git.sur5r.net Git - openldap/blob - servers/slapd/back-bdb/cache.c

   1 /* cache.c - routines to maintain an in-core cache of entries */
   2 /* $OpenLDAP$ */
   3 /*
   4  * Copyright 1998-2002 The OpenLDAP Foundation, All Rights Reserved.
   5  * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
   6  */
   7
   8 #include "portable.h"
   9
  10 #include <stdio.h>
  11
  12 #include <ac/errno.h>
  13 #include <ac/string.h>
  14 #include <ac/socket.h>
  15
  16 #include "slap.h"
  17
  18 #include "back-bdb.h"
  19
  20 /* BDB backend specific entry info -- visible only to the cache */
  21 typedef struct bdb_entry_info {
  22         ldap_pvt_thread_rdwr_t  bei_rdwr;       /* reader/writer lock */
  23
  24         /*
  25          * remaining fields require backend cache lock to access
  26          * These items are specific to the BDB backend and should
  27          * be hidden.
  28          */
  29         int             bei_state;      /* for the cache */
  30 #define CACHE_ENTRY_UNDEFINED   0
  31 #define CACHE_ENTRY_CREATING    1
  32 #define CACHE_ENTRY_READY       2
  33 #define CACHE_ENTRY_DELETED     3
  34 #define CACHE_ENTRY_COMMITTED   4
  35
  36         int             bei_refcnt;     /* # threads ref'ing this entry */
  37         Entry   *bei_lrunext;   /* for cache lru list */
  38         Entry   *bei_lruprev;
  39 } EntryInfo;
  40 #undef BEI
  41 #define BEI(e)  ((EntryInfo *) ((e)->e_private))
  42
  43 static int      bdb_cache_delete_entry_internal(Cache *cache, Entry *e);
  44 #ifdef LDAP_DEBUG
  45 static void     bdb_lru_print(Cache *cache);
  46 #endif
  47
  48 static int
  49 bdb_cache_entry_rdwr_lock(Entry *e, int rw)
  50 {
  51 #ifdef NEW_LOGGING
  52         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
  53                    "bdb_cache_entry_rdwr_lock: %s lock on ID %ld\n",
  54                    rw ? "w" : "r", e->e_id ));
  55 #else
  56         Debug( LDAP_DEBUG_ARGS, "entry_rdwr_%slock: ID: %ld\n",
  57                 rw ? "w" : "r", e->e_id, 0);
  58 #endif
  59
  60         if (rw)
  61                 return ldap_pvt_thread_rdwr_wlock(&BEI(e)->bei_rdwr);
  62         else
  63                 return ldap_pvt_thread_rdwr_rlock(&BEI(e)->bei_rdwr);
  64 }
  65
  66 static int
  67 bdb_cache_entry_rdwr_trylock(Entry *e, int rw)
  68 {
  69 #ifdef NEW_LOGGING
  70         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
  71                    "bdb_cache_entry_rdwr_trylock: try %s lock on ID: %ld.\n",
  72                    rw ? "w" : "r", e->e_id ));
  73 #else
  74         Debug( LDAP_DEBUG_ARGS, "entry_rdwr_%strylock: ID: %ld\n",
  75                 rw ? "w" : "r", e->e_id, 0);
  76 #endif
  77
  78         if (rw)
  79                 return ldap_pvt_thread_rdwr_wtrylock(&BEI(e)->bei_rdwr);
  80         else
  81                 return ldap_pvt_thread_rdwr_rtrylock(&BEI(e)->bei_rdwr);
  82 }
  83
  84 static int
  85 bdb_cache_entry_rdwr_unlock(Entry *e, int rw)
  86 {
  87 #ifdef NEW_LOGGING
  88         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
  89                    "bdb_cache_entry_rdwr_unlock: remove %s lock on ID %ld.\n",
  90                    rw ? "w" : "r", e->e_id ));
  91 #else
  92         Debug( LDAP_DEBUG_ARGS, "entry_rdwr_%sunlock: ID: %ld\n",
  93                 rw ? "w" : "r", e->e_id, 0);
  94 #endif
  95
  96         if (rw)
  97                 return ldap_pvt_thread_rdwr_wunlock(&BEI(e)->bei_rdwr);
  98         else
  99                 return ldap_pvt_thread_rdwr_runlock(&BEI(e)->bei_rdwr);
 100 }
 101
 102 static int
 103 bdb_cache_entry_rdwr_init(Entry *e)
 104 {
 105         return ldap_pvt_thread_rdwr_init( &BEI(e)->bei_rdwr );
 106 }
 107
 108 static int
 109 bdb_cache_entry_rdwr_destroy(Entry *e)
 110 {
 111         return ldap_pvt_thread_rdwr_destroy( &BEI(e)->bei_rdwr );
 112 }
 113
 114 static int
 115 bdb_cache_entry_private_init( Entry *e )
 116 {
 117         assert( e->e_private == NULL );
 118
 119         if( e->e_private != NULL ) {
 120                 /* this should never happen */
 121                 return 1;
 122         }
 123
 124         e->e_private = ch_calloc(1, sizeof(struct bdb_entry_info));
 125
 126         if( bdb_cache_entry_rdwr_init( e ) != 0 ) {
 127                 free( BEI(e) );
 128                 e->e_private = NULL;
 129                 return 1;
 130         }
 131
 132         return 0;
 133 }
 134
 135 int
 136 bdb_cache_entry_db_lock
 137 ( DB_ENV *env, u_int32_t locker, Entry *e, int rw, u_int32_t flags, DB_LOCK *lock )
 138 {
 139         int       rc;
 140         DBT       lockobj;
 141         int       db_rw;
 142
 143         if (rw)
 144                 db_rw = DB_LOCK_WRITE;
 145         else
 146                 db_rw = DB_LOCK_READ;
 147
 148         lockobj.data = e->e_nname.bv_val;
 149         lockobj.size = e->e_nname.bv_len;
 150         rc = LOCK_GET(env, locker, flags | DB_LOCK_NOWAIT,
 151                                         &lockobj, db_rw, lock);
 152         return rc;
 153 }
 154
 155 int
 156 bdb_cache_entry_db_unlock
 157 ( DB_ENV *env, DB_LOCK *lock )
 158 {
 159         int rc;
 160
 161         rc = LOCK_PUT ( env, lock );
 162         return rc;
 163 }
 164
 165 /*
 166  * marks an entry in CREATING state as committed, so it is really returned
 167  * to the cache. Otherwise an entry in CREATING state is removed.
 168  * Makes e_private be destroyed at the following cache_return_entry_w,
 169  * but lets the entry untouched (owned by someone else)
 170  */
 171 void
 172 bdb_cache_entry_commit( Entry *e )
 173 {
 174         assert( e );
 175         assert( e->e_private );
 176         assert( BEI(e)->bei_state == CACHE_ENTRY_CREATING );
 177         /* assert( BEI(e)->bei_refcnt == 1 ); */
 178
 179         BEI(e)->bei_state = CACHE_ENTRY_COMMITTED;
 180 }
 181
 182 static int
 183 bdb_cache_entry_private_destroy( Entry *e )
 184 {
 185         assert( e->e_private );
 186
 187         bdb_cache_entry_rdwr_destroy( e );
 188
 189         free( e->e_private );
 190         e->e_private = NULL;
 191         return 0;
 192 }
 193
 194 void
 195 bdb_unlocked_cache_return_entry_rw( Cache *cache, Entry *e, int rw )
 196 {
 197
 198         ID id;
 199         int refcnt, freeit = 1;
 200
 201         /* set cache write lock */
 202         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 203
 204         assert( e->e_private );
 205
 206 #if 0
 207         bdb_cache_entry_rdwr_unlock(e, rw);
 208 #endif
 209
 210         id = e->e_id;
 211         refcnt = --BEI(e)->bei_refcnt;
 212
 213         /*
 214          * if the entry is returned when in CREATING state, it is deleted
 215          * but not freed because it may belong to someone else (do_add,
 216          * for instance)
 217          */
 218         if (  BEI(e)->bei_state == CACHE_ENTRY_CREATING ) {
 219                 /* set lru mutex */
 220                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 221                 bdb_cache_delete_entry_internal( cache, e );
 222                 /* free lru mutex */
 223                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 224                 freeit = 0;
 225                 /* now the entry is in DELETED state */
 226         }
 227
 228         if ( BEI(e)->bei_state == CACHE_ENTRY_COMMITTED ) {
 229                 BEI(e)->bei_state = CACHE_ENTRY_READY;
 230
 231                 /* free cache write lock */
 232                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 233
 234 #ifdef NEW_LOGGING
 235                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 236                            "bdb_unlocked_cache_return_entry_rw: return (%ld):%s, refcnt=%d\n",
 237                            id, rw ? "w" : "r", refcnt ));
 238 #else
 239                 Debug( LDAP_DEBUG_TRACE,
 240                         "====> bdb_unlocked_cache_return_entry_%s( %ld ): created (%d)\n",
 241                         rw ? "w" : "r", id, refcnt );
 242 #endif
 243
 244
 245         } else if ( BEI(e)->bei_state == CACHE_ENTRY_DELETED ) {
 246                 if( refcnt > 0 ) {
 247                         /* free cache write lock */
 248                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 249
 250 #ifdef NEW_LOGGING
 251                         LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 252                                    "bdb_unlocked_cache_return_entry_rw: %ld, delete pending (%d).\n",
 253                                    id, refcnt ));
 254 #else
 255                         Debug( LDAP_DEBUG_TRACE,
 256                                 "====> bdb_unlocked_cache_return_entry_%s( %ld ): delete pending (%d)\n",
 257                                 rw ? "w" : "r", id, refcnt );
 258 #endif
 259
 260                 } else {
 261                         bdb_cache_entry_private_destroy( e );
 262                         if ( freeit ) {
 263                                 bdb_entry_return( e );
 264                         }
 265
 266                         /* free cache write lock */
 267                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 268
 269 #ifdef NEW_LOGGING
 270                         LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 271                                    "bdb_unlocked_cache_return_entry_rw: (%ld): deleted (%d)\n",
 272                                    id, refcnt ));
 273 #else
 274                         Debug( LDAP_DEBUG_TRACE,
 275                                 "====> bdb_unlocked_cache_return_entry_%s( %ld ): deleted (%d)\n",
 276                                 rw ? "w" : "r", id, refcnt );
 277 #endif
 278                 }
 279
 280         } else {
 281                 /* free cache write lock */
 282                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 283
 284 #ifdef NEW_LOGGING
 285                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 286                            "bdb_unlocked_cache_return_entry_rw: ID %ld:%s returned (%d)\n",
 287                            id, rw ? "w": "r", refcnt ));
 288 #else
 289                 Debug( LDAP_DEBUG_TRACE,
 290                         "====> bdb_unlocked_cache_return_entry_%s( %ld ): returned (%d)\n",
 291                         rw ? "w" : "r", id, refcnt);
 292 #endif
 293         }
 294 }
 295
 296 void
 297 bdb_cache_return_entry_rw
 298 ( DB_ENV *env, Cache *cache, Entry *e, int rw, DB_LOCK *lock )
 299 {
 300         ID id;
 301         int refcnt, freeit = 1;
 302
 303         /* set cache write lock */
 304         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 305
 306         assert( e->e_private );
 307
 308         bdb_cache_entry_db_unlock( env, lock );
 309 #if 0
 310         bdb_cache_entry_rdwr_unlock(e, rw);
 311 #endif
 312
 313         id = e->e_id;
 314         refcnt = --BEI(e)->bei_refcnt;
 315
 316         /*
 317          * if the entry is returned when in CREATING state, it is deleted
 318          * but not freed because it may belong to someone else (do_add,
 319          * for instance)
 320          */
 321         if (  BEI(e)->bei_state == CACHE_ENTRY_CREATING ) {
 322                 /* set lru mutex */
 323                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 324                 bdb_cache_delete_entry_internal( cache, e );
 325                 /* free lru mutex */
 326                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 327                 freeit = 0;
 328                 /* now the entry is in DELETED state */
 329         }
 330
 331         if ( BEI(e)->bei_state == CACHE_ENTRY_COMMITTED ) {
 332                 BEI(e)->bei_state = CACHE_ENTRY_READY;
 333
 334                 /* free cache write lock */
 335                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 336
 337 #ifdef NEW_LOGGING
 338                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 339                            "bdb_cache_return_entry_rw: return (%ld):%s, refcnt=%d\n",
 340                            id, rw ? "w" : "r", refcnt ));
 341 #else
 342                 Debug( LDAP_DEBUG_TRACE,
 343                         "====> bdb_cache_return_entry_%s( %ld ): created (%d)\n",
 344                         rw ? "w" : "r", id, refcnt );
 345 #endif
 346
 347
 348         } else if ( BEI(e)->bei_state == CACHE_ENTRY_DELETED ) {
 349                 if( refcnt > 0 ) {
 350                         /* free cache write lock */
 351                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 352
 353 #ifdef NEW_LOGGING
 354                         LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 355                                    "bdb_cache_return_entry_rw: %ld, delete pending (%d).\n",
 356                                    id, refcnt ));
 357 #else
 358                         Debug( LDAP_DEBUG_TRACE,
 359                                 "====> bdb_cache_return_entry_%s( %ld ): delete pending (%d)\n",
 360                                 rw ? "w" : "r", id, refcnt );
 361 #endif
 362
 363                 } else {
 364                         bdb_cache_entry_private_destroy( e );
 365                         if ( freeit ) {
 366                                 bdb_entry_return( e );
 367                         }
 368
 369                         /* free cache write lock */
 370                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 371
 372 #ifdef NEW_LOGGING
 373                         LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 374                                    "bdb_cache_return_entry_rw: (%ld): deleted (%d)\n",
 375                                    id, refcnt ));
 376 #else
 377                         Debug( LDAP_DEBUG_TRACE,
 378                                 "====> bdb_cache_return_entry_%s( %ld ): deleted (%d)\n",
 379                                 rw ? "w" : "r", id, refcnt );
 380 #endif
 381                 }
 382
 383         } else {
 384                 /* free cache write lock */
 385                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 386
 387 #ifdef NEW_LOGGING
 388                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 389                            "bdb_cache_return_entry_rw: ID %ld:%s returned (%d)\n",
 390                            id, rw ? "w": "r", refcnt ));
 391 #else
 392                 Debug( LDAP_DEBUG_TRACE,
 393                         "====> bdb_cache_return_entry_%s( %ld ): returned (%d)\n",
 394                         rw ? "w" : "r", id, refcnt);
 395 #endif
 396         }
 397 }
 398
 399 #define LRU_DELETE( cache, e ) do { \
 400         if ( BEI(e)->bei_lruprev != NULL ) { \
 401                 BEI(BEI(e)->bei_lruprev)->bei_lrunext = BEI(e)->bei_lrunext; \
 402         } else { \
 403                 (cache)->c_lruhead = BEI(e)->bei_lrunext; \
 404         } \
 405         if ( BEI(e)->bei_lrunext != NULL ) { \
 406                 BEI(BEI(e)->bei_lrunext)->bei_lruprev = BEI(e)->bei_lruprev; \
 407         } else { \
 408                 (cache)->c_lrutail = BEI(e)->bei_lruprev; \
 409         } \
 410 } while(0)
 411
 412 #define LRU_ADD( cache, e ) do { \
 413         BEI(e)->bei_lrunext = (cache)->c_lruhead; \
 414         if ( BEI(e)->bei_lrunext != NULL ) { \
 415                 BEI(BEI(e)->bei_lrunext)->bei_lruprev = (e); \
 416         } \
 417         (cache)->c_lruhead = (e); \
 418         BEI(e)->bei_lruprev = NULL; \
 419         if ( (cache)->c_lrutail == NULL ) { \
 420                 (cache)->c_lrutail = (e); \
 421         } \
 422 } while(0)
 423
 424 /*
 425  * cache_add_entry_rw - create and lock an entry in the cache
 426  * returns:     0       entry has been created and locked
 427  *              1       entry already existed
 428  *              -1      something bad happened
 429  *             other    Berkeley DB locking error code
 430  */
 431 int
 432 bdb_cache_add_entry_rw(
 433     DB_ENV      *env,
 434     Cache       *cache,
 435     Entry       *e,
 436     int         rw,
 437     u_int32_t   locker,
 438     DB_LOCK     *lock
 439 )
 440 {
 441         int     i, rc;
 442         Entry   *ee;
 443
 444 #ifdef NEW_LOGGING
 445         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
 446                    "bdb_cache_add_entry_rw: add (%s):%s to cache\n",
 447                    e->e_dn, rw ? "w" : "r" ));
 448 #endif
 449         /* set cache write lock */
 450         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 451
 452         assert( e->e_private == NULL );
 453
 454         if( bdb_cache_entry_private_init(e) != 0 ) {
 455                 /* free cache write lock */
 456                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 457
 458 #ifdef NEW_LOGGING
 459                 LDAP_LOG(( "cache", LDAP_LEVEL_ERR,
 460                            "bdb_cache_add_entry_rw: add (%s):%ld private init failed!\n",
 461                            e->e_dn, e->e_id ));
 462 #else
 463                 Debug( LDAP_DEBUG_ANY,
 464                         "====> bdb_cache_add_entry( %ld ): \"%s\": private init failed!\n",
 465                     e->e_id, e->e_dn, 0 );
 466 #endif
 467
 468
 469                 return( -1 );
 470         }
 471
 472         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 473                 (AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
 474         {
 475                 /* free cache write lock */
 476                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 477
 478 #ifdef NEW_LOGGING
 479                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 480                            "bdb_cache_add_entry: (%s):%ld already in cache.\n",
 481                            e->e_dn, e->e_id ));
 482 #else
 483                 Debug( LDAP_DEBUG_TRACE,
 484                         "====> bdb_cache_add_entry( %ld ): \"%s\": already in dn cache\n",
 485                     e->e_id, e->e_dn, 0 );
 486 #endif
 487
 488                 bdb_cache_entry_private_destroy(e);
 489
 490                 return( 1 );
 491         }
 492
 493         /* id tree */
 494         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 495                 (AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
 496         {
 497 #ifdef NEW_LOGGING
 498                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 499                            "bdb_cache_add_entry: (%s):%ls already in cache.\n",
 500                            e->e_dn, e->e_id ));
 501 #else
 502                 Debug( LDAP_DEBUG_ANY,
 503                         "====> bdb_cache_add_entry( %ld ): \"%s\": already in id cache\n",
 504                     e->e_id, e->e_dn, 0 );
 505 #endif
 506
 507                 /* delete from dn tree inserted above */
 508                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 509                         (AVL_CMP) entry_dn_cmp ) == NULL )
 510                 {
 511 #ifdef NEW_LOGGING
 512                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 513                                    "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 514                                    e->e_dn ));
 515 #else
 516                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 517                             0, 0, 0 );
 518 #endif
 519                 }
 520
 521                 bdb_cache_entry_private_destroy(e);
 522
 523                 /* free cache write lock */
 524                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 525                 return( -1 );
 526         }
 527
 528         rc = bdb_cache_entry_db_lock( env, locker, e, rw, 0, lock );
 529         switch ( rc ) {
 530         case 0 :
 531                 break;
 532         case DB_LOCK_DEADLOCK :
 533         case DB_LOCK_NOTGRANTED :
 534                 /* undo avl changes immediately */
 535                 if ( avl_delete( &cache->c_idtree, (caddr_t) e,
 536                         (AVL_CMP) entry_id_cmp ) == NULL ) {
 537 #ifdef NEW_LOGGING
 538                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 539                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n", e->e_dn ));
 540 #else
 541                         Debug( LDAP_DEBUG_ANY, "====> can't delete from id cache\n", 0, 0, 0 );
 542 #endif
 543                 }
 544                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 545                                 (AVL_CMP) entry_dn_cmp ) == NULL ) {
 546 #ifdef NEW_LOGGING
 547                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 548                                         "bdb_cache_add_entry: can't delete (%s) from cache.\n", e->e_dn ));
 549 #else
 550                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n", 0, 0, 0 );
 551 #endif
 552                 }
 553                 /* fall through */
 554         default :
 555                 bdb_cache_entry_private_destroy(e);
 556                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 557                 return rc;
 558         }
 559
 560         /* put the entry into 'CREATING' state */
 561         /* will be marked after when entry is returned */
 562         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 563         BEI(e)->bei_refcnt = 1;
 564
 565         /* set lru mutex */
 566         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 567         /* lru */
 568         LRU_ADD( cache, e );
 569         if ( ++cache->c_cursize > cache->c_maxsize ) {
 570                 /*
 571                  * find the lru entry not currently in use and delete it.
 572                  * in case a lot of entries are in use, only look at the
 573                  * first 10 on the tail of the list.
 574                  */
 575                 i = 0;
 576                 while ( cache->c_lrutail != NULL &&
 577                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 578                         i < 10 )
 579                 {
 580                         /* move this in-use entry to the front of the q */
 581                         ee = cache->c_lrutail;
 582                         LRU_DELETE( cache, ee );
 583                         LRU_ADD( cache, ee );
 584                         i++;
 585                 }
 586
 587                 /*
 588                  * found at least one to delete - try to get back under
 589                  * the max cache size.
 590                  */
 591                 while ( cache->c_lrutail != NULL &&
 592                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 593                         cache->c_cursize > cache->c_maxsize )
 594                 {
 595                         e = cache->c_lrutail;
 596
 597                         /* delete from cache and lru q */
 598                         /* XXX do we need rc ? */
 599                         rc = bdb_cache_delete_entry_internal( cache, e );
 600                         bdb_cache_entry_private_destroy( e );
 601                         bdb_entry_return( e );
 602                 }
 603         }
 604
 605         /* free lru mutex */
 606         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 607         /* free cache write lock */
 608         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 609         return( 0 );
 610 }
 611
 612 /*
 613  * cache_update_entry - update a LOCKED entry which has been deleted.
 614  * returns:     0       entry has been created and locked
 615  *              1       entry already existed
 616  *              -1      something bad happened
 617  */
 618 int
 619 bdb_cache_update_entry(
 620     Cache       *cache,
 621     Entry               *e
 622 )
 623 {
 624         int     i, rc;
 625         Entry   *ee;
 626
 627         /* set cache write lock */
 628         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 629
 630         assert( e->e_private );
 631
 632         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 633                 (AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
 634         {
 635 #ifdef NEW_LOGGING
 636                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 637                            "bdb_cache_update_entry: (%s):%ld already in dn cache\n",
 638                            e->e_dn, e->e_id ));
 639 #else
 640                 Debug( LDAP_DEBUG_TRACE,
 641                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in dn cache\n",
 642                     e->e_id, e->e_dn, 0 );
 643 #endif
 644
 645                 /* free cache write lock */
 646                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 647                 return( 1 );
 648         }
 649
 650         /* id tree */
 651         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 652                 (AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
 653         {
 654 #ifdef NEW_LOGGING
 655                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 656                            "bdb_cache_update_entry: (%s)%ld already in id cache\n",
 657                            e->e_dn, e->e_id ));
 658 #else
 659                 Debug( LDAP_DEBUG_ANY,
 660                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in id cache\n",
 661                     e->e_id, e->e_dn, 0 );
 662 #endif
 663
 664                 /* delete from dn tree inserted above */
 665                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 666                         (AVL_CMP) entry_dn_cmp ) == NULL )
 667                 {
 668 #ifdef NEW_LOGGING
 669                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 670                                    "bdb_cache_update_entry: can't delete (%s)%ld from dn cache.\n",
 671                                    e->e_dn, e->e_id ));
 672 #else
 673                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 674                             0, 0, 0 );
 675 #endif
 676                 }
 677
 678                 /* free cache write lock */
 679                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 680                 return( -1 );
 681         }
 682
 683
 684         /* put the entry into 'CREATING' state */
 685         /* will be marked after when entry is returned */
 686         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 687
 688         /* set lru mutex */
 689         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 690         /* lru */
 691         LRU_ADD( cache, e );
 692         if ( ++cache->c_cursize > cache->c_maxsize ) {
 693                 /*
 694                  * find the lru entry not currently in use and delete it.
 695                  * in case a lot of entries are in use, only look at the
 696                  * first 10 on the tail of the list.
 697                  */
 698                 i = 0;
 699                 while ( cache->c_lrutail != NULL &&
 700                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 701                         i < 10 )
 702                 {
 703                         /* move this in-use entry to the front of the q */
 704                         ee = cache->c_lrutail;
 705                         LRU_DELETE( cache, ee );
 706                         LRU_ADD( cache, ee );
 707                         i++;
 708                 }
 709
 710                 /*
 711                  * found at least one to delete - try to get back under
 712                  * the max cache size.
 713                  */
 714                 while ( cache->c_lrutail != NULL &&
 715                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 716                         cache->c_cursize > cache->c_maxsize )
 717                 {
 718                         e = cache->c_lrutail;
 719
 720                         /* delete from cache and lru q */
 721                         /* XXX do we need rc ? */
 722                         rc = bdb_cache_delete_entry_internal( cache, e );
 723                         bdb_cache_entry_private_destroy( e );
 724                         bdb_entry_return( e );
 725                 }
 726         }
 727
 728         /* free lru mutex */
 729         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 730         /* free cache write lock */
 731         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 732         return( 0 );
 733 }
 734
 735 ID
 736 bdb_cache_find_entry_ndn2id(
 737         Backend         *be,
 738     Cache       *cache,
 739     struct berval       *ndn
 740 )
 741 {
 742         Entry           e, *ep;
 743         ID                      id;
 744         int count = 0;
 745
 746         /* this function is always called with normalized DN */
 747         e.e_nname = *ndn;
 748
 749 try_again:
 750         /* set cache read lock */
 751         ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
 752
 753         if ( (ep = (Entry *) avl_find( cache->c_dntree, (caddr_t) &e,
 754                 (AVL_CMP) entry_dn_cmp )) != NULL )
 755         {
 756                 int state;
 757                 count++;
 758
 759                 /*
 760                  * ep now points to an unlocked entry
 761                  * we do not need to lock the entry if we only
 762                  * check the state, refcnt, LRU, and id.
 763                  */
 764
 765                 assert( ep->e_private );
 766
 767                 /* save id */
 768                 id = ep->e_id;
 769                 state = BEI(ep)->bei_state;
 770
 771                 /*
 772                  * entry is deleted or not fully created yet
 773                  */
 774                 if ( state != CACHE_ENTRY_READY ) {
 775                         assert(state != CACHE_ENTRY_UNDEFINED);
 776
 777                         /* free cache read lock */
 778                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 779
 780 #ifdef NEW_LOGGING
 781                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 782                                    "bdb_cache_find_entry_dn2id: (%s) %ld not ready: %d\n",
 783                                    ndn->bv_val, id, state ));
 784 #else
 785                         Debug(LDAP_DEBUG_TRACE,
 786                                 "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (not ready) %d\n",
 787                                 ndn->bv_val, id, state);
 788 #endif
 789
 790
 791                         ldap_pvt_thread_yield();
 792                         goto try_again;
 793                 }
 794
 795                 /* free cache read lock */
 796                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 797
 798                 /* set lru mutex */
 799                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 800
 801                 /* lru */
 802                 LRU_DELETE( cache, ep );
 803                 LRU_ADD( cache, ep );
 804
 805                 /* free lru mutex */
 806                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 807
 808 #ifdef NEW_LOGGING
 809                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 810                            "bdb_cache_find_entry_dn2id: (%s): %ld %d tries\n",
 811                            ndn->bv_val, id, count ));
 812 #else
 813                 Debug(LDAP_DEBUG_TRACE,
 814                         "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (%d tries)\n",
 815                         ndn->bv_val, id, count);
 816 #endif
 817
 818         } else {
 819                 /* free cache read lock */
 820                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 821
 822                 id = NOID;
 823         }
 824
 825         return( id );
 826 }
 827
 828 /*
 829  * cache_find_entry_id - find an entry in the cache, given id
 830  */
 831
 832 Entry *
 833 bdb_cache_find_entry_id(
 834         DB_ENV  *env,
 835         Cache   *cache,
 836         ID                              id,
 837         int                             rw,
 838         u_int32_t       locker,
 839         DB_LOCK         *lock
 840 )
 841 {
 842         Entry   e;
 843         Entry   *ep;
 844         int     count = 0;
 845         int     rc;
 846
 847         e.e_id = id;
 848
 849 try_again:
 850         /* set cache read lock */
 851         ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
 852
 853         if ( (ep = (Entry *) avl_find( cache->c_idtree, (caddr_t) &e,
 854                 (AVL_CMP) entry_id_cmp )) != NULL )
 855         {
 856                 int state;
 857                 ID      ep_id;
 858
 859                 count++;
 860
 861                 assert( ep->e_private );
 862
 863                 ep_id = ep->e_id;
 864                 state = BEI(ep)->bei_state;
 865
 866                 /*
 867                  * entry is deleted or not fully created yet
 868                  */
 869                 if ( state != CACHE_ENTRY_READY ) {
 870
 871                         assert(state != CACHE_ENTRY_UNDEFINED);
 872
 873                         /* free cache read lock */
 874                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 875
 876 #ifdef NEW_LOGGING
 877                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 878                                    "bdb_cache_find_entry_id: (%ld)->%ld not ready (%d).\n",
 879                                    id, ep_id, state ));
 880
 881 #else
 882                         Debug(LDAP_DEBUG_TRACE,
 883                                 "====> bdb_cache_find_entry_id( %ld ): %ld (not ready) %d\n",
 884                                 id, ep_id, state);
 885 #endif
 886
 887                         ldap_pvt_thread_yield();
 888                         goto try_again;
 889                 }
 890
 891                 /* acquire reader lock */
 892                 rc = bdb_cache_entry_db_lock ( env, locker, ep, rw, 0, lock );
 893
 894 #if 0
 895                 if ( bdb_cache_entry_rdwr_trylock(ep, rw) == LDAP_PVT_THREAD_EBUSY ) {
 896 #endif
 897
 898                 if ( rc ) { /* will be changed to retry beyond threshold */
 899                         /* could not acquire entry lock...
 900                          * owner cannot free as we have the cache locked.
 901                          * so, unlock the cache, yield, and try again.
 902                          */
 903
 904                         /* free cache read lock */
 905                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 906
 907 #ifdef NEW_LOGGING
 908                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 909                                    "bdb_cache_find_entry_id: %ld -> %ld (busy) %d.\n",
 910                                    id, ep_id, state ));
 911 #else
 912                         Debug(LDAP_DEBUG_TRACE,
 913                                 "====> bdb_cache_find_entry_id( %ld ): %ld (busy) %d\n",
 914                                 id, ep_id, state);
 915                         Debug(LDAP_DEBUG_TRACE,
 916                                 "locker = %d\n",
 917                                 locker, 0, 0);
 918 #endif
 919
 920                         ldap_pvt_thread_yield();
 921                         goto try_again;
 922                 }
 923
 924                 /* free cache read lock */
 925                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 926                 /* set lru mutex */
 927                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 928                 /* lru */
 929                 LRU_DELETE( cache, ep );
 930                 LRU_ADD( cache, ep );
 931
 932                 BEI(ep)->bei_refcnt++;
 933
 934                 /* free lru mutex */
 935                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 936
 937 #ifdef NEW_LOGGING
 938                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 939                            "bdb_cache_find_entry_id: %ld -> %s  found %d tries.\n",
 940                            ep_id, ep->e_dn, count ));
 941 #else
 942                 Debug(LDAP_DEBUG_TRACE,
 943                         "====> bdb_cache_find_entry_id( %ld ) \"%s\" (found) (%d tries)\n",
 944                         ep_id, ep->e_dn, count);
 945 #endif
 946
 947
 948                 return( ep );
 949         }
 950
 951         /* free cache read lock */
 952         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 953
 954         return( NULL );
 955 }
 956
 957 /*
 958  * cache_delete_entry - delete the entry e from the cache.  the caller
 959  * should have obtained e (increasing its ref count) via a call to one
 960  * of the cache_find_* routines.  the caller should *not* call the
 961  * cache_return_entry() routine prior to calling cache_delete_entry().
 962  * it performs this function.
 963  *
 964  * returns:     0       e was deleted ok
 965  *              1       e was not in the cache
 966  *              -1      something bad happened
 967  */
 968 int
 969 bdb_cache_delete_entry(
 970     Cache       *cache,
 971     Entry               *e
 972 )
 973 {
 974         int     rc;
 975
 976         /* set cache write lock */
 977         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 978
 979         assert( e->e_private );
 980
 981 #ifdef NEW_LOGGING
 982         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
 983                    "bdb_cache_delete_entry: delete %ld.\n", e->e_id ));
 984 #else
 985         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_delete_entry( %ld )\n",
 986                 e->e_id, 0, 0 );
 987 #endif
 988
 989         /* set lru mutex */
 990         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 991         rc = bdb_cache_delete_entry_internal( cache, e );
 992         /* free lru mutex */
 993         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 994
 995         /* free cache write lock */
 996         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 997         return( rc );
 998 }
 999
1000 static int
1001 bdb_cache_delete_entry_internal(
1002     Cache       *cache,
1003     Entry               *e
1004 )
1005 {
1006         int rc = 0;     /* return code */
1007
1008         /* dn tree */
1009         if ( avl_delete( &cache->c_dntree, (caddr_t) e, (AVL_CMP) entry_dn_cmp )
1010                 == NULL )
1011         {
1012                 rc = -1;
1013         }
1014
1015         /* id tree */
1016         if ( avl_delete( &cache->c_idtree, (caddr_t) e, (AVL_CMP) entry_id_cmp )
1017                 == NULL )
1018         {
1019                 rc = -1;
1020         }
1021
1022         if (rc != 0) {
1023                 return rc;
1024         }
1025
1026         /* lru */
1027         LRU_DELETE( cache, e );
1028         cache->c_cursize--;
1029
1030         /*
1031          * flag entry to be freed later by a call to cache_return_entry()
1032          */
1033         BEI(e)->bei_state = CACHE_ENTRY_DELETED;
1034
1035         return( 0 );
1036 }
1037
1038 void
1039 bdb_cache_release_all( Cache *cache )
1040 {
1041         Entry *e;
1042         int rc;
1043
1044         /* set cache write lock */
1045         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
1046         /* set lru mutex */
1047         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
1048
1049 #ifdef NEW_LOGGING
1050         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
1051                    "bdb_cache_release_all: enter\n" ));
1052 #else
1053         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_release_all\n", 0, 0, 0 );
1054 #endif
1055
1056         while ( (e = cache->c_lrutail) != NULL && BEI(e)->bei_refcnt == 0 ) {
1057 #ifdef LDAP_RDWR_DEBUG
1058                 assert(!ldap_pvt_thread_rdwr_active(&BEI(e)->bei_rdwr));
1059 #endif
1060
1061                 /* delete from cache and lru q */
1062                 /* XXX do we need rc ? */
1063                 rc = bdb_cache_delete_entry_internal( cache, e );
1064                 bdb_cache_entry_private_destroy( e );
1065                 bdb_entry_return( e );
1066         }
1067
1068         if ( cache->c_cursize ) {
1069 #ifdef NEW_LOGGING
1070                 LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
1071                            "bdb_cache_release_all: Entry cache could not be emptied.\n" ));
1072 #else
1073                 Debug( LDAP_DEBUG_TRACE, "Entry-cache could not be emptied\n", 0, 0, 0 );
1074 #endif
1075
1076         }
1077
1078         /* free lru mutex */
1079         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
1080         /* free cache write lock */
1081         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
1082 }
1083
1084 #ifdef LDAP_DEBUG
1085 static void
1086 bdb_lru_print( Cache *cache )
1087 {
1088         Entry   *e;
1089
1090         fprintf( stderr, "LRU queue (head to tail):\n" );
1091         for ( e = cache->c_lruhead; e != NULL; e = BEI(e)->bei_lrunext ) {
1092                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
1093                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
1094         }
1095         fprintf( stderr, "LRU queue (tail to head):\n" );
1096         for ( e = cache->c_lrutail; e != NULL; e = BEI(e)->bei_lruprev ) {
1097                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
1098                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
1099         }
1100 }
1101 #endif