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, ENTRY,
  53                 "bdb_cache_entry_rdwr_lock: %s lock on ID %ld\n",
  54                 rw ? "w" : "r", e->e_id, 0 );
  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, ENTRY,
  71                 "bdb_cache_entry_rdwr_trylock: try %s lock on ID: %ld.\n",
  72                 rw ? "w" : "r", e->e_id, 0 );
  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, ENTRY,
  89                 "bdb_cache_entry_rdwr_unlock: remove %s lock on ID %ld.\n",
  90                 rw ? "w" : "r", e->e_id, 0 );
  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, 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, DETAIL1,
 252                                    "bdb_unlocked_cache_return_entry_rw: %ld, delete pending (%d).\n",
 253                                    id, refcnt, 0 );
 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, DETAIL1,
 271                                    "bdb_unlocked_cache_return_entry_rw: (%ld): deleted (%d)\n",
 272                                    id, refcnt, 0 );
 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, 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, 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, DETAIL1,
 355                                    "bdb_cache_return_entry_rw: %ld, delete pending (%d).\n",
 356                                    id, refcnt, 0 );
 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, DETAIL1,
 374                                    "bdb_cache_return_entry_rw: (%ld): deleted (%d)\n",
 375                                    id, refcnt, 0 );
 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, 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, ENTRY,
 446                 "bdb_cache_add_entry_rw: add (%s):%s to cache\n",
 447                 e->e_dn, rw ? "w" : "r", 0 );
 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, ERR,
 460                         "bdb_cache_add_entry_rw: add (%s):%ld private init failed!\n",
 461                         e->e_dn, e->e_id, 0 );
 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, DETAIL1,
 480                         "bdb_cache_add_entry: (%s):%ld already in cache.\n",
 481                         e->e_dn, e->e_id, 0 );
 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, DETAIL1,
 499                         "bdb_cache_add_entry: (%s):%ls already in cache.\n",
 500                         e->e_dn, e->e_id, 0 );
 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, INFO,
 513                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 514                                 e->e_dn, 0, 0 );
 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, INFO,
 539                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 540                                 e->e_dn, 0, 0 );
 541 #else
 542                         Debug( LDAP_DEBUG_ANY, "====> can't delete from id cache\n", 0, 0, 0 );
 543 #endif
 544                 }
 545                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 546                                 (AVL_CMP) entry_dn_cmp ) == NULL ) {
 547 #ifdef NEW_LOGGING
 548                         LDAP_LOG( CACHE, INFO,
 549                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 550                                 e->e_dn, 0, 0 );
 551 #else
 552                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n", 0, 0, 0 );
 553 #endif
 554                 }
 555                 /* fall through */
 556         default :
 557                 bdb_cache_entry_private_destroy(e);
 558                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 559                 return rc;
 560         }
 561
 562         /* put the entry into 'CREATING' state */
 563         /* will be marked after when entry is returned */
 564         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 565         BEI(e)->bei_refcnt = 1;
 566
 567         /* set lru mutex */
 568         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 569         /* lru */
 570         LRU_ADD( cache, e );
 571         if ( ++cache->c_cursize > cache->c_maxsize ) {
 572                 /*
 573                  * find the lru entry not currently in use and delete it.
 574                  * in case a lot of entries are in use, only look at the
 575                  * first 10 on the tail of the list.
 576                  */
 577                 i = 0;
 578                 while ( cache->c_lrutail != NULL &&
 579                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 580                         i < 10 )
 581                 {
 582                         /* move this in-use entry to the front of the q */
 583                         ee = cache->c_lrutail;
 584                         LRU_DELETE( cache, ee );
 585                         LRU_ADD( cache, ee );
 586                         i++;
 587                 }
 588
 589                 /*
 590                  * found at least one to delete - try to get back under
 591                  * the max cache size.
 592                  */
 593                 while ( cache->c_lrutail != NULL &&
 594                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 595                         cache->c_cursize > cache->c_maxsize )
 596                 {
 597                         e = cache->c_lrutail;
 598
 599                         /* delete from cache and lru q */
 600                         /* XXX do we need rc ? */
 601                         rc = bdb_cache_delete_entry_internal( cache, e );
 602                         bdb_cache_entry_private_destroy( e );
 603                         bdb_entry_return( e );
 604                 }
 605         }
 606
 607         /* free lru mutex */
 608         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 609         /* free cache write lock */
 610         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 611         return( 0 );
 612 }
 613
 614 /*
 615  * cache_update_entry - update a LOCKED entry which has been deleted.
 616  * returns:     0       entry has been created and locked
 617  *              1       entry already existed
 618  *              -1      something bad happened
 619  */
 620 int
 621 bdb_cache_update_entry(
 622     Cache       *cache,
 623     Entry               *e
 624 )
 625 {
 626         int     i, rc;
 627         Entry   *ee;
 628
 629         /* set cache write lock */
 630         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 631
 632         assert( e->e_private );
 633
 634         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 635                 (AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
 636         {
 637 #ifdef NEW_LOGGING
 638                 LDAP_LOG( CACHE, DETAIL1,
 639                         "bdb_cache_update_entry: (%s):%ld already in dn cache\n",
 640                         e->e_dn, e->e_id, 0 );
 641 #else
 642                 Debug( LDAP_DEBUG_TRACE,
 643                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in dn cache\n",
 644                     e->e_id, e->e_dn, 0 );
 645 #endif
 646
 647                 /* free cache write lock */
 648                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 649                 return( 1 );
 650         }
 651
 652         /* id tree */
 653         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 654                 (AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
 655         {
 656 #ifdef NEW_LOGGING
 657                 LDAP_LOG( CACHE, DETAIL1,
 658                         "bdb_cache_update_entry: (%s)%ld already in id cache\n",
 659                         e->e_dn, e->e_id, 0 );
 660 #else
 661                 Debug( LDAP_DEBUG_ANY,
 662                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in id cache\n",
 663                     e->e_id, e->e_dn, 0 );
 664 #endif
 665
 666                 /* delete from dn tree inserted above */
 667                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 668                         (AVL_CMP) entry_dn_cmp ) == NULL )
 669                 {
 670 #ifdef NEW_LOGGING
 671                         LDAP_LOG( CACHE, INFO,
 672                                 "bdb_cache_update_entry: can't delete (%s)%ld from dn cache.\n",
 673                                 e->e_dn, e->e_id, 0 );
 674 #else
 675                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 676                             0, 0, 0 );
 677 #endif
 678                 }
 679
 680                 /* free cache write lock */
 681                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 682                 return( -1 );
 683         }
 684
 685
 686         /* put the entry into 'CREATING' state */
 687         /* will be marked after when entry is returned */
 688         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 689
 690         /* set lru mutex */
 691         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 692         /* lru */
 693         LRU_ADD( cache, e );
 694         if ( ++cache->c_cursize > cache->c_maxsize ) {
 695                 /*
 696                  * find the lru entry not currently in use and delete it.
 697                  * in case a lot of entries are in use, only look at the
 698                  * first 10 on the tail of the list.
 699                  */
 700                 i = 0;
 701                 while ( cache->c_lrutail != NULL &&
 702                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 703                         i < 10 )
 704                 {
 705                         /* move this in-use entry to the front of the q */
 706                         ee = cache->c_lrutail;
 707                         LRU_DELETE( cache, ee );
 708                         LRU_ADD( cache, ee );
 709                         i++;
 710                 }
 711
 712                 /*
 713                  * found at least one to delete - try to get back under
 714                  * the max cache size.
 715                  */
 716                 while ( cache->c_lrutail != NULL &&
 717                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 718                         cache->c_cursize > cache->c_maxsize )
 719                 {
 720                         e = cache->c_lrutail;
 721
 722                         /* delete from cache and lru q */
 723                         /* XXX do we need rc ? */
 724                         rc = bdb_cache_delete_entry_internal( cache, e );
 725                         bdb_cache_entry_private_destroy( e );
 726                         bdb_entry_return( e );
 727                 }
 728         }
 729
 730         /* free lru mutex */
 731         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 732         /* free cache write lock */
 733         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 734         return( 0 );
 735 }
 736
 737 ID
 738 bdb_cache_find_entry_ndn2id(
 739         Backend         *be,
 740     Cache       *cache,
 741     struct berval       *ndn
 742 )
 743 {
 744         Entry           e, *ep;
 745         ID                      id;
 746         int count = 0;
 747
 748         /* this function is always called with normalized DN */
 749         e.e_nname = *ndn;
 750
 751 try_again:
 752         /* set cache read lock */
 753         ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
 754
 755         if ( (ep = (Entry *) avl_find( cache->c_dntree, (caddr_t) &e,
 756                 (AVL_CMP) entry_dn_cmp )) != NULL )
 757         {
 758                 int state;
 759                 count++;
 760
 761                 /*
 762                  * ep now points to an unlocked entry
 763                  * we do not need to lock the entry if we only
 764                  * check the state, refcnt, LRU, and id.
 765                  */
 766
 767                 assert( ep->e_private );
 768
 769                 /* save id */
 770                 id = ep->e_id;
 771                 state = BEI(ep)->bei_state;
 772
 773                 /*
 774                  * entry is deleted or not fully created yet
 775                  */
 776                 if ( state != CACHE_ENTRY_READY ) {
 777                         assert(state != CACHE_ENTRY_UNDEFINED);
 778
 779                         /* free cache read lock */
 780                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 781
 782 #ifdef NEW_LOGGING
 783                         LDAP_LOG( CACHE, INFO,
 784                                 "bdb_cache_find_entry_dn2id: (%s) %ld not ready: %d\n",
 785                                 ndn->bv_val, id, state );
 786 #else
 787                         Debug(LDAP_DEBUG_TRACE,
 788                                 "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (not ready) %d\n",
 789                                 ndn->bv_val, id, state);
 790 #endif
 791
 792
 793                         ldap_pvt_thread_yield();
 794                         goto try_again;
 795                 }
 796
 797                 /* free cache read lock */
 798                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 799
 800                 /* set lru mutex */
 801                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 802
 803                 /* lru */
 804                 LRU_DELETE( cache, ep );
 805                 LRU_ADD( cache, ep );
 806
 807                 /* free lru mutex */
 808                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 809
 810 #ifdef NEW_LOGGING
 811                 LDAP_LOG( CACHE, DETAIL1,
 812                         "bdb_cache_find_entry_dn2id: (%s): %ld %d tries\n",
 813                         ndn->bv_val, id, count );
 814 #else
 815                 Debug(LDAP_DEBUG_TRACE,
 816                         "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (%d tries)\n",
 817                         ndn->bv_val, id, count);
 818 #endif
 819
 820         } else {
 821                 /* free cache read lock */
 822                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 823
 824                 id = NOID;
 825         }
 826
 827         return( id );
 828 }
 829
 830 /*
 831  * cache_find_entry_id - find an entry in the cache, given id
 832  */
 833
 834 Entry *
 835 bdb_cache_find_entry_id(
 836         DB_ENV  *env,
 837         Cache   *cache,
 838         ID                              id,
 839         int                             rw,
 840         u_int32_t       locker,
 841         DB_LOCK         *lock
 842 )
 843 {
 844         Entry   e;
 845         Entry   *ep;
 846         int     count = 0;
 847         int     rc;
 848
 849         e.e_id = id;
 850
 851 try_again:
 852         /* set cache read lock */
 853         ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
 854
 855         if ( (ep = (Entry *) avl_find( cache->c_idtree, (caddr_t) &e,
 856                 (AVL_CMP) entry_id_cmp )) != NULL )
 857         {
 858                 int state;
 859                 ID      ep_id;
 860
 861                 count++;
 862
 863                 assert( ep->e_private );
 864
 865                 ep_id = ep->e_id;
 866                 state = BEI(ep)->bei_state;
 867
 868                 /*
 869                  * entry is deleted or not fully created yet
 870                  */
 871                 if ( state != CACHE_ENTRY_READY ) {
 872
 873                         assert(state != CACHE_ENTRY_UNDEFINED);
 874
 875                         /* free cache read lock */
 876                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 877
 878 #ifdef NEW_LOGGING
 879                         LDAP_LOG( CACHE, INFO,
 880                                 "bdb_cache_find_entry_id: (%ld)->%ld not ready (%d).\n",
 881                                 id, ep_id, state );
 882
 883 #else
 884                         Debug(LDAP_DEBUG_TRACE,
 885                                 "====> bdb_cache_find_entry_id( %ld ): %ld (not ready) %d\n",
 886                                 id, ep_id, state);
 887 #endif
 888
 889                         ldap_pvt_thread_yield();
 890                         goto try_again;
 891                 }
 892
 893                 /* acquire reader lock */
 894                 rc = bdb_cache_entry_db_lock ( env, locker, ep, rw, 0, lock );
 895
 896 #if 0
 897                 if ( bdb_cache_entry_rdwr_trylock(ep, rw) == LDAP_PVT_THREAD_EBUSY ) {
 898 #endif
 899
 900                 if ( rc ) { /* will be changed to retry beyond threshold */
 901                         /* could not acquire entry lock...
 902                          * owner cannot free as we have the cache locked.
 903                          * so, unlock the cache, yield, and try again.
 904                          */
 905
 906                         /* free cache read lock */
 907                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 908
 909 #ifdef NEW_LOGGING
 910                         LDAP_LOG( CACHE, INFO,
 911                                 "bdb_cache_find_entry_id: %ld -> %ld (busy) %d.\n",
 912                                 id, ep_id, state );
 913 #else
 914                         Debug(LDAP_DEBUG_TRACE,
 915                                 "====> bdb_cache_find_entry_id( %ld ): %ld (busy) %d\n",
 916                                 id, ep_id, state);
 917                         Debug(LDAP_DEBUG_TRACE,
 918                                 "locker = %d\n",
 919                                 locker, 0, 0);
 920 #endif
 921
 922                         ldap_pvt_thread_yield();
 923                         goto try_again;
 924                 }
 925
 926                 /* free cache read lock */
 927                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 928                 /* set lru mutex */
 929                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 930                 /* lru */
 931                 LRU_DELETE( cache, ep );
 932                 LRU_ADD( cache, ep );
 933
 934                 BEI(ep)->bei_refcnt++;
 935
 936                 /* free lru mutex */
 937                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 938
 939 #ifdef NEW_LOGGING
 940                 LDAP_LOG( CACHE, DETAIL1,
 941                         "bdb_cache_find_entry_id: %ld -> %s  found %d tries.\n",
 942                         ep_id, ep->e_dn, count );
 943 #else
 944                 Debug(LDAP_DEBUG_TRACE,
 945                         "====> bdb_cache_find_entry_id( %ld ) \"%s\" (found) (%d tries)\n",
 946                         ep_id, ep->e_dn, count);
 947 #endif
 948
 949
 950                 return( ep );
 951         }
 952
 953         /* free cache read lock */
 954         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 955
 956         return( NULL );
 957 }
 958
 959 /*
 960  * cache_delete_entry - delete the entry e from the cache.  the caller
 961  * should have obtained e (increasing its ref count) via a call to one
 962  * of the cache_find_* routines.  the caller should *not* call the
 963  * cache_return_entry() routine prior to calling cache_delete_entry().
 964  * it performs this function.
 965  *
 966  * returns:     0       e was deleted ok
 967  *              1       e was not in the cache
 968  *              -1      something bad happened
 969  */
 970 int
 971 bdb_cache_delete_entry(
 972     Cache       *cache,
 973     Entry               *e
 974 )
 975 {
 976         int     rc;
 977
 978         /* set cache write lock */
 979         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 980
 981         assert( e->e_private );
 982
 983 #ifdef NEW_LOGGING
 984         LDAP_LOG( CACHE, ENTRY,
 985                 "bdb_cache_delete_entry: delete %ld.\n", e->e_id, 0, 0 );
 986 #else
 987         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_delete_entry( %ld )\n",
 988                 e->e_id, 0, 0 );
 989 #endif
 990
 991         /* set lru mutex */
 992         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 993         rc = bdb_cache_delete_entry_internal( cache, e );
 994         /* free lru mutex */
 995         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 996
 997         /* free cache write lock */
 998         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 999         return( rc );
1000 }
1001
1002 static int
1003 bdb_cache_delete_entry_internal(
1004     Cache       *cache,
1005     Entry               *e
1006 )
1007 {
1008         int rc = 0;     /* return code */
1009
1010         /* dn tree */
1011         if ( avl_delete( &cache->c_dntree, (caddr_t) e, (AVL_CMP) entry_dn_cmp )
1012                 == NULL )
1013         {
1014                 rc = -1;
1015         }
1016
1017         /* id tree */
1018         if ( avl_delete( &cache->c_idtree, (caddr_t) e, (AVL_CMP) entry_id_cmp )
1019                 == NULL )
1020         {
1021                 rc = -1;
1022         }
1023
1024         if (rc != 0) {
1025                 return rc;
1026         }
1027
1028         /* lru */
1029         LRU_DELETE( cache, e );
1030         cache->c_cursize--;
1031
1032         /*
1033          * flag entry to be freed later by a call to cache_return_entry()
1034          */
1035         BEI(e)->bei_state = CACHE_ENTRY_DELETED;
1036
1037         return( 0 );
1038 }
1039
1040 void
1041 bdb_cache_release_all( Cache *cache )
1042 {
1043         Entry *e;
1044         int rc;
1045
1046         /* set cache write lock */
1047         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
1048         /* set lru mutex */
1049         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
1050
1051 #ifdef NEW_LOGGING
1052         LDAP_LOG( CACHE, ENTRY, "bdb_cache_release_all: enter\n", 0, 0, 0 );
1053 #else
1054         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_release_all\n", 0, 0, 0 );
1055 #endif
1056
1057         while ( (e = cache->c_lrutail) != NULL && BEI(e)->bei_refcnt == 0 ) {
1058 #ifdef LDAP_RDWR_DEBUG
1059                 assert(!ldap_pvt_thread_rdwr_active(&BEI(e)->bei_rdwr));
1060 #endif
1061
1062                 /* delete from cache and lru q */
1063                 /* XXX do we need rc ? */
1064                 rc = bdb_cache_delete_entry_internal( cache, e );
1065                 bdb_cache_entry_private_destroy( e );
1066                 bdb_entry_return( e );
1067         }
1068
1069         if ( cache->c_cursize ) {
1070 #ifdef NEW_LOGGING
1071                 LDAP_LOG( CACHE, INFO,
1072                    "bdb_cache_release_all: Entry cache could not be emptied.\n", 0, 0, 0 );
1073 #else
1074                 Debug( LDAP_DEBUG_TRACE, "Entry-cache could not be emptied\n", 0, 0, 0 );
1075 #endif
1076
1077         }
1078
1079         /* free lru mutex */
1080         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
1081         /* free cache write lock */
1082         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
1083 }
1084
1085 #ifdef LDAP_DEBUG
1086 static void
1087 bdb_lru_print( Cache *cache )
1088 {
1089         Entry   *e;
1090
1091         fprintf( stderr, "LRU queue (head to tail):\n" );
1092         for ( e = cache->c_lruhead; e != NULL; e = BEI(e)->bei_lrunext ) {
1093                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
1094                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
1095         }
1096         fprintf( stderr, "LRU queue (tail to head):\n" );
1097         for ( e = cache->c_lrutail; e != NULL; e = BEI(e)->bei_lruprev ) {
1098                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
1099                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
1100         }
1101 }
1102 #endif