1 /* cache.c - routines to maintain an in-core cache of entries */
2 /* $OpenLDAP$ */
3 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
4 *
5 * Copyright 2000-2021 The OpenLDAP Foundation.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted only as authorized by the OpenLDAP
10 * Public License.
11 *
12 * A copy of this license is available in the file LICENSE in the
13 * top-level directory of the distribution or, alternatively, at
14 * <http://www.OpenLDAP.org/license.html>.
15 */
16
17 #include "portable.h"
18
19 #include <stdio.h>
20
21 #include <ac/errno.h>
22 #include <ac/string.h>
23 #include <ac/socket.h>
24
25 #include "slap.h"
26
27 #include "back-bdb.h"
28
29 #include "ldap_rq.h"
30
31 #ifdef BDB_HIER
32 #define bdb_cache_lru_purge hdb_cache_lru_purge
33 #endif
34 static void bdb_cache_lru_purge( struct bdb_info *bdb );
35
36 static int bdb_cache_delete_internal(Cache *cache, EntryInfo *e, int decr);
37 #ifdef LDAP_DEBUG
38 #define SLAPD_UNUSED
39 #ifdef SLAPD_UNUSED
40 static void bdb_lru_print(Cache *cache);
41 static void bdb_idtree_print(Cache *cache);
42 #endif
43 #endif
44
45 /* For concurrency experiments only! */
46 #if 0
47 #define ldap_pvt_thread_rdwr_wlock(a) 0
48 #define ldap_pvt_thread_rdwr_wunlock(a) 0
49 #define ldap_pvt_thread_rdwr_rlock(a) 0
50 #define ldap_pvt_thread_rdwr_runlock(a) 0
51 #endif
52
53 #if 0
54 #define ldap_pvt_thread_mutex_trylock(a) 0
55 #endif
56
57 static EntryInfo *
bdb_cache_entryinfo_new(Cache * cache)58 bdb_cache_entryinfo_new( Cache *cache )
59 {
60 EntryInfo *ei = NULL;
61
62 if ( cache->c_eifree ) {
63 ldap_pvt_thread_mutex_lock( &cache->c_eifree_mutex );
64 if ( cache->c_eifree ) {
65 ei = cache->c_eifree;
66 cache->c_eifree = ei->bei_lrunext;
67 ei->bei_finders = 0;
68 ei->bei_lrunext = NULL;
69 }
70 ldap_pvt_thread_mutex_unlock( &cache->c_eifree_mutex );
71 }
72 if ( !ei ) {
73 ei = ch_calloc(1, sizeof(EntryInfo));
74 ldap_pvt_thread_mutex_init( &ei->bei_kids_mutex );
75 }
76
77 ei->bei_state = CACHE_ENTRY_REFERENCED;
78
79 return ei;
80 }
81
82 static void
bdb_cache_entryinfo_free(Cache * cache,EntryInfo * ei)83 bdb_cache_entryinfo_free( Cache *cache, EntryInfo *ei )
84 {
85 free( ei->bei_nrdn.bv_val );
86 BER_BVZERO( &ei->bei_nrdn );
87 #ifdef BDB_HIER
88 free( ei->bei_rdn.bv_val );
89 BER_BVZERO( &ei->bei_rdn );
90 ei->bei_modrdns = 0;
91 ei->bei_ckids = 0;
92 ei->bei_dkids = 0;
93 #endif
94 ei->bei_parent = NULL;
95 ei->bei_kids = NULL;
96 ei->bei_lruprev = NULL;
97
98 #if 0
99 ldap_pvt_thread_mutex_lock( &cache->c_eifree_mutex );
100 ei->bei_lrunext = cache->c_eifree;
101 cache->c_eifree = ei;
102 ldap_pvt_thread_mutex_unlock( &cache->c_eifree_mutex );
103 #else
104 ldap_pvt_thread_mutex_destroy( &ei->bei_kids_mutex );
105 ch_free( ei );
106 #endif
107 }
108
109 #define LRU_DEL( c, e ) do { \
110 if ( e == e->bei_lruprev ) { \
111 (c)->c_lruhead = (c)->c_lrutail = NULL; \
112 } else { \
113 if ( e == (c)->c_lruhead ) (c)->c_lruhead = e->bei_lruprev; \
114 if ( e == (c)->c_lrutail ) (c)->c_lrutail = e->bei_lruprev; \
115 e->bei_lrunext->bei_lruprev = e->bei_lruprev; \
116 e->bei_lruprev->bei_lrunext = e->bei_lrunext; \
117 } \
118 e->bei_lruprev = NULL; \
119 } while ( 0 )
120
121 /* Note - we now use a Second-Chance / Clock algorithm instead of
122 * Least-Recently-Used. This tremendously improves concurrency
123 * because we no longer need to manipulate the lists every time an
124 * entry is touched. We only need to lock the lists when adding
125 * or deleting an entry. It's now a circular doubly-linked list.
126 * We always append to the tail, but the head traverses the circle
127 * during a purge operation.
128 */
129 static void
bdb_cache_lru_link(struct bdb_info * bdb,EntryInfo * ei)130 bdb_cache_lru_link( struct bdb_info *bdb, EntryInfo *ei )
131 {
132
133 /* Already linked, ignore */
134 if ( ei->bei_lruprev )
135 return;
136
137 /* Insert into circular LRU list */
138 ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_lru_mutex );
139
140 ei->bei_lruprev = bdb->bi_cache.c_lrutail;
141 if ( bdb->bi_cache.c_lrutail ) {
142 ei->bei_lrunext = bdb->bi_cache.c_lrutail->bei_lrunext;
143 bdb->bi_cache.c_lrutail->bei_lrunext = ei;
144 if ( ei->bei_lrunext )
145 ei->bei_lrunext->bei_lruprev = ei;
146 } else {
147 ei->bei_lrunext = ei->bei_lruprev = ei;
148 bdb->bi_cache.c_lruhead = ei;
149 }
150 bdb->bi_cache.c_lrutail = ei;
151 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_lru_mutex );
152 }
153
154 #ifdef NO_THREADS
155 #define NO_DB_LOCK
156 #endif
157
158 /* #define NO_DB_LOCK 1 */
159 /* Note: The BerkeleyDB locks are much slower than regular
160 * mutexes or rdwr locks. But the BDB implementation has the
161 * advantage of using a fixed size lock table, instead of
162 * allocating a lock object per entry in the DB. That's a
163 * key benefit for scaling. It also frees us from worrying
164 * about undetectable deadlocks between BDB activity and our
165 * own cache activity. It's still worth exploring faster
166 * alternatives though.
167 */
168
169 /* Atomically release and reacquire a lock */
170 int
bdb_cache_entry_db_relock(struct bdb_info * bdb,DB_TXN * txn,EntryInfo * ei,int rw,int tryOnly,DB_LOCK * lock)171 bdb_cache_entry_db_relock(
172 struct bdb_info *bdb,
173 DB_TXN *txn,
174 EntryInfo *ei,
175 int rw,
176 int tryOnly,
177 DB_LOCK *lock )
178 {
179 #ifdef NO_DB_LOCK
180 return 0;
181 #else
182 int rc;
183 DBT lockobj;
184 DB_LOCKREQ list[2];
185
186 if ( !lock ) return 0;
187
188 DBTzero( &lockobj );
189 lockobj.data = &ei->bei_id;
190 lockobj.size = sizeof(ei->bei_id) + 1;
191
192 list[0].op = DB_LOCK_PUT;
193 list[0].lock = *lock;
194 list[1].op = DB_LOCK_GET;
195 list[1].lock = *lock;
196 list[1].mode = rw ? DB_LOCK_WRITE : DB_LOCK_READ;
197 list[1].obj = &lockobj;
198 rc = bdb->bi_dbenv->lock_vec(bdb->bi_dbenv, TXN_ID(txn), tryOnly ? DB_LOCK_NOWAIT : 0,
199 list, 2, NULL );
200
201 if (rc && !tryOnly) {
202 Debug( LDAP_DEBUG_TRACE,
203 "bdb_cache_entry_db_relock: entry %ld, rw %d, rc %d\n",
204 ei->bei_id, rw, rc );
205 } else {
206 *lock = list[1].lock;
207 }
208 return rc;
209 #endif
210 }
211
212 static int
bdb_cache_entry_db_lock(struct bdb_info * bdb,DB_TXN * txn,EntryInfo * ei,int rw,int tryOnly,DB_LOCK * lock)213 bdb_cache_entry_db_lock( struct bdb_info *bdb, DB_TXN *txn, EntryInfo *ei,
214 int rw, int tryOnly, DB_LOCK *lock )
215 {
216 #ifdef NO_DB_LOCK
217 return 0;
218 #else
219 int rc;
220 DBT lockobj;
221 int db_rw;
222
223 if ( !lock ) return 0;
224
225 if (rw)
226 db_rw = DB_LOCK_WRITE;
227 else
228 db_rw = DB_LOCK_READ;
229
230 DBTzero( &lockobj );
231 lockobj.data = &ei->bei_id;
232 lockobj.size = sizeof(ei->bei_id) + 1;
233
234 rc = LOCK_GET(bdb->bi_dbenv, TXN_ID(txn), tryOnly ? DB_LOCK_NOWAIT : 0,
235 &lockobj, db_rw, lock);
236 if (rc && !tryOnly) {
237 Debug( LDAP_DEBUG_TRACE,
238 "bdb_cache_entry_db_lock: entry %ld, rw %d, rc %d\n",
239 ei->bei_id, rw, rc );
240 }
241 return rc;
242 #endif /* NO_DB_LOCK */
243 }
244
245 int
bdb_cache_entry_db_unlock(struct bdb_info * bdb,DB_LOCK * lock)246 bdb_cache_entry_db_unlock ( struct bdb_info *bdb, DB_LOCK *lock )
247 {
248 #ifdef NO_DB_LOCK
249 return 0;
250 #else
251 int rc;
252
253 if ( !lock || lock->mode == DB_LOCK_NG ) return 0;
254
255 rc = LOCK_PUT ( bdb->bi_dbenv, lock );
256 return rc;
257 #endif
258 }
259
260 void
bdb_cache_return_entry_rw(struct bdb_info * bdb,Entry * e,int rw,DB_LOCK * lock)261 bdb_cache_return_entry_rw( struct bdb_info *bdb, Entry *e,
262 int rw, DB_LOCK *lock )
263 {
264 EntryInfo *ei;
265 int free = 0;
266
267 ei = e->e_private;
268 if ( ei && ( ei->bei_state & CACHE_ENTRY_NOT_CACHED )) {
269 bdb_cache_entryinfo_lock( ei );
270 if ( ei->bei_state & CACHE_ENTRY_NOT_CACHED ) {
271 /* Releasing the entry can only be done when
272 * we know that nobody else is using it, i.e we
273 * should have an entry_db writelock. But the
274 * flag is only set by the thread that loads the
275 * entry, and only if no other threads has found
276 * it while it was working. All other threads
277 * clear the flag, which mean that we should be
278 * the only thread using the entry if the flag
279 * is set here.
280 */
281 ei->bei_e = NULL;
282 ei->bei_state ^= CACHE_ENTRY_NOT_CACHED;
283 free = 1;
284 }
285 bdb_cache_entryinfo_unlock( ei );
286 }
287 bdb_cache_entry_db_unlock( bdb, lock );
288 if ( free ) {
289 e->e_private = NULL;
290 bdb_entry_return( e );
291 }
292 }
293
294 static int
bdb_cache_entryinfo_destroy(EntryInfo * e)295 bdb_cache_entryinfo_destroy( EntryInfo *e )
296 {
297 ldap_pvt_thread_mutex_destroy( &e->bei_kids_mutex );
298 free( e->bei_nrdn.bv_val );
299 #ifdef BDB_HIER
300 free( e->bei_rdn.bv_val );
301 #endif
302 free( e );
303 return 0;
304 }
305
306 /* Do a length-ordered sort on normalized RDNs */
307 static int
bdb_rdn_cmp(const void * v_e1,const void * v_e2)308 bdb_rdn_cmp( const void *v_e1, const void *v_e2 )
309 {
310 const EntryInfo *e1 = v_e1, *e2 = v_e2;
311 int rc = e1->bei_nrdn.bv_len - e2->bei_nrdn.bv_len;
312 if (rc == 0) {
313 rc = strncmp( e1->bei_nrdn.bv_val, e2->bei_nrdn.bv_val,
314 e1->bei_nrdn.bv_len );
315 }
316 return rc;
317 }
318
319 static int
bdb_id_cmp(const void * v_e1,const void * v_e2)320 bdb_id_cmp( const void *v_e1, const void *v_e2 )
321 {
322 const EntryInfo *e1 = v_e1, *e2 = v_e2;
323 return e1->bei_id - e2->bei_id;
324 }
325
326 static int
bdb_id_dup_err(void * v1,void * v2)327 bdb_id_dup_err( void *v1, void *v2 )
328 {
329 EntryInfo *e2 = v2;
330 e2->bei_lrunext = v1;
331 return -1;
332 }
333
334 /* Create an entryinfo in the cache. Caller must release the locks later.
335 */
336 static int
bdb_entryinfo_add_internal(struct bdb_info * bdb,EntryInfo * ei,EntryInfo ** res)337 bdb_entryinfo_add_internal(
338 struct bdb_info *bdb,
339 EntryInfo *ei,
340 EntryInfo **res )
341 {
342 EntryInfo *ei2 = NULL;
343
344 *res = NULL;
345
346 ei2 = bdb_cache_entryinfo_new( &bdb->bi_cache );
347
348 bdb_cache_entryinfo_lock( ei->bei_parent );
349 ldap_pvt_thread_rdwr_wlock( &bdb->bi_cache.c_rwlock );
350
351 ei2->bei_id = ei->bei_id;
352 ei2->bei_parent = ei->bei_parent;
353 #ifdef BDB_HIER
354 ei2->bei_rdn = ei->bei_rdn;
355 #endif
356 #ifdef SLAP_ZONE_ALLOC
357 ei2->bei_bdb = bdb;
358 #endif
359
360 /* Add to cache ID tree */
361 if (avl_insert( &bdb->bi_cache.c_idtree, ei2, bdb_id_cmp,
362 bdb_id_dup_err )) {
363 EntryInfo *eix = ei2->bei_lrunext;
364 bdb_cache_entryinfo_free( &bdb->bi_cache, ei2 );
365 ei2 = eix;
366 #ifdef BDB_HIER
367 /* It got freed above because its value was
368 * assigned to ei2.
369 */
370 ei->bei_rdn.bv_val = NULL;
371 #endif
372 } else {
373 int rc;
374
375 bdb->bi_cache.c_eiused++;
376 ber_dupbv( &ei2->bei_nrdn, &ei->bei_nrdn );
377
378 /* This is a new leaf node. But if parent had no kids, then it was
379 * a leaf and we would be decrementing that. So, only increment if
380 * the parent already has kids.
381 */
382 if ( ei->bei_parent->bei_kids || !ei->bei_parent->bei_id )
383 bdb->bi_cache.c_leaves++;
384 rc = avl_insert( &ei->bei_parent->bei_kids, ei2, bdb_rdn_cmp,
385 avl_dup_error );
386 #ifdef BDB_HIER
387 /* it's possible for hdb_cache_find_parent to beat us to it */
388 if ( !rc ) {
389 ei->bei_parent->bei_ckids++;
390 }
391 #endif
392 }
393
394 *res = ei2;
395 return 0;
396 }
397
398 /* Find the EntryInfo for the requested DN. If the DN cannot be found, return
399 * the info for its closest ancestor. *res should be NULL to process a
400 * complete DN starting from the tree root. Otherwise *res must be the
401 * immediate parent of the requested DN, and only the RDN will be searched.
402 * The EntryInfo is locked upon return and must be unlocked by the caller.
403 */
404 int
bdb_cache_find_ndn(Operation * op,DB_TXN * txn,struct berval * ndn,EntryInfo ** res)405 bdb_cache_find_ndn(
406 Operation *op,
407 DB_TXN *txn,
408 struct berval *ndn,
409 EntryInfo **res )
410 {
411 struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
412 EntryInfo ei, *eip, *ei2;
413 int rc = 0;
414 char *ptr;
415
416 /* this function is always called with normalized DN */
417 if ( *res ) {
418 /* we're doing a onelevel search for an RDN */
419 ei.bei_nrdn.bv_val = ndn->bv_val;
420 ei.bei_nrdn.bv_len = dn_rdnlen( op->o_bd, ndn );
421 eip = *res;
422 } else {
423 /* we're searching a full DN from the root */
424 ptr = ndn->bv_val + ndn->bv_len - op->o_bd->be_nsuffix[0].bv_len;
425 ei.bei_nrdn.bv_val = ptr;
426 ei.bei_nrdn.bv_len = op->o_bd->be_nsuffix[0].bv_len;
427 /* Skip to next rdn if suffix is empty */
428 if ( ei.bei_nrdn.bv_len == 0 ) {
429 for (ptr = ei.bei_nrdn.bv_val - 2; ptr > ndn->bv_val
430 && !DN_SEPARATOR(*ptr); ptr--) /* empty */;
431 if ( ptr >= ndn->bv_val ) {
432 if (DN_SEPARATOR(*ptr)) ptr++;
433 ei.bei_nrdn.bv_len = ei.bei_nrdn.bv_val - ptr;
434 ei.bei_nrdn.bv_val = ptr;
435 }
436 }
437 eip = &bdb->bi_cache.c_dntree;
438 }
439
440 for ( bdb_cache_entryinfo_lock( eip ); eip; ) {
441 eip->bei_state |= CACHE_ENTRY_REFERENCED;
442 ei.bei_parent = eip;
443 ei2 = (EntryInfo *)avl_find( eip->bei_kids, &ei, bdb_rdn_cmp );
444 if ( !ei2 ) {
445 DBC *cursor;
446 int len = ei.bei_nrdn.bv_len;
447
448 if ( BER_BVISEMPTY( ndn )) {
449 *res = eip;
450 return LDAP_SUCCESS;
451 }
452
453 ei.bei_nrdn.bv_len = ndn->bv_len -
454 (ei.bei_nrdn.bv_val - ndn->bv_val);
455 eip->bei_finders++;
456 bdb_cache_entryinfo_unlock( eip );
457
458 BDB_LOG_PRINTF( bdb->bi_dbenv, NULL, "slapd Reading %s",
459 ei.bei_nrdn.bv_val );
460
461 cursor = NULL;
462 rc = bdb_dn2id( op, &ei.bei_nrdn, &ei, txn, &cursor );
463 if (rc) {
464 bdb_cache_entryinfo_lock( eip );
465 eip->bei_finders--;
466 if ( cursor ) cursor->c_close( cursor );
467 *res = eip;
468 return rc;
469 }
470
471 BDB_LOG_PRINTF( bdb->bi_dbenv, NULL, "slapd Read got %s(%d)",
472 ei.bei_nrdn.bv_val, ei.bei_id );
473
474 /* DN exists but needs to be added to cache */
475 ei.bei_nrdn.bv_len = len;
476 rc = bdb_entryinfo_add_internal( bdb, &ei, &ei2 );
477 /* add_internal left eip and c_rwlock locked */
478 eip->bei_finders--;
479 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
480 if ( cursor ) cursor->c_close( cursor );
481 if ( rc ) {
482 *res = eip;
483 return rc;
484 }
485 }
486 bdb_cache_entryinfo_lock( ei2 );
487 if ( ei2->bei_state & CACHE_ENTRY_DELETED ) {
488 /* In the midst of deleting? Give it a chance to
489 * complete.
490 */
491 bdb_cache_entryinfo_unlock( ei2 );
492 bdb_cache_entryinfo_unlock( eip );
493 ldap_pvt_thread_yield();
494 bdb_cache_entryinfo_lock( eip );
495 *res = eip;
496 return DB_NOTFOUND;
497 }
498 bdb_cache_entryinfo_unlock( eip );
499
500 eip = ei2;
501
502 /* Advance to next lower RDN */
503 for (ptr = ei.bei_nrdn.bv_val - 2; ptr > ndn->bv_val
504 && !DN_SEPARATOR(*ptr); ptr--) /* empty */;
505 if ( ptr >= ndn->bv_val ) {
506 if (DN_SEPARATOR(*ptr)) ptr++;
507 ei.bei_nrdn.bv_len = ei.bei_nrdn.bv_val - ptr - 1;
508 ei.bei_nrdn.bv_val = ptr;
509 }
510 if ( ptr < ndn->bv_val ) {
511 *res = eip;
512 break;
513 }
514 }
515
516 return rc;
517 }
518
519 #ifdef BDB_HIER
520 /* Walk up the tree from a child node, looking for an ID that's already
521 * been linked into the cache.
522 */
523 int
hdb_cache_find_parent(Operation * op,DB_TXN * txn,ID id,EntryInfo ** res)524 hdb_cache_find_parent(
525 Operation *op,
526 DB_TXN *txn,
527 ID id,
528 EntryInfo **res )
529 {
530 struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
531 EntryInfo ei, eip, *ei2 = NULL, *ein = NULL, *eir = NULL;
532 int rc, add;
533
534 ei.bei_id = id;
535 ei.bei_kids = NULL;
536 ei.bei_ckids = 0;
537
538 for (;;) {
539 rc = hdb_dn2id_parent( op, txn, &ei, &eip.bei_id );
540 if ( rc ) break;
541
542 /* Save the previous node, if any */
543 ei2 = ein;
544
545 /* Create a new node for the current ID */
546 ein = bdb_cache_entryinfo_new( &bdb->bi_cache );
547 ein->bei_id = ei.bei_id;
548 ein->bei_kids = ei.bei_kids;
549 ein->bei_nrdn = ei.bei_nrdn;
550 ein->bei_rdn = ei.bei_rdn;
551 ein->bei_ckids = ei.bei_ckids;
552 #ifdef SLAP_ZONE_ALLOC
553 ein->bei_bdb = bdb;
554 #endif
555 ei.bei_ckids = 0;
556 add = 1;
557
558 /* This node is not fully connected yet */
559 ein->bei_state |= CACHE_ENTRY_NOT_LINKED;
560
561 /* If this is the first time, save this node
562 * to be returned later.
563 */
564 if ( eir == NULL ) {
565 eir = ein;
566 ein->bei_finders++;
567 }
568
569 again:
570 /* Insert this node into the ID tree */
571 ldap_pvt_thread_rdwr_wlock( &bdb->bi_cache.c_rwlock );
572 if ( avl_insert( &bdb->bi_cache.c_idtree, (caddr_t)ein,
573 bdb_id_cmp, bdb_id_dup_err ) ) {
574 EntryInfo *eix = ein->bei_lrunext;
575
576 if ( bdb_cache_entryinfo_trylock( eix )) {
577 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
578 ldap_pvt_thread_yield();
579 goto again;
580 }
581 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
582
583 /* Someone else created this node just before us.
584 * Free our new copy and use the existing one.
585 */
586 bdb_cache_entryinfo_free( &bdb->bi_cache, ein );
587
588 /* if it was the node we were looking for, just return it */
589 if ( eir == ein ) {
590 *res = eix;
591 rc = 0;
592 break;
593 }
594
595 ein = ei2;
596 ei2 = eix;
597 add = 0;
598
599 /* otherwise, link up what we have and return */
600 goto gotparent;
601 }
602
603 /* If there was a previous node, link it to this one */
604 if ( ei2 ) ei2->bei_parent = ein;
605
606 /* Look for this node's parent */
607 par2:
608 if ( eip.bei_id ) {
609 ei2 = (EntryInfo *) avl_find( bdb->bi_cache.c_idtree,
610 (caddr_t) &eip, bdb_id_cmp );
611 } else {
612 ei2 = &bdb->bi_cache.c_dntree;
613 }
614 if ( ei2 && bdb_cache_entryinfo_trylock( ei2 )) {
615 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
616 ldap_pvt_thread_yield();
617 ldap_pvt_thread_rdwr_wlock( &bdb->bi_cache.c_rwlock );
618 goto par2;
619 }
620 if ( add )
621 bdb->bi_cache.c_eiused++;
622 if ( ei2 && ( ei2->bei_kids || !ei2->bei_id ))
623 bdb->bi_cache.c_leaves++;
624 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
625
626 gotparent:
627 /* Got the parent, link in and we're done. */
628 if ( ei2 ) {
629 bdb_cache_entryinfo_lock( eir );
630 ein->bei_parent = ei2;
631
632 if ( avl_insert( &ei2->bei_kids, (caddr_t)ein, bdb_rdn_cmp,
633 avl_dup_error) == 0 )
634 ei2->bei_ckids++;
635
636 /* Reset all the state info */
637 for (ein = eir; ein != ei2; ein=ein->bei_parent)
638 ein->bei_state &= ~CACHE_ENTRY_NOT_LINKED;
639
640 bdb_cache_entryinfo_unlock( ei2 );
641 eir->bei_finders--;
642
643 *res = eir;
644 break;
645 }
646 ei.bei_kids = NULL;
647 ei.bei_id = eip.bei_id;
648 ei.bei_ckids = 1;
649 avl_insert( &ei.bei_kids, (caddr_t)ein, bdb_rdn_cmp,
650 avl_dup_error );
651 }
652 return rc;
653 }
654
655 /* Used by hdb_dn2idl when loading the EntryInfo for all the children
656 * of a given node
657 */
hdb_cache_load(struct bdb_info * bdb,EntryInfo * ei,EntryInfo ** res)658 int hdb_cache_load(
659 struct bdb_info *bdb,
660 EntryInfo *ei,
661 EntryInfo **res )
662 {
663 EntryInfo *ei2;
664 int rc;
665
666 /* See if we already have this one */
667 bdb_cache_entryinfo_lock( ei->bei_parent );
668 ei2 = (EntryInfo *)avl_find( ei->bei_parent->bei_kids, ei, bdb_rdn_cmp );
669 bdb_cache_entryinfo_unlock( ei->bei_parent );
670
671 if ( !ei2 ) {
672 /* Not found, add it */
673 struct berval bv;
674
675 /* bei_rdn was not malloc'd before, do it now */
676 ber_dupbv( &bv, &ei->bei_rdn );
677 ei->bei_rdn = bv;
678
679 rc = bdb_entryinfo_add_internal( bdb, ei, res );
680 bdb_cache_entryinfo_unlock( ei->bei_parent );
681 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
682 } else {
683 /* Found, return it */
684 *res = ei2;
685 return 0;
686 }
687 return rc;
688 }
689 #endif
690
691 /* This is best-effort only. If all entries in the cache are
692 * busy, they will all be kept. This is unlikely to happen
693 * unless the cache is very much smaller than the working set.
694 */
695 static void
bdb_cache_lru_purge(struct bdb_info * bdb)696 bdb_cache_lru_purge( struct bdb_info *bdb )
697 {
698 DB_LOCK lock, *lockp;
699 EntryInfo *elru, *elnext = NULL;
700 int islocked;
701 ID eicount, ecount;
702 ID count, efree, eifree = 0;
703 #ifdef LDAP_DEBUG
704 int iter;
705 #endif
706
707 /* Wait for the mutex; we're the only one trying to purge. */
708 ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_lru_mutex );
709
710 if ( bdb->bi_cache.c_cursize > bdb->bi_cache.c_maxsize ) {
711 efree = bdb->bi_cache.c_cursize - bdb->bi_cache.c_maxsize;
712 efree += bdb->bi_cache.c_minfree;
713 } else {
714 efree = 0;
715 }
716
717 /* maximum number of EntryInfo leaves to cache. In slapcat
718 * we always free all leaf nodes.
719 */
720
721 if ( slapMode & SLAP_TOOL_READONLY ) {
722 eifree = bdb->bi_cache.c_leaves;
723 } else if ( bdb->bi_cache.c_eimax &&
724 bdb->bi_cache.c_leaves > bdb->bi_cache.c_eimax ) {
725 eifree = bdb->bi_cache.c_minfree * 10;
726 if ( eifree >= bdb->bi_cache.c_leaves )
727 eifree /= 2;
728 }
729
730 if ( !efree && !eifree ) {
731 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_lru_mutex );
732 bdb->bi_cache.c_purging = 0;
733 return;
734 }
735
736 if ( bdb->bi_cache.c_txn ) {
737 lockp = &lock;
738 } else {
739 lockp = NULL;
740 }
741
742 count = 0;
743 eicount = 0;
744 ecount = 0;
745 #ifdef LDAP_DEBUG
746 iter = 0;
747 #endif
748
749 /* Look for an unused entry to remove */
750 for ( elru = bdb->bi_cache.c_lruhead; elru; elru = elnext ) {
751 elnext = elru->bei_lrunext;
752
753 if ( bdb_cache_entryinfo_trylock( elru ))
754 goto bottom;
755
756 /* This flag implements the clock replacement behavior */
757 if ( elru->bei_state & ( CACHE_ENTRY_REFERENCED )) {
758 elru->bei_state &= ~CACHE_ENTRY_REFERENCED;
759 bdb_cache_entryinfo_unlock( elru );
760 goto bottom;
761 }
762
763 /* If this node is in the process of linking into the cache,
764 * or this node is being deleted, skip it.
765 */
766 if (( elru->bei_state & ( CACHE_ENTRY_NOT_LINKED |
767 CACHE_ENTRY_DELETED | CACHE_ENTRY_LOADING |
768 CACHE_ENTRY_ONELEVEL )) ||
769 elru->bei_finders > 0 ) {
770 bdb_cache_entryinfo_unlock( elru );
771 goto bottom;
772 }
773
774 if ( bdb_cache_entryinfo_trylock( elru->bei_parent )) {
775 bdb_cache_entryinfo_unlock( elru );
776 goto bottom;
777 }
778
779 /* entryinfo is locked */
780 islocked = 1;
781
782 /* If we can successfully writelock it, then
783 * the object is idle.
784 */
785 if ( bdb_cache_entry_db_lock( bdb,
786 bdb->bi_cache.c_txn, elru, 1, 1, lockp ) == 0 ) {
787
788 /* Free entry for this node if it's present */
789 if ( elru->bei_e ) {
790 ecount++;
791
792 /* the cache may have gone over the limit while we
793 * weren't looking, so double check.
794 */
795 if ( !efree && ecount > bdb->bi_cache.c_maxsize )
796 efree = bdb->bi_cache.c_minfree;
797
798 if ( count < efree ) {
799 elru->bei_e->e_private = NULL;
800 #ifdef SLAP_ZONE_ALLOC
801 bdb_entry_return( bdb, elru->bei_e, elru->bei_zseq );
802 #else
803 bdb_entry_return( elru->bei_e );
804 #endif
805 elru->bei_e = NULL;
806 count++;
807 } else {
808 /* Keep this node cached, skip to next */
809 bdb_cache_entry_db_unlock( bdb, lockp );
810 goto next;
811 }
812 }
813 bdb_cache_entry_db_unlock( bdb, lockp );
814
815 /*
816 * If it is a leaf node, and we're over the limit, free it.
817 */
818 if ( elru->bei_kids ) {
819 /* Drop from list, we ignore it... */
820 LRU_DEL( &bdb->bi_cache, elru );
821 } else if ( eicount < eifree ) {
822 /* Too many leaf nodes, free this one */
823 bdb_cache_delete_internal( &bdb->bi_cache, elru, 0 );
824 bdb_cache_delete_cleanup( &bdb->bi_cache, elru );
825 islocked = 0;
826 eicount++;
827 } /* Leave on list until we need to free it */
828 }
829
830 next:
831 if ( islocked ) {
832 bdb_cache_entryinfo_unlock( elru );
833 bdb_cache_entryinfo_unlock( elru->bei_parent );
834 }
835
836 if ( count >= efree && eicount >= eifree )
837 break;
838 bottom:
839 if ( elnext == bdb->bi_cache.c_lruhead )
840 break;
841 #ifdef LDAP_DEBUG
842 iter++;
843 #endif
844 }
845
846 if ( count || ecount > bdb->bi_cache.c_cursize ) {
847 ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_count_mutex );
848 /* HACK: we seem to be losing track, fix up now */
849 if ( ecount > bdb->bi_cache.c_cursize )
850 bdb->bi_cache.c_cursize = ecount;
851 bdb->bi_cache.c_cursize -= count;
852 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_count_mutex );
853 }
854 bdb->bi_cache.c_lruhead = elnext;
855 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_lru_mutex );
856 bdb->bi_cache.c_purging = 0;
857 }
858
859 /*
860 * cache_find_id - find an entry in the cache, given id.
861 * The entry is locked for Read upon return. Call with flag ID_LOCKED if
862 * the supplied *eip was already locked.
863 */
864
865 int
bdb_cache_find_id(Operation * op,DB_TXN * tid,ID id,EntryInfo ** eip,int flag,DB_LOCK * lock)866 bdb_cache_find_id(
867 Operation *op,
868 DB_TXN *tid,
869 ID id,
870 EntryInfo **eip,
871 int flag,
872 DB_LOCK *lock )
873 {
874 struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
875 Entry *ep = NULL;
876 int rc = 0, load = 0;
877 EntryInfo ei = { 0 };
878
879 ei.bei_id = id;
880
881 #ifdef SLAP_ZONE_ALLOC
882 slap_zh_rlock(bdb->bi_cache.c_zctx);
883 #endif
884 /* If we weren't given any info, see if we have it already cached */
885 if ( !*eip ) {
886 again: ldap_pvt_thread_rdwr_rlock( &bdb->bi_cache.c_rwlock );
887 *eip = (EntryInfo *) avl_find( bdb->bi_cache.c_idtree,
888 (caddr_t) &ei, bdb_id_cmp );
889 if ( *eip ) {
890 /* If the lock attempt fails, the info is in use */
891 if ( bdb_cache_entryinfo_trylock( *eip )) {
892 int del = (*eip)->bei_state & CACHE_ENTRY_DELETED;
893 ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
894 /* If this node is being deleted, treat
895 * as if the delete has already finished
896 */
897 if ( del ) {
898 return DB_NOTFOUND;
899 }
900 /* otherwise, wait for the info to free up */
901 ldap_pvt_thread_yield();
902 goto again;
903 }
904 /* If this info isn't hooked up to its parent yet,
905 * unlock and wait for it to be fully initialized
906 */
907 if ( (*eip)->bei_state & CACHE_ENTRY_NOT_LINKED ) {
908 bdb_cache_entryinfo_unlock( *eip );
909 ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
910 ldap_pvt_thread_yield();
911 goto again;
912 }
913 flag |= ID_LOCKED;
914 }
915 ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
916 }
917
918 /* See if the ID exists in the database; add it to the cache if so */
919 if ( !*eip ) {
920 #ifndef BDB_HIER
921 rc = bdb_id2entry( op->o_bd, tid, id, &ep );
922 if ( rc == 0 ) {
923 rc = bdb_cache_find_ndn( op, tid,
924 &ep->e_nname, eip );
925 if ( *eip ) flag |= ID_LOCKED;
926 if ( rc ) {
927 ep->e_private = NULL;
928 #ifdef SLAP_ZONE_ALLOC
929 bdb_entry_return( bdb, ep, (*eip)->bei_zseq );
930 #else
931 bdb_entry_return( ep );
932 #endif
933 ep = NULL;
934 }
935 }
936 #else
937 rc = hdb_cache_find_parent(op, tid, id, eip );
938 if ( rc == 0 ) flag |= ID_LOCKED;
939 #endif
940 }
941
942 /* Ok, we found the info, do we have the entry? */
943 if ( rc == 0 ) {
944 if ( !( flag & ID_LOCKED )) {
945 bdb_cache_entryinfo_lock( *eip );
946 flag |= ID_LOCKED;
947 }
948
949 if ( (*eip)->bei_state & CACHE_ENTRY_DELETED ) {
950 rc = DB_NOTFOUND;
951 } else {
952 (*eip)->bei_finders++;
953 (*eip)->bei_state |= CACHE_ENTRY_REFERENCED;
954 if ( flag & ID_NOENTRY ) {
955 bdb_cache_entryinfo_unlock( *eip );
956 return 0;
957 }
958 /* Make sure only one thread tries to load the entry */
959 load1:
960 #ifdef SLAP_ZONE_ALLOC
961 if ((*eip)->bei_e && !slap_zn_validate(
962 bdb->bi_cache.c_zctx, (*eip)->bei_e, (*eip)->bei_zseq)) {
963 (*eip)->bei_e = NULL;
964 (*eip)->bei_zseq = 0;
965 }
966 #endif
967 if ( !(*eip)->bei_e && !((*eip)->bei_state & CACHE_ENTRY_LOADING)) {
968 load = 1;
969 (*eip)->bei_state |= CACHE_ENTRY_LOADING;
970 flag |= ID_CHKPURGE;
971 }
972
973 if ( !load ) {
974 /* Clear the uncached state if we are not
975 * loading it, i.e it is already cached or
976 * another thread is currently loading it.
977 */
978 if ( (*eip)->bei_state & CACHE_ENTRY_NOT_CACHED ) {
979 (*eip)->bei_state ^= CACHE_ENTRY_NOT_CACHED;
980 flag |= ID_CHKPURGE;
981 }
982 }
983
984 if ( flag & ID_LOCKED ) {
985 bdb_cache_entryinfo_unlock( *eip );
986 flag ^= ID_LOCKED;
987 }
988 rc = bdb_cache_entry_db_lock( bdb, tid, *eip, load, 0, lock );
989 if ( (*eip)->bei_state & CACHE_ENTRY_DELETED ) {
990 rc = DB_NOTFOUND;
991 bdb_cache_entry_db_unlock( bdb, lock );
992 bdb_cache_entryinfo_lock( *eip );
993 (*eip)->bei_finders--;
994 bdb_cache_entryinfo_unlock( *eip );
995 } else if ( rc == 0 ) {
996 if ( load ) {
997 if ( !ep) {
998 rc = bdb_id2entry( op->o_bd, tid, id, &ep );
999 }
1000 if ( rc == 0 ) {
1001 ep->e_private = *eip;
1002 #ifdef BDB_HIER
1003 while ( (*eip)->bei_state & CACHE_ENTRY_NOT_LINKED )
1004 ldap_pvt_thread_yield();
1005 bdb_fix_dn( ep, 0 );
1006 #endif
1007 bdb_cache_entryinfo_lock( *eip );
1008
1009 (*eip)->bei_e = ep;
1010 #ifdef SLAP_ZONE_ALLOC
1011 (*eip)->bei_zseq = *((ber_len_t *)ep - 2);
1012 #endif
1013 ep = NULL;
1014 if ( flag & ID_NOCACHE ) {
1015 /* Set the cached state only if no other thread
1016 * found the info while we were loading the entry.
1017 */
1018 if ( (*eip)->bei_finders == 1 ) {
1019 (*eip)->bei_state |= CACHE_ENTRY_NOT_CACHED;
1020 flag ^= ID_CHKPURGE;
1021 }
1022 }
1023 bdb_cache_entryinfo_unlock( *eip );
1024 bdb_cache_lru_link( bdb, *eip );
1025 }
1026 if ( rc == 0 ) {
1027 /* If we succeeded, downgrade back to a readlock. */
1028 rc = bdb_cache_entry_db_relock( bdb, tid,
1029 *eip, 0, 0, lock );
1030 } else {
1031 /* Otherwise, release the lock. */
1032 bdb_cache_entry_db_unlock( bdb, lock );
1033 }
1034 } else if ( !(*eip)->bei_e ) {
1035 /* Some other thread is trying to load the entry,
1036 * wait for it to finish.
1037 */
1038 bdb_cache_entry_db_unlock( bdb, lock );
1039 bdb_cache_entryinfo_lock( *eip );
1040 flag |= ID_LOCKED;
1041 goto load1;
1042 #ifdef BDB_HIER
1043 } else {
1044 /* Check for subtree renames
1045 */
1046 rc = bdb_fix_dn( (*eip)->bei_e, 1 );
1047 if ( rc ) {
1048 bdb_cache_entry_db_relock( bdb,
1049 tid, *eip, 1, 0, lock );
1050 /* check again in case other modifier did it already */
1051 if ( bdb_fix_dn( (*eip)->bei_e, 1 ) )
1052 rc = bdb_fix_dn( (*eip)->bei_e, 2 );
1053 bdb_cache_entry_db_relock( bdb,
1054 tid, *eip, 0, 0, lock );
1055 }
1056 #endif
1057 }
1058 bdb_cache_entryinfo_lock( *eip );
1059 (*eip)->bei_finders--;
1060 if ( load )
1061 (*eip)->bei_state ^= CACHE_ENTRY_LOADING;
1062 bdb_cache_entryinfo_unlock( *eip );
1063 }
1064 }
1065 }
1066 if ( flag & ID_LOCKED ) {
1067 bdb_cache_entryinfo_unlock( *eip );
1068 }
1069 if ( ep ) {
1070 ep->e_private = NULL;
1071 #ifdef SLAP_ZONE_ALLOC
1072 bdb_entry_return( bdb, ep, (*eip)->bei_zseq );
1073 #else
1074 bdb_entry_return( ep );
1075 #endif
1076 }
1077 if ( rc == 0 ) {
1078 int purge = 0;
1079
1080 if (( flag & ID_CHKPURGE ) || bdb->bi_cache.c_eimax ) {
1081 ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_count_mutex );
1082 if ( flag & ID_CHKPURGE ) {
1083 bdb->bi_cache.c_cursize++;
1084 if ( !bdb->bi_cache.c_purging && bdb->bi_cache.c_cursize > bdb->bi_cache.c_maxsize ) {
1085 purge = 1;
1086 bdb->bi_cache.c_purging = 1;
1087 }
1088 } else if ( !bdb->bi_cache.c_purging && bdb->bi_cache.c_eimax && bdb->bi_cache.c_leaves > bdb->bi_cache.c_eimax ) {
1089 purge = 1;
1090 bdb->bi_cache.c_purging = 1;
1091 }
1092 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_count_mutex );
1093 }
1094 if ( purge )
1095 bdb_cache_lru_purge( bdb );
1096 }
1097
1098 #ifdef SLAP_ZONE_ALLOC
1099 if (rc == 0 && (*eip)->bei_e) {
1100 slap_zn_rlock(bdb->bi_cache.c_zctx, (*eip)->bei_e);
1101 }
1102 slap_zh_runlock(bdb->bi_cache.c_zctx);
1103 #endif
1104 return rc;
1105 }
1106
1107 int
bdb_cache_children(Operation * op,DB_TXN * txn,Entry * e)1108 bdb_cache_children(
1109 Operation *op,
1110 DB_TXN *txn,
1111 Entry *e )
1112 {
1113 int rc;
1114
1115 if ( BEI(e)->bei_kids ) {
1116 return 0;
1117 }
1118 if ( BEI(e)->bei_state & CACHE_ENTRY_NO_KIDS ) {
1119 return DB_NOTFOUND;
1120 }
1121 rc = bdb_dn2id_children( op, txn, e );
1122 if ( rc == DB_NOTFOUND ) {
1123 BEI(e)->bei_state |= CACHE_ENTRY_NO_KIDS | CACHE_ENTRY_NO_GRANDKIDS;
1124 }
1125 return rc;
1126 }
1127
1128 /* Update the cache after a successful database Add. */
1129 int
bdb_cache_add(struct bdb_info * bdb,EntryInfo * eip,Entry * e,struct berval * nrdn,DB_TXN * txn,DB_LOCK * lock)1130 bdb_cache_add(
1131 struct bdb_info *bdb,
1132 EntryInfo *eip,
1133 Entry *e,
1134 struct berval *nrdn,
1135 DB_TXN *txn,
1136 DB_LOCK *lock )
1137 {
1138 EntryInfo *new, ei;
1139 int rc, purge = 0;
1140 #ifdef BDB_HIER
1141 struct berval rdn = e->e_name;
1142 #endif
1143
1144 ei.bei_id = e->e_id;
1145 ei.bei_parent = eip;
1146 ei.bei_nrdn = *nrdn;
1147 ei.bei_lockpad = 0;
1148
1149 #if 0
1150 /* Lock this entry so that bdb_add can run to completion.
1151 * It can only fail if BDB has run out of lock resources.
1152 */
1153 rc = bdb_cache_entry_db_lock( bdb, txn, &ei, 0, 0, lock );
1154 if ( rc ) {
1155 bdb_cache_entryinfo_unlock( eip );
1156 return rc;
1157 }
1158 #endif
1159
1160 #ifdef BDB_HIER
1161 if ( nrdn->bv_len != e->e_nname.bv_len ) {
1162 char *ptr = ber_bvchr( &rdn, ',' );
1163 assert( ptr != NULL );
1164 rdn.bv_len = ptr - rdn.bv_val;
1165 }
1166 ber_dupbv( &ei.bei_rdn, &rdn );
1167 if ( eip->bei_dkids ) eip->bei_dkids++;
1168 #endif
1169
1170 if (eip->bei_parent) {
1171 bdb_cache_entryinfo_lock( eip->bei_parent );
1172 eip->bei_parent->bei_state &= ~CACHE_ENTRY_NO_GRANDKIDS;
1173 bdb_cache_entryinfo_unlock( eip->bei_parent );
1174 }
1175
1176 rc = bdb_entryinfo_add_internal( bdb, &ei, &new );
1177 /* bdb_csn_commit can cause this when adding the database root entry */
1178 if ( new->bei_e ) {
1179 new->bei_e->e_private = NULL;
1180 #ifdef SLAP_ZONE_ALLOC
1181 bdb_entry_return( bdb, new->bei_e, new->bei_zseq );
1182 #else
1183 bdb_entry_return( new->bei_e );
1184 #endif
1185 }
1186 new->bei_e = e;
1187 e->e_private = new;
1188 new->bei_state |= CACHE_ENTRY_NO_KIDS | CACHE_ENTRY_NO_GRANDKIDS;
1189 eip->bei_state &= ~CACHE_ENTRY_NO_KIDS;
1190 bdb_cache_entryinfo_unlock( eip );
1191
1192 ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
1193 ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_count_mutex );
1194 ++bdb->bi_cache.c_cursize;
1195 if ( bdb->bi_cache.c_cursize > bdb->bi_cache.c_maxsize &&
1196 !bdb->bi_cache.c_purging ) {
1197 purge = 1;
1198 bdb->bi_cache.c_purging = 1;
1199 }
1200 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_count_mutex );
1201
1202 new->bei_finders = 1;
1203 bdb_cache_lru_link( bdb, new );
1204
1205 if ( purge )
1206 bdb_cache_lru_purge( bdb );
1207
1208 return rc;
1209 }
1210
bdb_cache_deref(EntryInfo * ei)1211 void bdb_cache_deref(
1212 EntryInfo *ei
1213 )
1214 {
1215 bdb_cache_entryinfo_lock( ei );
1216 ei->bei_finders--;
1217 bdb_cache_entryinfo_unlock( ei );
1218 }
1219
1220 int
bdb_cache_modify(struct bdb_info * bdb,Entry * e,Attribute * newAttrs,DB_TXN * txn,DB_LOCK * lock)1221 bdb_cache_modify(
1222 struct bdb_info *bdb,
1223 Entry *e,
1224 Attribute *newAttrs,
1225 DB_TXN *txn,
1226 DB_LOCK *lock )
1227 {
1228 EntryInfo *ei = BEI(e);
1229 int rc;
1230 /* Get write lock on data */
1231 rc = bdb_cache_entry_db_relock( bdb, txn, ei, 1, 0, lock );
1232
1233 /* If we've done repeated mods on a cached entry, then e_attrs
1234 * is no longer contiguous with the entry, and must be freed.
1235 */
1236 if ( ! rc ) {
1237 if ( (void *)e->e_attrs != (void *)(e+1) ) {
1238 attrs_free( e->e_attrs );
1239 }
1240 e->e_attrs = newAttrs;
1241 }
1242 return rc;
1243 }
1244
1245 /*
1246 * Change the rdn in the entryinfo. Also move to a new parent if needed.
1247 */
1248 int
bdb_cache_modrdn(struct bdb_info * bdb,Entry * e,struct berval * nrdn,Entry * new,EntryInfo * ein,DB_TXN * txn,DB_LOCK * lock)1249 bdb_cache_modrdn(
1250 struct bdb_info *bdb,
1251 Entry *e,
1252 struct berval *nrdn,
1253 Entry *new,
1254 EntryInfo *ein,
1255 DB_TXN *txn,
1256 DB_LOCK *lock )
1257 {
1258 EntryInfo *ei = BEI(e), *pei;
1259 int rc;
1260 #ifdef BDB_HIER
1261 struct berval rdn;
1262 #endif
1263
1264 /* Get write lock on data */
1265 rc = bdb_cache_entry_db_relock( bdb, txn, ei, 1, 0, lock );
1266 if ( rc ) return rc;
1267
1268 /* If we've done repeated mods on a cached entry, then e_attrs
1269 * is no longer contiguous with the entry, and must be freed.
1270 */
1271 if ( (void *)e->e_attrs != (void *)(e+1) ) {
1272 attrs_free( e->e_attrs );
1273 }
1274 e->e_attrs = new->e_attrs;
1275 if( e->e_nname.bv_val < e->e_bv.bv_val ||
1276 e->e_nname.bv_val > e->e_bv.bv_val + e->e_bv.bv_len )
1277 {
1278 ch_free(e->e_name.bv_val);
1279 ch_free(e->e_nname.bv_val);
1280 }
1281 e->e_name = new->e_name;
1282 e->e_nname = new->e_nname;
1283
1284 /* Lock the parent's kids AVL tree */
1285 pei = ei->bei_parent;
1286 bdb_cache_entryinfo_lock( pei );
1287 avl_delete( &pei->bei_kids, (caddr_t) ei, bdb_rdn_cmp );
1288 free( ei->bei_nrdn.bv_val );
1289 ber_dupbv( &ei->bei_nrdn, nrdn );
1290
1291 #ifdef BDB_HIER
1292 free( ei->bei_rdn.bv_val );
1293
1294 rdn = e->e_name;
1295 if ( nrdn->bv_len != e->e_nname.bv_len ) {
1296 char *ptr = ber_bvchr(&rdn, ',');
1297 assert( ptr != NULL );
1298 rdn.bv_len = ptr - rdn.bv_val;
1299 }
1300 ber_dupbv( &ei->bei_rdn, &rdn );
1301
1302 /* If new parent, decrement kid counts */
1303 if ( ein ) {
1304 pei->bei_ckids--;
1305 if ( pei->bei_dkids ) {
1306 pei->bei_dkids--;
1307 if ( pei->bei_dkids < 2 )
1308 pei->bei_state |= CACHE_ENTRY_NO_KIDS | CACHE_ENTRY_NO_GRANDKIDS;
1309 }
1310 }
1311 #endif
1312
1313 if (!ein) {
1314 ein = ei->bei_parent;
1315 } else {
1316 ei->bei_parent = ein;
1317 bdb_cache_entryinfo_unlock( pei );
1318 bdb_cache_entryinfo_lock( ein );
1319
1320 /* new parent now has kids */
1321 if ( ein->bei_state & CACHE_ENTRY_NO_KIDS )
1322 ein->bei_state ^= CACHE_ENTRY_NO_KIDS;
1323 /* grandparent has grandkids */
1324 if ( ein->bei_parent )
1325 ein->bei_parent->bei_state &= ~CACHE_ENTRY_NO_GRANDKIDS;
1326 #ifdef BDB_HIER
1327 /* parent might now have grandkids */
1328 if ( ein->bei_state & CACHE_ENTRY_NO_GRANDKIDS &&
1329 !(ei->bei_state & CACHE_ENTRY_NO_KIDS))
1330 ein->bei_state ^= CACHE_ENTRY_NO_GRANDKIDS;
1331
1332 ein->bei_ckids++;
1333 if ( ein->bei_dkids ) ein->bei_dkids++;
1334 #endif
1335 }
1336
1337 #ifdef BDB_HIER
1338 /* Record the generation number of this change */
1339 ldap_pvt_thread_mutex_lock( &bdb->bi_modrdns_mutex );
1340 bdb->bi_modrdns++;
1341 ei->bei_modrdns = bdb->bi_modrdns;
1342 ldap_pvt_thread_mutex_unlock( &bdb->bi_modrdns_mutex );
1343 #endif
1344
1345 avl_insert( &ein->bei_kids, ei, bdb_rdn_cmp, avl_dup_error );
1346 bdb_cache_entryinfo_unlock( ein );
1347 return rc;
1348 }
1349 /*
1350 * cache_delete - delete the entry e from the cache.
1351 *
1352 * returns: 0 e was deleted ok
1353 * 1 e was not in the cache
1354 * -1 something bad happened
1355 */
1356 int
bdb_cache_delete(struct bdb_info * bdb,Entry * e,DB_TXN * txn,DB_LOCK * lock)1357 bdb_cache_delete(
1358 struct bdb_info *bdb,
1359 Entry *e,
1360 DB_TXN *txn,
1361 DB_LOCK *lock )
1362 {
1363 EntryInfo *ei = BEI(e);
1364 int rc, busy = 0, counter = 0;
1365
1366 assert( e->e_private != NULL );
1367
1368 /* Lock the entry's info */
1369 bdb_cache_entryinfo_lock( ei );
1370
1371 /* Set this early, warn off any queriers */
1372 ei->bei_state |= CACHE_ENTRY_DELETED;
1373
1374 if (( ei->bei_state & ( CACHE_ENTRY_NOT_LINKED |
1375 CACHE_ENTRY_LOADING | CACHE_ENTRY_ONELEVEL )) ||
1376 ei->bei_finders > 0 )
1377 busy = 1;
1378
1379 bdb_cache_entryinfo_unlock( ei );
1380
1381 while ( busy && counter < 1000) {
1382 ldap_pvt_thread_yield();
1383 busy = 0;
1384 bdb_cache_entryinfo_lock( ei );
1385 if (( ei->bei_state & ( CACHE_ENTRY_NOT_LINKED |
1386 CACHE_ENTRY_LOADING | CACHE_ENTRY_ONELEVEL )) ||
1387 ei->bei_finders > 0 )
1388 busy = 1;
1389 bdb_cache_entryinfo_unlock( ei );
1390 counter ++;
1391 }
1392 if( busy ) {
1393 bdb_cache_entryinfo_lock( ei );
1394 ei->bei_state ^= CACHE_ENTRY_DELETED;
1395 bdb_cache_entryinfo_unlock( ei );
1396 return DB_LOCK_DEADLOCK;
1397 }
1398
1399 /* Get write lock on the data */
1400 rc = bdb_cache_entry_db_relock( bdb, txn, ei, 1, 0, lock );
1401 if ( rc ) {
1402 bdb_cache_entryinfo_lock( ei );
1403 /* couldn't lock, undo and give up */
1404 ei->bei_state ^= CACHE_ENTRY_DELETED;
1405 bdb_cache_entryinfo_unlock( ei );
1406 return rc;
1407 }
1408
1409 Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_delete( %ld )\n",
1410 e->e_id, 0, 0 );
1411
1412 /* set lru mutex */
1413 ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_lru_mutex );
1414
1415 bdb_cache_entryinfo_lock( ei->bei_parent );
1416 bdb_cache_entryinfo_lock( ei );
1417 rc = bdb_cache_delete_internal( &bdb->bi_cache, e->e_private, 1 );
1418 bdb_cache_entryinfo_unlock( ei );
1419
1420 /* free lru mutex */
1421 ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_lru_mutex );
1422
1423 return( rc );
1424 }
1425
1426 void
bdb_cache_delete_cleanup(Cache * cache,EntryInfo * ei)1427 bdb_cache_delete_cleanup(
1428 Cache *cache,
1429 EntryInfo *ei )
1430 {
1431 /* Enter with ei locked */
1432
1433 /* already freed? */
1434 if ( !ei->bei_parent ) return;
1435
1436 if ( ei->bei_e ) {
1437 ei->bei_e->e_private = NULL;
1438 #ifdef SLAP_ZONE_ALLOC
1439 bdb_entry_return( ei->bei_bdb, ei->bei_e, ei->bei_zseq );
1440 #else
1441 bdb_entry_return( ei->bei_e );
1442 #endif
1443 ei->bei_e = NULL;
1444 }
1445
1446 bdb_cache_entryinfo_unlock( ei );
1447 bdb_cache_entryinfo_free( cache, ei );
1448 }
1449
1450 static int
bdb_cache_delete_internal(Cache * cache,EntryInfo * e,int decr)1451 bdb_cache_delete_internal(
1452 Cache *cache,
1453 EntryInfo *e,
1454 int decr )
1455 {
1456 int rc = 0; /* return code */
1457 int decr_leaf = 0;
1458
1459 /* already freed? */
1460 if ( !e->bei_parent ) {
1461 assert(0);
1462 return -1;
1463 }
1464
1465 #ifdef BDB_HIER
1466 e->bei_parent->bei_ckids--;
1467 if ( decr && e->bei_parent->bei_dkids ) e->bei_parent->bei_dkids--;
1468 #endif
1469 /* dn tree */
1470 if ( avl_delete( &e->bei_parent->bei_kids, (caddr_t) e, bdb_rdn_cmp )
1471 == NULL )
1472 {
1473 rc = -1;
1474 assert(0);
1475 }
1476 if ( e->bei_parent->bei_kids )
1477 decr_leaf = 1;
1478
1479 ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
1480 /* id tree */
1481 if ( avl_delete( &cache->c_idtree, (caddr_t) e, bdb_id_cmp )) {
1482 cache->c_eiused--;
1483 if ( decr_leaf )
1484 cache->c_leaves--;
1485 } else {
1486 rc = -1;
1487 assert(0);
1488 }
1489 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
1490 bdb_cache_entryinfo_unlock( e->bei_parent );
1491
1492 if ( rc == 0 ){
1493 /* lru */
1494 LRU_DEL( cache, e );
1495
1496 if ( e->bei_e ) {
1497 ldap_pvt_thread_mutex_lock( &cache->c_count_mutex );
1498 cache->c_cursize--;
1499 ldap_pvt_thread_mutex_unlock( &cache->c_count_mutex );
1500 }
1501 }
1502
1503 return( rc );
1504 }
1505
1506 static void
bdb_entryinfo_release(void * data)1507 bdb_entryinfo_release( void *data )
1508 {
1509 EntryInfo *ei = (EntryInfo *)data;
1510 if ( ei->bei_kids ) {
1511 avl_free( ei->bei_kids, NULL );
1512 }
1513 if ( ei->bei_e ) {
1514 ei->bei_e->e_private = NULL;
1515 #ifdef SLAP_ZONE_ALLOC
1516 bdb_entry_return( ei->bei_bdb, ei->bei_e, ei->bei_zseq );
1517 #else
1518 bdb_entry_return( ei->bei_e );
1519 #endif
1520 }
1521 bdb_cache_entryinfo_destroy( ei );
1522 }
1523
1524 void
bdb_cache_release_all(Cache * cache)1525 bdb_cache_release_all( Cache *cache )
1526 {
1527 /* set cache write lock */
1528 ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
1529 /* set lru mutex */
1530 ldap_pvt_thread_mutex_lock( &cache->c_lru_mutex );
1531
1532 Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_release_all\n", 0, 0, 0 );
1533
1534 avl_free( cache->c_dntree.bei_kids, NULL );
1535 avl_free( cache->c_idtree, bdb_entryinfo_release );
1536 for (;cache->c_eifree;cache->c_eifree = cache->c_lruhead) {
1537 cache->c_lruhead = cache->c_eifree->bei_lrunext;
1538 bdb_cache_entryinfo_destroy(cache->c_eifree);
1539 }
1540 cache->c_cursize = 0;
1541 cache->c_eiused = 0;
1542 cache->c_leaves = 0;
1543 cache->c_idtree = NULL;
1544 cache->c_lruhead = NULL;
1545 cache->c_lrutail = NULL;
1546 cache->c_dntree.bei_kids = NULL;
1547
1548 /* free lru mutex */
1549 ldap_pvt_thread_mutex_unlock( &cache->c_lru_mutex );
1550 /* free cache write lock */
1551 ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
1552 }
1553
1554 #ifdef LDAP_DEBUG
1555 static void
bdb_lru_count(Cache * cache)1556 bdb_lru_count( Cache *cache )
1557 {
1558 EntryInfo *e;
1559 int ei = 0, ent = 0, nc = 0;
1560
1561 for ( e = cache->c_lrutail; ; ) {
1562 ei++;
1563 if ( e->bei_e ) {
1564 ent++;
1565 if ( e->bei_state & CACHE_ENTRY_NOT_CACHED )
1566 nc++;
1567 fprintf( stderr, "ei %d entry %p dn %s\n", ei, (void *) e->bei_e, e->bei_e->e_name.bv_val );
1568 }
1569 e = e->bei_lrunext;
1570 if ( e == cache->c_lrutail )
1571 break;
1572 }
1573 fprintf( stderr, "counted %d entryInfos and %d entries, %d notcached\n",
1574 ei, ent, nc );
1575 ei = 0;
1576 for ( e = cache->c_lrutail; ; ) {
1577 ei++;
1578 e = e->bei_lruprev;
1579 if ( e == cache->c_lrutail )
1580 break;
1581 }
1582 fprintf( stderr, "counted %d entryInfos (on lruprev)\n", ei );
1583 }
1584
1585 #ifdef SLAPD_UNUSED
1586 static void
bdb_lru_print(Cache * cache)1587 bdb_lru_print( Cache *cache )
1588 {
1589 EntryInfo *e;
1590
1591 fprintf( stderr, "LRU circle head: %p\n", (void *) cache->c_lruhead );
1592 fprintf( stderr, "LRU circle (tail forward):\n" );
1593 for ( e = cache->c_lrutail; ; ) {
1594 fprintf( stderr, "\t%p, %p id %ld rdn \"%s\"\n",
1595 (void *) e, (void *) e->bei_e, e->bei_id, e->bei_nrdn.bv_val );
1596 e = e->bei_lrunext;
1597 if ( e == cache->c_lrutail )
1598 break;
1599 }
1600 fprintf( stderr, "LRU circle (tail backward):\n" );
1601 for ( e = cache->c_lrutail; ; ) {
1602 fprintf( stderr, "\t%p, %p id %ld rdn \"%s\"\n",
1603 (void *) e, (void *) e->bei_e, e->bei_id, e->bei_nrdn.bv_val );
1604 e = e->bei_lruprev;
1605 if ( e == cache->c_lrutail )
1606 break;
1607 }
1608 }
1609
1610 static int
bdb_entryinfo_print(void * data,void * arg)1611 bdb_entryinfo_print(void *data, void *arg)
1612 {
1613 EntryInfo *e = data;
1614 fprintf( stderr, "\t%p, %p id %ld rdn \"%s\"\n",
1615 (void *) e, (void *) e->bei_e, e->bei_id, e->bei_nrdn.bv_val );
1616 return 0;
1617 }
1618
1619 static void
bdb_idtree_print(Cache * cache)1620 bdb_idtree_print(Cache *cache)
1621 {
1622 avl_apply( cache->c_idtree, bdb_entryinfo_print, NULL, -1, AVL_INORDER );
1623 }
1624 #endif
1625 #endif
1626
1627 static void
bdb_reader_free(void * key,void * data)1628 bdb_reader_free( void *key, void *data )
1629 {
1630 /* DB_ENV *env = key; */
1631 DB_TXN *txn = data;
1632
1633 if ( txn ) TXN_ABORT( txn );
1634 }
1635
1636 /* free up any keys used by the main thread */
1637 void
bdb_reader_flush(DB_ENV * env)1638 bdb_reader_flush( DB_ENV *env )
1639 {
1640 void *data;
1641 void *ctx = ldap_pvt_thread_pool_context();
1642
1643 if ( !ldap_pvt_thread_pool_getkey( ctx, env, &data, NULL ) ) {
1644 ldap_pvt_thread_pool_setkey( ctx, env, NULL, 0, NULL, NULL );
1645 bdb_reader_free( env, data );
1646 }
1647 }
1648
1649 int
bdb_reader_get(Operation * op,DB_ENV * env,DB_TXN ** txn)1650 bdb_reader_get( Operation *op, DB_ENV *env, DB_TXN **txn )
1651 {
1652 int i, rc;
1653 void *data;
1654 void *ctx;
1655
1656 if ( !env || !txn ) return -1;
1657
1658 /* If no op was provided, try to find the ctx anyway... */
1659 if ( op ) {
1660 ctx = op->o_threadctx;
1661 } else {
1662 ctx = ldap_pvt_thread_pool_context();
1663 }
1664
1665 /* Shouldn't happen unless we're single-threaded */
1666 if ( !ctx ) {
1667 *txn = NULL;
1668 return 0;
1669 }
1670
1671 if ( ldap_pvt_thread_pool_getkey( ctx, env, &data, NULL ) ) {
1672 for ( i=0, rc=1; rc != 0 && i<4; i++ ) {
1673 rc = TXN_BEGIN( env, NULL, txn, DB_READ_COMMITTED );
1674 if (rc) ldap_pvt_thread_yield();
1675 }
1676 if ( rc != 0) {
1677 return rc;
1678 }
1679 data = *txn;
1680 if ( ( rc = ldap_pvt_thread_pool_setkey( ctx, env,
1681 data, bdb_reader_free, NULL, NULL ) ) ) {
1682 TXN_ABORT( *txn );
1683 Debug( LDAP_DEBUG_ANY, "bdb_reader_get: err %s(%d)\n",
1684 db_strerror(rc), rc, 0 );
1685
1686 return rc;
1687 }
1688 } else {
1689 *txn = data;
1690 }
1691 return 0;
1692 }
1693