openldap/servers/slapd/back-bdb2/cache.c
Kurt Zeilenga 588a458d78 MSVC5 cleanup...
lber: ifdef'ed out lber_..set_nonblock() function because it used ioctl's.
  If it remains, it needs to be written to support various methods for
  setting non-blocking.  ioctls should probably be last choice.  configure
  could detect existance of fcntl(), ioctl(), etc.
bdb2:
  added .dsp/.dsw files and did some basic cleanup (still needs work).
1999-03-06 00:57:25 +00:00

586 lines
13 KiB
C

/* cache.c - routines to maintain an in-core cache of entries */
#include "portable.h"
#include <stdio.h>
#include <ac/errno.h>
#include <ac/string.h>
#include <ac/socket.h>
#include "slap.h"
#include "back-bdb2.h"
/* LDBM backend specific entry info -- visible only to the cache */
struct ldbm_entry_info {
/*
* These items are specific to the LDBM backend and should
* be hidden.
*/
int lei_state; /* for the cache */
#define CACHE_ENTRY_UNDEFINED 0
#define CACHE_ENTRY_CREATING 1
#define CACHE_ENTRY_READY 2
#define CACHE_ENTRY_DELETED 3
int lei_refcnt; /* # threads ref'ing this entry */
struct entry *lei_lrunext; /* for cache lru list */
struct entry *lei_lruprev;
};
#define LEI(e) ((struct ldbm_entry_info *) ((e)->e_private))
static int cache_delete_entry_internal(struct cache *cache, Entry *e);
#ifdef LDAP_DEBUG
static void lru_print(struct cache *cache);
#endif
static int
cache_entry_private_init( Entry*e )
{
#ifdef LDAP_DEBUG
assert( e->e_private == NULL );
#endif
if( e->e_private != NULL ) {
/* this should never happen */
return 1;
}
e->e_private = ch_calloc(1, sizeof(struct ldbm_entry_info));
return 0;
}
static int
cache_entry_private_destroy( Entry*e )
{
#ifdef LDAP_DEBUG
assert( e->e_private );
#endif
free( e->e_private );
e->e_private = NULL;
return 0;
}
void
bdb2i_cache_return_entry_rw( struct cache *cache, Entry *e, int rw )
{
/* set cache mutex */
ldap_pvt_thread_mutex_lock( &cache->c_mutex );
#ifdef LDAP_DEBUG
assert( e->e_private );
#endif
LEI(e)->lei_refcnt--;
if ( LEI(e)->lei_state == CACHE_ENTRY_CREATING ) {
Debug( LDAP_DEBUG_TRACE,
"====> bdb2i_cache_return_entry_%s( %ld ): created (%d)\n",
rw ? "w" : "r", e->e_id, LEI(e)->lei_refcnt );
LEI(e)->lei_state = CACHE_ENTRY_READY;
} else if ( LEI(e)->lei_state == CACHE_ENTRY_DELETED ) {
if( LEI(e)->lei_refcnt > 0 ) {
Debug( LDAP_DEBUG_TRACE,
"====> bdb2i_cache_return_entry_%s( %ld ): delete pending (%d)\n",
rw ? "w" : "r", e->e_id, LEI(e)->lei_refcnt );
} else {
Debug( LDAP_DEBUG_TRACE,
"====> bdb2i_cache_return_entry_%s( %ld ): deleted (%d)\n",
rw ? "w" : "r", e->e_id, LEI(e)->lei_refcnt );
cache_entry_private_destroy( e );
entry_free( e );
}
} else {
Debug( LDAP_DEBUG_TRACE,
"====> bdb2i_cache_return_entry_%s( %ld ): returned (%d)\n",
rw ? "w" : "r", e->e_id, LEI(e)->lei_refcnt);
}
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
}
#define LRU_DELETE( cache, e ) { \
if ( LEI(e)->lei_lruprev != NULL ) { \
LEI(LEI(e)->lei_lruprev)->lei_lrunext = LEI(e)->lei_lrunext; \
} else { \
cache->c_lruhead = LEI(e)->lei_lrunext; \
} \
if ( LEI(e)->lei_lrunext != NULL ) { \
LEI(LEI(e)->lei_lrunext)->lei_lruprev = LEI(e)->lei_lruprev; \
} else { \
cache->c_lrutail = LEI(e)->lei_lruprev; \
} \
}
#define LRU_ADD( cache, e ) { \
LEI(e)->lei_lrunext = cache->c_lruhead; \
if ( LEI(e)->lei_lrunext != NULL ) { \
LEI(LEI(e)->lei_lrunext)->lei_lruprev = e; \
} \
cache->c_lruhead = e; \
LEI(e)->lei_lruprev = NULL; \
if ( cache->c_lrutail == NULL ) { \
cache->c_lrutail = e; \
} \
}
/*
* bdb2i_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
*/
int
bdb2i_cache_add_entry_rw(
struct cache *cache,
Entry *e,
int rw
)
{
int i;
Entry *ee;
/* set cache mutex */
ldap_pvt_thread_mutex_lock( &cache->c_mutex );
#ifdef LDAP_DEBUG
assert( e->e_private == NULL );
#endif
if( cache_entry_private_init(e) != 0 ) {
Debug( LDAP_DEBUG_ANY,
"====> bdb2i_cache_add_entry( %ld ): \"%s\": private init failed!\n",
e->e_id, e->e_dn, 0 );
return( -1 );
}
if ( avl_insert( &cache->c_dntree, (caddr_t) e,
(AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
{
Debug( LDAP_DEBUG_TRACE,
"====> bdb2i_cache_add_entry( %ld ): \"%s\": already in dn cache\n",
e->e_id, e->e_dn, 0 );
cache_entry_private_destroy(e);
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( 1 );
}
/* id tree */
if ( avl_insert( &cache->c_idtree, (caddr_t) e,
(AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
{
Debug( LDAP_DEBUG_ANY,
"====> bdb2i_cache_add_entry( %ld ): \"%s\": already in id cache\n",
e->e_id, e->e_dn, 0 );
/* delete from dn tree inserted above */
if ( avl_delete( &cache->c_dntree, (caddr_t) e,
(AVL_CMP) entry_dn_cmp ) == NULL )
{
Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
0, 0, 0 );
}
cache_entry_private_destroy(e);
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( -1 );
}
/* put the entry into 'CREATING' state */
/* will be marked after when entry is returned */
LEI(e)->lei_state = CACHE_ENTRY_CREATING;
LEI(e)->lei_refcnt = 1;
/* 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 &&
LEI(cache->c_lrutail)->lei_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 &&
LEI(cache->c_lrutail)->lei_refcnt == 0 &&
cache->c_cursize > cache->c_maxsize )
{
e = cache->c_lrutail;
/* delete from cache and lru q */
cache_delete_entry_internal( cache, e );
cache_entry_private_destroy( e );
entry_free( e );
}
}
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( 0 );
}
/*
* cache_update_entry - update a LOCKED entry which has been deleted.
* returns: 0 entry has been created and locked
* 1 entry already existed
* -1 something bad happened
*/
int
bdb2i_cache_update_entry(
struct cache *cache,
Entry *e
)
{
int i;
Entry *ee;
/* set cache mutex */
ldap_pvt_thread_mutex_lock( &cache->c_mutex );
#ifdef LDAP_DEBUG
assert( e->e_private );
#endif
if ( avl_insert( &cache->c_dntree, (caddr_t) e,
(AVL_CMP) entry_dn_cmp, avl_dup_error ) != 0 )
{
Debug( LDAP_DEBUG_TRACE,
"====> bdb2i_cache_add_entry( %ld ): \"%s\": already in dn cache\n",
e->e_id, e->e_dn, 0 );
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( 1 );
}
/* id tree */
if ( avl_insert( &cache->c_idtree, (caddr_t) e,
(AVL_CMP) entry_id_cmp, avl_dup_error ) != 0 )
{
Debug( LDAP_DEBUG_ANY,
"====> bdb2i_cache_update_entry( %ld ): \"%s\": already in id cache\n",
e->e_id, e->e_dn, 0 );
/* delete from dn tree inserted above */
if ( avl_delete( &cache->c_dntree, (caddr_t) e,
(AVL_CMP) entry_dn_cmp ) == NULL )
{
Debug( LDAP_DEBUG_ANY, "====> can't delete from dn cache\n",
0, 0, 0 );
}
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( -1 );
}
/* put the entry into 'CREATING' state */
/* will be marked after when entry is returned */
LEI(e)->lei_state = CACHE_ENTRY_CREATING;
/* 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 &&
LEI(cache->c_lrutail)->lei_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 &&
LEI(cache->c_lrutail)->lei_refcnt == 0 &&
cache->c_cursize > cache->c_maxsize )
{
e = cache->c_lrutail;
/* delete from cache and lru q */
cache_delete_entry_internal( cache, e );
cache_entry_private_destroy( e );
entry_free( e );
}
}
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( 0 );
}
/*
* bdb2i_cache_find_entry_dn2id - find an entry in the cache, given dn
*/
ID
bdb2i_cache_find_entry_dn2id(
BackendDB *be,
struct cache *cache,
char *dn
)
{
struct ldbminfo *li = (struct ldbminfo *) be->be_private;
Entry e, *ep;
ID id;
/* set cache mutex */
ldap_pvt_thread_mutex_lock( &cache->c_mutex );
e.e_dn = dn;
e.e_ndn = dn_normalize_case( ch_strdup( dn ) );
if ( (ep = (Entry *) avl_find( cache->c_dntree, (caddr_t) &e,
(AVL_CMP) entry_dn_cmp )) != NULL )
{
/*
* ep now points to an unlocked entry
* we do not need to lock the entry if we only
* check the state, refcnt, LRU, and id.
*/
free(e.e_ndn);
#ifdef LDAP_DEBUG
assert( ep->e_private );
#endif
/*
* entry is deleted or not fully created yet
*/
if ( LEI(ep)->lei_state != CACHE_ENTRY_READY ) {
#ifdef LDAP_DEBUG
assert(LEI(ep)->lei_state != CACHE_ENTRY_UNDEFINED);
#endif
Debug(LDAP_DEBUG_TRACE,
"====> bdb2i_cache_find_entry_dn2id(\"%s\"): %ld (not ready) %d\n",
dn, ep->e_id, LEI(ep)->lei_state);
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( NOID );
}
Debug(LDAP_DEBUG_TRACE,
"====> bdb2i_cache_find_entry_dn2id(\"%s\"): %ld\n",
dn, ep->e_id, 0);
/* lru */
LRU_DELETE( cache, ep );
LRU_ADD( cache, ep );
/* save id */
id = ep->e_id;
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( id );
}
free(e.e_ndn);
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( NOID );
}
/*
* cache_find_entry_id - find an entry in the cache, given id
*/
Entry *
bdb2i_cache_find_entry_id(
struct cache *cache,
ID id,
int rw
)
{
Entry e;
Entry *ep;
e.e_id = id;
/* set cache mutex */
ldap_pvt_thread_mutex_lock( &cache->c_mutex );
if ( (ep = (Entry *) avl_find( cache->c_idtree, (caddr_t) &e,
(AVL_CMP) entry_id_cmp )) != NULL )
{
#ifdef LDAP_DEBUG
assert( ep->e_private );
#endif
/*
* entry is deleted or not fully created yet
*/
if ( LEI(ep)->lei_state != CACHE_ENTRY_READY ) {
#ifdef LDAP_DEBUG
assert(LEI(ep)->lei_state != CACHE_ENTRY_UNDEFINED);
#endif
Debug(LDAP_DEBUG_TRACE,
"====> bdb2i_cache_find_entry_id( %ld ): %ld (not ready) %d\n",
id, ep->e_id, LEI(ep)->lei_state);
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( NULL );
}
Debug(LDAP_DEBUG_TRACE,
"====> bdb2i_cache_find_entry_id( %ld, %s ) \"%s\" (found)\n",
id, rw ? "w" : "r", ep->e_dn);
/* lru */
LRU_DELETE( cache, ep );
LRU_ADD( cache, ep );
LEI(ep)->lei_refcnt++;
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( ep );
}
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
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
bdb2i_cache_delete_entry(
struct cache *cache,
Entry *e
)
{
int rc;
/* set cache mutex */
ldap_pvt_thread_mutex_lock( &cache->c_mutex );
#ifdef LDAP_DEBUG
assert( e->e_private );
#endif
Debug( LDAP_DEBUG_TRACE, "====> bdb2i_cache_delete_entry( %ld )\n",
e->e_id, 0, 0 );
rc = cache_delete_entry_internal( cache, e );
/* free cache mutex */
ldap_pvt_thread_mutex_unlock( &cache->c_mutex );
return( rc );
}
static int
cache_delete_entry_internal(
struct cache *cache,
Entry *e
)
{
int rc = 0; /* return code */
/* dn tree */
if ( avl_delete( &cache->c_dntree, (caddr_t) e, (AVL_CMP) entry_dn_cmp )
== NULL )
{
rc = -1;
}
/* id tree */
if ( avl_delete( &cache->c_idtree, (caddr_t) e, (AVL_CMP) entry_id_cmp )
== NULL )
{
rc = -1;
}
if (rc != 0) {
return rc;
}
/* lru */
LRU_DELETE( cache, e );
cache->c_cursize--;
/*
* flag entry to be freed later by a call to cache_return_entry()
*/
LEI(e)->lei_state = CACHE_ENTRY_DELETED;
return( 0 );
}
#ifdef LDAP_DEBUG
static void
lru_print( struct cache *cache )
{
Entry *e;
fprintf( stderr, "LRU queue (head to tail):\n" );
for ( e = cache->c_lruhead; e != NULL; e = LEI(e)->lei_lrunext ) {
fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
e->e_dn, e->e_id, LEI(e)->lei_refcnt );
}
fprintf( stderr, "LRU queue (tail to head):\n" );
for ( e = cache->c_lrutail; e != NULL; e = LEI(e)->lei_lruprev ) {
fprintf( stderr, "\tdn \"%20s\" id %ld refcnt %d\n",
e->e_dn, e->e_id, LEI(e)->lei_refcnt );
}
}
#endif