int
bdb_cache_find_id(
Operation *op,
DB_TXN *tid,
ID id,
EntryInfo **eip,
int flag,
DB_LOCK *lock )
{
struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
Entry *ep = NULL;
int rc = 0, load = 0;
EntryInfo ei = { 0 };
ei.bei_id = id;
#ifdef SLAP_ZONE_ALLOC
slap_zh_rlock(bdb->bi_cache.c_zctx);
#endif
/* If we weren't given any info, see if we have it already cached */
if ( !*eip ) {
again: ldap_pvt_thread_rdwr_rlock( &bdb->bi_cache.c_rwlock );
*eip = (EntryInfo *) avl_find( bdb->bi_cache.c_idtree,
(caddr_t) &ei, bdb_id_cmp );
if ( *eip ) {
/* If the lock attempt fails, the info is in use */
if ( bdb_cache_entryinfo_trylock( *eip )) {
int del = (*eip)->bei_state & CACHE_ENTRY_DELETED;
ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
/* If this node is being deleted, treat
* as if the delete has already finished
*/
if ( del ) {
return DB_NOTFOUND;
}
/* otherwise, wait for the info to free up */
ldap_pvt_thread_yield();
goto again;
}
/* If this info isn't hooked up to its parent yet,
* unlock and wait for it to be fully initialized
*/
if ( (*eip)->bei_state & CACHE_ENTRY_NOT_LINKED ) {
bdb_cache_entryinfo_unlock( *eip );
ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
ldap_pvt_thread_yield();
goto again;
}
flag |= ID_LOCKED;
}
ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
}
/* See if the ID exists in the database; add it to the cache if so */
if ( !*eip ) {
#ifndef BDB_HIER
rc = bdb_id2entry( op->o_bd, tid, id, &ep );
if ( rc == 0 ) {
rc = bdb_cache_find_ndn( op, tid,
&ep->e_nname, eip );
if ( *eip ) flag |= ID_LOCKED;
if ( rc ) {
ep->e_private = NULL;
#ifdef SLAP_ZONE_ALLOC
bdb_entry_return( bdb, ep, (*eip)->bei_zseq );
#else
bdb_entry_return( ep );
#endif
ep = NULL;
}
}
#else
rc = hdb_cache_find_parent(op, tid, id, eip );
if ( rc == 0 ) flag |= ID_LOCKED;
#endif
}
/* Ok, we found the info, do we have the entry? */
if ( rc == 0 ) {
if ( !( flag & ID_LOCKED )) {
bdb_cache_entryinfo_lock( *eip );
flag |= ID_LOCKED;
}
if ( (*eip)->bei_state & CACHE_ENTRY_DELETED ) {
rc = DB_NOTFOUND;
} else {
(*eip)->bei_finders++;
(*eip)->bei_state |= CACHE_ENTRY_REFERENCED;
if ( flag & ID_NOENTRY ) {
bdb_cache_entryinfo_unlock( *eip );
return 0;
}
/* Make sure only one thread tries to load the entry */
load1:
#ifdef SLAP_ZONE_ALLOC
if ((*eip)->bei_e && !slap_zn_validate(
bdb->bi_cache.c_zctx, (*eip)->bei_e, (*eip)->bei_zseq)) {
(*eip)->bei_e = NULL;
(*eip)->bei_zseq = 0;
}
#endif
if ( !(*eip)->bei_e && !((*eip)->bei_state & CACHE_ENTRY_LOADING)) {
load = 1;
(*eip)->bei_state |= CACHE_ENTRY_LOADING;
flag |= ID_CHKPURGE;
}
if ( !load ) {
/* Clear the uncached state if we are not
* loading it, i.e it is already cached or
* another thread is currently loading it.
*/
if ( (*eip)->bei_state & CACHE_ENTRY_NOT_CACHED ) {
(*eip)->bei_state ^= CACHE_ENTRY_NOT_CACHED;
flag |= ID_CHKPURGE;
}
}
if ( flag & ID_LOCKED ) {
bdb_cache_entryinfo_unlock( *eip );
flag ^= ID_LOCKED;
}
rc = bdb_cache_entry_db_lock( bdb, tid, *eip, load, 0, lock );
if ( (*eip)->bei_state & CACHE_ENTRY_DELETED ) {
rc = DB_NOTFOUND;
bdb_cache_entry_db_unlock( bdb, lock );
bdb_cache_entryinfo_lock( *eip );
(*eip)->bei_finders--;
bdb_cache_entryinfo_unlock( *eip );
} else if ( rc == 0 ) {
if ( load ) {
if ( !ep) {
rc = bdb_id2entry( op->o_bd, tid, id, &ep );
}
if ( rc == 0 ) {
ep->e_private = *eip;
#ifdef BDB_HIER
while ( (*eip)->bei_state & CACHE_ENTRY_NOT_LINKED )
ldap_pvt_thread_yield();
bdb_fix_dn( ep, 0 );
#endif
bdb_cache_entryinfo_lock( *eip );
(*eip)->bei_e = ep;
#ifdef SLAP_ZONE_ALLOC
(*eip)->bei_zseq = *((ber_len_t *)ep - 2);
#endif
ep = NULL;
if ( flag & ID_NOCACHE ) {
/* Set the cached state only if no other thread
* found the info while we were loading the entry.
*/
if ( (*eip)->bei_finders == 1 ) {
(*eip)->bei_state |= CACHE_ENTRY_NOT_CACHED;
flag ^= ID_CHKPURGE;
}
}
bdb_cache_entryinfo_unlock( *eip );
bdb_cache_lru_link( bdb, *eip );
}
if ( rc == 0 ) {
/* If we succeeded, downgrade back to a readlock. */
rc = bdb_cache_entry_db_relock( bdb, tid,
*eip, 0, 0, lock );
} else {
/* Otherwise, release the lock. */
bdb_cache_entry_db_unlock( bdb, lock );
}
} else if ( !(*eip)->bei_e ) {
/* Some other thread is trying to load the entry,
* wait for it to finish.
*/
bdb_cache_entry_db_unlock( bdb, lock );
bdb_cache_entryinfo_lock( *eip );
flag |= ID_LOCKED;
goto load1;
#ifdef BDB_HIER
} else {
/* Check for subtree renames
*/
rc = bdb_fix_dn( (*eip)->bei_e, 1 );
if ( rc ) {
bdb_cache_entry_db_relock( bdb,
tid, *eip, 1, 0, lock );
/* check again in case other modifier did it already */
if ( bdb_fix_dn( (*eip)->bei_e, 1 ) )
rc = bdb_fix_dn( (*eip)->bei_e, 2 );
bdb_cache_entry_db_relock( bdb,
tid, *eip, 0, 0, lock );
}
#endif
}
bdb_cache_entryinfo_lock( *eip );
(*eip)->bei_finders--;
if ( load )
(*eip)->bei_state ^= CACHE_ENTRY_LOADING;
bdb_cache_entryinfo_unlock( *eip );
}
}
}
if ( flag & ID_LOCKED ) {
bdb_cache_entryinfo_unlock( *eip );
}
if ( ep ) {
ep->e_private = NULL;
#ifdef SLAP_ZONE_ALLOC
bdb_entry_return( bdb, ep, (*eip)->bei_zseq );
#else
bdb_entry_return( ep );
#endif
}
if ( rc == 0 ) {
int purge = 0;
if (( flag & ID_CHKPURGE ) || bdb->bi_cache.c_eimax ) {
ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_count_mutex );
if ( flag & ID_CHKPURGE ) {
bdb->bi_cache.c_cursize++;
if ( !bdb->bi_cache.c_purging && bdb->bi_cache.c_cursize > bdb->bi_cache.c_maxsize ) {
purge = 1;
bdb->bi_cache.c_purging = 1;
}
} else if ( !bdb->bi_cache.c_purging && bdb->bi_cache.c_eimax && bdb->bi_cache.c_leaves > bdb->bi_cache.c_eimax ) {
purge = 1;
bdb->bi_cache.c_purging = 1;
}
ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_count_mutex );
}
if ( purge )
bdb_cache_lru_purge( bdb );
}
#ifdef SLAP_ZONE_ALLOC
if (rc == 0 && (*eip)->bei_e) {
slap_zn_rlock(bdb->bi_cache.c_zctx, (*eip)->bei_e);
}
slap_zh_runlock(bdb->bi_cache.c_zctx);
#endif
return rc;
}
/* This is best-effort only. If all entries in the cache are
* busy, they will all be kept. This is unlikely to happen
* unless the cache is very much smaller than the working set.
*/
static void
bdb_cache_lru_purge( struct bdb_info *bdb )
{
DB_LOCK lock, *lockp;
EntryInfo *elru, *elnext = NULL;
int islocked;
ID eicount, ecount;
ID count, efree, eifree = 0;
#ifdef LDAP_DEBUG
int iter;
#endif
/* Wait for the mutex; we're the only one trying to purge. */
ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_lru_mutex );
if ( bdb->bi_cache.c_cursize > bdb->bi_cache.c_maxsize ) {
efree = bdb->bi_cache.c_cursize - bdb->bi_cache.c_maxsize;
efree += bdb->bi_cache.c_minfree;
} else {
efree = 0;
}
/* maximum number of EntryInfo leaves to cache. In slapcat
* we always free all leaf nodes.
*/
if ( slapMode & SLAP_TOOL_READONLY ) {
eifree = bdb->bi_cache.c_leaves;
} else if ( bdb->bi_cache.c_eimax &&
bdb->bi_cache.c_leaves > bdb->bi_cache.c_eimax ) {
eifree = bdb->bi_cache.c_minfree * 10;
if ( eifree >= bdb->bi_cache.c_leaves )
eifree /= 2;
}
if ( !efree && !eifree ) {
ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_lru_mutex );
bdb->bi_cache.c_purging = 0;
return;
}
if ( bdb->bi_cache.c_txn ) {
lockp = &lock;
} else {
lockp = NULL;
}
count = 0;
eicount = 0;
ecount = 0;
#ifdef LDAP_DEBUG
iter = 0;
#endif
/* Look for an unused entry to remove */
for ( elru = bdb->bi_cache.c_lruhead; elru; elru = elnext ) {
elnext = elru->bei_lrunext;
if ( bdb_cache_entryinfo_trylock( elru ))
goto bottom;
/* This flag implements the clock replacement behavior */
if ( elru->bei_state & ( CACHE_ENTRY_REFERENCED )) {
elru->bei_state &= ~CACHE_ENTRY_REFERENCED;
bdb_cache_entryinfo_unlock( elru );
goto bottom;
}
/* If this node is in the process of linking into the cache,
* or this node is being deleted, skip it.
*/
if (( elru->bei_state & ( CACHE_ENTRY_NOT_LINKED |
CACHE_ENTRY_DELETED | CACHE_ENTRY_LOADING |
CACHE_ENTRY_ONELEVEL )) ||
elru->bei_finders > 0 ) {
bdb_cache_entryinfo_unlock( elru );
goto bottom;
}
if ( bdb_cache_entryinfo_trylock( elru->bei_parent )) {
bdb_cache_entryinfo_unlock( elru );
goto bottom;
}
/* entryinfo is locked */
islocked = 1;
/* If we can successfully writelock it, then
* the object is idle.
*/
if ( bdb_cache_entry_db_lock( bdb,
bdb->bi_cache.c_txn, elru, 1, 1, lockp ) == 0 ) {
/* Free entry for this node if it's present */
if ( elru->bei_e ) {
ecount++;
/* the cache may have gone over the limit while we
* weren't looking, so double check.
*/
if ( !efree && ecount > bdb->bi_cache.c_maxsize )
efree = bdb->bi_cache.c_minfree;
if ( count < efree ) {
elru->bei_e->e_private = NULL;
#ifdef SLAP_ZONE_ALLOC
bdb_entry_return( bdb, elru->bei_e, elru->bei_zseq );
#else
bdb_entry_return( elru->bei_e );
#endif
elru->bei_e = NULL;
count++;
} else {
/* Keep this node cached, skip to next */
bdb_cache_entry_db_unlock( bdb, lockp );
goto next;
}
}
bdb_cache_entry_db_unlock( bdb, lockp );
/*
* If it is a leaf node, and we're over the limit, free it.
*/
if ( elru->bei_kids ) {
/* Drop from list, we ignore it... */
LRU_DEL( &bdb->bi_cache, elru );
} else if ( eicount < eifree ) {
/* Too many leaf nodes, free this one */
bdb_cache_delete_internal( &bdb->bi_cache, elru, 0 );
bdb_cache_delete_cleanup( &bdb->bi_cache, elru );
islocked = 0;
eicount++;
} /* Leave on list until we need to free it */
}
next:
if ( islocked ) {
bdb_cache_entryinfo_unlock( elru );
bdb_cache_entryinfo_unlock( elru->bei_parent );
}
if ( count >= efree && eicount >= eifree )
break;
bottom:
if ( elnext == bdb->bi_cache.c_lruhead )
break;
#ifdef LDAP_DEBUG
iter++;
#endif
}
if ( count || ecount > bdb->bi_cache.c_cursize ) {
ldap_pvt_thread_mutex_lock( &bdb->bi_cache.c_count_mutex );
/* HACK: we seem to be losing track, fix up now */
if ( ecount > bdb->bi_cache.c_cursize )
bdb->bi_cache.c_cursize = ecount;
bdb->bi_cache.c_cursize -= count;
ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_count_mutex );
}
bdb->bi_cache.c_lruhead = elnext;
ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.c_lru_mutex );
bdb->bi_cache.c_purging = 0;
}
Entry *
bdb_cache_find_entry_id(
DB_ENV *env,
Cache *cache,
ID id,
int rw,
u_int32_t locker,
DB_LOCK *lock
)
{
Entry e;
Entry *ep;
int count = 0;
int rc;
e.e_id = id;
try_again:
/* set cache read lock */
ldap_pvt_thread_rdwr_rlock( &cache->c_rwlock );
if ( (ep = (Entry *) avl_find( cache->c_idtree, (caddr_t) &e,
entry_id_cmp )) != NULL )
{
int state;
ID ep_id;
count++;
assert( ep->e_private );
ep_id = ep->e_id;
state = BEI(ep)->bei_state;
/*
* entry is deleted or not fully created yet
*/
if ( state != CACHE_ENTRY_READY && state != CACHE_ENTRY_COMMITTED ) {
assert(state != CACHE_ENTRY_UNDEFINED);
/* free cache read lock */
ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, INFO,
"bdb_cache_find_entry_id: (%ld)->%ld not ready (%d).\n",
id, ep_id, state );
#else
Debug(LDAP_DEBUG_TRACE,
"====> bdb_cache_find_entry_id( %ld ): %ld (not ready) %d\n",
id, ep_id, state);
#endif
ldap_pvt_thread_yield();
goto try_again;
}
/* acquire reader lock */
rc = bdb_cache_entry_db_lock ( env, locker, ep, rw, 0, lock );
#if 0
if ( bdb_cache_entry_rdwr_trylock(ep, rw) == LDAP_PVT_THREAD_EBUSY ) {
#endif
if ( rc ) { /* will be changed to retry beyond threshold */
/* could not acquire entry lock...
* owner cannot free as we have the cache locked.
* so, unlock the cache, yield, and try again.
*/
/* free cache read lock */
ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, INFO,
"bdb_cache_find_entry_id: %ld -> %ld (busy) %d.\n",
id, ep_id, state );
#else
Debug(LDAP_DEBUG_TRACE,
"====> bdb_cache_find_entry_id( %ld ): %ld (busy) %d\n",
id, ep_id, state);
Debug(LDAP_DEBUG_TRACE,
"locker = %d\n",
locker, 0, 0);
#endif
ldap_pvt_thread_yield();
goto try_again;
}
/* Mark entry in-use */
BEI(ep)->bei_refcnt++;
/* free cache read lock */
ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
/* set lru mutex */
ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
/* lru */
LRU_DELETE( cache, ep );
LRU_ADD( cache, ep );
/* free lru mutex */
ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, DETAIL1,
"bdb_cache_find_entry_id: %ld -> %s found %d tries.\n",
ep_id, ep->e_dn, count );
#else
Debug(LDAP_DEBUG_TRACE,
"====> bdb_cache_find_entry_id( %ld ) \"%s\" (found) (%d tries)\n",
ep_id, ep->e_dn, count);
#endif
return( ep );
}
/* free cache read lock */
ldap_pvt_thread_rdwr_runlock( &cache->c_rwlock );
return( NULL );
}
/*
* cache_delete_entry - delete the entry e from the cache. the caller
* should have obtained e (increasing its ref count) via a call to one
* of the cache_find_* routines. the caller should *not* call the
* cache_return_entry() routine prior to calling cache_delete_entry().
* it performs this function.
*
* returns: 0 e was deleted ok
* 1 e was not in the cache
* -1 something bad happened
*/
int
bdb_cache_delete_entry(
Cache *cache,
Entry *e
)
{
int rc;
/* set cache write lock */
ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
assert( e->e_private );
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, ENTRY,
"bdb_cache_delete_entry: delete %ld.\n", e->e_id, 0, 0 );
#else
Debug( LDAP_DEBUG_TRACE, "====> bdb_cache_delete_entry( %ld )\n",
e->e_id, 0, 0 );
#endif
/* set lru mutex */
ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
rc = bdb_cache_delete_entry_internal( cache, e );
/* free lru mutex */
ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
/* free cache write lock */
ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
return( rc );
}
EntryInfo *new, ei;
int rc, purge = 0;
#ifdef BDB_HIER
struct berval rdn = e->e_name;
#endif
ei.bei_id = e->e_id;
ei.bei_parent = eip;
ei.bei_nrdn = *nrdn;
ei.bei_lockpad = 0;
#if 0
/* Lock this entry so that bdb_add can run to completion.
* It can only fail if BDB has run out of lock resources.
*/
rc = bdb_cache_entry_db_lock( bdb, txn, &ei, 0, 0, lock );
if ( rc ) {
bdb_cache_entryinfo_unlock( eip );
return rc;
}
#endif
#ifdef BDB_HIER
if ( nrdn->bv_len != e->e_nname.bv_len ) {
char *ptr = ber_bvchr( &rdn, ',' );
assert( ptr != NULL );
rdn.bv_len = ptr - rdn.bv_val;
}
ber_dupbv( &ei.bei_rdn, &rdn );
if ( eip->bei_dkids ) eip->bei_dkids++;
#endif
/*
* cache_add_entry_rw - create and lock an entry in the cache
* returns: 0 entry has been created and locked
* 1 entry already existed
* -1 something bad happened
* other Berkeley DB locking error code
*/
int
bdb_cache_add_entry_rw(
DB_ENV *env,
Cache *cache,
Entry *e,
int rw,
u_int32_t locker,
DB_LOCK *lock
)
{
int i, rc;
Entry *ee;
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, ENTRY,
"bdb_cache_add_entry_rw: add (%s):%s to cache\n",
e->e_dn, rw ? "w" : "r", 0 );
#endif
/* set cache write lock */
ldap_pvt_thread_rdwr_wlock( &cache->c_rwlock );
assert( e->e_private == NULL );
if( bdb_cache_entry_private_init(e) != 0 ) {
/* free cache write lock */
ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, ERR,
"bdb_cache_add_entry_rw: add (%s):%ld private init failed!\n",
e->e_dn, e->e_id, 0 );
#else
Debug( LDAP_DEBUG_ANY,
"====> bdb_cache_add_entry( %ld ): \"%s\": private init failed!\n",
e->e_id, e->e_dn, 0 );
#endif
return( -1 );
}
if ( avl_insert( &cache->c_dntree, (caddr_t) e,
entry_dn_cmp, avl_dup_error ) != 0 )
{
/* free cache write lock */
ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, DETAIL1,
"bdb_cache_add_entry: (%s):%ld already in cache.\n",
e->e_dn, e->e_id, 0 );
#else
Debug( LDAP_DEBUG_TRACE,
"====> bdb_cache_add_entry( %ld ): \"%s\": already in dn cache\n",
e->e_id, e->e_dn, 0 );
#endif
bdb_cache_entry_private_destroy(e);
return( 1 );
}
/* id tree */
if ( avl_insert( &cache->c_idtree, (caddr_t) e,
entry_id_cmp, avl_dup_error ) != 0 )
{
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, DETAIL1,
"bdb_cache_add_entry: (%s):%ls already in cache.\n",
e->e_dn, e->e_id, 0 );
#else
Debug( LDAP_DEBUG_ANY,
"====> bdb_cache_add_entry( %ld ): \"%s\": already in id cache\n",
e->e_id, e->e_dn, 0 );
#endif
/* delete from dn tree inserted above */
if ( avl_delete( &cache->c_dntree, (caddr_t) e,
entry_dn_cmp ) == NULL )
{
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, INFO,
"bdb_cache_add_entry: can't delete (%s) from cache.\n",
e->e_dn, 0, 0 );
#else
Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
0, 0, 0 );
#endif
}
bdb_cache_entry_private_destroy(e);
/* free cache write lock */
ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
return( -1 );
}
rc = bdb_cache_entry_db_lock( env, locker, e, rw, 0, lock );
switch ( rc ) {
case 0 :
break;
case DB_LOCK_DEADLOCK :
case DB_LOCK_NOTGRANTED :
/* undo avl changes immediately */
if ( avl_delete( &cache->c_idtree, (caddr_t) e,
entry_id_cmp ) == NULL ) {
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, INFO,
"bdb_cache_add_entry: can't delete (%s) from cache.\n",
e->e_dn, 0, 0 );
#else
Debug( LDAP_DEBUG_ANY, "====> can't delete from id cache\n", 0, 0, 0 );
#endif
}
if ( avl_delete( &cache->c_dntree, (caddr_t) e,
entry_dn_cmp ) == NULL ) {
#ifdef NEW_LOGGING
LDAP_LOG( CACHE, INFO,
"bdb_cache_add_entry: can't delete (%s) from cache.\n",
e->e_dn, 0, 0 );
#else
Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n", 0, 0, 0 );
#endif
}
/* fall through */
default :
bdb_cache_entry_private_destroy(e);
ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
return rc;
}
/* put the entry into 'CREATING' state */
/* will be marked after when entry is returned */
BEI(e)->bei_state = CACHE_ENTRY_CREATING;
BEI(e)->bei_refcnt = 1;
/* set lru mutex */
ldap_pvt_thread_mutex_lock( &cache->lru_mutex );
/* lru */
LRU_ADD( cache, e );
if ( ++cache->c_cursize > cache->c_maxsize ) {
/*
* find the lru entry not currently in use and delete it.
* in case a lot of entries are in use, only look at the
* first 10 on the tail of the list.
*/
i = 0;
while ( cache->c_lrutail != NULL &&
BEI(cache->c_lrutail)->bei_refcnt != 0 &&
i < 10 )
{
/* move this in-use entry to the front of the q */
ee = cache->c_lrutail;
LRU_DELETE( cache, ee );
LRU_ADD( cache, ee );
i++;
}
/*
* found at least one to delete - try to get back under
* the max cache size.
*/
while ( cache->c_lrutail != NULL &&
BEI(cache->c_lrutail)->bei_refcnt == 0 &&
cache->c_cursize > cache->c_maxsize )
{
e = cache->c_lrutail;
/* delete from cache and lru q */
/* XXX do we need rc ? */
rc = bdb_cache_delete_entry_internal( cache, e );
bdb_cache_entry_private_destroy( e );
bdb_entry_return( e );
}
}
/* free lru mutex */
ldap_pvt_thread_mutex_unlock( &cache->lru_mutex );
/* free cache write lock */
ldap_pvt_thread_rdwr_wunlock( &cache->c_rwlock );
return( 0 );
}