = n+1; 1190 return cd->hash_table[hash]; 1191 } 1192 1193 static void *c_next(struct seq_file *m, void *p, loff_t *pos) 1194 { 1195 struct cache_head *ch = p; 1196 int hash = (*pos >> 32); 1197 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1198 1199 if (p == SEQ_START_TOKEN) 1200 hash = 0; 1201 else if (ch->next == NULL) { 1202 hash++; 1203 *pos += 1LL<<32; 1204 } else { 1205 ++*pos; 1206 return ch->next; 1207 } 1208 *pos &= ~((1LL<<32) - 1); 1209 while (hash < cd->hash_size && 1210 cd->hash_table[hash] == NULL) { 1211 hash++; 1212 *pos += 1LL<<32; 1213 } 1214 if (hash >= cd->hash_size) 1215 return NULL; 1216 ++*pos; 1217 return cd->hash_table[hash]; 1218 } 1219 1220 static void c_stop(struct seq_file *m, void *p) 1221 __releases(cd->hash_lock) 1222 { 1223 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1224 read_unlock(&cd->hash_lock); 1225 } 1226 1227 static int c_show(struct seq_file *m, void *p) 1228 { 1229 struct cache_head *cp = p; 1230 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1231 1232 if (p == SEQ_START_TOKEN) 1233 return cd->cache_show(m, cd, NULL); 1234 1235 ifdebug(CACHE) 1236 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n", 1237 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags); 1238 cache_get(cp); 1239 if (cache_check(cd, cp, NULL)) 1240 /* cache_check does a cache_put on failure */ 1241 seq_printf(m, "# "); 1242 else 1243 cache_put(cp, cd); 1244 1245 return cd->cache_show(m, cd, cp); 1246 } 1247 1248 static const struct seq_operations cache_content_op = { 1249 .start = c_start, 1250 .next = c_next, 1251 .stop = c_stop, 1252 .show = c_show, 1253 }; 1254 1255 static int content_open(struct inode *inode, struct file *file) 1256 { 1257 struct handle *han; 1258 struct cache_detail *cd = PDE(inode)->data; 1259 1260 han = __seq_open_private(file, &cache_content_op, sizeof(*han)); 1261 if (han == NULL) 1262 return -ENOMEM; 1263 1264 han->cd = cd; 1265 return 0; 1266 } 1267 1268 static const struct file_operations content_file_operations = { 1269 .open = content_open, 1270 .read = seq_read, 1271 .llseek = seq_lseek, 1272 .release = seq_release_private, 1273 }; 1274 1275 static ssize_t read_flush(struct file *file, char __user *buf, 1276 size_t count, loff_t *ppos) 1277 { 1278 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; 1279 char tbuf[20]; 1280 unsigned long p = *ppos; 1281 size_t len; 1282 1283 sprintf(tbuf, "%lu\n", cd->flush_time); 1284 len = strlen(tbuf); 1285 if (p >= len) 1286 return 0; 1287 len -= p; 1288 if (len > count) 1289 len = count; 1290 if (copy_to_user(buf, (void*)(tbuf+p), len)) 1291 return -EFAULT; 1292 *ppos += len; 1293 return len; 1294 } 1295 1296 static ssize_t write_flush(struct file * file, const char __user * buf, 1297 size_t count, loff_t *ppos) 1298 { 1299 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; 1300 char tbuf[20]; 1301 char *ep; 1302 long flushtime; 1303 if (*ppos || count > sizeof(tbuf)-1) 1304 return -EINVAL; 1305 if (copy_from_user(tbuf, buf, count)) 1306 return -EFAULT; 1307 tbuf[count] = 0; 1308 flushtime = simple_strtoul(tbuf, &ep, 0); 1309 if (*ep && *ep != '\n') 1310 return -EINVAL; 1311 1312 cd->flush_time = flushtime; 1313 cd->nextcheck = get_seconds(); 1314 cache_flush(); 1315 1316 *ppos += count; 1317 return count; 1318 } 1319 1320 static const struct file_operations cache_flush_operations = { 1321 .open = nonseekable_open, 1322 .read = read_flush, 1323 .write = write_flush, 1324 }; 1325