ITS#8752 fix syncrepl deadlock from updateCookie

Must release cookieState->cs_mutex before invoking backend.
Add a condvar to serialize calls of updateCookie, so we can
release the mutex and still update sequentially.

Also added tid logging, useful in conjunction with
7ab0e1aff0cc48cdfb299ca7dbd27900a9e3d1a8

diff --git a/servers/slapd/syncrepl.c b/servers/slapd/syncrepl.c
index 6e157e700c63926a8dd3083c4f79673934ea0cfe..60e5e7c13e820d9ec963ffb8396adc9b76ec3ac8 100644 (file)
--- a/servers/slapd/syncrepl.c
+++ b/servers/slapd/syncrepl.c
@@ -46,11 +46,13 @@ struct nonpresent_entry {
 
 typedef struct cookie_state {
        ldap_pvt_thread_mutex_t cs_mutex;
+       ldap_pvt_thread_cond_t cs_cond;
        struct berval *cs_vals;
        int *cs_sids;
        int     cs_num;
        int cs_age;
        int cs_ref;
+       int cs_updating;
 
        /* pending changes, not yet committed */
        ldap_pvt_thread_mutex_t cs_pmutex;
@@ -2447,6 +2449,9 @@ syncrepl_message_to_op(
        op->o_callback = &cb;
        slap_op_time( &op->o_time, &op->o_tincr );
 
+       Debug( LDAP_DEBUG_SYNC, "syncrepl_message_to_op: %s tid %x\n",
+               si->si_ridtxt, op->o_tid, 0 );
+
        switch( op->o_tag ) {
        case LDAP_REQ_ADD:
        case LDAP_REQ_MODIFY:
@@ -2954,8 +2959,8 @@ syncrepl_entry(
        int     freecsn = 1;
 
        Debug( LDAP_DEBUG_SYNC,
-               "syncrepl_entry: %s LDAP_RES_SEARCH_ENTRY(LDAP_SYNC_%s)\n",
-               si->si_ridtxt, syncrepl_state2str( syncstate ), 0 );
+               "syncrepl_entry: %s LDAP_RES_SEARCH_ENTRY(LDAP_SYNC_%s) tid %x\n",
+               si->si_ridtxt, syncrepl_state2str( syncstate ), op->o_tid );
 
        if (( syncstate == LDAP_SYNC_PRESENT || syncstate == LDAP_SYNC_ADD ) ) {
                if ( !si->si_refreshPresent && !si->si_refreshDone ) {
@@ -3950,6 +3955,8 @@ syncrepl_updateCookie(
        mod.sml_next = NULL;
 
        ldap_pvt_thread_mutex_lock( &si->si_cookieState->cs_mutex );
+       while ( si->si_cookieState->cs_updating )
+               ldap_pvt_thread_cond_wait( &si->si_cookieState->cs_cond, &si->si_cookieState->cs_mutex );
 
 #ifdef CHECK_CSN
        for ( i=0; i<syncCookie->numcsns; i++ ) {
@@ -4012,6 +4019,10 @@ syncrepl_updateCookie(
                ch_free( sc.sids );
                return 0;
        }
+
+       si->si_cookieState->cs_updating = 1;
+       ldap_pvt_thread_mutex_unlock( &si->si_cookieState->cs_mutex );
+
        op->o_bd = si->si_wbe;
        slap_queue_csn( op, &first );
 
@@ -4050,6 +4061,7 @@ syncrepl_updateCookie(
 
        op->orm_no_opattrs = 0;
        op->o_dont_replicate = 0;
+       ldap_pvt_thread_mutex_lock( &si->si_cookieState->cs_mutex );
 
        if ( rs_modify.sr_err == LDAP_SUCCESS ) {
                slap_sync_cookie_free( &si->si_syncCookie, 0 );
@@ -4082,6 +4094,8 @@ syncrepl_updateCookie(
        }
 #endif
 
+       si->si_cookieState->cs_updating = 0;
+       ldap_pvt_thread_cond_broadcast( &si->si_cookieState->cs_cond );
        ldap_pvt_thread_mutex_unlock( &si->si_cookieState->cs_mutex );
 
        op->o_bd = be;
@@ -4746,6 +4760,7 @@ syncinfo_free( syncinfo_t *sie, int free_all )
                        if ( !sie->si_cookieState->cs_ref ) {
                                ch_free( sie->si_cookieState->cs_sids );
                                ber_bvarray_free( sie->si_cookieState->cs_vals );
+                               ldap_pvt_thread_cond_destroy( &sie->si_cookieState->cs_cond );
                                ldap_pvt_thread_mutex_destroy( &sie->si_cookieState->cs_mutex );
                                ch_free( sie->si_cookieState->cs_psids );
                                ber_bvarray_free( sie->si_cookieState->cs_pvals );
@@ -5552,6 +5567,7 @@ add_syncrepl(
                        si->si_cookieState = ch_calloc( 1, sizeof( cookie_state ));
                        ldap_pvt_thread_mutex_init( &si->si_cookieState->cs_mutex );
                        ldap_pvt_thread_mutex_init( &si->si_cookieState->cs_pmutex );
+                       ldap_pvt_thread_cond_init( &si->si_cookieState->cs_cond );
 
                        c->be->be_syncinfo = si;
                }