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 #if 0   /* unused */
  49 static int
  50 bdb_cache_entry_rdwr_lock(Entry *e, int rw)
  51 {
  52 #ifdef NEW_LOGGING
  53         LDAP_LOG( CACHE, ENTRY,
  54                 "bdb_cache_entry_rdwr_lock: %s lock on ID %ld\n",
  55                 rw ? "w" : "r", e->e_id, 0 );
  56 #else
  57         Debug( LDAP_DEBUG_ARGS, "entry_rdwr_%slock: ID: %ld\n",
  58                 rw ? "w" : "r", e->e_id, 0);
  59 #endif
  60
  61         if (rw)
  62                 return ldap_pvt_thread_rdwr_wlock(&BEI(e)->bei_rdwr);
  63         else
  64                 return ldap_pvt_thread_rdwr_rlock(&BEI(e)->bei_rdwr);
  65 }
  66
  67 static int
  68 bdb_cache_entry_rdwr_trylock(Entry *e, int rw)
  69 {
  70 #ifdef NEW_LOGGING
  71         LDAP_LOG( CACHE, ENTRY,
  72                 "bdb_cache_entry_rdwr_trylock: try %s lock on ID: %ld.\n",
  73                 rw ? "w" : "r", e->e_id, 0 );
  74 #else
  75         Debug( LDAP_DEBUG_ARGS, "entry_rdwr_%strylock: ID: %ld\n",
  76                 rw ? "w" : "r", e->e_id, 0);
  77 #endif
  78
  79         if (rw)
  80                 return ldap_pvt_thread_rdwr_wtrylock(&BEI(e)->bei_rdwr);
  81         else
  82                 return ldap_pvt_thread_rdwr_rtrylock(&BEI(e)->bei_rdwr);
  83 }
  84
  85 static int
  86 bdb_cache_entry_rdwr_unlock(Entry *e, int rw)
  87 {
  88 #ifdef NEW_LOGGING
  89         LDAP_LOG( CACHE, ENTRY,
  90                 "bdb_cache_entry_rdwr_unlock: remove %s lock on ID %ld.\n",
  91                 rw ? "w" : "r", e->e_id, 0 );
  92 #else
  93         Debug( LDAP_DEBUG_ARGS, "entry_rdwr_%sunlock: ID: %ld\n",
  94                 rw ? "w" : "r", e->e_id, 0);
  95 #endif
  96
  97         if (rw)
  98                 return ldap_pvt_thread_rdwr_wunlock(&BEI(e)->bei_rdwr);
  99         else
 100                 return ldap_pvt_thread_rdwr_runlock(&BEI(e)->bei_rdwr);
 101 }
 102 #endif  /* unused */
 103
 104 static int
 105 bdb_cache_entry_rdwr_init(Entry *e)
 106 {
 107         return ldap_pvt_thread_rdwr_init( &BEI(e)->bei_rdwr );
 108 }
 109
 110 static int
 111 bdb_cache_entry_rdwr_destroy(Entry *e)
 112 {
 113         return ldap_pvt_thread_rdwr_destroy( &BEI(e)->bei_rdwr );
 114 }
 115
 116 static int
 117 bdb_cache_entry_private_init( Entry *e )
 118 {
 119         assert( e->e_private == NULL );
 120
 121         if( e->e_private != NULL ) {
 122                 /* this should never happen */
 123                 return 1;
 124         }
 125
 126         e->e_private = ch_calloc(1, sizeof(struct bdb_entry_info));
 127
 128         if( bdb_cache_entry_rdwr_init( e ) != 0 ) {
 129                 free( BEI(e) );
 130                 e->e_private = NULL;
 131                 return 1;
 132         }
 133
 134         return 0;
 135 }
 136
 137 int
 138 bdb_cache_entry_db_lock
 139 ( DB_ENV *env, u_int32_t locker, Entry *e, int rw, u_int32_t flags, DB_LOCK *lock )
 140 {
 141 #ifdef NO_THREADS
 142         return 0;
 143 #else
 144         int       rc;
 145         DBT       lockobj;
 146         int       db_rw;
 147
 148         if (rw)
 149                 db_rw = DB_LOCK_WRITE;
 150         else
 151                 db_rw = DB_LOCK_READ;
 152
 153         lockobj.data = e->e_nname.bv_val;
 154         lockobj.size = e->e_nname.bv_len;
 155         rc = LOCK_GET(env, locker, flags | DB_LOCK_NOWAIT,
 156                                         &lockobj, db_rw, lock);
 157         if (rc) {
 158 #ifdef NEW_LOGGING
 159                 LDAP_LOG( CACHE, DETAIL1,
 160                         "bdb_cache_entry_db_lock: entry %s, rw %d, rc %d\n",
 161                         e->e_nname.bv_val, rw, rc );
 162 #else
 163                 Debug( LDAP_DEBUG_TRACE,
 164                         "bdb_cache_entry_db_lock: entry %s, rw %d, rc %d\n",
 165                         e->e_nname.bv_val, rw, rc );
 166 #endif
 167         }
 168         return rc;
 169 #endif /* NO_THREADS */
 170 }
 171
 172 int
 173 bdb_cache_entry_db_unlock
 174 ( DB_ENV *env, DB_LOCK *lock )
 175 {
 176 #ifdef NO_THREADS
 177         return 0;
 178 #else
 179         int rc;
 180
 181         rc = LOCK_PUT ( env, lock );
 182         return rc;
 183 #endif
 184 }
 185
 186 /*
 187  * marks an entry in CREATING state as committed, so it is really returned
 188  * to the cache. Otherwise an entry in CREATING state is removed.
 189  * Makes e_private be destroyed at the following cache_return_entry_w,
 190  * but lets the entry untouched (owned by someone else)
 191  */
 192 void
 193 bdb_cache_entry_commit( Entry *e )
 194 {
 195         assert( e );
 196         assert( e->e_private );
 197         assert( BEI(e)->bei_state == CACHE_ENTRY_CREATING );
 198         /* assert( BEI(e)->bei_refcnt == 1 ); */
 199
 200         BEI(e)->bei_state = CACHE_ENTRY_COMMITTED;
 201 }
 202
 203 static int
 204 bdb_cache_entry_private_destroy( Entry *e )
 205 {
 206         assert( e->e_private );
 207
 208         bdb_cache_entry_rdwr_destroy( e );
 209
 210         free( e->e_private );
 211         e->e_private = NULL;
 212         return 0;
 213 }
 214
 215 void
 216 bdb_unlocked_cache_return_entry_rw( Cache *cache, Entry *e, int rw )
 217 {
 218
 219         ID id;
 220         int refcnt, freeit = 1;
 221
 222         /* set cache write lock */
 223         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 224
 225         assert( e->e_private );
 226
 227 #if 0
 228         bdb_cache_entry_rdwr_unlock(e, rw);
 229 #endif
 230
 231         id = e->e_id;
 232         refcnt = --BEI(e)->bei_refcnt;
 233
 234         /*
 235          * if the entry is returned when in CREATING state, it is deleted
 236          * but not freed because it may belong to someone else (do_add,
 237          * for instance)
 238          */
 239         if (  BEI(e)->bei_state == CACHE_ENTRY_CREATING ) {
 240                 /* set lru mutex */
 241                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 242                 bdb_cache_delete_entry_internal( cache, e );
 243                 /* free lru mutex */
 244                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 245                 freeit = 0;
 246                 /* now the entry is in DELETED state */
 247         }
 248
 249         if ( BEI(e)->bei_state == CACHE_ENTRY_COMMITTED ) {
 250                 BEI(e)->bei_state = CACHE_ENTRY_READY;
 251
 252                 /* free cache write lock */
 253                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 254
 255 #ifdef NEW_LOGGING
 256                 LDAP_LOG( CACHE, DETAIL1,
 257                            "bdb_unlocked_cache_return_entry_rw: return (%ld):%s, refcnt=%d\n",
 258                            id, rw ? "w" : "r", refcnt );
 259 #else
 260                 Debug( LDAP_DEBUG_TRACE,
 261                         "====> bdb_unlocked_cache_return_entry_%s( %ld ): created (%d)\n",
 262                         rw ? "w" : "r", id, refcnt );
 263 #endif
 264
 265
 266         } else if ( BEI(e)->bei_state == CACHE_ENTRY_DELETED ) {
 267                 if( refcnt > 0 ) {
 268                         /* free cache write lock */
 269                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 270
 271 #ifdef NEW_LOGGING
 272                         LDAP_LOG( CACHE, DETAIL1,
 273                                    "bdb_unlocked_cache_return_entry_rw: %ld, delete pending (%d).\n",
 274                                    id, refcnt, 0 );
 275 #else
 276                         Debug( LDAP_DEBUG_TRACE,
 277                                 "====> bdb_unlocked_cache_return_entry_%s( %ld ): delete pending (%d)\n",
 278                                 rw ? "w" : "r", id, refcnt );
 279 #endif
 280
 281                 } else {
 282                         bdb_cache_entry_private_destroy( e );
 283                         if ( freeit ) {
 284                                 bdb_entry_return( e );
 285                         }
 286
 287                         /* free cache write lock */
 288                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 289
 290 #ifdef NEW_LOGGING
 291                         LDAP_LOG( CACHE, DETAIL1,
 292                                    "bdb_unlocked_cache_return_entry_rw: (%ld): deleted (%d)\n",
 293                                    id, refcnt, 0 );
 294 #else
 295                         Debug( LDAP_DEBUG_TRACE,
 296                                 "====> bdb_unlocked_cache_return_entry_%s( %ld ): deleted (%d)\n",
 297                                 rw ? "w" : "r", id, refcnt );
 298 #endif
 299                 }
 300
 301         } else {
 302                 /* free cache write lock */
 303                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 304
 305 #ifdef NEW_LOGGING
 306                 LDAP_LOG( CACHE, DETAIL1,
 307                            "bdb_unlocked_cache_return_entry_rw: ID %ld:%s returned (%d)\n",
 308                            id, rw ? "w": "r", refcnt );
 309 #else
 310                 Debug( LDAP_DEBUG_TRACE,
 311                         "====> bdb_unlocked_cache_return_entry_%s( %ld ): returned (%d)\n",
 312                         rw ? "w" : "r", id, refcnt);
 313 #endif
 314         }
 315 }
 316
 317 void
 318 bdb_cache_return_entry_rw
 319 ( DB_ENV *env, Cache *cache, Entry *e, int rw, DB_LOCK *lock )
 320 {
 321         ID id;
 322         int refcnt, freeit = 1;
 323
 324         /* set cache write lock */
 325         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 326
 327         assert( e->e_private );
 328
 329         bdb_cache_entry_db_unlock( env, lock );
 330 #if 0
 331         bdb_cache_entry_rdwr_unlock(e, rw);
 332 #endif
 333
 334         id = e->e_id;
 335         refcnt = --BEI(e)->bei_refcnt;
 336
 337         /*
 338          * if the entry is returned when in CREATING state, it is deleted
 339          * but not freed because it may belong to someone else (do_add,
 340          * for instance)
 341          */
 342         if (  BEI(e)->bei_state == CACHE_ENTRY_CREATING ) {
 343                 /* set lru mutex */
 344                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 345                 bdb_cache_delete_entry_internal( cache, e );
 346                 /* free lru mutex */
 347                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 348                 freeit = 0;
 349                 /* now the entry is in DELETED state */
 350         }
 351
 352         if ( BEI(e)->bei_state == CACHE_ENTRY_COMMITTED ) {
 353                 BEI(e)->bei_state = CACHE_ENTRY_READY;
 354
 355                 /* free cache write lock */
 356                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 357
 358 #ifdef NEW_LOGGING
 359                 LDAP_LOG( CACHE, DETAIL1,
 360                            "bdb_cache_return_entry_rw: return (%ld):%s, refcnt=%d\n",
 361                            id, rw ? "w" : "r", refcnt );
 362 #else
 363                 Debug( LDAP_DEBUG_TRACE,
 364                         "====> bdb_cache_return_entry_%s( %ld ): created (%d)\n",
 365                         rw ? "w" : "r", id, refcnt );
 366 #endif
 367
 368
 369         } else if ( BEI(e)->bei_state == CACHE_ENTRY_DELETED ) {
 370                 if( refcnt > 0 ) {
 371                         /* free cache write lock */
 372                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 373
 374 #ifdef NEW_LOGGING
 375                         LDAP_LOG( CACHE, DETAIL1,
 376                                    "bdb_cache_return_entry_rw: %ld, delete pending (%d).\n",
 377                                    id, refcnt, 0 );
 378 #else
 379                         Debug( LDAP_DEBUG_TRACE,
 380                                 "====> bdb_cache_return_entry_%s( %ld ): delete pending (%d)\n",
 381                                 rw ? "w" : "r", id, refcnt );
 382 #endif
 383
 384                 } else {
 385                         bdb_cache_entry_private_destroy( e );
 386                         if ( freeit ) {
 387                                 bdb_entry_return( e );
 388                         }
 389
 390                         /* free cache write lock */
 391                         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 392
 393 #ifdef NEW_LOGGING
 394                         LDAP_LOG( CACHE, DETAIL1,
 395                                    "bdb_cache_return_entry_rw: (%ld): deleted (%d)\n",
 396                                    id, refcnt, 0 );
 397 #else
 398                         Debug( LDAP_DEBUG_TRACE,
 399                                 "====> bdb_cache_return_entry_%s( %ld ): deleted (%d)\n",
 400                                 rw ? "w" : "r", id, refcnt );
 401 #endif
 402                 }
 403
 404         } else {
 405                 /* free cache write lock */
 406                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 407
 408 #ifdef NEW_LOGGING
 409                 LDAP_LOG( CACHE, DETAIL1,
 410                            "bdb_cache_return_entry_rw: ID %ld:%s returned (%d)\n",
 411                            id, rw ? "w": "r", refcnt );
 412 #else
 413                 Debug( LDAP_DEBUG_TRACE,
 414                         "====> bdb_cache_return_entry_%s( %ld ): returned (%d)\n",
 415                         rw ? "w" : "r", id, refcnt);
 416 #endif
 417         }
 418 }
 419
 420 #define LRU_DELETE( cache, e ) do { \
 421         if ( BEI(e)->bei_lruprev != NULL ) { \
 422                 BEI(BEI(e)->bei_lruprev)->bei_lrunext = BEI(e)->bei_lrunext; \
 423         } else { \
 424                 (cache)->c_lruhead = BEI(e)->bei_lrunext; \
 425         } \
 426         if ( BEI(e)->bei_lrunext != NULL ) { \
 427                 BEI(BEI(e)->bei_lrunext)->bei_lruprev = BEI(e)->bei_lruprev; \
 428         } else { \
 429                 (cache)->c_lrutail = BEI(e)->bei_lruprev; \
 430         } \
 431 } while(0)
 432
 433 #define LRU_ADD( cache, e ) do { \
 434         BEI(e)->bei_lrunext = (cache)->c_lruhead; \
 435         if ( BEI(e)->bei_lrunext != NULL ) { \
 436                 BEI(BEI(e)->bei_lrunext)->bei_lruprev = (e); \
 437         } \
 438         (cache)->c_lruhead = (e); \
 439         BEI(e)->bei_lruprev = NULL; \
 440         if ( (cache)->c_lrutail == NULL ) { \
 441                 (cache)->c_lrutail = (e); \
 442         } \
 443 } while(0)
 444
 445 /*
 446  * cache_add_entry_rw - create and lock an entry in the cache
 447  * returns:     0       entry has been created and locked
 448  *              1       entry already existed
 449  *              -1      something bad happened
 450  *             other    Berkeley DB locking error code
 451  */
 452 int
 453 bdb_cache_add_entry_rw(
 454     DB_ENV      *env,
 455     Cache       *cache,
 456     Entry       *e,
 457     int         rw,
 458     u_int32_t   locker,
 459     DB_LOCK     *lock
 460 )
 461 {
 462         int     i, rc;
 463         Entry   *ee;
 464
 465 #ifdef NEW_LOGGING
 466         LDAP_LOG( CACHE, ENTRY,
 467                 "bdb_cache_add_entry_rw: add (%s):%s to cache\n",
 468                 e->e_dn, rw ? "w" : "r", 0 );
 469 #endif
 470         /* set cache write lock */
 471         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 472
 473         assert( e->e_private == NULL );
 474
 475         if( bdb_cache_entry_private_init(e) != 0 ) {
 476                 /* free cache write lock */
 477                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 478
 479 #ifdef NEW_LOGGING
 480                 LDAP_LOG( CACHE, ERR,
 481                         "bdb_cache_add_entry_rw: add (%s):%ld private init failed!\n",
 482                         e->e_dn, e->e_id, 0 );
 483 #else
 484                 Debug( LDAP_DEBUG_ANY,
 485                         "====> bdb_cache_add_entry( %ld ): \"%s\": private init failed!\n",
 486                     e->e_id, e->e_dn, 0 );
 487 #endif
 488
 489
 490                 return( -1 );
 491         }
 492
 493         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 494                          entry_dn_cmp, avl_dup_error ) != 0 )
 495         {
 496                 /* free cache write lock */
 497                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 498
 499 #ifdef NEW_LOGGING
 500                 LDAP_LOG( CACHE, DETAIL1,
 501                         "bdb_cache_add_entry: (%s):%ld already in cache.\n",
 502                         e->e_dn, e->e_id, 0 );
 503 #else
 504                 Debug( LDAP_DEBUG_TRACE,
 505                         "====> bdb_cache_add_entry( %ld ): \"%s\": already in dn cache\n",
 506                     e->e_id, e->e_dn, 0 );
 507 #endif
 508
 509                 bdb_cache_entry_private_destroy(e);
 510
 511                 return( 1 );
 512         }
 513
 514         /* id tree */
 515         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 516                          entry_id_cmp, avl_dup_error ) != 0 )
 517         {
 518 #ifdef NEW_LOGGING
 519                 LDAP_LOG( CACHE, DETAIL1,
 520                         "bdb_cache_add_entry: (%s):%ls already in cache.\n",
 521                         e->e_dn, e->e_id, 0 );
 522 #else
 523                 Debug( LDAP_DEBUG_ANY,
 524                         "====> bdb_cache_add_entry( %ld ): \"%s\": already in id cache\n",
 525                     e->e_id, e->e_dn, 0 );
 526 #endif
 527
 528                 /* delete from dn tree inserted above */
 529                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 530                                  entry_dn_cmp ) == NULL )
 531                 {
 532 #ifdef NEW_LOGGING
 533                         LDAP_LOG( CACHE, INFO,
 534                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 535                                 e->e_dn, 0, 0 );
 536 #else
 537                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 538                             0, 0, 0 );
 539 #endif
 540                 }
 541
 542                 bdb_cache_entry_private_destroy(e);
 543
 544                 /* free cache write lock */
 545                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 546                 return( -1 );
 547         }
 548
 549         rc = bdb_cache_entry_db_lock( env, locker, e, rw, 0, lock );
 550         switch ( rc ) {
 551         case 0 :
 552                 break;
 553         case DB_LOCK_DEADLOCK :
 554         case DB_LOCK_NOTGRANTED :
 555                 /* undo avl changes immediately */
 556                 if ( avl_delete( &cache->c_idtree, (caddr_t) e,
 557                                  entry_id_cmp ) == NULL ) {
 558 #ifdef NEW_LOGGING
 559                         LDAP_LOG( CACHE, INFO,
 560                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 561                                 e->e_dn, 0, 0 );
 562 #else
 563                         Debug( LDAP_DEBUG_ANY, "====> can't delete from id cache\n", 0, 0, 0 );
 564 #endif
 565                 }
 566                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 567                                  entry_dn_cmp ) == NULL ) {
 568 #ifdef NEW_LOGGING
 569                         LDAP_LOG( CACHE, INFO,
 570                                 "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 571                                 e->e_dn, 0, 0 );
 572 #else
 573                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n", 0, 0, 0 );
 574 #endif
 575                 }
 576                 /* fall through */
 577         default :
 578                 bdb_cache_entry_private_destroy(e);
 579                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 580                 return rc;
 581         }
 582
 583         /* put the entry into 'CREATING' state */
 584         /* will be marked after when entry is returned */
 585         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 586         BEI(e)->bei_refcnt = 1;
 587
 588         /* set lru mutex */
 589         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 590         /* lru */
 591         LRU_ADD( cache, e );
 592         if ( ++cache->c_cursize > cache->c_maxsize ) {
 593                 /*
 594                  * find the lru entry not currently in use and delete it.
 595                  * in case a lot of entries are in use, only look at the
 596                  * first 10 on the tail of the list.
 597                  */
 598                 i = 0;
 599                 while ( cache->c_lrutail != NULL &&
 600                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 601                         i < 10 )
 602                 {
 603                         /* move this in-use entry to the front of the q */
 604                         ee = cache->c_lrutail;
 605                         LRU_DELETE( cache, ee );
 606                         LRU_ADD( cache, ee );
 607                         i++;
 608                 }
 609
 610                 /*
 611                  * found at least one to delete - try to get back under
 612                  * the max cache size.
 613                  */
 614                 while ( cache->c_lrutail != NULL &&
 615                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 616                         cache->c_cursize > cache->c_maxsize )
 617                 {
 618                         e = cache->c_lrutail;
 619
 620                         /* delete from cache and lru q */
 621                         /* XXX do we need rc ? */
 622                         rc = bdb_cache_delete_entry_internal( cache, e );
 623                         bdb_cache_entry_private_destroy( e );
 624                         bdb_entry_return( e );
 625                 }
 626         }
 627
 628         /* free lru mutex */
 629         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 630         /* free cache write lock */
 631         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 632         return( 0 );
 633 }
 634
 635 /*
 636  * cache_update_entry - update a LOCKED entry which has been deleted.
 637  * returns:     0       entry has been created and locked
 638  *              1       entry already existed
 639  *              -1      something bad happened
 640  */
 641 int
 642 bdb_cache_update_entry(
 643     Cache       *cache,
 644     Entry               *e
 645 )
 646 {
 647         int     i, rc;
 648         Entry   *ee;
 649
 650         /* set cache write lock */
 651         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
 652
 653         assert( e->e_private );
 654
 655         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 656                          entry_dn_cmp, avl_dup_error ) != 0 )
 657         {
 658 #ifdef NEW_LOGGING
 659                 LDAP_LOG( CACHE, DETAIL1,
 660                         "bdb_cache_update_entry: (%s):%ld already in dn cache\n",
 661                         e->e_dn, e->e_id, 0 );
 662 #else
 663                 Debug( LDAP_DEBUG_TRACE,
 664                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in dn cache\n",
 665                     e->e_id, e->e_dn, 0 );
 666 #endif
 667
 668                 /* free cache write lock */
 669                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 670                 return( 1 );
 671         }
 672
 673         /* id tree */
 674         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 675                          entry_id_cmp, avl_dup_error ) != 0 )
 676         {
 677 #ifdef NEW_LOGGING
 678                 LDAP_LOG( CACHE, DETAIL1,
 679                         "bdb_cache_update_entry: (%s)%ld already in id cache\n",
 680                         e->e_dn, e->e_id, 0 );
 681 #else
 682                 Debug( LDAP_DEBUG_ANY,
 683                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in id cache\n",
 684                     e->e_id, e->e_dn, 0 );
 685 #endif
 686
 687                 /* delete from dn tree inserted above */
 688                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 689                                  entry_dn_cmp ) == NULL )
 690                 {
 691 #ifdef NEW_LOGGING
 692                         LDAP_LOG( CACHE, INFO,
 693                                 "bdb_cache_update_entry: can't delete (%s)%ld from dn cache.\n",
 694                                 e->e_dn, e->e_id, 0 );
 695 #else
 696                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 697                             0, 0, 0 );
 698 #endif
 699                 }
 700
 701                 /* free cache write lock */
 702                 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 703                 return( -1 );
 704         }
 705
 706
 707         /* put the entry into 'CREATING' state */
 708         /* will be marked after when entry is returned */
 709         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 710
 711         /* set lru mutex */
 712         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 713         /* lru */
 714         LRU_ADD( cache, e );
 715         if ( ++cache->c_cursize > cache->c_maxsize ) {
 716                 /*
 717                  * find the lru entry not currently in use and delete it.
 718                  * in case a lot of entries are in use, only look at the
 719                  * first 10 on the tail of the list.
 720                  */
 721                 i = 0;
 722                 while ( cache->c_lrutail != NULL &&
 723                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 724                         i < 10 )
 725                 {
 726                         /* move this in-use entry to the front of the q */
 727                         ee = cache->c_lrutail;
 728                         LRU_DELETE( cache, ee );
 729                         LRU_ADD( cache, ee );
 730                         i++;
 731                 }
 732
 733                 /*
 734                  * found at least one to delete - try to get back under
 735                  * the max cache size.
 736                  */
 737                 while ( cache->c_lrutail != NULL &&
 738                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 739                         cache->c_cursize > cache->c_maxsize )
 740                 {
 741                         e = cache->c_lrutail;
 742
 743                         /* delete from cache and lru q */
 744                         /* XXX do we need rc ? */
 745                         rc = bdb_cache_delete_entry_internal( cache, e );
 746                         bdb_cache_entry_private_destroy( e );
 747                         bdb_entry_return( e );
 748                 }
 749         }
 750
 751         /* free lru mutex */
 752         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 753         /* free cache write lock */
 754         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
 755         return( 0 );
 756 }
 757
 758 ID
 759 bdb_cache_find_entry_ndn2id(
 760         Backend         *be,
 761     Cache       *cache,
 762     struct berval       *ndn
 763 )
 764 {
 765         Entry           e, *ep;
 766         ID                      id;
 767         int count = 0;
 768
 769         /* this function is always called with normalized DN */
 770         e.e_nname = *ndn;
 771
 772 try_again:
 773         /* set cache read lock */
 774         ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
 775
 776         if ( (ep = (Entry *) avl_find( cache->c_dntree, (caddr_t) &e,
 777                                        entry_dn_cmp )) != NULL )
 778         {
 779                 int state;
 780                 count++;
 781
 782                 /*
 783                  * ep now points to an unlocked entry
 784                  * we do not need to lock the entry if we only
 785                  * check the state, refcnt, LRU, and id.
 786                  */
 787
 788                 assert( ep->e_private );
 789
 790                 /* save id */
 791                 id = ep->e_id;
 792                 state = BEI(ep)->bei_state;
 793
 794                 /*
 795                  * entry is deleted or not fully created yet
 796                  */
 797                 if ( state != CACHE_ENTRY_READY ) {
 798                         assert(state != CACHE_ENTRY_UNDEFINED);
 799
 800                         /* free cache read lock */
 801                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 802
 803 #ifdef NEW_LOGGING
 804                         LDAP_LOG( CACHE, INFO,
 805                                 "bdb_cache_find_entry_dn2id: (%s) %ld not ready: %d\n",
 806                                 ndn->bv_val, id, state );
 807 #else
 808                         Debug(LDAP_DEBUG_TRACE,
 809                                 "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (not ready) %d\n",
 810                                 ndn->bv_val, id, state);
 811 #endif
 812
 813
 814                         ldap_pvt_thread_yield();
 815                         goto try_again;
 816                 }
 817
 818                 /* free cache read lock */
 819                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 820
 821                 /* set lru mutex */
 822                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 823
 824                 /* lru */
 825                 LRU_DELETE( cache, ep );
 826                 LRU_ADD( cache, ep );
 827
 828                 /* free lru mutex */
 829                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 830
 831 #ifdef NEW_LOGGING
 832                 LDAP_LOG( CACHE, DETAIL1,
 833                         "bdb_cache_find_entry_dn2id: (%s): %ld %d tries\n",
 834                         ndn->bv_val, id, count );
 835 #else
 836                 Debug(LDAP_DEBUG_TRACE,
 837                         "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (%d tries)\n",
 838                         ndn->bv_val, id, count);
 839 #endif
 840
 841         } else {
 842                 /* free cache read lock */
 843                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 844
 845                 id = NOID;
 846         }
 847
 848         return( id );
 849 }
 850
 851 /*
 852  * cache_find_entry_id - find an entry in the cache, given id
 853  */
 854
 855 Entry *
 856 bdb_cache_find_entry_id(
 857         DB_ENV  *env,
 858         Cache   *cache,
 859         ID                              id,
 860         int                             rw,
 861         u_int32_t       locker,
 862         DB_LOCK         *lock
 863 )
 864 {
 865         Entry   e;
 866         Entry   *ep;
 867         int     count = 0;
 868         int     rc;
 869
 870         e.e_id = id;
 871
 872 try_again:
 873         /* set cache read lock */
 874         ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
 875
 876         if ( (ep = (Entry *) avl_find( cache->c_idtree, (caddr_t) &e,
 877                                        entry_id_cmp )) != NULL )
 878         {
 879                 int state;
 880                 ID      ep_id;
 881
 882                 count++;
 883
 884                 assert( ep->e_private );
 885
 886                 ep_id = ep->e_id;
 887                 state = BEI(ep)->bei_state;
 888
 889                 /*
 890                  * entry is deleted or not fully created yet
 891                  */
 892                 if ( state != CACHE_ENTRY_READY ) {
 893
 894                         assert(state != CACHE_ENTRY_UNDEFINED);
 895
 896                         /* free cache read lock */
 897                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 898
 899 #ifdef NEW_LOGGING
 900                         LDAP_LOG( CACHE, INFO,
 901                                 "bdb_cache_find_entry_id: (%ld)->%ld not ready (%d).\n",
 902                                 id, ep_id, state );
 903
 904 #else
 905                         Debug(LDAP_DEBUG_TRACE,
 906                                 "====> bdb_cache_find_entry_id( %ld ): %ld (not ready) %d\n",
 907                                 id, ep_id, state);
 908 #endif
 909
 910                         ldap_pvt_thread_yield();
 911                         goto try_again;
 912                 }
 913
 914                 /* acquire reader lock */
 915                 rc = bdb_cache_entry_db_lock ( env, locker, ep, rw, 0, lock );
 916
 917 #if 0
 918                 if ( bdb_cache_entry_rdwr_trylock(ep, rw) == LDAP_PVT_THREAD_EBUSY ) {
 919 #endif
 920
 921                 if ( rc ) { /* will be changed to retry beyond threshold */
 922                         /* could not acquire entry lock...
 923                          * owner cannot free as we have the cache locked.
 924                          * so, unlock the cache, yield, and try again.
 925                          */
 926
 927                         /* free cache read lock */
 928                         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 929
 930 #ifdef NEW_LOGGING
 931                         LDAP_LOG( CACHE, INFO,
 932                                 "bdb_cache_find_entry_id: %ld -> %ld (busy) %d.\n",
 933                                 id, ep_id, state );
 934 #else
 935                         Debug(LDAP_DEBUG_TRACE,
 936                                 "====> bdb_cache_find_entry_id( %ld ): %ld (busy) %d\n",
 937                                 id, ep_id, state);
 938                         Debug(LDAP_DEBUG_TRACE,
 939                                 "locker = %d\n",
 940                                 locker, 0, 0);
 941 #endif
 942
 943                         ldap_pvt_thread_yield();
 944                         goto try_again;
 945                 }
 946
 947                 /* free cache read lock */
 948                 ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 949                 /* set lru mutex */
 950                 ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
 951                 /* lru */
 952                 LRU_DELETE( cache, ep );
 953                 LRU_ADD( cache, ep );
 954
 955                 BEI(ep)->bei_refcnt++;
 956
 957                 /* free lru mutex */
 958                 ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
 959
 960 #ifdef NEW_LOGGING
 961                 LDAP_LOG( CACHE, DETAIL1,
 962                         "bdb_cache_find_entry_id: %ld -> %s  found %d tries.\n",
 963                         ep_id, ep->e_dn, count );
 964 #else
 965                 Debug(LDAP_DEBUG_TRACE,
 966                         "====> bdb_cache_find_entry_id( %ld ) \"%s\" (found) (%d tries)\n",
 967                         ep_id, ep->e_dn, count);
 968 #endif
 969
 970
 971                 return( ep );
 972         }
 973
 974         /* free cache read lock */
 975         ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
 976
 977         return( NULL );
 978 }
 979
 980 /*
 981  * cache_delete_entry - delete the entry e from the cache.  the caller
 982  * should have obtained e (increasing its ref count) via a call to one
 983  * of the cache_find_* routines.  the caller should *not* call the
 984  * cache_return_entry() routine prior to calling cache_delete_entry().
 985  * it performs this function.
 986  *
 987  * returns:     0       e was deleted ok
 988  *              1       e was not in the cache
 989  *              -1      something bad happened
 990  */
 991 int
 992 bdb_cache_delete_entry(
 993     Cache       *cache,
 994     Entry               *e
 995 )
 996 {
 997         int     rc;
 998
 999         /* set cache write lock */
1000         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
1001
1002         assert( e->e_private );
1003
1004 #ifdef NEW_LOGGING
1005         LDAP_LOG( CACHE, ENTRY,
1006                 "bdb_cache_delete_entry: delete %ld.\n", e->e_id, 0, 0 );
1007 #else
1008         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_delete_entry( %ld )\n",
1009                 e->e_id, 0, 0 );
1010 #endif
1011
1012         /* set lru mutex */
1013         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
1014         rc = bdb_cache_delete_entry_internal( cache, e );
1015         /* free lru mutex */
1016         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
1017
1018         /* free cache write lock */
1019         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
1020         return( rc );
1021 }
1022
1023 static int
1024 bdb_cache_delete_entry_internal(
1025     Cache       *cache,
1026     Entry               *e
1027 )
1028 {
1029         int rc = 0;     /* return code */
1030
1031         /* dn tree */
1032         if ( avl_delete( &cache->c_dntree, (caddr_t) e, entry_dn_cmp ) == NULL )
1033         {
1034                 rc = -1;
1035         }
1036
1037         /* id tree */
1038         if ( avl_delete( &cache->c_idtree, (caddr_t) e, entry_id_cmp ) == NULL )
1039         {
1040                 rc = -1;
1041         }
1042
1043         if (rc != 0) {
1044                 return rc;
1045         }
1046
1047         /* lru */
1048         LRU_DELETE( cache, e );
1049         cache->c_cursize--;
1050
1051         /*
1052          * flag entry to be freed later by a call to cache_return_entry()
1053          */
1054         BEI(e)->bei_state = CACHE_ENTRY_DELETED;
1055
1056         return( 0 );
1057 }
1058
1059 void
1060 bdb_cache_release_all( Cache *cache )
1061 {
1062         Entry *e;
1063         int rc;
1064
1065         /* set cache write lock */
1066         ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
1067         /* set lru mutex */
1068         ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
1069
1070 #ifdef NEW_LOGGING
1071         LDAP_LOG( CACHE, ENTRY, "bdb_cache_release_all: enter\n", 0, 0, 0 );
1072 #else
1073         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_release_all\n", 0, 0, 0 );
1074 #endif
1075
1076         while ( (e = cache->c_lrutail) != NULL && BEI(e)->bei_refcnt == 0 ) {
1077 #ifdef LDAP_RDWR_DEBUG
1078                 assert(!ldap_pvt_thread_rdwr_active(&BEI(e)->bei_rdwr));
1079 #endif
1080
1081                 /* delete from cache and lru q */
1082                 /* XXX do we need rc ? */
1083                 rc = bdb_cache_delete_entry_internal( cache, e );
1084                 bdb_cache_entry_private_destroy( e );
1085                 bdb_entry_return( e );
1086         }
1087
1088         if ( cache->c_cursize ) {
1089 #ifdef NEW_LOGGING
1090                 LDAP_LOG( CACHE, INFO,
1091                    "bdb_cache_release_all: Entry cache could not be emptied.\n", 0, 0, 0 );
1092 #else
1093                 Debug( LDAP_DEBUG_TRACE, "Entry-cache could not be emptied\n", 0, 0, 0 );
1094 #endif
1095
1096         }
1097
1098         /* free lru mutex */
1099         ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
1100         /* free cache write lock */
1101         ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
1102 }
1103
1104 #ifdef LDAP_DEBUG
1105 static void
1106 bdb_lru_print( Cache *cache )
1107 {
1108         Entry   *e;
1109
1110         fprintf( stderr, "LRU queue (head to tail):\n" );
1111         for ( e = cache->c_lruhead; e != NULL; e = BEI(e)->bei_lrunext ) {
1112                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
1113                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
1114         }
1115         fprintf( stderr, "LRU queue (tail to head):\n" );
1116         for ( e = cache->c_lrutail; e != NULL; e = BEI(e)->bei_lruprev ) {
1117                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
1118                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
1119         }
1120 }
1121 #endif
1122
1123 #ifdef BDB_REUSE_LOCKERS
1124 void
1125 bdb_locker_id_free( void *key, void *data )
1126 {
1127         DB_ENV *env = key;
1128         int lockid = (int) data;
1129
1130         XLOCK_ID_FREE( env, lockid );
1131 }
1132
1133 int
1134 bdb_locker_id( Operation *op, DB_ENV *env, int *locker )
1135 {
1136         int i, rc, lockid;
1137         void *data;
1138
1139         if ( !env || !op || !locker ) return -1;
1140
1141         /* Shouldn't happen unless we're single-threaded */
1142         if ( !op->o_threadctx ) {
1143                 *locker = 0;
1144                 return 0;
1145         }
1146
1147         if ( ldap_pvt_thread_pool_getkey( op->o_threadctx, env, &data, NULL ) ) {
1148                 for ( i=0, rc=1; rc != 0 && i<4; i++ ) {
1149                         rc = XLOCK_ID( env, &lockid );
1150                         if (rc) ldap_pvt_thread_yield();
1151                 }
1152                 if ( rc != 0) {
1153                         return rc;
1154                 }
1155                 data = (void *)lockid;
1156                 if ( ( rc = ldap_pvt_thread_pool_setkey( op->o_threadctx, env,
1157                         data, bdb_locker_id_free ) ) ) {
1158                         XLOCK_ID_FREE( env, lockid );
1159 #ifdef NEW_LOGGING
1160                         LDAP_LOG( BACK_BDB, ERR, "bdb_locker_id: err %s(%d)\n",
1161                                 db_strerror(rc), rc, 0 );
1162 #else
1163                         Debug( LDAP_DEBUG_ANY, "bdb_locker_id: err %s(%d)\n",
1164                                 db_strerror(rc), rc, 0 );
1165 #endif
1166
1167                         return rc;
1168                 }
1169         } else {
1170                 lockid = (int)data;
1171         }
1172         *locker = lockid;
1173         return 0;
1174 }
1175 #endif