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     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 /*
 136  * marks an entry in CREATING state as committed, so it is really returned
 137  * to the cache. Otherwise an entry in CREATING state is removed.
 138  * Makes e_private be destroyed at the following cache_return_entry_w,
 139  * but lets the entry untouched (owned by someone else)
 140  */
 141 void
 142 bdb_cache_entry_commit( Entry *e )
 143 {
 144         assert( e );
 145         assert( e->e_private );
 146         assert( BEI(e)->bei_state == CACHE_ENTRY_CREATING );
 147         /* assert( BEI(e)->bei_refcnt == 1 ); */
 148
 149         BEI(e)->bei_state = CACHE_ENTRY_COMMITTED;
 150 }
 151
 152 static int
 153 bdb_cache_entry_private_destroy( Entry *e )
 154 {
 155         assert( e->e_private );
 156
 157         bdb_cache_entry_rdwr_destroy( e );
 158
 159         free( e->e_private );
 160         e->e_private = NULL;
 161         return 0;
 162 }
 163
 164 void
 165 bdb_cache_return_entry_rw( Cache *cache, Entry *e, int rw )
 166 {
 167         ID id;
 168         int refcnt, freeit = 1;
 169
 170         /* set cache mutex */
 171         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 172
 173         assert( e->e_private );
 174
 175         bdb_cache_entry_rdwr_unlock(e, rw);
 176
 177         id = e->e_id;
 178         refcnt = --BEI(e)->bei_refcnt;
 179
 180         /*
 181          * if the entry is returned when in CREATING state, it is deleted
 182          * but not freed because it may belong to someone else (do_add,
 183          * for instance)
 184          */
 185         if (  BEI(e)->bei_state == CACHE_ENTRY_CREATING ) {
 186                 bdb_cache_delete_entry_internal( cache, e );
 187                 freeit = 0;
 188                 /* now the entry is in DELETED state */
 189         }
 190
 191         if ( BEI(e)->bei_state == CACHE_ENTRY_COMMITTED ) {
 192                 BEI(e)->bei_state = CACHE_ENTRY_READY;
 193
 194                 /* free cache mutex */
 195                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 196
 197 #ifdef NEW_LOGGING
 198                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 199                            "bdb_cache_return_entry_rw: return (%ld):%s, refcnt=%d\n",
 200                            id, rw ? "w" : "r", refcnt ));
 201 #else
 202                 Debug( LDAP_DEBUG_TRACE,
 203                         "====> bdb_cache_return_entry_%s( %ld ): created (%d)\n",
 204                         rw ? "w" : "r", id, refcnt );
 205 #endif
 206
 207
 208         } else if ( BEI(e)->bei_state == CACHE_ENTRY_DELETED ) {
 209                 if( refcnt > 0 ) {
 210                         /* free cache mutex */
 211                         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 212
 213 #ifdef NEW_LOGGING
 214                         LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 215                                    "bdb_cache_return_entry_rw: %ld, delete pending (%d).\n",
 216                                    id, refcnt ));
 217 #else
 218                         Debug( LDAP_DEBUG_TRACE,
 219                                 "====> bdb_cache_return_entry_%s( %ld ): delete pending (%d)\n",
 220                                 rw ? "w" : "r", id, refcnt );
 221 #endif
 222
 223                 } else {
 224                         bdb_cache_entry_private_destroy( e );
 225                         if ( freeit ) {
 226                                 bdb_entry_return( e );
 227                         }
 228
 229                         /* free cache mutex */
 230                         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 231
 232 #ifdef NEW_LOGGING
 233                         LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 234                                    "bdb_cache_return_entry_rw: (%ld): deleted (%d)\n",
 235                                    id, refcnt ));
 236 #else
 237                         Debug( LDAP_DEBUG_TRACE,
 238                                 "====> bdb_cache_return_entry_%s( %ld ): deleted (%d)\n",
 239                                 rw ? "w" : "r", id, refcnt );
 240 #endif
 241                 }
 242
 243         } else {
 244                 /* free cache mutex */
 245                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 246
 247 #ifdef NEW_LOGGING
 248                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 249                            "bdb_cache_return_entry_rw: ID %ld:%s returned (%d)\n",
 250                            id, rw ? "w": "r", refcnt ));
 251 #else
 252                 Debug( LDAP_DEBUG_TRACE,
 253                         "====> bdb_cache_return_entry_%s( %ld ): returned (%d)\n",
 254                         rw ? "w" : "r", id, refcnt);
 255 #endif
 256         }
 257 }
 258
 259 #define LRU_DELETE( cache, e ) do { \
 260         if ( BEI(e)->bei_lruprev != NULL ) { \
 261                 BEI(BEI(e)->bei_lruprev)->bei_lrunext = BEI(e)->bei_lrunext; \
 262         } else { \
 263                 (cache)->c_lruhead = BEI(e)->bei_lrunext; \
 264         } \
 265         if ( BEI(e)->bei_lrunext != NULL ) { \
 266                 BEI(BEI(e)->bei_lrunext)->bei_lruprev = BEI(e)->bei_lruprev; \
 267         } else { \
 268                 (cache)->c_lrutail = BEI(e)->bei_lruprev; \
 269         } \
 270 } while(0)
 271
 272 #define LRU_ADD( cache, e ) do { \
 273         BEI(e)->bei_lrunext = (cache)->c_lruhead; \
 274         if ( BEI(e)->bei_lrunext != NULL ) { \
 275                 BEI(BEI(e)->bei_lrunext)->bei_lruprev = (e); \
 276         } \
 277         (cache)->c_lruhead = (e); \
 278         BEI(e)->bei_lruprev = NULL; \
 279         if ( (cache)->c_lrutail == NULL ) { \
 280                 (cache)->c_lrutail = (e); \
 281         } \
 282 } while(0)
 283
 284 /*
 285  * cache_add_entry_rw - create and lock an entry in the cache
 286  * returns:     0       entry has been created and locked
 287  *              1       entry already existed
 288  *              -1      something bad happened
 289  */
 290 int
 291 bdb_cache_add_entry_rw(
 292     Cache       *cache,
 293     Entry       *e,
 294     int         rw
 295 )
 296 {
 297         int     i, rc;
 298         Entry   *ee;
 299
 300 #ifdef NEW_LOGGING
 301         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
 302                    "bdb_cache_add_entry_rw: add (%s):%s to cache\n",
 303                    e->e_dn, rw ? "w" : "r" ));
 304 #endif
 305         /* set cache mutex */
 306         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 307
 308         assert( e->e_private == NULL );
 309
 310         if( bdb_cache_entry_private_init(e) != 0 ) {
 311                 /* free cache mutex */
 312                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 313
 314 #ifdef NEW_LOGGING
 315                 LDAP_LOG(( "cache", LDAP_LEVEL_ERR,
 316                            "bdb_cache_add_entry_rw: add (%s):%ld private init failed!\n",
 317                            e->e_dn, e->e_id ));
 318 #else
 319                 Debug( LDAP_DEBUG_ANY,
 320                         "====> bdb_cache_add_entry( %ld ): \"%s\": private init failed!\n",
 321                     e->e_id, e->e_dn, 0 );
 322 #endif
 323
 324
 325                 return( -1 );
 326         }
 327
 328         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 329                 (AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
 330         {
 331                 /* free cache mutex */
 332                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 333
 334 #ifdef NEW_LOGGING
 335                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 336                            "bdb_cache_add_entry: (%s):%ld already in cache.\n",
 337                            e->e_dn, e->e_id ));
 338 #else
 339                 Debug( LDAP_DEBUG_TRACE,
 340                         "====> bdb_cache_add_entry( %ld ): \"%s\": already in dn cache\n",
 341                     e->e_id, e->e_dn, 0 );
 342 #endif
 343
 344                 bdb_cache_entry_private_destroy(e);
 345
 346                 return( 1 );
 347         }
 348
 349         /* id tree */
 350         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 351                 (AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
 352         {
 353 #ifdef NEW_LOGGING
 354                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 355                            "bdb_cache_add_entry: (%s):%ls already in cache.\n",
 356                            e->e_dn, e->e_id ));
 357 #else
 358                 Debug( LDAP_DEBUG_ANY,
 359                         "====> bdb_cache_add_entry( %ld ): \"%s\": already in id cache\n",
 360                     e->e_id, e->e_dn, 0 );
 361 #endif
 362
 363                 /* delete from dn tree inserted above */
 364                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 365                         (AVL_CMP) entry_dn_cmp ) == NULL )
 366                 {
 367 #ifdef NEW_LOGGING
 368                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 369                                    "bdb_cache_add_entry: can't delete (%s) from cache.\n",
 370                                    e->e_dn ));
 371 #else
 372                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 373                             0, 0, 0 );
 374 #endif
 375                 }
 376
 377                 bdb_cache_entry_private_destroy(e);
 378
 379                 /* free cache mutex */
 380                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 381                 return( -1 );
 382         }
 383
 384         bdb_cache_entry_rdwr_lock( e, rw );
 385
 386         /* put the entry into 'CREATING' state */
 387         /* will be marked after when entry is returned */
 388         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 389         BEI(e)->bei_refcnt = 1;
 390
 391         /* lru */
 392         LRU_ADD( cache, e );
 393         if ( ++cache->c_cursize > cache->c_maxsize ) {
 394                 /*
 395                  * find the lru entry not currently in use and delete it.
 396                  * in case a lot of entries are in use, only look at the
 397                  * first 10 on the tail of the list.
 398                  */
 399                 i = 0;
 400                 while ( cache->c_lrutail != NULL &&
 401                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 402                         i < 10 )
 403                 {
 404                         /* move this in-use entry to the front of the q */
 405                         ee = cache->c_lrutail;
 406                         LRU_DELETE( cache, ee );
 407                         LRU_ADD( cache, ee );
 408                         i++;
 409                 }
 410
 411                 /*
 412                  * found at least one to delete - try to get back under
 413                  * the max cache size.
 414                  */
 415                 while ( cache->c_lrutail != NULL &&
 416                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 417                         cache->c_cursize > cache->c_maxsize )
 418                 {
 419                         e = cache->c_lrutail;
 420
 421                         /* delete from cache and lru q */
 422                         /* XXX do we need rc ? */
 423                         rc = bdb_cache_delete_entry_internal( cache, e );
 424                         bdb_cache_entry_private_destroy( e );
 425                         bdb_entry_return( e );
 426                 }
 427         }
 428
 429         /* free cache mutex */
 430         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 431         return( 0 );
 432 }
 433
 434 /*
 435  * cache_update_entry - update a LOCKED entry which has been deleted.
 436  * returns:     0       entry has been created and locked
 437  *              1       entry already existed
 438  *              -1      something bad happened
 439  */
 440 int
 441 bdb_cache_update_entry(
 442     Cache       *cache,
 443     Entry               *e
 444 )
 445 {
 446         int     i, rc;
 447         Entry   *ee;
 448
 449         /* set cache mutex */
 450         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 451
 452         assert( e->e_private );
 453
 454         if ( avl_insert( &cache->c_dntree, (caddr_t) e,
 455                 (AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
 456         {
 457 #ifdef NEW_LOGGING
 458                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 459                            "bdb_cache_update_entry: (%s):%ld already in dn cache\n",
 460                            e->e_dn, e->e_id ));
 461 #else
 462                 Debug( LDAP_DEBUG_TRACE,
 463                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in dn cache\n",
 464                     e->e_id, e->e_dn, 0 );
 465 #endif
 466
 467                 /* free cache mutex */
 468                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 469                 return( 1 );
 470         }
 471
 472         /* id tree */
 473         if ( avl_insert( &cache->c_idtree, (caddr_t) e,
 474                 (AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
 475         {
 476 #ifdef NEW_LOGGING
 477                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 478                            "bdb_cache_update_entry: (%s)%ld already in id cache\n",
 479                            e->e_dn, e->e_id ));
 480 #else
 481                 Debug( LDAP_DEBUG_ANY,
 482                         "====> bdb_cache_update_entry( %ld ): \"%s\": already in id cache\n",
 483                     e->e_id, e->e_dn, 0 );
 484 #endif
 485
 486                 /* delete from dn tree inserted above */
 487                 if ( avl_delete( &cache->c_dntree, (caddr_t) e,
 488                         (AVL_CMP) entry_dn_cmp ) == NULL )
 489                 {
 490 #ifdef NEW_LOGGING
 491                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 492                                    "bdb_cache_update_entry: can't delete (%s)%ld from dn cache.\n",
 493                                    e->e_dn, e->e_id ));
 494 #else
 495                         Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
 496                             0, 0, 0 );
 497 #endif
 498                 }
 499
 500                 /* free cache mutex */
 501                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 502                 return( -1 );
 503         }
 504
 505
 506         /* put the entry into 'CREATING' state */
 507         /* will be marked after when entry is returned */
 508         BEI(e)->bei_state = CACHE_ENTRY_CREATING;
 509
 510         /* lru */
 511         LRU_ADD( cache, e );
 512         if ( ++cache->c_cursize > cache->c_maxsize ) {
 513                 /*
 514                  * find the lru entry not currently in use and delete it.
 515                  * in case a lot of entries are in use, only look at the
 516                  * first 10 on the tail of the list.
 517                  */
 518                 i = 0;
 519                 while ( cache->c_lrutail != NULL &&
 520                         BEI(cache->c_lrutail)->bei_refcnt != 0 &&
 521                         i < 10 )
 522                 {
 523                         /* move this in-use entry to the front of the q */
 524                         ee = cache->c_lrutail;
 525                         LRU_DELETE( cache, ee );
 526                         LRU_ADD( cache, ee );
 527                         i++;
 528                 }
 529
 530                 /*
 531                  * found at least one to delete - try to get back under
 532                  * the max cache size.
 533                  */
 534                 while ( cache->c_lrutail != NULL &&
 535                         BEI(cache->c_lrutail)->bei_refcnt == 0 &&
 536                         cache->c_cursize > cache->c_maxsize )
 537                 {
 538                         e = cache->c_lrutail;
 539
 540                         /* delete from cache and lru q */
 541                         /* XXX do we need rc ? */
 542                         rc = bdb_cache_delete_entry_internal( cache, e );
 543                         bdb_cache_entry_private_destroy( e );
 544                         bdb_entry_return( e );
 545                 }
 546         }
 547
 548         /* free cache mutex */
 549         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 550         return( 0 );
 551 }
 552
 553 ID
 554 bdb_cache_find_entry_ndn2id(
 555         Backend         *be,
 556     Cache       *cache,
 557     struct berval       *ndn
 558 )
 559 {
 560         Entry           e, *ep;
 561         ID                      id;
 562         int count = 0;
 563
 564         /* this function is always called with normalized DN */
 565         e.e_nname = *ndn;
 566
 567 try_again:
 568         /* set cache mutex */
 569         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 570
 571         if ( (ep = (Entry *) avl_find( cache->c_dntree, (caddr_t) &e,
 572                 (AVL_CMP) entry_dn_cmp )) != NULL )
 573         {
 574                 int state;
 575                 count++;
 576
 577                 /*
 578                  * ep now points to an unlocked entry
 579                  * we do not need to lock the entry if we only
 580                  * check the state, refcnt, LRU, and id.
 581                  */
 582
 583                 assert( ep->e_private );
 584
 585                 /* save id */
 586                 id = ep->e_id;
 587                 state = BEI(ep)->bei_state;
 588
 589                 /*
 590                  * entry is deleted or not fully created yet
 591                  */
 592                 if ( state != CACHE_ENTRY_READY ) {
 593                         assert(state != CACHE_ENTRY_UNDEFINED);
 594
 595                         /* free cache mutex */
 596                         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 597
 598 #ifdef NEW_LOGGING
 599                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 600                                    "bdb_cache_find_entry_dn2id: (%s) %ld not ready: %d\n",
 601                                    ndn->bv_val, id, state ));
 602 #else
 603                         Debug(LDAP_DEBUG_TRACE,
 604                                 "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (not ready) %d\n",
 605                                 ndn->bv_val, id, state);
 606 #endif
 607
 608
 609                         ldap_pvt_thread_yield();
 610                         goto try_again;
 611                 }
 612
 613                 /* lru */
 614                 LRU_DELETE( cache, ep );
 615                 LRU_ADD( cache, ep );
 616
 617                 /* free cache mutex */
 618                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 619
 620 #ifdef NEW_LOGGING
 621                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 622                            "bdb_cache_find_entry_dn2id: (%s): %ld %d tries\n",
 623                            ndn->bv_val, id, count ));
 624 #else
 625                 Debug(LDAP_DEBUG_TRACE,
 626                         "====> bdb_cache_find_entry_dn2id(\"%s\"): %ld (%d tries)\n",
 627                         ndn->bv_val, id, count);
 628 #endif
 629
 630         } else {
 631                 /* free cache mutex */
 632                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 633
 634                 id = NOID;
 635         }
 636
 637         return( id );
 638 }
 639
 640 /*
 641  * cache_find_entry_id - find an entry in the cache, given id
 642  */
 643
 644 Entry *
 645 bdb_cache_find_entry_id(
 646         Cache   *cache,
 647         ID                              id,
 648         int                             rw
 649 )
 650 {
 651         Entry   e;
 652         Entry   *ep;
 653         int     count = 0;
 654
 655         e.e_id = id;
 656
 657 try_again:
 658         /* set cache mutex */
 659         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 660
 661         if ( (ep = (Entry *) avl_find( cache->c_idtree, (caddr_t) &e,
 662                 (AVL_CMP) entry_id_cmp )) != NULL )
 663         {
 664                 int state;
 665                 ID      ep_id;
 666
 667                 count++;
 668
 669                 assert( ep->e_private );
 670
 671                 ep_id = ep->e_id;
 672                 state = BEI(ep)->bei_state;
 673
 674                 /*
 675                  * entry is deleted or not fully created yet
 676                  */
 677                 if ( state != CACHE_ENTRY_READY ) {
 678
 679                         assert(state != CACHE_ENTRY_UNDEFINED);
 680
 681                         /* free cache mutex */
 682                         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 683
 684 #ifdef NEW_LOGGING
 685                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 686                                    "bdb_cache_find_entry_id: (%ld)->%ld not ready (%d).\n",
 687                                    id, ep_id, state ));
 688
 689 #else
 690                         Debug(LDAP_DEBUG_TRACE,
 691                                 "====> bdb_cache_find_entry_id( %ld ): %ld (not ready) %d\n",
 692                                 id, ep_id, state);
 693 #endif
 694
 695                         ldap_pvt_thread_yield();
 696                         goto try_again;
 697                 }
 698
 699                 /* acquire reader lock */
 700                 if ( bdb_cache_entry_rdwr_trylock(ep, rw) == LDAP_PVT_THREAD_EBUSY ) {
 701                         /* could not acquire entry lock...
 702                          * owner cannot free as we have the cache locked.
 703                          * so, unlock the cache, yield, and try again.
 704                          */
 705
 706                         /* free cache mutex */
 707                         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 708
 709 #ifdef NEW_LOGGING
 710                         LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 711                                    "bdb_cache_find_entry_id: %ld -> %ld (busy) %d.\n",
 712                                    id, ep_id, state ));
 713 #else
 714                         Debug(LDAP_DEBUG_TRACE,
 715                                 "====> bdb_cache_find_entry_id( %ld ): %ld (busy) %d\n",
 716                                 id, ep_id, state);
 717 #endif
 718
 719                         ldap_pvt_thread_yield();
 720                         goto try_again;
 721                 }
 722
 723                 /* lru */
 724                 LRU_DELETE( cache, ep );
 725                 LRU_ADD( cache, ep );
 726
 727                 BEI(ep)->bei_refcnt++;
 728
 729                 /* free cache mutex */
 730                 ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 731
 732 #ifdef NEW_LOGGING
 733                 LDAP_LOG(( "cache", LDAP_LEVEL_DETAIL1,
 734                            "bdb_cache_find_entry_id: %ld -> %s  found %d tries.\n",
 735                            ep_id, ep->e_dn, count ));
 736 #else
 737                 Debug(LDAP_DEBUG_TRACE,
 738                         "====> bdb_cache_find_entry_id( %ld ) \"%s\" (found) (%d tries)\n",
 739                         ep_id, ep->e_dn, count);
 740 #endif
 741
 742
 743                 return( ep );
 744         }
 745
 746         /* free cache mutex */
 747         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 748
 749         return( NULL );
 750 }
 751
 752 /*
 753  * cache_delete_entry - delete the entry e from the cache.  the caller
 754  * should have obtained e (increasing its ref count) via a call to one
 755  * of the cache_find_* routines.  the caller should *not* call the
 756  * cache_return_entry() routine prior to calling cache_delete_entry().
 757  * it performs this function.
 758  *
 759  * returns:     0       e was deleted ok
 760  *              1       e was not in the cache
 761  *              -1      something bad happened
 762  */
 763 int
 764 bdb_cache_delete_entry(
 765     Cache       *cache,
 766     Entry               *e
 767 )
 768 {
 769         int     rc;
 770
 771         /* set cache mutex */
 772         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 773
 774         assert( e->e_private );
 775
 776 #ifdef NEW_LOGGING
 777         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
 778                    "bdb_cache_delete_entry: delete %ld.\n", e->e_id ));
 779 #else
 780         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_delete_entry( %ld )\n",
 781                 e->e_id, 0, 0 );
 782 #endif
 783
 784         rc = bdb_cache_delete_entry_internal( cache, e );
 785
 786         /* free cache mutex */
 787         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 788         return( rc );
 789 }
 790
 791 static int
 792 bdb_cache_delete_entry_internal(
 793     Cache       *cache,
 794     Entry               *e
 795 )
 796 {
 797         int rc = 0;     /* return code */
 798
 799         /* dn tree */
 800         if ( avl_delete( &cache->c_dntree, (caddr_t) e, (AVL_CMP) entry_dn_cmp )
 801                 == NULL )
 802         {
 803                 rc = -1;
 804         }
 805
 806         /* id tree */
 807         if ( avl_delete( &cache->c_idtree, (caddr_t) e, (AVL_CMP) entry_id_cmp )
 808                 == NULL )
 809         {
 810                 rc = -1;
 811         }
 812
 813         if (rc != 0) {
 814                 return rc;
 815         }
 816
 817         /* lru */
 818         LRU_DELETE( cache, e );
 819         cache->c_cursize--;
 820
 821         /*
 822          * flag entry to be freed later by a call to cache_return_entry()
 823          */
 824         BEI(e)->bei_state = CACHE_ENTRY_DELETED;
 825
 826         return( 0 );
 827 }
 828
 829 void
 830 bdb_cache_release_all( Cache *cache )
 831 {
 832         Entry *e;
 833         int rc;
 834
 835         /* set cache mutex */
 836         ldap_pvt_thread_mutex_lock( &cache->c_mutex );
 837
 838 #ifdef NEW_LOGGING
 839         LDAP_LOG(( "cache", LDAP_LEVEL_ENTRY,
 840                    "bdb_cache_release_all: enter\n" ));
 841 #else
 842         Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_release_all\n", 0, 0, 0 );
 843 #endif
 844
 845         while ( (e = cache->c_lrutail) != NULL && BEI(e)->bei_refcnt == 0 ) {
 846 #ifdef LDAP_RDWR_DEBUG
 847                 assert(!ldap_pvt_thread_rdwr_active(&BEI(e)->bei_rdwr));
 848 #endif
 849
 850                 /* delete from cache and lru q */
 851                 /* XXX do we need rc ? */
 852                 rc = bdb_cache_delete_entry_internal( cache, e );
 853                 bdb_cache_entry_private_destroy( e );
 854                 bdb_entry_return( e );
 855         }
 856
 857         if ( cache->c_cursize ) {
 858 #ifdef NEW_LOGGING
 859                 LDAP_LOG(( "cache", LDAP_LEVEL_INFO,
 860                            "bdb_cache_release_all: Entry cache could not be emptied.\n" ));
 861 #else
 862                 Debug( LDAP_DEBUG_TRACE, "Entry-cache could not be emptied\n", 0, 0, 0 );
 863 #endif
 864
 865         }
 866
 867         /* free cache mutex */
 868         ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
 869 }
 870
 871 #ifdef LDAP_DEBUG
 872 static void
 873 bdb_lru_print( Cache *cache )
 874 {
 875         Entry   *e;
 876
 877         fprintf( stderr, "LRU queue (head to tail):\n" );
 878         for ( e = cache->c_lruhead; e != NULL; e = BEI(e)->bei_lrunext ) {
 879                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
 880                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
 881         }
 882         fprintf( stderr, "LRU queue (tail to head):\n" );
 883         for ( e = cache->c_lrutail; e != NULL; e = BEI(e)->bei_lruprev ) {
 884                 fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
 885                         e->e_dn, e->e_id, BEI(e)->bei_refcnt );
 886         }
 887 }
 888 #endif