libcfs/libcfs/upcall_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2012, 2014, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * libcfs/libcfs/upcall_cache.c
  37  *
  38  * Supplementary groups cache.
  39  */
  40 #define DEBUG_SUBSYSTEM S_SEC
  41
  42 #include <libcfs/lucache.h>
  43 #include <lnet/types.h>
  44
  45 static struct upcall_cache_entry *alloc_entry(struct upcall_cache *cache,
  46                                               __u64 key, void *args)
  47 {
  48         struct upcall_cache_entry *entry;
  49
  50         LIBCFS_ALLOC(entry, sizeof(*entry));
  51         if (!entry)
  52                 return NULL;
  53
  54         UC_CACHE_SET_NEW(entry);
  55         INIT_LIST_HEAD(&entry->ue_hash);
  56         entry->ue_key = key;
  57         atomic_set(&entry->ue_refcount, 0);
  58         init_waitqueue_head(&entry->ue_waitq);
  59         if (cache->uc_ops->init_entry)
  60                 cache->uc_ops->init_entry(entry, args);
  61         return entry;
  62 }
  63
  64 /* protected by cache lock */
  65 static void free_entry(struct upcall_cache *cache,
  66                        struct upcall_cache_entry *entry)
  67 {
  68         if (cache->uc_ops->free_entry)
  69                 cache->uc_ops->free_entry(cache, entry);
  70
  71         list_del(&entry->ue_hash);
  72         CDEBUG(D_OTHER, "destroy cache entry %p for key "LPU64"\n",
  73                 entry, entry->ue_key);
  74         LIBCFS_FREE(entry, sizeof(*entry));
  75 }
  76
  77 static inline int upcall_compare(struct upcall_cache *cache,
  78                                  struct upcall_cache_entry *entry,
  79                                  __u64 key, void *args)
  80 {
  81         if (entry->ue_key != key)
  82                 return -1;
  83
  84         if (cache->uc_ops->upcall_compare)
  85                 return cache->uc_ops->upcall_compare(cache, entry, key, args);
  86
  87         return 0;
  88 }
  89
  90 static inline int downcall_compare(struct upcall_cache *cache,
  91                                    struct upcall_cache_entry *entry,
  92                                    __u64 key, void *args)
  93 {
  94         if (entry->ue_key != key)
  95                 return -1;
  96
  97         if (cache->uc_ops->downcall_compare)
  98                 return cache->uc_ops->downcall_compare(cache, entry, key, args);
  99
 100         return 0;
 101 }
 102
 103 static inline void get_entry(struct upcall_cache_entry *entry)
 104 {
 105         atomic_inc(&entry->ue_refcount);
 106 }
 107
 108 static inline void put_entry(struct upcall_cache *cache,
 109                              struct upcall_cache_entry *entry)
 110 {
 111         if (atomic_dec_and_test(&entry->ue_refcount) &&
 112             (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry))) {
 113                 free_entry(cache, entry);
 114         }
 115 }
 116
 117 static int check_unlink_entry(struct upcall_cache *cache,
 118                               struct upcall_cache_entry *entry)
 119 {
 120         if (UC_CACHE_IS_VALID(entry) &&
 121             cfs_time_before(cfs_time_current(), entry->ue_expire))
 122                 return 0;
 123
 124         if (UC_CACHE_IS_ACQUIRING(entry)) {
 125                 if (entry->ue_acquire_expire == 0 ||
 126                     cfs_time_before(cfs_time_current(),
 127                                     entry->ue_acquire_expire))
 128                         return 0;
 129
 130                 UC_CACHE_SET_EXPIRED(entry);
 131                 wake_up_all(&entry->ue_waitq);
 132         } else if (!UC_CACHE_IS_INVALID(entry)) {
 133                 UC_CACHE_SET_EXPIRED(entry);
 134         }
 135
 136         list_del_init(&entry->ue_hash);
 137         if (!atomic_read(&entry->ue_refcount))
 138                 free_entry(cache, entry);
 139         return 1;
 140 }
 141
 142 static inline int refresh_entry(struct upcall_cache *cache,
 143                          struct upcall_cache_entry *entry)
 144 {
 145         LASSERT(cache->uc_ops->do_upcall);
 146         return cache->uc_ops->do_upcall(cache, entry);
 147 }
 148
 149 struct upcall_cache_entry *upcall_cache_get_entry(struct upcall_cache *cache,
 150                                                   __u64 key, void *args)
 151 {
 152         struct upcall_cache_entry *entry = NULL, *new = NULL, *next;
 153         struct list_head *head;
 154         wait_queue_t wait;
 155         int rc, found;
 156         ENTRY;
 157
 158         LASSERT(cache);
 159
 160         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 161 find_again:
 162         found = 0;
 163         spin_lock(&cache->uc_lock);
 164         list_for_each_entry_safe(entry, next, head, ue_hash) {
 165                 /* check invalid & expired items */
 166                 if (check_unlink_entry(cache, entry))
 167                         continue;
 168                 if (upcall_compare(cache, entry, key, args) == 0) {
 169                         found = 1;
 170                         break;
 171                 }
 172         }
 173
 174         if (!found) {
 175                 if (!new) {
 176                         spin_unlock(&cache->uc_lock);
 177                         new = alloc_entry(cache, key, args);
 178                         if (!new) {
 179                                 CERROR("fail to alloc entry\n");
 180                                 RETURN(ERR_PTR(-ENOMEM));
 181                         }
 182                         goto find_again;
 183                 } else {
 184                         list_add(&new->ue_hash, head);
 185                         entry = new;
 186                 }
 187         } else {
 188                 if (new) {
 189                         free_entry(cache, new);
 190                         new = NULL;
 191                 }
 192                 list_move(&entry->ue_hash, head);
 193         }
 194         get_entry(entry);
 195
 196         /* acquire for new one */
 197         if (UC_CACHE_IS_NEW(entry)) {
 198                 UC_CACHE_SET_ACQUIRING(entry);
 199                 UC_CACHE_CLEAR_NEW(entry);
 200                 spin_unlock(&cache->uc_lock);
 201                 rc = refresh_entry(cache, entry);
 202                 spin_lock(&cache->uc_lock);
 203                 entry->ue_acquire_expire =
 204                         cfs_time_shift(cache->uc_acquire_expire);
 205                 if (rc < 0) {
 206                         UC_CACHE_CLEAR_ACQUIRING(entry);
 207                         UC_CACHE_SET_INVALID(entry);
 208                         wake_up_all(&entry->ue_waitq);
 209                         if (unlikely(rc == -EREMCHG)) {
 210                                 put_entry(cache, entry);
 211                                 GOTO(out, entry = ERR_PTR(rc));
 212                         }
 213                 }
 214         }
 215         /* someone (and only one) is doing upcall upon this item,
 216          * wait it to complete */
 217         if (UC_CACHE_IS_ACQUIRING(entry)) {
 218                 long expiry = (entry == new) ?
 219                               cfs_time_seconds(cache->uc_acquire_expire) :
 220                               MAX_SCHEDULE_TIMEOUT;
 221                 long left;
 222
 223                 init_waitqueue_entry_current(&wait);
 224                 add_wait_queue(&entry->ue_waitq, &wait);
 225                 set_current_state(TASK_INTERRUPTIBLE);
 226                 spin_unlock(&cache->uc_lock);
 227
 228                 left = waitq_timedwait(&wait, TASK_INTERRUPTIBLE,
 229                                            expiry);
 230
 231                 spin_lock(&cache->uc_lock);
 232                 remove_wait_queue(&entry->ue_waitq, &wait);
 233                 if (UC_CACHE_IS_ACQUIRING(entry)) {
 234                         /* we're interrupted or upcall failed in the middle */
 235                         rc = left > 0 ? -EINTR : -ETIMEDOUT;
 236                         CERROR("acquire for key "LPU64": error %d\n",
 237                                entry->ue_key, rc);
 238                         put_entry(cache, entry);
 239                         GOTO(out, entry = ERR_PTR(rc));
 240                 }
 241         }
 242
 243         /* invalid means error, don't need to try again */
 244         if (UC_CACHE_IS_INVALID(entry)) {
 245                 put_entry(cache, entry);
 246                 GOTO(out, entry = ERR_PTR(-EIDRM));
 247         }
 248
 249         /* check expired
 250          * We can't refresh the existing one because some
 251          * memory might be shared by multiple processes.
 252          */
 253         if (check_unlink_entry(cache, entry)) {
 254                 /* if expired, try again. but if this entry is
 255                  * created by me but too quickly turn to expired
 256                  * without any error, should at least give a
 257                  * chance to use it once.
 258                  */
 259                 if (entry != new) {
 260                         put_entry(cache, entry);
 261                         spin_unlock(&cache->uc_lock);
 262                         new = NULL;
 263                         goto find_again;
 264                 }
 265         }
 266
 267         /* Now we know it's good */
 268 out:
 269         spin_unlock(&cache->uc_lock);
 270         RETURN(entry);
 271 }
 272 EXPORT_SYMBOL(upcall_cache_get_entry);
 273
 274 void upcall_cache_put_entry(struct upcall_cache *cache,
 275                             struct upcall_cache_entry *entry)
 276 {
 277         ENTRY;
 278
 279         if (!entry) {
 280                 EXIT;
 281                 return;
 282         }
 283
 284         LASSERT(atomic_read(&entry->ue_refcount) > 0);
 285         spin_lock(&cache->uc_lock);
 286         put_entry(cache, entry);
 287         spin_unlock(&cache->uc_lock);
 288         EXIT;
 289 }
 290 EXPORT_SYMBOL(upcall_cache_put_entry);
 291
 292 int upcall_cache_downcall(struct upcall_cache *cache, __u32 err, __u64 key,
 293                           void *args)
 294 {
 295         struct upcall_cache_entry *entry = NULL;
 296         struct list_head *head;
 297         int found = 0, rc = 0;
 298         ENTRY;
 299
 300         LASSERT(cache);
 301
 302         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 303
 304         spin_lock(&cache->uc_lock);
 305         list_for_each_entry(entry, head, ue_hash) {
 306                 if (downcall_compare(cache, entry, key, args) == 0) {
 307                         found = 1;
 308                         get_entry(entry);
 309                         break;
 310                 }
 311         }
 312
 313         if (!found) {
 314                 CDEBUG(D_OTHER, "%s: upcall for key "LPU64" not expected\n",
 315                        cache->uc_name, key);
 316                 /* haven't found, it's possible */
 317                 spin_unlock(&cache->uc_lock);
 318                 RETURN(-EINVAL);
 319         }
 320
 321         if (err) {
 322                 CDEBUG(D_OTHER, "%s: upcall for key "LPU64" returned %d\n",
 323                        cache->uc_name, entry->ue_key, err);
 324                 GOTO(out, rc = -EINVAL);
 325         }
 326
 327         if (!UC_CACHE_IS_ACQUIRING(entry)) {
 328                 CDEBUG(D_RPCTRACE,"%s: found uptodate entry %p (key "LPU64")\n",
 329                        cache->uc_name, entry, entry->ue_key);
 330                 GOTO(out, rc = 0);
 331         }
 332
 333         if (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry)) {
 334                 CERROR("%s: found a stale entry %p (key "LPU64") in ioctl\n",
 335                        cache->uc_name, entry, entry->ue_key);
 336                 GOTO(out, rc = -EINVAL);
 337         }
 338
 339         spin_unlock(&cache->uc_lock);
 340         if (cache->uc_ops->parse_downcall)
 341                 rc = cache->uc_ops->parse_downcall(cache, entry, args);
 342         spin_lock(&cache->uc_lock);
 343         if (rc)
 344                 GOTO(out, rc);
 345
 346         entry->ue_expire = cfs_time_shift(cache->uc_entry_expire);
 347         UC_CACHE_SET_VALID(entry);
 348         CDEBUG(D_OTHER, "%s: created upcall cache entry %p for key "LPU64"\n",
 349                cache->uc_name, entry, entry->ue_key);
 350 out:
 351         if (rc) {
 352                 UC_CACHE_SET_INVALID(entry);
 353                 list_del_init(&entry->ue_hash);
 354         }
 355         UC_CACHE_CLEAR_ACQUIRING(entry);
 356         spin_unlock(&cache->uc_lock);
 357         wake_up_all(&entry->ue_waitq);
 358         put_entry(cache, entry);
 359
 360         RETURN(rc);
 361 }
 362 EXPORT_SYMBOL(upcall_cache_downcall);
 363
 364 static void cache_flush(struct upcall_cache *cache, int force)
 365 {
 366         struct upcall_cache_entry *entry, *next;
 367         int i;
 368         ENTRY;
 369
 370         spin_lock(&cache->uc_lock);
 371         for (i = 0; i < UC_CACHE_HASH_SIZE; i++) {
 372                 list_for_each_entry_safe(entry, next,
 373                                          &cache->uc_hashtable[i], ue_hash) {
 374                         if (!force && atomic_read(&entry->ue_refcount)) {
 375                                 UC_CACHE_SET_EXPIRED(entry);
 376                                 continue;
 377                         }
 378                         LASSERT(!atomic_read(&entry->ue_refcount));
 379                         free_entry(cache, entry);
 380                 }
 381         }
 382         spin_unlock(&cache->uc_lock);
 383         EXIT;
 384 }
 385
 386 void upcall_cache_flush_idle(struct upcall_cache *cache)
 387 {
 388         cache_flush(cache, 0);
 389 }
 390 EXPORT_SYMBOL(upcall_cache_flush_idle);
 391
 392 void upcall_cache_flush_all(struct upcall_cache *cache)
 393 {
 394         cache_flush(cache, 1);
 395 }
 396 EXPORT_SYMBOL(upcall_cache_flush_all);
 397
 398 void upcall_cache_flush_one(struct upcall_cache *cache, __u64 key, void *args)
 399 {
 400         struct list_head *head;
 401         struct upcall_cache_entry *entry;
 402         int found = 0;
 403         ENTRY;
 404
 405         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 406
 407         spin_lock(&cache->uc_lock);
 408         list_for_each_entry(entry, head, ue_hash) {
 409                 if (upcall_compare(cache, entry, key, args) == 0) {
 410                         found = 1;
 411                         break;
 412                 }
 413         }
 414
 415         if (found) {
 416                 CWARN("%s: flush entry %p: key "LPU64", ref %d, fl %x, "
 417                       "cur %lu, ex %ld/%ld\n",
 418                       cache->uc_name, entry, entry->ue_key,
 419                       atomic_read(&entry->ue_refcount), entry->ue_flags,
 420                       cfs_time_current_sec(), entry->ue_acquire_expire,
 421                       entry->ue_expire);
 422                 UC_CACHE_SET_EXPIRED(entry);
 423                 if (!atomic_read(&entry->ue_refcount))
 424                         free_entry(cache, entry);
 425         }
 426         spin_unlock(&cache->uc_lock);
 427 }
 428 EXPORT_SYMBOL(upcall_cache_flush_one);
 429
 430 struct upcall_cache *upcall_cache_init(const char *name, const char *upcall,
 431                                        struct upcall_cache_ops *ops)
 432 {
 433         struct upcall_cache *cache;
 434         int i;
 435         ENTRY;
 436
 437         LIBCFS_ALLOC(cache, sizeof(*cache));
 438         if (!cache)
 439                 RETURN(ERR_PTR(-ENOMEM));
 440
 441         spin_lock_init(&cache->uc_lock);
 442         rwlock_init(&cache->uc_upcall_rwlock);
 443         for (i = 0; i < UC_CACHE_HASH_SIZE; i++)
 444                 INIT_LIST_HEAD(&cache->uc_hashtable[i]);
 445         strlcpy(cache->uc_name, name, sizeof(cache->uc_name));
 446         /* upcall pathname proc tunable */
 447         strlcpy(cache->uc_upcall, upcall, sizeof(cache->uc_upcall));
 448         cache->uc_entry_expire = 20 * 60;
 449         cache->uc_acquire_expire = 30;
 450         cache->uc_ops = ops;
 451
 452         RETURN(cache);
 453 }
 454 EXPORT_SYMBOL(upcall_cache_init);
 455
 456 void upcall_cache_cleanup(struct upcall_cache *cache)
 457 {
 458         if (!cache)
 459                 return;
 460         upcall_cache_flush_all(cache);
 461         LIBCFS_FREE(cache, sizeof(*cache));
 462 }
 463 EXPORT_SYMBOL(upcall_cache_cleanup);