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 /*
  31  * This file is part of Lustre, http://www.lustre.org/
  32  * Lustre is a trademark of Sun Microsystems, Inc.
  33  *
  34  * libcfs/libcfs/upcall_cache.c
  35  *
  36  * Supplementary groups cache.
  37  */
  38 #define DEBUG_SUBSYSTEM S_SEC
  39
  40 #include <libcfs/lucache.h>
  41
  42 static struct upcall_cache_entry *alloc_entry(struct upcall_cache *cache,
  43                                               __u64 key, void *args)
  44 {
  45         struct upcall_cache_entry *entry;
  46
  47         LIBCFS_ALLOC(entry, sizeof(*entry));
  48         if (!entry)
  49                 return NULL;
  50
  51         UC_CACHE_SET_NEW(entry);
  52         CFS_INIT_LIST_HEAD(&entry->ue_hash);
  53         entry->ue_key = key;
  54         cfs_atomic_set(&entry->ue_refcount, 0);
  55         cfs_waitq_init(&entry->ue_waitq);
  56         if (cache->uc_ops->init_entry)
  57                 cache->uc_ops->init_entry(entry, args);
  58         return entry;
  59 }
  60
  61 /* protected by cache lock */
  62 static void free_entry(struct upcall_cache *cache,
  63                        struct upcall_cache_entry *entry)
  64 {
  65         if (cache->uc_ops->free_entry)
  66                 cache->uc_ops->free_entry(cache, entry);
  67
  68         cfs_list_del(&entry->ue_hash);
  69         CDEBUG(D_OTHER, "destroy cache entry %p for key "LPU64"\n",
  70                entry, entry->ue_key);
  71         LIBCFS_FREE(entry, sizeof(*entry));
  72 }
  73
  74 static inline int upcall_compare(struct upcall_cache *cache,
  75                                  struct upcall_cache_entry *entry,
  76                                  __u64 key, void *args)
  77 {
  78         if (entry->ue_key != key)
  79                 return -1;
  80
  81         if (cache->uc_ops->upcall_compare)
  82                 return cache->uc_ops->upcall_compare(cache, entry, key, args);
  83
  84         return 0;
  85 }
  86
  87 static inline int downcall_compare(struct upcall_cache *cache,
  88                                    struct upcall_cache_entry *entry,
  89                                    __u64 key, void *args)
  90 {
  91         if (entry->ue_key != key)
  92                 return -1;
  93
  94         if (cache->uc_ops->downcall_compare)
  95                 return cache->uc_ops->downcall_compare(cache, entry, key, args);
  96
  97         return 0;
  98 }
  99
 100 static inline void get_entry(struct upcall_cache_entry *entry)
 101 {
 102         cfs_atomic_inc(&entry->ue_refcount);
 103 }
 104
 105 static inline void put_entry(struct upcall_cache *cache,
 106                              struct upcall_cache_entry *entry)
 107 {
 108         if (cfs_atomic_dec_and_test(&entry->ue_refcount) &&
 109             (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry))) {
 110                 free_entry(cache, entry);
 111         }
 112 }
 113
 114 static int check_unlink_entry(struct upcall_cache *cache,
 115                               struct upcall_cache_entry *entry)
 116 {
 117         if (UC_CACHE_IS_VALID(entry) &&
 118             cfs_time_before(cfs_time_current(), entry->ue_expire))
 119                 return 0;
 120
 121         if (UC_CACHE_IS_ACQUIRING(entry)) {
 122                 if (entry->ue_acquire_expire == 0 ||
 123                     cfs_time_before(cfs_time_current(),
 124                                     entry->ue_acquire_expire))
 125                         return 0;
 126
 127                 UC_CACHE_SET_EXPIRED(entry);
 128                 cfs_waitq_broadcast(&entry->ue_waitq);
 129         } else if (!UC_CACHE_IS_INVALID(entry)) {
 130                 UC_CACHE_SET_EXPIRED(entry);
 131         }
 132
 133         cfs_list_del_init(&entry->ue_hash);
 134         if (!cfs_atomic_read(&entry->ue_refcount))
 135                 free_entry(cache, entry);
 136         return 1;
 137 }
 138
 139 static inline int refresh_entry(struct upcall_cache *cache,
 140                          struct upcall_cache_entry *entry)
 141 {
 142         LASSERT(cache->uc_ops->do_upcall);
 143         return cache->uc_ops->do_upcall(cache, entry);
 144 }
 145
 146 struct upcall_cache_entry *upcall_cache_get_entry(struct upcall_cache *cache,
 147                                                   __u64 key, void *args)
 148 {
 149         struct upcall_cache_entry *entry = NULL, *new = NULL, *next;
 150         cfs_list_t *head;
 151         cfs_waitlink_t wait;
 152         int rc, found;
 153         ENTRY;
 154
 155         LASSERT(cache);
 156
 157         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 158 find_again:
 159         found = 0;
 160         cfs_spin_lock(&cache->uc_lock);
 161         cfs_list_for_each_entry_safe(entry, next, head, ue_hash) {
 162                 /* check invalid & expired items */
 163                 if (check_unlink_entry(cache, entry))
 164                         continue;
 165                 if (upcall_compare(cache, entry, key, args) == 0) {
 166                         found = 1;
 167                         break;
 168                 }
 169         }
 170
 171         if (!found) {
 172                 if (!new) {
 173                         cfs_spin_unlock(&cache->uc_lock);
 174                         new = alloc_entry(cache, key, args);
 175                         if (!new) {
 176                                 CERROR("fail to alloc entry\n");
 177                                 RETURN(ERR_PTR(-ENOMEM));
 178                         }
 179                         goto find_again;
 180                 } else {
 181                         cfs_list_add(&new->ue_hash, head);
 182                         entry = new;
 183                 }
 184         } else {
 185                 if (new) {
 186                         free_entry(cache, new);
 187                         new = NULL;
 188                 }
 189                 cfs_list_move(&entry->ue_hash, head);
 190         }
 191         get_entry(entry);
 192
 193         /* acquire for new one */
 194         if (UC_CACHE_IS_NEW(entry)) {
 195                 UC_CACHE_SET_ACQUIRING(entry);
 196                 UC_CACHE_CLEAR_NEW(entry);
 197                 cfs_spin_unlock(&cache->uc_lock);
 198                 rc = refresh_entry(cache, entry);
 199                 cfs_spin_lock(&cache->uc_lock);
 200                 entry->ue_acquire_expire =
 201                         cfs_time_shift(cache->uc_acquire_expire);
 202                 if (rc < 0) {
 203                         UC_CACHE_CLEAR_ACQUIRING(entry);
 204                         UC_CACHE_SET_INVALID(entry);
 205                         cfs_waitq_broadcast(&entry->ue_waitq);
 206                         if (unlikely(rc == -EREMCHG)) {
 207                                 put_entry(cache, entry);
 208                                 GOTO(out, entry = ERR_PTR(rc));
 209                         }
 210                 }
 211         }
 212         /* someone (and only one) is doing upcall upon this item,
 213          * wait it to complete */
 214         if (UC_CACHE_IS_ACQUIRING(entry)) {
 215                 long expiry = (entry == new) ?
 216                               cfs_time_seconds(cache->uc_acquire_expire) :
 217                               CFS_MAX_SCHEDULE_TIMEOUT;
 218                 long left;
 219
 220                 cfs_waitlink_init(&wait);
 221                 cfs_waitq_add(&entry->ue_waitq, &wait);
 222                 cfs_set_current_state(CFS_TASK_INTERRUPTIBLE);
 223                 cfs_spin_unlock(&cache->uc_lock);
 224
 225                 left = cfs_waitq_timedwait(&wait, CFS_TASK_INTERRUPTIBLE,
 226                                            expiry);
 227
 228                 cfs_spin_lock(&cache->uc_lock);
 229                 cfs_waitq_del(&entry->ue_waitq, &wait);
 230                 if (UC_CACHE_IS_ACQUIRING(entry)) {
 231                         /* we're interrupted or upcall failed in the middle */
 232                         rc = left > 0 ? -EINTR : -ETIMEDOUT;
 233                         CERROR("acquire for key "LPU64": error %d\n",
 234                                entry->ue_key, rc);
 235                         put_entry(cache, entry);
 236                         GOTO(out, entry = ERR_PTR(rc));
 237                 }
 238         }
 239
 240         /* invalid means error, don't need to try again */
 241         if (UC_CACHE_IS_INVALID(entry)) {
 242                 put_entry(cache, entry);
 243                 GOTO(out, entry = ERR_PTR(-EIDRM));
 244         }
 245
 246         /* check expired
 247          * We can't refresh the existing one because some
 248          * memory might be shared by multiple processes.
 249          */
 250         if (check_unlink_entry(cache, entry)) {
 251                 /* if expired, try again. but if this entry is
 252                  * created by me but too quickly turn to expired
 253                  * without any error, should at least give a
 254                  * chance to use it once.
 255                  */
 256                 if (entry != new) {
 257                         put_entry(cache, entry);
 258                         cfs_spin_unlock(&cache->uc_lock);
 259                         new = NULL;
 260                         goto find_again;
 261                 }
 262         }
 263
 264         /* Now we know it's good */
 265 out:
 266         cfs_spin_unlock(&cache->uc_lock);
 267         RETURN(entry);
 268 }
 269 EXPORT_SYMBOL(upcall_cache_get_entry);
 270
 271 void upcall_cache_put_entry(struct upcall_cache *cache,
 272                             struct upcall_cache_entry *entry)
 273 {
 274         ENTRY;
 275
 276         if (!entry) {
 277                 EXIT;
 278                 return;
 279         }
 280
 281         LASSERT(cfs_atomic_read(&entry->ue_refcount) > 0);
 282         cfs_spin_lock(&cache->uc_lock);
 283         put_entry(cache, entry);
 284         cfs_spin_unlock(&cache->uc_lock);
 285         EXIT;
 286 }
 287 EXPORT_SYMBOL(upcall_cache_put_entry);
 288
 289 int upcall_cache_downcall(struct upcall_cache *cache, __u32 err, __u64 key,
 290                           void *args)
 291 {
 292         struct upcall_cache_entry *entry = NULL;
 293         cfs_list_t *head;
 294         int found = 0, rc = 0;
 295         ENTRY;
 296
 297         LASSERT(cache);
 298
 299         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 300
 301         cfs_spin_lock(&cache->uc_lock);
 302         cfs_list_for_each_entry(entry, head, ue_hash) {
 303                 if (downcall_compare(cache, entry, key, args) == 0) {
 304                         found = 1;
 305                         get_entry(entry);
 306                         break;
 307                 }
 308         }
 309
 310         if (!found) {
 311                 CDEBUG(D_OTHER, "%s: upcall for key "LPU64" not expected\n",
 312                        cache->uc_name, key);
 313                 /* haven't found, it's possible */
 314                 cfs_spin_unlock(&cache->uc_lock);
 315                 RETURN(-EINVAL);
 316         }
 317
 318         if (err) {
 319                 CDEBUG(D_OTHER, "%s: upcall for key "LPU64" returned %d\n",
 320                        cache->uc_name, entry->ue_key, err);
 321                 GOTO(out, rc = -EINVAL);
 322         }
 323
 324         if (!UC_CACHE_IS_ACQUIRING(entry)) {
 325                 CDEBUG(D_RPCTRACE,"%s: found uptodate entry %p (key "LPU64")\n",
 326                        cache->uc_name, entry, entry->ue_key);
 327                 GOTO(out, rc = 0);
 328         }
 329
 330         if (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry)) {
 331                 CERROR("%s: found a stale entry %p (key "LPU64") in ioctl\n",
 332                        cache->uc_name, entry, entry->ue_key);
 333                 GOTO(out, rc = -EINVAL);
 334         }
 335
 336         cfs_spin_unlock(&cache->uc_lock);
 337         if (cache->uc_ops->parse_downcall)
 338                 rc = cache->uc_ops->parse_downcall(cache, entry, args);
 339         cfs_spin_lock(&cache->uc_lock);
 340         if (rc)
 341                 GOTO(out, rc);
 342
 343         entry->ue_expire = cfs_time_shift(cache->uc_entry_expire);
 344         UC_CACHE_SET_VALID(entry);
 345         CDEBUG(D_OTHER, "%s: created upcall cache entry %p for key "LPU64"\n",
 346                cache->uc_name, entry, entry->ue_key);
 347 out:
 348         if (rc) {
 349                 UC_CACHE_SET_INVALID(entry);
 350                 cfs_list_del_init(&entry->ue_hash);
 351         }
 352         UC_CACHE_CLEAR_ACQUIRING(entry);
 353         cfs_spin_unlock(&cache->uc_lock);
 354         cfs_waitq_broadcast(&entry->ue_waitq);
 355         put_entry(cache, entry);
 356
 357         RETURN(rc);
 358 }
 359 EXPORT_SYMBOL(upcall_cache_downcall);
 360
 361 static void cache_flush(struct upcall_cache *cache, int force)
 362 {
 363         struct upcall_cache_entry *entry, *next;
 364         int i;
 365         ENTRY;
 366
 367         cfs_spin_lock(&cache->uc_lock);
 368         for (i = 0; i < UC_CACHE_HASH_SIZE; i++) {
 369                 cfs_list_for_each_entry_safe(entry, next,
 370                                          &cache->uc_hashtable[i], ue_hash) {
 371                         if (!force && cfs_atomic_read(&entry->ue_refcount)) {
 372                                 UC_CACHE_SET_EXPIRED(entry);
 373                                 continue;
 374                         }
 375                         LASSERT(!cfs_atomic_read(&entry->ue_refcount));
 376                         free_entry(cache, entry);
 377                 }
 378         }
 379         cfs_spin_unlock(&cache->uc_lock);
 380         EXIT;
 381 }
 382
 383 void upcall_cache_flush_idle(struct upcall_cache *cache)
 384 {
 385         cache_flush(cache, 0);
 386 }
 387 EXPORT_SYMBOL(upcall_cache_flush_idle);
 388
 389 void upcall_cache_flush_all(struct upcall_cache *cache)
 390 {
 391         cache_flush(cache, 1);
 392 }
 393 EXPORT_SYMBOL(upcall_cache_flush_all);
 394
 395 void upcall_cache_flush_one(struct upcall_cache *cache, __u64 key, void *args)
 396 {
 397         cfs_list_t *head;
 398         struct upcall_cache_entry *entry;
 399         int found = 0;
 400         ENTRY;
 401
 402         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 403
 404         cfs_spin_lock(&cache->uc_lock);
 405         cfs_list_for_each_entry(entry, head, ue_hash) {
 406                 if (upcall_compare(cache, entry, key, args) == 0) {
 407                         found = 1;
 408                         break;
 409                 }
 410         }
 411
 412         if (found) {
 413                 CWARN("%s: flush entry %p: key "LPU64", ref %d, fl %x, "
 414                       "cur %lu, ex %ld/%ld\n",
 415                       cache->uc_name, entry, entry->ue_key,
 416                       cfs_atomic_read(&entry->ue_refcount), entry->ue_flags,
 417                       cfs_time_current_sec(), entry->ue_acquire_expire,
 418                       entry->ue_expire);
 419                 UC_CACHE_SET_EXPIRED(entry);
 420                 if (!cfs_atomic_read(&entry->ue_refcount))
 421                         free_entry(cache, entry);
 422         }
 423         cfs_spin_unlock(&cache->uc_lock);
 424 }
 425 EXPORT_SYMBOL(upcall_cache_flush_one);
 426
 427 struct upcall_cache *upcall_cache_init(const char *name, const char *upcall,
 428                                        struct upcall_cache_ops *ops)
 429 {
 430         struct upcall_cache *cache;
 431         int i;
 432         ENTRY;
 433
 434         LIBCFS_ALLOC(cache, sizeof(*cache));
 435         if (!cache)
 436                 RETURN(ERR_PTR(-ENOMEM));
 437
 438         cfs_spin_lock_init(&cache->uc_lock);
 439         cfs_rwlock_init(&cache->uc_upcall_rwlock);
 440         for (i = 0; i < UC_CACHE_HASH_SIZE; i++)
 441                 CFS_INIT_LIST_HEAD(&cache->uc_hashtable[i]);
 442         strncpy(cache->uc_name, name, sizeof(cache->uc_name) - 1);
 443         /* upcall pathname proc tunable */
 444         strncpy(cache->uc_upcall, upcall, sizeof(cache->uc_upcall) - 1);
 445         cache->uc_entry_expire = 20 * 60;
 446         cache->uc_acquire_expire = 30;
 447         cache->uc_ops = ops;
 448
 449         RETURN(cache);
 450 }
 451 EXPORT_SYMBOL(upcall_cache_init);
 452
 453 void upcall_cache_cleanup(struct upcall_cache *cache)
 454 {
 455         if (!cache)
 456                 return;
 457         upcall_cache_flush_all(cache);
 458         LIBCFS_FREE(cache, sizeof(*cache));
 459 }
 460 EXPORT_SYMBOL(upcall_cache_cleanup);