net/sunrpc/cache.c

   1 /*
   2  * net/sunrpc/cache.c
   3  *
   4  * Generic code for various authentication-related caches
   5  * used by sunrpc clients and servers.
   6  *
   7  * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
   8  *
   9  * Released under terms in GPL version 2.  See COPYING.
  10  *
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/fs.h>
  15 #include <linux/file.h>
  16 #include <linux/slab.h>
  17 #include <linux/signal.h>
  18 #include <linux/sched.h>
  19 #include <linux/kmod.h>
  20 #include <linux/list.h>
  21 #include <linux/module.h>
  22 #include <linux/ctype.h>
  23 #include <linux/string_helpers.h>
  24 #include <asm/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>
  37 #include "netns.h"
  38
  39 #define  RPCDBG_FACILITY RPCDBG_CACHE
  40
  41 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
  42 static void cache_revisit_request(struct cache_head *item);
  43
  44 static void cache_init(struct cache_head *h, struct cache_detail *detail)
  45 {
  46         time_t now = seconds_since_boot();
  47         INIT_HLIST_NODE(&h->cache_list);
  48         h->flags = 0;
  49         kref_init(&h->ref);
  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;
  55 }
  56
  57 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
  58                                        struct cache_head *key, int hash)
  59 {
  60         struct cache_head *new = NULL, *freeme = NULL, *tmp = NULL;
  61         struct hlist_head *head;
  62
  63         head = &detail->hash_table[hash];
  64
  65         read_lock(&detail->hash_lock);
  66
  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. */
  71                                 break;
  72                         cache_get(tmp);
  73                         read_unlock(&detail->hash_lock);
  74                         return tmp;
  75                 }
  76         }
  77         read_unlock(&detail->hash_lock);
  78         /* Didn't find anything, insert an empty entry */
  79
  80         new = detail->alloc();
  81         if (!new)
  82                 return NULL;
  83         /* must fully initialise 'new', else
  84          * we might get lose if we need to
  85          * cache_put it soon.
  86          */
  87         cache_init(new, detail);
  88         detail->init(new, key);
  89
  90         write_lock(&detail->hash_lock);
  91
  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);
  97                                 detail->entries --;
  98                                 freeme = tmp;
  99                                 break;
 100                         }
 101                         cache_get(tmp);
 102                         write_unlock(&detail->hash_lock);
 103                         cache_put(new, detail);
 104                         return tmp;
 105                 }
 106         }
 107
 108         hlist_add_head(&new->cache_list, head);
 109         detail->entries++;
 110         cache_get(new);
 111         write_unlock(&detail->hash_lock);
 112
 113         if (freeme)
 114                 cache_put(freeme, detail);
 115         return new;
 116 }
 117 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
 118
 119
 120 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
 121
 122 static void cache_fresh_locked(struct cache_head *head, time_t expiry,
 123                                struct cache_detail *detail)
 124 {
 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);
 133 }
 134
 135 static void cache_fresh_unlocked(struct cache_head *head,
 136                                  struct cache_detail *detail)
 137 {
 138         if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
 139                 cache_revisit_request(head);
 140                 cache_dequeue(detail, head);
 141         }
 142 }
 143
 144 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 145                                        struct cache_head *new, struct cache_head *old, int hash)
 146 {
 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
 150          */
 151         struct cache_head *tmp;
 152
 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);
 158                         else
 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);
 163                         return old;
 164                 }
 165                 write_unlock(&detail->hash_lock);
 166         }
 167         /* We need to insert a new entry */
 168         tmp = detail->alloc();
 169         if (!tmp) {
 170                 cache_put(old, detail);
 171                 return NULL;
 172         }
 173         cache_init(tmp, detail);
 174         detail->init(tmp, old);
 175
 176         write_lock(&detail->hash_lock);
 177         if (test_bit(CACHE_NEGATIVE, &new->flags))
 178                 set_bit(CACHE_NEGATIVE, &tmp->flags);
 179         else
 180                 detail->update(tmp, new);
 181         hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
 182         detail->entries++;
 183         cache_get(tmp);
 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);
 190         return tmp;
 191 }
 192 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
 193
 194 static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
 195 {
 196         if (cd->cache_upcall)
 197                 return cd->cache_upcall(cd, h);
 198         return sunrpc_cache_pipe_upcall(cd, h);
 199 }
 200
 201 static inline int cache_is_valid(struct cache_head *h)
 202 {
 203         if (!test_bit(CACHE_VALID, &h->flags))
 204                 return -EAGAIN;
 205         else {
 206                 /* entry is valid */
 207                 if (test_bit(CACHE_NEGATIVE, &h->flags))
 208                         return -ENOENT;
 209                 else {
 210                         /*
 211                          * In combination with write barrier in
 212                          * sunrpc_cache_update, ensures that anyone
 213                          * using the cache entry after this sees the
 214                          * updated contents:
 215                          */
 216                         smp_rmb();
 217                         return 0;
 218                 }
 219         }
 220 }
 221
 222 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
 223 {
 224         int rv;
 225
 226         write_lock(&detail->hash_lock);
 227         rv = cache_is_valid(h);
 228         if (rv == -EAGAIN) {
 229                 set_bit(CACHE_NEGATIVE, &h->flags);
 230                 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
 231                                    detail);
 232                 rv = -ENOENT;
 233         }
 234         write_unlock(&detail->hash_lock);
 235         cache_fresh_unlocked(h, detail);
 236         return rv;
 237 }
 238
 239 /*
 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.
 244  *
 245  *
 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
 252  */
 253 int cache_check(struct cache_detail *detail,
 254                     struct cache_head *h, struct cache_req *rqstp)
 255 {
 256         int rv;
 257         long refresh_age, age;
 258
 259         /* First decide return status as best we can */
 260         rv = cache_is_valid(h);
 261
 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;
 265
 266         if (rqstp == NULL) {
 267                 if (rv == -EAGAIN)
 268                         rv = -ENOENT;
 269         } else if (rv == -EAGAIN ||
 270                    (h->expiry_time != 0 && age > refresh_age/2)) {
 271                 dprintk("RPC:       Want update, refage=%ld, age=%ld\n",
 272                                 refresh_age, age);
 273                 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
 274                         switch (cache_make_upcall(detail, h)) {
 275                         case -EINVAL:
 276                                 rv = try_to_negate_entry(detail, h);
 277                                 break;
 278                         case -EAGAIN:
 279                                 cache_fresh_unlocked(h, detail);
 280                                 break;
 281                         }
 282                 }
 283         }
 284
 285         if (rv == -EAGAIN) {
 286                 if (!cache_defer_req(rqstp, h)) {
 287                         /*
 288                          * Request was not deferred; handle it as best
 289                          * we can ourselves:
 290                          */
 291                         rv = cache_is_valid(h);
 292                         if (rv == -EAGAIN)
 293                                 rv = -ETIMEDOUT;
 294                 }
 295         }
 296         if (rv)
 297                 cache_put(h, detail);
 298         return rv;
 299 }
 300 EXPORT_SYMBOL_GPL(cache_check);
 301
 302 /*
 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
 306  * for that entry.
 307  *
 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.
 311  *
 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
 315  *
 316  * later we might drop old entries with non-NEVER expiry if that table
 317  * is getting 'full' for some definition of 'full'
 318  *
 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
 321  * cache_detail.
 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.
 328  *
 329  * A table is then only scanned if the current time is at least
 330  * the nextcheck time.
 331  *
 332  */
 333
 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;
 338
 339 static void do_cache_clean(struct work_struct *work);
 340 static struct delayed_work cache_cleaner;
 341
 342 void sunrpc_init_cache_detail(struct cache_detail *cd)
 343 {
 344         rwlock_init(&cd->hash_lock);
 345         INIT_LIST_HEAD(&cd->queue);
 346         spin_lock(&cache_list_lock);
 347         cd->nextcheck = 0;
 348         cd->entries = 0;
 349         atomic_set(&cd->readers, 0);
 350         cd->last_close = 0;
 351         cd->last_warn = -1;
 352         list_add(&cd->others, &cache_list);
 353         spin_unlock(&cache_list_lock);
 354
 355         /* start the cleaning process */
 356         schedule_delayed_work(&cache_cleaner, 0);
 357 }
 358 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
 359
 360 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 361 {
 362         cache_purge(cd);
 363         spin_lock(&cache_list_lock);
 364         write_lock(&cd->hash_lock);
 365         if (cd->entries) {
 366                 write_unlock(&cd->hash_lock);
 367                 spin_unlock(&cache_list_lock);
 368                 goto out;
 369         }
 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);
 378         }
 379         return;
 380 out:
 381         printk(KERN_ERR "RPC: failed to unregister %s cache\n", cd->name);
 382 }
 383 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
 384
 385 /* clean cache tries to find something to clean
 386  * and cleans it.
 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.
 390  */
 391 static int cache_clean(void)
 392 {
 393         int rv = 0;
 394         struct list_head *next;
 395
 396         spin_lock(&cache_list_lock);
 397
 398         /* find a suitable table if we don't already have one */
 399         while (current_detail == NULL ||
 400             current_index >= current_detail->hash_size) {
 401                 if (current_detail)
 402                         next = current_detail->others.next;
 403                 else
 404                         next = cache_list.next;
 405                 if (next == &cache_list) {
 406                         current_detail = NULL;
 407                         spin_unlock(&cache_list_lock);
 408                         return -1;
 409                 }
 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;
 413                 else {
 414                         current_index = 0;
 415                         current_detail->nextcheck = seconds_since_boot()+30*60;
 416                 }
 417         }
 418
 419         /* find a non-empty bucket in the table */
 420         while (current_detail &&
 421                current_index < current_detail->hash_size &&
 422                hlist_empty(&current_detail->hash_table[current_index]))
 423                 current_index++;
 424
 425         /* find a cleanable entry in the bucket and clean it, or set to next bucket */
 426
 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;
 432
 433                 write_lock(&current_detail->hash_lock);
 434
 435                 /* Ok, now to clean this strand */
 436
 437                 head = &current_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))
 442                                 continue;
 443
 444                         hlist_del_init(&ch->cache_list);
 445                         current_detail->entries--;
 446                         rv = 1;
 447                         break;
 448                 }
 449
 450                 write_unlock(&current_detail->hash_lock);
 451                 d = current_detail;
 452                 if (!ch)
 453                         current_index ++;
 454                 spin_unlock(&cache_list_lock);
 455                 if (ch) {
 456                         set_bit(CACHE_CLEANED, &ch->flags);
 457                         cache_fresh_unlocked(ch, d);
 458                         cache_put(ch, d);
 459                 }
 460         } else
 461                 spin_unlock(&cache_list_lock);
 462
 463         return rv;
 464 }
 465
 466 /*
 467  * We want to regularly clean the cache, so we need to schedule some work ...
 468  */
 469 static void do_cache_clean(struct work_struct *work)
 470 {
 471         int delay = 5;
 472         if (cache_clean() == -1)
 473                 delay = round_jiffies_relative(30*HZ);
 474
 475         if (list_empty(&cache_list))
 476                 delay = 0;
 477
 478         if (delay)
 479                 schedule_delayed_work(&cache_cleaner, delay);
 480 }
 481
 482
 483 /*
 484  * Clean all caches promptly.  This just calls cache_clean
 485  * repeatedly until we are sure that every cache has had a chance to
 486  * be fully cleaned
 487  */
 488 void cache_flush(void)
 489 {
 490         while (cache_clean() != -1)
 491                 cond_resched();
 492         while (cache_clean() != -1)
 493                 cond_resched();
 494 }
 495 EXPORT_SYMBOL_GPL(cache_flush);
 496
 497 void cache_purge(struct cache_detail *detail)
 498 {
 499         time_t now = seconds_since_boot();
 500         if (detail->flush_time >= now)
 501                 now = detail->flush_time + 1;
 502         /* 'now' is the maximum value any 'last_refresh' can have */
 503         detail->flush_time = now;
 504         detail->nextcheck = seconds_since_boot();
 505         cache_flush();
 506 }
 507 EXPORT_SYMBOL_GPL(cache_purge);
 508
 509
 510 /*
 511  * Deferral and Revisiting of Requests.
 512  *
 513  * If a cache lookup finds a pending entry, we
 514  * need to defer the request and revisit it later.
 515  * All deferred requests are stored in a hash table,
 516  * indexed by "struct cache_head *".
 517  * As it may be wasteful to store a whole request
 518  * structure, we allow the request to provide a
 519  * deferred form, which must contain a
 520  * 'struct cache_deferred_req'
 521  * This cache_deferred_req contains a method to allow
 522  * it to be revisited when cache info is available
 523  */
 524
 525 #define DFR_HASHSIZE    (PAGE_SIZE/sizeof(struct list_head))
 526 #define DFR_HASH(item)  ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
 527
 528 #define DFR_MAX 300     /* ??? */
 529
 530 static DEFINE_SPINLOCK(cache_defer_lock);
 531 static LIST_HEAD(cache_defer_list);
 532 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
 533 static int cache_defer_cnt;
 534
 535 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
 536 {
 537         hlist_del_init(&dreq->hash);
 538         if (!list_empty(&dreq->recent)) {
 539                 list_del_init(&dreq->recent);
 540                 cache_defer_cnt--;
 541         }
 542 }
 543
 544 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
 545 {
 546         int hash = DFR_HASH(item);
 547
 548         INIT_LIST_HEAD(&dreq->recent);
 549         hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
 550 }
 551
 552 static void setup_deferral(struct cache_deferred_req *dreq,
 553                            struct cache_head *item,
 554                            int count_me)
 555 {
 556
 557         dreq->item = item;
 558
 559         spin_lock(&cache_defer_lock);
 560
 561         __hash_deferred_req(dreq, item);
 562
 563         if (count_me) {
 564                 cache_defer_cnt++;
 565                 list_add(&dreq->recent, &cache_defer_list);
 566         }
 567
 568         spin_unlock(&cache_defer_lock);
 569
 570 }
 571
 572 struct thread_deferred_req {
 573         struct cache_deferred_req handle;
 574         struct completion completion;
 575 };
 576
 577 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
 578 {
 579         struct thread_deferred_req *dr =
 580                 container_of(dreq, struct thread_deferred_req, handle);
 581         complete(&dr->completion);
 582 }
 583
 584 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
 585 {
 586         struct thread_deferred_req sleeper;
 587         struct cache_deferred_req *dreq = &sleeper.handle;
 588
 589         sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
 590         dreq->revisit = cache_restart_thread;
 591
 592         setup_deferral(dreq, item, 0);
 593
 594         if (!test_bit(CACHE_PENDING, &item->flags) ||
 595             wait_for_completion_interruptible_timeout(
 596                     &sleeper.completion, req->thread_wait) <= 0) {
 597                 /* The completion wasn't completed, so we need
 598                  * to clean up
 599                  */
 600                 spin_lock(&cache_defer_lock);
 601                 if (!hlist_unhashed(&sleeper.handle.hash)) {
 602                         __unhash_deferred_req(&sleeper.handle);
 603                         spin_unlock(&cache_defer_lock);
 604                 } else {
 605                         /* cache_revisit_request already removed
 606                          * this from the hash table, but hasn't
 607                          * called ->revisit yet.  It will very soon
 608                          * and we need to wait for it.
 609                          */
 610                         spin_unlock(&cache_defer_lock);
 611                         wait_for_completion(&sleeper.completion);
 612                 }
 613         }
 614 }
 615
 616 static void cache_limit_defers(void)
 617 {
 618         /* Make sure we haven't exceed the limit of allowed deferred
 619          * requests.
 620          */
 621         struct cache_deferred_req *discard = NULL;
 622
 623         if (cache_defer_cnt <= DFR_MAX)
 624                 return;
 625
 626         spin_lock(&cache_defer_lock);
 627
 628         /* Consider removing either the first or the last */
 629         if (cache_defer_cnt > DFR_MAX) {
 630                 if (prandom_u32() & 1)
 631                         discard = list_entry(cache_defer_list.next,
 632                                              struct cache_deferred_req, recent);
 633                 else
 634                         discard = list_entry(cache_defer_list.prev,
 635                                              struct cache_deferred_req, recent);
 636                 __unhash_deferred_req(discard);
 637         }
 638         spin_unlock(&cache_defer_lock);
 639         if (discard)
 640                 discard->revisit(discard, 1);
 641 }
 642
 643 /* Return true if and only if a deferred request is queued. */
 644 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
 645 {
 646         struct cache_deferred_req *dreq;
 647
 648         if (req->thread_wait) {
 649                 cache_wait_req(req, item);
 650                 if (!test_bit(CACHE_PENDING, &item->flags))
 651                         return false;
 652         }
 653         dreq = req->defer(req);
 654         if (dreq == NULL)
 655                 return false;
 656         setup_deferral(dreq, item, 1);
 657         if (!test_bit(CACHE_PENDING, &item->flags))
 658                 /* Bit could have been cleared before we managed to
 659                  * set up the deferral, so need to revisit just in case
 660                  */
 661                 cache_revisit_request(item);
 662
 663         cache_limit_defers();
 664         return true;
 665 }
 666
 667 static void cache_revisit_request(struct cache_head *item)
 668 {
 669         struct cache_deferred_req *dreq;
 670         struct list_head pending;
 671         struct hlist_node *tmp;
 672         int hash = DFR_HASH(item);
 673
 674         INIT_LIST_HEAD(&pending);
 675         spin_lock(&cache_defer_lock);
 676
 677         hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
 678                 if (dreq->item == item) {
 679                         __unhash_deferred_req(dreq);
 680                         list_add(&dreq->recent, &pending);
 681                 }
 682
 683         spin_unlock(&cache_defer_lock);
 684
 685         while (!list_empty(&pending)) {
 686                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 687                 list_del_init(&dreq->recent);
 688                 dreq->revisit(dreq, 0);
 689         }
 690 }
 691
 692 void cache_clean_deferred(void *owner)
 693 {
 694         struct cache_deferred_req *dreq, *tmp;
 695         struct list_head pending;
 696
 697
 698         INIT_LIST_HEAD(&pending);
 699         spin_lock(&cache_defer_lock);
 700
 701         list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
 702                 if (dreq->owner == owner) {
 703                         __unhash_deferred_req(dreq);
 704                         list_add(&dreq->recent, &pending);
 705                 }
 706         }
 707         spin_unlock(&cache_defer_lock);
 708
 709         while (!list_empty(&pending)) {
 710                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 711                 list_del_init(&dreq->recent);
 712                 dreq->revisit(dreq, 1);
 713         }
 714 }
 715
 716 /*
 717  * communicate with user-space
 718  *
 719  * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
 720  * On read, you get a full request, or block.
 721  * On write, an update request is processed.
 722  * Poll works if anything to read, and always allows write.
 723  *
 724  * Implemented by linked list of requests.  Each open file has
 725  * a ->private that also exists in this list.  New requests are added
 726  * to the end and may wakeup and preceding readers.
 727  * New readers are added to the head.  If, on read, an item is found with
 728  * CACHE_UPCALLING clear, we free it from the list.
 729  *
 730  */
 731
 732 static DEFINE_SPINLOCK(queue_lock);
 733 static DEFINE_MUTEX(queue_io_mutex);
 734
 735 struct cache_queue {
 736         struct list_head        list;
 737         int                     reader; /* if 0, then request */
 738 };
 739 struct cache_request {
 740         struct cache_queue      q;
 741         struct cache_head       *item;
 742         char                    * buf;
 743         int                     len;
 744         int                     readers;
 745 };
 746 struct cache_reader {
 747         struct cache_queue      q;
 748         int                     offset; /* if non-0, we have a refcnt on next request */
 749 };
 750
 751 static int cache_request(struct cache_detail *detail,
 752                                struct cache_request *crq)
 753 {
 754         char *bp = crq->buf;
 755         int len = PAGE_SIZE;
 756
 757         detail->cache_request(detail, crq->item, &bp, &len);
 758         if (len < 0)
 759                 return -EAGAIN;
 760         return PAGE_SIZE - len;
 761 }
 762
 763 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 764                           loff_t *ppos, struct cache_detail *cd)
 765 {
 766         struct cache_reader *rp = filp->private_data;
 767         struct cache_request *rq;
 768         struct inode *inode = file_inode(filp);
 769         int err;
 770
 771         if (count == 0)
 772                 return 0;
 773
 774         inode_lock(inode); /* protect against multiple concurrent
 775                               * readers on this file */
 776  again:
 777         spin_lock(&queue_lock);
 778         /* need to find next request */
 779         while (rp->q.list.next != &cd->queue &&
 780                list_entry(rp->q.list.next, struct cache_queue, list)
 781                ->reader) {
 782                 struct list_head *next = rp->q.list.next;
 783                 list_move(&rp->q.list, next);
 784         }
 785         if (rp->q.list.next == &cd->queue) {
 786                 spin_unlock(&queue_lock);
 787                 inode_unlock(inode);
 788                 WARN_ON_ONCE(rp->offset);
 789                 return 0;
 790         }
 791         rq = container_of(rp->q.list.next, struct cache_request, q.list);
 792         WARN_ON_ONCE(rq->q.reader);
 793         if (rp->offset == 0)
 794                 rq->readers++;
 795         spin_unlock(&queue_lock);
 796
 797         if (rq->len == 0) {
 798                 err = cache_request(cd, rq);
 799                 if (err < 0)
 800                         goto out;
 801                 rq->len = err;
 802         }
 803
 804         if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
 805                 err = -EAGAIN;
 806                 spin_lock(&queue_lock);
 807                 list_move(&rp->q.list, &rq->q.list);
 808                 spin_unlock(&queue_lock);
 809         } else {
 810                 if (rp->offset + count > rq->len)
 811                         count = rq->len - rp->offset;
 812                 err = -EFAULT;
 813                 if (copy_to_user(buf, rq->buf + rp->offset, count))
 814                         goto out;
 815                 rp->offset += count;
 816                 if (rp->offset >= rq->len) {
 817                         rp->offset = 0;
 818                         spin_lock(&queue_lock);
 819                         list_move(&rp->q.list, &rq->q.list);
 820                         spin_unlock(&queue_lock);
 821                 }
 822                 err = 0;
 823         }
 824  out:
 825         if (rp->offset == 0) {
 826                 /* need to release rq */
 827                 spin_lock(&queue_lock);
 828                 rq->readers--;
 829                 if (rq->readers == 0 &&
 830                     !test_bit(CACHE_PENDING, &rq->item->flags)) {
 831                         list_del(&rq->q.list);
 832                         spin_unlock(&queue_lock);
 833                         cache_put(rq->item, cd);
 834                         kfree(rq->buf);
 835                         kfree(rq);
 836                 } else
 837                         spin_unlock(&queue_lock);
 838         }
 839         if (err == -EAGAIN)
 840                 goto again;
 841         inode_unlock(inode);
 842         return err ? err :  count;
 843 }
 844
 845 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
 846                                  size_t count, struct cache_detail *cd)
 847 {
 848         ssize_t ret;
 849
 850         if (count == 0)
 851                 return -EINVAL;
 852         if (copy_from_user(kaddr, buf, count))
 853                 return -EFAULT;
 854         kaddr[count] = '\0';
 855         ret = cd->cache_parse(cd, kaddr, count);
 856         if (!ret)
 857                 ret = count;
 858         return ret;
 859 }
 860
 861 static ssize_t cache_slow_downcall(const char __user *buf,
 862                                    size_t count, struct cache_detail *cd)
 863 {
 864         static char write_buf[8192]; /* protected by queue_io_mutex */
 865         ssize_t ret = -EINVAL;
 866
 867         if (count >= sizeof(write_buf))
 868                 goto out;
 869         mutex_lock(&queue_io_mutex);
 870         ret = cache_do_downcall(write_buf, buf, count, cd);
 871         mutex_unlock(&queue_io_mutex);
 872 out:
 873         return ret;
 874 }
 875
 876 static ssize_t cache_downcall(struct address_space *mapping,
 877                               const char __user *buf,
 878                               size_t count, struct cache_detail *cd)
 879 {
 880         struct page *page;
 881         char *kaddr;
 882         ssize_t ret = -ENOMEM;
 883
 884         if (count >= PAGE_SIZE)
 885                 goto out_slow;
 886
 887         page = find_or_create_page(mapping, 0, GFP_KERNEL);
 888         if (!page)
 889                 goto out_slow;
 890
 891         kaddr = kmap(page);
 892         ret = cache_do_downcall(kaddr, buf, count, cd);
 893         kunmap(page);
 894         unlock_page(page);
 895         put_page(page);
 896         return ret;
 897 out_slow:
 898         return cache_slow_downcall(buf, count, cd);
 899 }
 900
 901 static ssize_t cache_write(struct file *filp, const char __user *buf,
 902                            size_t count, loff_t *ppos,
 903                            struct cache_detail *cd)
 904 {
 905         struct address_space *mapping = filp->f_mapping;
 906         struct inode *inode = file_inode(filp);
 907         ssize_t ret = -EINVAL;
 908
 909         if (!cd->cache_parse)
 910                 goto out;
 911
 912         inode_lock(inode);
 913         ret = cache_downcall(mapping, buf, count, cd);
 914         inode_unlock(inode);
 915 out:
 916         return ret;
 917 }
 918
 919 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
 920
 921 static unsigned int cache_poll(struct file *filp, poll_table *wait,
 922                                struct cache_detail *cd)
 923 {
 924         unsigned int mask;
 925         struct cache_reader *rp = filp->private_data;
 926         struct cache_queue *cq;
 927
 928         poll_wait(filp, &queue_wait, wait);
 929
 930         /* alway allow write */
 931         mask = POLLOUT | POLLWRNORM;
 932
 933         if (!rp)
 934                 return mask;
 935
 936         spin_lock(&queue_lock);
 937
 938         for (cq= &rp->q; &cq->list != &cd->queue;
 939              cq = list_entry(cq->list.next, struct cache_queue, list))
 940                 if (!cq->reader) {
 941                         mask |= POLLIN | POLLRDNORM;
 942                         break;
 943                 }
 944         spin_unlock(&queue_lock);
 945         return mask;
 946 }
 947
 948 static int cache_ioctl(struct inode *ino, struct file *filp,
 949                        unsigned int cmd, unsigned long arg,
 950                        struct cache_detail *cd)
 951 {
 952         int len = 0;
 953         struct cache_reader *rp = filp->private_data;
 954         struct cache_queue *cq;
 955
 956         if (cmd != FIONREAD || !rp)
 957                 return -EINVAL;
 958
 959         spin_lock(&queue_lock);
 960
 961         /* only find the length remaining in current request,
 962          * or the length of the next request
 963          */
 964         for (cq= &rp->q; &cq->list != &cd->queue;
 965              cq = list_entry(cq->list.next, struct cache_queue, list))
 966                 if (!cq->reader) {
 967                         struct cache_request *cr =
 968                                 container_of(cq, struct cache_request, q);
 969                         len = cr->len - rp->offset;
 970                         break;
 971                 }
 972         spin_unlock(&queue_lock);
 973
 974         return put_user(len, (int __user *)arg);
 975 }
 976
 977 static int cache_open(struct inode *inode, struct file *filp,
 978                       struct cache_detail *cd)
 979 {
 980         struct cache_reader *rp = NULL;
 981
 982         if (!cd || !try_module_get(cd->owner))
 983                 return -EACCES;
 984         nonseekable_open(inode, filp);
 985         if (filp->f_mode & FMODE_READ) {
 986                 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
 987                 if (!rp) {
 988                         module_put(cd->owner);
 989                         return -ENOMEM;
 990                 }
 991                 rp->offset = 0;
 992                 rp->q.reader = 1;
 993                 atomic_inc(&cd->readers);
 994                 spin_lock(&queue_lock);
 995                 list_add(&rp->q.list, &cd->queue);
 996                 spin_unlock(&queue_lock);
 997         }
 998         filp->private_data = rp;
 999         return 0;
1000 }
1001
1002 static int cache_release(struct inode *inode, struct file *filp,
1003                          struct cache_detail *cd)
1004 {
1005         struct cache_reader *rp = filp->private_data;
1006
1007         if (rp) {
1008                 spin_lock(&queue_lock);
1009                 if (rp->offset) {
1010                         struct cache_queue *cq;
1011                         for (cq= &rp->q; &cq->list != &cd->queue;
1012                              cq = list_entry(cq->list.next, struct cache_queue, list))
1013                                 if (!cq->reader) {
1014                                         container_of(cq, struct cache_request, q)
1015                                                 ->readers--;
1016                                         break;
1017                                 }
1018                         rp->offset = 0;
1019                 }
1020                 list_del(&rp->q.list);
1021                 spin_unlock(&queue_lock);
1022
1023                 filp->private_data = NULL;
1024                 kfree(rp);
1025
1026                 cd->last_close = seconds_since_boot();
1027                 atomic_dec(&cd->readers);
1028         }
1029         module_put(cd->owner);
1030         return 0;
1031 }
1032
1033
1034
1035 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1036 {
1037         struct cache_queue *cq, *tmp;
1038         struct cache_request *cr;
1039         struct list_head dequeued;
1040
1041         INIT_LIST_HEAD(&dequeued);
1042         spin_lock(&queue_lock);
1043         list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1044                 if (!cq->reader) {
1045                         cr = container_of(cq, struct cache_request, q);
1046                         if (cr->item != ch)
1047                                 continue;
1048                         if (test_bit(CACHE_PENDING, &ch->flags))
1049                                 /* Lost a race and it is pending again */
1050                                 break;
1051                         if (cr->readers != 0)
1052                                 continue;
1053                         list_move(&cr->q.list, &dequeued);
1054                 }
1055         spin_unlock(&queue_lock);
1056         while (!list_empty(&dequeued)) {
1057                 cr = list_entry(dequeued.next, struct cache_request, q.list);
1058                 list_del(&cr->q.list);
1059                 cache_put(cr->item, detail);
1060                 kfree(cr->buf);
1061                 kfree(cr);
1062         }
1063 }
1064
1065 /*
1066  * Support routines for text-based upcalls.
1067  * Fields are separated by spaces.
1068  * Fields are either mangled to quote space tab newline slosh with slosh
1069  * or a hexified with a leading \x
1070  * Record is terminated with newline.
1071  *
1072  */
1073
1074 void qword_add(char **bpp, int *lp, char *str)
1075 {
1076         char *bp = *bpp;
1077         int len = *lp;
1078         int ret;
1079
1080         if (len < 0) return;
1081
1082         ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1083         if (ret >= len) {
1084                 bp += len;
1085                 len = -1;
1086         } else {
1087                 bp += ret;
1088                 len -= ret;
1089                 *bp++ = ' ';
1090                 len--;
1091         }
1092         *bpp = bp;
1093         *lp = len;
1094 }
1095 EXPORT_SYMBOL_GPL(qword_add);
1096
1097 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1098 {
1099         char *bp = *bpp;
1100         int len = *lp;
1101
1102         if (len < 0) return;
1103
1104         if (len > 2) {
1105                 *bp++ = '\\';
1106                 *bp++ = 'x';
1107                 len -= 2;
1108                 while (blen && len >= 2) {
1109                         bp = hex_byte_pack(bp, *buf++);
1110                         len -= 2;
1111                         blen--;
1112                 }
1113         }
1114         if (blen || len<1) len = -1;
1115         else {
1116                 *bp++ = ' ';
1117                 len--;
1118         }
1119         *bpp = bp;
1120         *lp = len;
1121 }
1122 EXPORT_SYMBOL_GPL(qword_addhex);
1123
1124 static void warn_no_listener(struct cache_detail *detail)
1125 {
1126         if (detail->last_warn != detail->last_close) {
1127                 detail->last_warn = detail->last_close;
1128                 if (detail->warn_no_listener)
1129                         detail->warn_no_listener(detail, detail->last_close != 0);
1130         }
1131 }
1132
1133 static bool cache_listeners_exist(struct cache_detail *detail)
1134 {
1135         if (atomic_read(&detail->readers))
1136                 return true;
1137         if (detail->last_close == 0)
1138                 /* This cache was never opened */
1139                 return false;
1140         if (detail->last_close < seconds_since_boot() - 30)
1141                 /*
1142                  * We allow for the possibility that someone might
1143                  * restart a userspace daemon without restarting the
1144                  * server; but after 30 seconds, we give up.
1145                  */
1146                  return false;
1147         return true;
1148 }
1149
1150 /*
1151  * register an upcall request to user-space and queue it up for read() by the
1152  * upcall daemon.
1153  *
1154  * Each request is at most one page long.
1155  */
1156 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1157 {
1158
1159         char *buf;
1160         struct cache_request *crq;
1161         int ret = 0;
1162
1163         if (!detail->cache_request)
1164                 return -EINVAL;
1165
1166         if (!cache_listeners_exist(detail)) {
1167                 warn_no_listener(detail);
1168                 return -EINVAL;
1169         }
1170         if (test_bit(CACHE_CLEANED, &h->flags))
1171                 /* Too late to make an upcall */
1172                 return -EAGAIN;
1173
1174         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1175         if (!buf)
1176                 return -EAGAIN;
1177
1178         crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1179         if (!crq) {
1180                 kfree(buf);
1181                 return -EAGAIN;
1182         }
1183
1184         crq->q.reader = 0;
1185         crq->buf = buf;
1186         crq->len = 0;
1187         crq->readers = 0;
1188         spin_lock(&queue_lock);
1189         if (test_bit(CACHE_PENDING, &h->flags)) {
1190                 crq->item = cache_get(h);
1191                 list_add_tail(&crq->q.list, &detail->queue);
1192         } else
1193                 /* Lost a race, no longer PENDING, so don't enqueue */
1194                 ret = -EAGAIN;
1195         spin_unlock(&queue_lock);
1196         wake_up(&queue_wait);
1197         if (ret == -EAGAIN) {
1198                 kfree(buf);
1199                 kfree(crq);
1200         }
1201         return ret;
1202 }
1203 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1204
1205 /*
1206  * parse a message from user-space and pass it
1207  * to an appropriate cache
1208  * Messages are, like requests, separated into fields by
1209  * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1210  *
1211  * Message is
1212  *   reply cachename expiry key ... content....
1213  *
1214  * key and content are both parsed by cache
1215  */
1216
1217 int qword_get(char **bpp, char *dest, int bufsize)
1218 {
1219         /* return bytes copied, or -1 on error */
1220         char *bp = *bpp;
1221         int len = 0;
1222
1223         while (*bp == ' ') bp++;
1224
1225         if (bp[0] == '\\' && bp[1] == 'x') {
1226                 /* HEX STRING */
1227                 bp += 2;
1228                 while (len < bufsize - 1) {
1229                         int h, l;
1230
1231                         h = hex_to_bin(bp[0]);
1232                         if (h < 0)
1233                                 break;
1234
1235                         l = hex_to_bin(bp[1]);
1236                         if (l < 0)
1237                                 break;
1238
1239                         *dest++ = (h << 4) | l;
1240                         bp += 2;
1241                         len++;
1242                 }
1243         } else {
1244                 /* text with \nnn octal quoting */
1245                 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1246                         if (*bp == '\\' &&
1247                             isodigit(bp[1]) && (bp[1] <= '3') &&
1248                             isodigit(bp[2]) &&
1249                             isodigit(bp[3])) {
1250                                 int byte = (*++bp -'0');
1251                                 bp++;
1252                                 byte = (byte << 3) | (*bp++ - '0');
1253                                 byte = (byte << 3) | (*bp++ - '0');
1254                                 *dest++ = byte;
1255                                 len++;
1256                         } else {
1257                                 *dest++ = *bp++;
1258                                 len++;
1259                         }
1260                 }
1261         }
1262
1263         if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1264                 return -1;
1265         while (*bp == ' ') bp++;
1266         *bpp = bp;
1267         *dest = '\0';
1268         return len;
1269 }
1270 EXPORT_SYMBOL_GPL(qword_get);
1271
1272
1273 /*
1274  * support /proc/sunrpc/cache/$CACHENAME/content
1275  * as a seqfile.
1276  * We call ->cache_show passing NULL for the item to
1277  * get a header, then pass each real item in the cache
1278  */
1279
1280 void *cache_seq_start(struct seq_file *m, loff_t *pos)
1281         __acquires(cd->hash_lock)
1282 {
1283         loff_t n = *pos;
1284         unsigned int hash, entry;
1285         struct cache_head *ch;
1286         struct cache_detail *cd = m->private;
1287
1288         read_lock(&cd->hash_lock);
1289         if (!n--)
1290                 return SEQ_START_TOKEN;
1291         hash = n >> 32;
1292         entry = n & ((1LL<<32) - 1);
1293
1294         hlist_for_each_entry(ch, &cd->hash_table[hash], cache_list)
1295                 if (!entry--)
1296                         return ch;
1297         n &= ~((1LL<<32) - 1);
1298         do {
1299                 hash++;
1300                 n += 1LL<<32;
1301         } while(hash < cd->hash_size &&
1302                 hlist_empty(&cd->hash_table[hash]));
1303         if (hash >= cd->hash_size)
1304                 return NULL;
1305         *pos = n+1;
1306         return hlist_entry_safe(cd->hash_table[hash].first,
1307                                 struct cache_head, cache_list);
1308 }
1309 EXPORT_SYMBOL_GPL(cache_seq_start);
1310
1311 void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1312 {
1313         struct cache_head *ch = p;
1314         int hash = (*pos >> 32);
1315         struct cache_detail *cd = m->private;
1316
1317         if (p == SEQ_START_TOKEN)
1318                 hash = 0;
1319         else if (ch->cache_list.next == NULL) {
1320                 hash++;
1321                 *pos += 1LL<<32;
1322         } else {
1323                 ++*pos;
1324                 return hlist_entry_safe(ch->cache_list.next,
1325                                         struct cache_head, cache_list);
1326         }
1327         *pos &= ~((1LL<<32) - 1);
1328         while (hash < cd->hash_size &&
1329                hlist_empty(&cd->hash_table[hash])) {
1330                 hash++;
1331                 *pos += 1LL<<32;
1332         }
1333         if (hash >= cd->hash_size)
1334                 return NULL;
1335         ++*pos;
1336         return hlist_entry_safe(cd->hash_table[hash].first,
1337                                 struct cache_head, cache_list);
1338 }
1339 EXPORT_SYMBOL_GPL(cache_seq_next);
1340
1341 void cache_seq_stop(struct seq_file *m, void *p)
1342         __releases(cd->hash_lock)
1343 {
1344         struct cache_detail *cd = m->private;
1345         read_unlock(&cd->hash_lock);
1346 }
1347 EXPORT_SYMBOL_GPL(cache_seq_stop);
1348
1349 static int c_show(struct seq_file *m, void *p)
1350 {
1351         struct cache_head *cp = p;
1352         struct cache_detail *cd = m->private;
1353
1354         if (p == SEQ_START_TOKEN)
1355                 return cd->cache_show(m, cd, NULL);
1356
1357         ifdebug(CACHE)
1358                 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1359                            convert_to_wallclock(cp->expiry_time),
1360                            atomic_read(&cp->ref.refcount), cp->flags);
1361         cache_get(cp);
1362         if (cache_check(cd, cp, NULL))
1363                 /* cache_check does a cache_put on failure */
1364                 seq_printf(m, "# ");
1365         else {
1366                 if (cache_is_expired(cd, cp))
1367                         seq_printf(m, "# ");
1368                 cache_put(cp, cd);
1369         }
1370
1371         return cd->cache_show(m, cd, cp);
1372 }
1373
1374 static const struct seq_operations cache_content_op = {
1375         .start  = cache_seq_start,
1376         .next   = cache_seq_next,
1377         .stop   = cache_seq_stop,
1378         .show   = c_show,
1379 };
1380
1381 static int content_open(struct inode *inode, struct file *file,
1382                         struct cache_detail *cd)
1383 {
1384         struct seq_file *seq;
1385         int err;
1386
1387         if (!cd || !try_module_get(cd->owner))
1388                 return -EACCES;
1389
1390         err = seq_open(file, &cache_content_op);
1391         if (err) {
1392                 module_put(cd->owner);
1393                 return err;
1394         }
1395
1396         seq = file->private_data;
1397         seq->private = cd;
1398         return 0;
1399 }
1400
1401 static int content_release(struct inode *inode, struct file *file,
1402                 struct cache_detail *cd)
1403 {
1404         int ret = seq_release(inode, file);
1405         module_put(cd->owner);
1406         return ret;
1407 }
1408
1409 static int open_flush(struct inode *inode, struct file *file,
1410                         struct cache_detail *cd)
1411 {
1412         if (!cd || !try_module_get(cd->owner))
1413                 return -EACCES;
1414         return nonseekable_open(inode, file);
1415 }
1416
1417 static int release_flush(struct inode *inode, struct file *file,
1418                         struct cache_detail *cd)
1419 {
1420         module_put(cd->owner);
1421         return 0;
1422 }
1423
1424 static ssize_t read_flush(struct file *file, char __user *buf,
1425                           size_t count, loff_t *ppos,
1426                           struct cache_detail *cd)
1427 {
1428         char tbuf[22];
1429         unsigned long p = *ppos;
1430         size_t len;
1431
1432         snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
1433         len = strlen(tbuf);
1434         if (p >= len)
1435                 return 0;
1436         len -= p;
1437         if (len > count)
1438                 len = count;
1439         if (copy_to_user(buf, (void*)(tbuf+p), len))
1440                 return -EFAULT;
1441         *ppos += len;
1442         return len;
1443 }
1444
1445 static ssize_t write_flush(struct file *file, const char __user *buf,
1446                            size_t count, loff_t *ppos,
1447                            struct cache_detail *cd)
1448 {
1449         char tbuf[20];
1450         char *bp, *ep;
1451         time_t then, now;
1452
1453         if (*ppos || count > sizeof(tbuf)-1)
1454                 return -EINVAL;
1455         if (copy_from_user(tbuf, buf, count))
1456                 return -EFAULT;
1457         tbuf[count] = 0;
1458         simple_strtoul(tbuf, &ep, 0);
1459         if (*ep && *ep != '\n')
1460                 return -EINVAL;
1461
1462         bp = tbuf;
1463         then = get_expiry(&bp);
1464         now = seconds_since_boot();
1465         cd->nextcheck = now;
1466         /* Can only set flush_time to 1 second beyond "now", or
1467          * possibly 1 second beyond flushtime.  This is because
1468          * flush_time never goes backwards so it mustn't get too far
1469          * ahead of time.
1470          */
1471         if (then >= now) {
1472                 /* Want to flush everything, so behave like cache_purge() */
1473                 if (cd->flush_time >= now)
1474                         now = cd->flush_time + 1;
1475                 then = now;
1476         }
1477
1478         cd->flush_time = then;
1479         cache_flush();
1480
1481         *ppos += count;
1482         return count;
1483 }
1484
1485 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1486                                  size_t count, loff_t *ppos)
1487 {
1488         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1489
1490         return cache_read(filp, buf, count, ppos, cd);
1491 }
1492
1493 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1494                                   size_t count, loff_t *ppos)
1495 {
1496         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1497
1498         return cache_write(filp, buf, count, ppos, cd);
1499 }
1500
1501 static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1502 {
1503         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1504
1505         return cache_poll(filp, wait, cd);
1506 }
1507
1508 static long cache_ioctl_procfs(struct file *filp,
1509                                unsigned int cmd, unsigned long arg)
1510 {
1511         struct inode *inode = file_inode(filp);
1512         struct cache_detail *cd = PDE_DATA(inode);
1513
1514         return cache_ioctl(inode, filp, cmd, arg, cd);
1515 }
1516
1517 static int cache_open_procfs(struct inode *inode, struct file *filp)
1518 {
1519         struct cache_detail *cd = PDE_DATA(inode);
1520
1521         return cache_open(inode, filp, cd);
1522 }
1523
1524 static int cache_release_procfs(struct inode *inode, struct file *filp)
1525 {
1526         struct cache_detail *cd = PDE_DATA(inode);
1527
1528         return cache_release(inode, filp, cd);
1529 }
1530
1531 static const struct file_operations cache_file_operations_procfs = {
1532         .owner          = THIS_MODULE,
1533         .llseek         = no_llseek,
1534         .read           = cache_read_procfs,
1535         .write          = cache_write_procfs,
1536         .poll           = cache_poll_procfs,
1537         .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1538         .open           = cache_open_procfs,
1539         .release        = cache_release_procfs,
1540 };
1541
1542 static int content_open_procfs(struct inode *inode, struct file *filp)
1543 {
1544         struct cache_detail *cd = PDE_DATA(inode);
1545
1546         return content_open(inode, filp, cd);
1547 }
1548
1549 static int content_release_procfs(struct inode *inode, struct file *filp)
1550 {
1551         struct cache_detail *cd = PDE_DATA(inode);
1552
1553         return content_release(inode, filp, cd);
1554 }
1555
1556 static const struct file_operations content_file_operations_procfs = {
1557         .open           = content_open_procfs,
1558         .read           = seq_read,
1559         .llseek         = seq_lseek,
1560         .release        = content_release_procfs,
1561 };
1562
1563 static int open_flush_procfs(struct inode *inode, struct file *filp)
1564 {
1565         struct cache_detail *cd = PDE_DATA(inode);
1566
1567         return open_flush(inode, filp, cd);
1568 }
1569
1570 static int release_flush_procfs(struct inode *inode, struct file *filp)
1571 {
1572         struct cache_detail *cd = PDE_DATA(inode);
1573
1574         return release_flush(inode, filp, cd);
1575 }
1576
1577 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1578                             size_t count, loff_t *ppos)
1579 {
1580         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1581
1582         return read_flush(filp, buf, count, ppos, cd);
1583 }
1584
1585 static ssize_t write_flush_procfs(struct file *filp,
1586                                   const char __user *buf,
1587                                   size_t count, loff_t *ppos)
1588 {
1589         struct cache_detail *cd = PDE_DATA(file_inode(filp));
1590
1591         return write_flush(filp, buf, count, ppos, cd);
1592 }
1593
1594 static const struct file_operations cache_flush_operations_procfs = {
1595         .open           = open_flush_procfs,
1596         .read           = read_flush_procfs,
1597         .write          = write_flush_procfs,
1598         .release        = release_flush_procfs,
1599         .llseek         = no_llseek,
1600 };
1601
1602 static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1603 {
1604         struct sunrpc_net *sn;
1605
1606         if (cd->u.procfs.proc_ent == NULL)
1607                 return;
1608         if (cd->u.procfs.flush_ent)
1609                 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1610         if (cd->u.procfs.channel_ent)
1611                 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1612         if (cd->u.procfs.content_ent)
1613                 remove_proc_entry("content", cd->u.procfs.proc_ent);
1614         cd->u.procfs.proc_ent = NULL;
1615         sn = net_generic(net, sunrpc_net_id);
1616         remove_proc_entry(cd->name, sn->proc_net_rpc);
1617 }
1618
1619 #ifdef CONFIG_PROC_FS
1620 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1621 {
1622         struct proc_dir_entry *p;
1623         struct sunrpc_net *sn;
1624
1625         sn = net_generic(net, sunrpc_net_id);
1626         cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1627         if (cd->u.procfs.proc_ent == NULL)
1628                 goto out_nomem;
1629         cd->u.procfs.channel_ent = NULL;
1630         cd->u.procfs.content_ent = NULL;
1631
1632         p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1633                              cd->u.procfs.proc_ent,
1634                              &cache_flush_operations_procfs, cd);
1635         cd->u.procfs.flush_ent = p;
1636         if (p == NULL)
1637                 goto out_nomem;
1638
1639         if (cd->cache_request || cd->cache_parse) {
1640                 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1641                                      cd->u.procfs.proc_ent,
1642                                      &cache_file_operations_procfs, cd);
1643                 cd->u.procfs.channel_ent = p;
1644                 if (p == NULL)
1645                         goto out_nomem;
1646         }
1647         if (cd->cache_show) {
1648                 p = proc_create_data("content", S_IFREG|S_IRUSR,
1649                                 cd->u.procfs.proc_ent,
1650                                 &content_file_operations_procfs, cd);
1651                 cd->u.procfs.content_ent = p;
1652                 if (p == NULL)
1653                         goto out_nomem;
1654         }
1655         return 0;
1656 out_nomem:
1657         remove_cache_proc_entries(cd, net);
1658         return -ENOMEM;
1659 }
1660 #else /* CONFIG_PROC_FS */
1661 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1662 {
1663         return 0;
1664 }
1665 #endif
1666
1667 void __init cache_initialize(void)
1668 {
1669         INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1670 }
1671
1672 int cache_register_net(struct cache_detail *cd, struct net *net)
1673 {
1674         int ret;
1675
1676         sunrpc_init_cache_detail(cd);
1677         ret = create_cache_proc_entries(cd, net);
1678         if (ret)
1679                 sunrpc_destroy_cache_detail(cd);
1680         return ret;
1681 }
1682 EXPORT_SYMBOL_GPL(cache_register_net);
1683
1684 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1685 {
1686         remove_cache_proc_entries(cd, net);
1687         sunrpc_destroy_cache_detail(cd);
1688 }
1689 EXPORT_SYMBOL_GPL(cache_unregister_net);
1690
1691 struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
1692 {
1693         struct cache_detail *cd;
1694         int i;
1695
1696         cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1697         if (cd == NULL)
1698                 return ERR_PTR(-ENOMEM);
1699
1700         cd->hash_table = kzalloc(cd->hash_size * sizeof(struct hlist_head),
1701                                  GFP_KERNEL);
1702         if (cd->hash_table == NULL) {
1703                 kfree(cd);
1704                 return ERR_PTR(-ENOMEM);
1705         }
1706
1707         for (i = 0; i < cd->hash_size; i++)
1708                 INIT_HLIST_HEAD(&cd->hash_table[i]);
1709         cd->net = net;
1710         return cd;
1711 }
1712 EXPORT_SYMBOL_GPL(cache_create_net);
1713
1714 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1715 {
1716         kfree(cd->hash_table);
1717         kfree(cd);
1718 }
1719 EXPORT_SYMBOL_GPL(cache_destroy_net);
1720
1721 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1722                                  size_t count, loff_t *ppos)
1723 {
1724         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1725
1726         return cache_read(filp, buf, count, ppos, cd);
1727 }
1728
1729 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1730                                   size_t count, loff_t *ppos)
1731 {
1732         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1733
1734         return cache_write(filp, buf, count, ppos, cd);
1735 }
1736
1737 static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1738 {
1739         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1740
1741         return cache_poll(filp, wait, cd);
1742 }
1743
1744 static long cache_ioctl_pipefs(struct file *filp,
1745                               unsigned int cmd, unsigned long arg)
1746 {
1747         struct inode *inode = file_inode(filp);
1748         struct cache_detail *cd = RPC_I(inode)->private;
1749
1750         return cache_ioctl(inode, filp, cmd, arg, cd);
1751 }
1752
1753 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1754 {
1755         struct cache_detail *cd = RPC_I(inode)->private;
1756
1757         return cache_open(inode, filp, cd);
1758 }
1759
1760 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1761 {
1762         struct cache_detail *cd = RPC_I(inode)->private;
1763
1764         return cache_release(inode, filp, cd);
1765 }
1766
1767 const struct file_operations cache_file_operations_pipefs = {
1768         .owner          = THIS_MODULE,
1769         .llseek         = no_llseek,
1770         .read           = cache_read_pipefs,
1771         .write          = cache_write_pipefs,
1772         .poll           = cache_poll_pipefs,
1773         .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1774         .open           = cache_open_pipefs,
1775         .release        = cache_release_pipefs,
1776 };
1777
1778 static int content_open_pipefs(struct inode *inode, struct file *filp)
1779 {
1780         struct cache_detail *cd = RPC_I(inode)->private;
1781
1782         return content_open(inode, filp, cd);
1783 }
1784
1785 static int content_release_pipefs(struct inode *inode, struct file *filp)
1786 {
1787         struct cache_detail *cd = RPC_I(inode)->private;
1788
1789         return content_release(inode, filp, cd);
1790 }
1791
1792 const struct file_operations content_file_operations_pipefs = {
1793         .open           = content_open_pipefs,
1794         .read           = seq_read,
1795         .llseek         = seq_lseek,
1796         .release        = content_release_pipefs,
1797 };
1798
1799 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1800 {
1801         struct cache_detail *cd = RPC_I(inode)->private;
1802
1803         return open_flush(inode, filp, cd);
1804 }
1805
1806 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1807 {
1808         struct cache_detail *cd = RPC_I(inode)->private;
1809
1810         return release_flush(inode, filp, cd);
1811 }
1812
1813 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1814                             size_t count, loff_t *ppos)
1815 {
1816         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1817
1818         return read_flush(filp, buf, count, ppos, cd);
1819 }
1820
1821 static ssize_t write_flush_pipefs(struct file *filp,
1822                                   const char __user *buf,
1823                                   size_t count, loff_t *ppos)
1824 {
1825         struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1826
1827         return write_flush(filp, buf, count, ppos, cd);
1828 }
1829
1830 const struct file_operations cache_flush_operations_pipefs = {
1831         .open           = open_flush_pipefs,
1832         .read           = read_flush_pipefs,
1833         .write          = write_flush_pipefs,
1834         .release        = release_flush_pipefs,
1835         .llseek         = no_llseek,
1836 };
1837
1838 int sunrpc_cache_register_pipefs(struct dentry *parent,
1839                                  const char *name, umode_t umode,
1840                                  struct cache_detail *cd)
1841 {
1842         struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1843         if (IS_ERR(dir))
1844                 return PTR_ERR(dir);
1845         cd->u.pipefs.dir = dir;
1846         return 0;
1847 }
1848 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1849
1850 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1851 {
1852         rpc_remove_cache_dir(cd->u.pipefs.dir);
1853         cd->u.pipefs.dir = NULL;
1854 }
1855 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1856