lustre/sec/upcall_cache.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2004 Cluster File Systems, Inc.
   5  *
   6  *   This file is part of Lustre, http://www.lustre.org.
   7  *
   8  *   Lustre is free software; you can redistribute it and/or
   9  *   modify it under the terms of version 2 of the GNU General Public
  10  *   License as published by the Free Software Foundation.
  11  *
  12  *   Lustre is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with Lustre; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #ifndef EXPORT_SYMTAB
  23 # define EXPORT_SYMTAB
  24 #endif
  25 #define DEBUG_SUBSYSTEM S_LOV
  26 #include <linux/slab.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/slab.h>
  30
  31 #include <linux/obd_support.h>
  32 #include <linux/lustre_lib.h>
  33 #include <linux/lustre_idl.h>
  34 #include <linux/obd_class.h>
  35 #include <linux/lustre_ucache.h>
  36
  37 /* FIXME
  38  * current ucache implementation is simply took from group hash code, almost
  39  * without any change. it's very simple and have very limited functionality,
  40  * and probably it's also only suitable for usage of group hash.
  41  */
  42
  43 void upcall_cache_init_entry(struct upcall_cache *cache,
  44                              struct upcall_cache_entry *entry,
  45                              __u64 key)
  46 {
  47         UC_CACHE_SET_NEW(entry);
  48         INIT_LIST_HEAD(&entry->ue_hash);
  49         atomic_set(&entry->ue_refcount, 0);
  50         entry->ue_key = key;
  51         entry->ue_cache = cache;
  52         init_waitqueue_head(&entry->ue_waitq);
  53 }
  54 EXPORT_SYMBOL(upcall_cache_init_entry);
  55
  56 static inline struct upcall_cache_entry *
  57 alloc_entry(struct upcall_cache *cache, __u64 key)
  58 {
  59         LASSERT(cache->alloc_entry);
  60         return cache->alloc_entry(cache, key);
  61 }
  62
  63 static void free_entry(struct upcall_cache_entry *entry)
  64 {
  65         struct upcall_cache *cache = entry->ue_cache;
  66
  67         LASSERT(cache);
  68         LASSERT(cache->free_entry);
  69         LASSERT(atomic_read(&entry->ue_refcount) == 0);
  70
  71         CDEBUG(D_SEC, "destroy %s entry %p for key "LPU64"\n",
  72                cache->uc_name, entry, entry->ue_key);
  73
  74         list_del(&entry->ue_hash);
  75         cache->free_entry(cache, entry);
  76 }
  77
  78 static inline void get_entry(struct upcall_cache_entry *entry)
  79 {
  80         atomic_inc(&entry->ue_refcount);
  81 }
  82
  83 static inline void put_entry(struct upcall_cache_entry *entry)
  84 {
  85         if (atomic_dec_and_test(&entry->ue_refcount) &&
  86             !UC_CACHE_IS_VALID(entry)) {
  87                 free_entry(entry);
  88         }
  89 }
  90
  91 static inline int refresh_entry(struct upcall_cache_entry *entry)
  92 {
  93         struct upcall_cache *cache = entry->ue_cache;
  94
  95         LASSERT(cache);
  96         LASSERT(cache->make_upcall);
  97
  98         return cache->make_upcall(cache, entry);
  99 }
 100
 101 static int check_unlink_entry(struct upcall_cache_entry *entry)
 102 {
 103         /* upcall will be issued upon new entries immediately
 104          * after they are created
 105          */
 106         LASSERT(!UC_CACHE_IS_NEW(entry));
 107
 108         if (UC_CACHE_IS_VALID(entry) &&
 109             time_before(get_seconds(), entry->ue_expire))
 110                 return 0;
 111
 112         if (UC_CACHE_IS_ACQUIRING(entry)) {
 113                 if (time_before(get_seconds(), entry->ue_acquire_expire))
 114                         return 0;
 115                 else {
 116                         UC_CACHE_SET_EXPIRED(entry);
 117                         wake_up_all(&entry->ue_waitq);
 118                 }
 119         } else if (!UC_CACHE_IS_INVALID(entry)) {
 120                 UC_CACHE_SET_EXPIRED(entry);
 121         }
 122
 123         list_del_init(&entry->ue_hash);
 124         if (!atomic_read(&entry->ue_refcount))
 125                 free_entry(entry);
 126         return 1;
 127 }
 128
 129 /* XXX
 130  * currently always use write_lock
 131  */
 132 static struct upcall_cache_entry *
 133 __get_entry(struct upcall_cache *cache, unsigned int hash, __u64 key,
 134             int create, int async)
 135 {
 136         struct list_head *head;
 137         struct upcall_cache_entry *entry, *next, *new = NULL;
 138         int found = 0, rc;
 139         ENTRY;
 140
 141         LASSERT(hash < cache->uc_hashsize);
 142
 143         head = &cache->uc_hashtable[hash];
 144
 145 find_again:
 146         write_lock(&cache->uc_hashlock);
 147         list_for_each_entry_safe(entry, next, head, ue_hash) {
 148                 if (check_unlink_entry(entry))
 149                         continue;
 150                 if (entry->ue_key == key) {
 151                         found = 1;
 152                         break;
 153                 }
 154         }
 155
 156         if (!found) {
 157                 if (!create)
 158                         RETURN(NULL);
 159                 if (!new) {
 160                         write_unlock(&cache->uc_hashlock);
 161                         new = alloc_entry(cache, key);
 162                         if (!new) {
 163                                 CERROR("fail to alloc entry\n");
 164                                 RETURN(NULL);
 165                         }
 166                         goto find_again;
 167                 } else {
 168                         list_add(&new->ue_hash, head);
 169                         entry = new;
 170                 }
 171         } else {
 172                 if (new) {
 173                         free_entry(new);
 174                         new = NULL;
 175                 }
 176                 list_move(&entry->ue_hash, head);
 177         }
 178         get_entry(entry);
 179
 180         /* as for this moment, we have found matched entry
 181          * and hold a ref of it. if it's NEW (we created it),
 182          * we must give it a push to refresh
 183          */
 184         if (UC_CACHE_IS_NEW(entry)) {
 185                 LASSERT(entry == new);
 186                 UC_CACHE_SET_ACQUIRING(entry);
 187                 UC_CACHE_CLEAR_NEW(entry);
 188                 entry->ue_acquire_expire = get_seconds() +
 189                                            cache->uc_acquire_expire;
 190
 191                 write_unlock(&cache->uc_hashlock);
 192                 rc = refresh_entry(entry);
 193                 write_lock(&cache->uc_hashlock);
 194                 if (rc) {
 195                         UC_CACHE_CLEAR_ACQUIRING(entry);
 196                         UC_CACHE_SET_INVALID(entry);
 197                 }
 198         }
 199
 200         /* caller don't want to wait */
 201         if (async) {
 202                 write_unlock(&cache->uc_hashlock);
 203                 RETURN(entry);
 204         }
 205
 206         /* someone (and only one) is doing upcall upon
 207          * this item, just wait it complete
 208          */
 209         if (UC_CACHE_IS_ACQUIRING(entry)) {
 210                 wait_queue_t wait;
 211
 212                 init_waitqueue_entry(&wait, current);
 213                 add_wait_queue(&entry->ue_waitq, &wait);
 214                 set_current_state(TASK_INTERRUPTIBLE);
 215                 write_unlock(&cache->uc_hashlock);
 216
 217                 schedule_timeout(cache->uc_acquire_expire * HZ);
 218
 219                 write_lock(&cache->uc_hashlock);
 220                 remove_wait_queue(&entry->ue_waitq, &wait);
 221                 if (UC_CACHE_IS_ACQUIRING(entry)) {
 222                         /* we're interrupted or upcall failed
 223                          * in the middle
 224                          */
 225                         CERROR("entry %p not refreshed: cur %lu, key "LPU64", "
 226                                "ref %d fl %u, ac %ld, ex %ld\n",
 227                                entry, get_seconds(), entry->ue_key,
 228                                atomic_read(&entry->ue_refcount),
 229                                entry->ue_flags, entry->ue_acquire_expire,
 230                                entry->ue_expire);
 231                         put_entry(entry);
 232                         write_unlock(&cache->uc_hashlock);
 233                         CERROR("Interrupted? Or check whether %s is in place\n",
 234                                cache->uc_upcall);
 235                         RETURN(NULL);
 236                 }
 237                 /* fall through */
 238         }
 239
 240         /* invalid means error, don't need to try again */
 241         if (UC_CACHE_IS_INVALID(entry)) {
 242                 put_entry(entry);
 243                 write_unlock(&cache->uc_hashlock);
 244                 RETURN(NULL);
 245         }
 246
 247         /* check expired
 248          * We can't refresh the existed one because some
 249          * memory might be shared by multiple processes.
 250          */
 251         if (check_unlink_entry(entry)) {
 252                 /* if expired, try again. but if this entry is
 253                  * created by me and too quickly turn to expired
 254                  * without any error, should at least give a
 255                  * chance to use it once.
 256                  */
 257                 if (entry != new) {
 258                         put_entry(entry);
 259                         write_unlock(&cache->uc_hashlock);
 260                         new = NULL;
 261                         goto find_again;
 262                 }
 263         }
 264
 265         /* Now we know it's good */
 266         LASSERT(UC_CACHE_IS_VALID(entry));
 267         write_unlock(&cache->uc_hashlock);
 268
 269         RETURN(entry);
 270 }
 271
 272 struct upcall_cache_entry *
 273 upcall_cache_get_entry(struct upcall_cache *cache, __u64 key)
 274 {
 275         unsigned int hash;
 276
 277         LASSERT(cache->hash);
 278
 279         hash = cache->hash(cache, key);
 280
 281         return __get_entry(cache, hash, key, 1, 0);
 282 }
 283 EXPORT_SYMBOL(upcall_cache_get_entry);
 284
 285 void upcall_cache_put_entry(struct upcall_cache_entry *entry)
 286 {
 287         struct upcall_cache *cache = entry->ue_cache;
 288
 289         write_lock(&cache->uc_hashlock);
 290         LASSERTF(atomic_read(&entry->ue_refcount) > 0,
 291                  "entry %p: ref %d\n", entry, atomic_read(&entry->ue_refcount));
 292         put_entry(entry);
 293         write_unlock(&cache->uc_hashlock);
 294 }
 295 EXPORT_SYMBOL(upcall_cache_put_entry);
 296
 297 int upcall_cache_downcall(struct upcall_cache *cache, __u64 key, void *args)
 298 {
 299         struct list_head *head;
 300         struct upcall_cache_entry *entry;
 301         int found = 0, rc;
 302         unsigned int hash;
 303         ENTRY;
 304
 305         hash = cache->hash(cache, key);
 306         LASSERT(hash < cache->uc_hashsize);
 307
 308         head = &cache->uc_hashtable[hash];
 309
 310         write_lock(&cache->uc_hashlock);
 311         list_for_each_entry(entry, head, ue_hash) {
 312                 if (entry->ue_key == key) {
 313                         found = 1;
 314                         break;
 315                 }
 316         }
 317         if (!found) {
 318                 /* haven't found, it's possible */
 319                 write_unlock(&cache->uc_hashlock);
 320                 CWARN("key "LPU64" entry dosen't found\n", key);
 321                 RETURN(-EINVAL);
 322         }
 323
 324         if (!UC_CACHE_IS_ACQUIRING(entry)) {
 325                 if (UC_CACHE_IS_VALID(entry)) {
 326                         /* This should not happen, just give a warning
 327                          * at this moment.
 328                          */
 329                         CWARN("entry %p(key "LPU64", ac %ld, ex %ld): "
 330                               "already valid???\n", entry, entry->ue_key,
 331                               entry->ue_acquire_expire, entry->ue_expire);
 332                         GOTO(out, rc = 0);
 333                 }
 334
 335                 CWARN("stale entry %p: cur %lu, key "LPU64", ref %d, "
 336                       "fl %u, ac %ld, ex %ld\n",
 337                        entry, get_seconds(), entry->ue_key,
 338                        atomic_read(&entry->ue_refcount), entry->ue_flags,
 339                        entry->ue_acquire_expire, entry->ue_expire);
 340                 GOTO(out, rc = -EINVAL);
 341         }
 342
 343         if (!UC_CACHE_IS_ACQUIRING(entry) ||
 344             UC_CACHE_IS_INVALID(entry) ||
 345             UC_CACHE_IS_EXPIRED(entry)) {
 346                 CWARN("stale entry %p: cur %lu, key "LPU64", ref %d, "
 347                       "fl %u, ac %ld, ex %ld\n",
 348                        entry, get_seconds(), entry->ue_key,
 349                        atomic_read(&entry->ue_refcount), entry->ue_flags,
 350                        entry->ue_acquire_expire, entry->ue_expire);
 351                 GOTO(out, rc = -EINVAL);
 352         }
 353
 354         atomic_inc(&entry->ue_refcount);
 355         write_unlock(&cache->uc_hashlock);
 356         rc = cache->parse_downcall(cache, entry, args);
 357         write_lock(&cache->uc_hashlock);
 358         atomic_dec(&entry->ue_refcount);
 359
 360         if (rc < 0) {
 361                 UC_CACHE_SET_INVALID(entry);
 362                 list_del_init(&entry->ue_hash);
 363                 GOTO(out, rc);
 364         } else if (rc == 0) {
 365                 entry->ue_expire = get_seconds() + cache->uc_entry_expire;
 366         } else {
 367                 entry->ue_expire = get_seconds() + cache->uc_err_entry_expire;
 368         }
 369
 370         UC_CACHE_SET_VALID(entry);
 371         CDEBUG(D_SEC, "create ucache entry %p(key "LPU64")\n",
 372                entry, entry->ue_key);
 373 out:
 374         wake_up_all(&entry->ue_waitq);
 375         write_unlock(&cache->uc_hashlock);
 376         RETURN(rc);
 377 }
 378 EXPORT_SYMBOL(upcall_cache_downcall);
 379
 380 void upcall_cache_flush_one(struct upcall_cache *cache, __u64 key)
 381 {
 382         struct list_head *head;
 383         struct upcall_cache_entry *entry;
 384         unsigned int hash;
 385         int found = 0;
 386         ENTRY;
 387
 388         hash = cache->hash(cache, key);
 389         LASSERT(hash < cache->uc_hashsize);
 390
 391         head = &cache->uc_hashtable[hash];
 392
 393         write_lock(&cache->uc_hashlock);
 394         list_for_each_entry(entry, head, ue_hash) {
 395                 if (entry->ue_key == key) {
 396                         found = 1;
 397                         break;
 398                 }
 399         }
 400
 401         if (found) {
 402                 UC_CACHE_SET_EXPIRED(entry);
 403                 if (!atomic_read(&entry->ue_refcount))
 404                         free_entry(entry);
 405         }
 406         write_unlock(&cache->uc_hashlock);
 407 }
 408 EXPORT_SYMBOL(upcall_cache_flush_one);
 409
 410 static void cache_flush(struct upcall_cache *cache, int force, int sync)
 411 {
 412         struct upcall_cache_entry *entry, *next;
 413         int i;
 414         ENTRY;
 415
 416         write_lock(&cache->uc_hashlock);
 417         for (i = 0; i < cache->uc_hashsize; i++) {
 418                 list_for_each_entry_safe(entry, next,
 419                                          &cache->uc_hashtable[i], ue_hash) {
 420                         if (!force && atomic_read(&entry->ue_refcount)) {
 421                                 UC_CACHE_SET_EXPIRED(entry);
 422                                 continue;
 423                         }
 424                         LASSERT(!atomic_read(&entry->ue_refcount));
 425                         free_entry(entry);
 426                 }
 427         }
 428         write_unlock(&cache->uc_hashlock);
 429         EXIT;
 430 }
 431
 432 void upcall_cache_flush_idle(struct upcall_cache *cache)
 433 {
 434         cache_flush(cache, 0, 0);
 435 }
 436
 437 void upcall_cache_flush_all(struct upcall_cache *cache)
 438 {
 439         cache_flush(cache, 1, 0);
 440 }
 441 EXPORT_SYMBOL(upcall_cache_flush_idle);
 442 EXPORT_SYMBOL(upcall_cache_flush_all);