ITS#2580 - avoid cache deadlock

diff --git a/servers/slapd/back-bdb/cache.c b/servers/slapd/back-bdb/cache.c
index d1e99534637253b2f4ebf7273a792f296a7c6b52..36b46089bdebd4a37c228f14865684de7448176d 100644 (file)
--- a/servers/slapd/back-bdb/cache.c
+++ b/servers/slapd/back-bdb/cache.c
@@ -442,7 +442,7 @@ hdb_cache_find_parent(
                ein->bei_state = CACHE_ENTRY_NOT_LINKED;
 
                /* Insert this node into the ID tree */
-               ldap_pvt_thread_rdwr_rlock( &bdb->bi_cache.c_rwlock );
+               ldap_pvt_thread_rdwr_wlock( &bdb->bi_cache.c_rwlock );
                if ( avl_insert( &bdb->bi_cache.c_idtree, (caddr_t)ein,
                        bdb_id_cmp, avl_dup_error ) ) {
 
@@ -482,7 +482,7 @@ hdb_cache_find_parent(
                        *res = eir;
                        bdb_cache_entryinfo_lock( eir );
                }
-               ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
+               ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
                if ( ei2 ) {
                        /* Found a link. Reset all the state info */
                        for (ein = eir; ein != ei2; ein=ein->bei_parent)
@@ -524,11 +524,16 @@ bdb_cache_find_id(
 
        /* If we weren't given any info, see if we have it already cached */
        if ( !*eip ) {
-               ldap_pvt_thread_rdwr_rlock( &bdb->bi_cache.c_rwlock );
+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 ) {
-                       bdb_cache_entryinfo_lock( *eip );
+                       if ( ldap_pvt_thread_mutex_trylock(
+                                       &(*eip)->bei_kids_mutex )) {
+                               ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );
+                               ldap_pvt_thread_yield();
+                               goto again;
+                       }
                        islocked = 1;
                }
                ldap_pvt_thread_rdwr_runlock( &bdb->bi_cache.c_rwlock );