Trac Ticket #499 - Handling URP results is not corrrect

https://fedorahosted.org/389/ticket/499

Bug description: When an urp resolution occurred as follows
  [] - urp_delete: Entry "nsuniqueid=<UNIQID>,uid=<UID>,o=<ORG>"
is already a Tombstone.
the operation should be skipped in the backend, but should return
SUCCESS to the supplier.  Otherwise, the supplier continues to
send the relay and the replication stops there.

Fix description: This patch introduced SLAPI_PLUGIN_NOOP (-2)
to the bepre and betxnpre plugin return value set (SLAPI_
PLUGIN_SUCCESS == 0; SLAPI_PLUGIN_FAILURE == -1).  If SLAPI_
PLUGIN_NOOP is returned, the backend code skips the operation,
but it returns SUCCESS.  Note that urp is only executed on the
replicated operation (not on the end user ones).

ldap/servers/plugins/replication/urp.c

@@ -53,10 +53,10 @@
 extern int slapi_log_urp;
 
 static int urp_add_resolve_parententry (Slapi_PBlock *pb, char *sessionid, Slapi_Entry *entry, Slapi_Entry *parententry, CSN *opcsn);
-static int urp_annotate_dn (char *sessionid, Slapi_Entry *entry, CSN *opcsn, const char *optype);
+static int urp_annotate_dn (char *sessionid, const Slapi_Entry *entry, CSN *opcsn, const char *optype);
 static int urp_naming_conflict_removal (Slapi_PBlock *pb, char *sessionid, CSN *opcsn, const char *optype);
 static int mod_namingconflict_attr (const char *uniqueid, const Slapi_DN *entrysdn, const Slapi_DN *conflictsdn, CSN *opcsn);
-static int del_replconflict_attr (Slapi_Entry *entry, CSN *opcsn, int opflags);
+static int del_replconflict_attr (const Slapi_Entry *entry, CSN *opcsn, int opflags);
 static char *get_dn_plus_uniqueid(char *sessionid,const char *olddn,const char *uniqueid);
 static char *get_rdn_plus_uniqueid(char *sessionid,const char *olddn,const char *uniqueid);
 static int is_suffix_entry (Slapi_PBlock *pb, Slapi_Entry *entry, Slapi_DN **parenddn);
@@ -69,19 +69,21 @@ urp_modify_operation( Slapi_PBlock *pb )
 {
 	Slapi_Entry *modifyentry= NULL;
 	int op_result= 0;
-    int rc= 0; /* OK */
+	int rc= 0; /* OK */
+	char sessionid[REPL_SESSION_ID_SIZE];
+	CSN *opcsn;
 
 	if ( slapi_op_abandoned(pb) )
 	{
 		return rc;
 	}
 
-   	slapi_pblock_get( pb, SLAPI_MODIFY_EXISTING_ENTRY, &modifyentry );
-
+	get_repl_session_id (pb, sessionid, &opcsn);
+	slapi_pblock_get( pb, SLAPI_MODIFY_EXISTING_ENTRY, &modifyentry );
 	if(modifyentry!=NULL)
 	{
-	    /*
-	     * The entry to be modified exists.
+		/*
+		 * The entry to be modified exists.
 		 * - the entry could be a tombstone... but that's OK.
 		 * - the entry could be glue... that may not be OK. JCMREPL
 		 */
@@ -90,12 +92,14 @@ urp_modify_operation( Slapi_PBlock *pb )
 	}
 	else
 	{
-	    /*
-	     * The entry to be modified could not be found.
-	     */ 
+		/*
+		 * The entry to be modified could not be found.
+		 */ 
 		op_result= LDAP_NO_SUCH_OBJECT;
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-		rc= -1; /* Must discard this Modification */
+		rc = SLAPI_PLUGIN_NOOP; /* Must discard this Modification */
+		slapi_log_error (slapi_log_urp, sessionid,
+		                 "urp_modify: No such entry\n");
 		PROFILE_POINT; /* Modify Conflict; Entry Does Not Exist; Discard Modification */
 	}
 	return rc;
@@ -129,6 +133,7 @@ urp_add_operation( Slapi_PBlock *pb )
 		return rc;
 	}
 
+	get_repl_session_id (pb, sessionid, &opcsn);
 	slapi_pblock_get( pb, SLAPI_ADD_EXISTING_UNIQUEID_ENTRY, &existing_uniqueid_entry );
 	if (existing_uniqueid_entry!=NULL)
 	{
@@ -149,12 +154,11 @@ urp_add_operation( Slapi_PBlock *pb )
 		          slapi_entry_get_dn_const(existing_uniqueid_entry));
 		op_result= LDAP_UNWILLING_TO_PERFORM;
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-		rc= -1; /* Ignore this Operation */
+		rc = SLAPI_PLUGIN_NOOP; /* Ignore this Operation */
 		PROFILE_POINT; /* Add Conflict; UniqueID Exists;  Ignore */
 		goto bailout;
 	}
 
-	get_repl_session_id (pb, sessionid, &opcsn);
 	slapi_pblock_get( pb, SLAPI_ADD_ENTRY, &addentry );
 	slapi_pblock_get( pb, SLAPI_ADD_EXISTING_DN_ENTRY, &existing_dn_entry );
 	if (existing_dn_entry==NULL) /* The target DN does not exist */
@@ -185,7 +189,10 @@ urp_add_operation( Slapi_PBlock *pb )
 		{
 			op_result= LDAP_OPERATIONS_ERROR;
 			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-			rc= -1; /* Abort this Operation */
+			rc = SLAPI_PLUGIN_NOOP; /* Abort this Operation */
+			slapi_log_error(slapi_log_urp, sessionid,
+			      "urp_add (%s): Add conflict; Unique ID (%s) already in RDN\n",
+			      basedn, adduniqueid);
 			PROFILE_POINT; /* Add Conflict; Entry Exists; Unique ID already in RDN - Abort this update. */
 		}
 		else
@@ -200,7 +207,8 @@ urp_add_operation( Slapi_PBlock *pb )
 			if (slapi_entry_attr_find (addentry, ATTR_NSDS5_REPLCONFLICT, &attr) == 0)
 			{
 				/* ATTR_NSDS5_REPLCONFLICT exists */
-				slapi_log_error (SLAPI_LOG_FATAL, sessionid, "New entry has nsds5ReplConflict already\n");
+				slapi_log_error(SLAPI_LOG_FATAL, sessionid,
+				          "urp_add: New entry has nsds5ReplConflict already\n");
 				vals = attr_get_present_values (attr); /* this returns a pointer to the contents */
 			}
 			if ( vals == NULL || *vals == NULL )
@@ -227,7 +235,8 @@ urp_add_operation( Slapi_PBlock *pb )
 
 			rdn = slapi_rdn_new_sdn ( slapi_entry_get_sdn_const(addentry) );
 			slapi_log_error (slapi_log_urp, sessionid,
-					"Naming conflict ADD. Add %s instead\n", slapi_rdn_get_rdn(rdn) );
+			                 "urp_add: Naming conflict ADD. Add %s instead\n",
+			                 slapi_rdn_get_rdn(rdn));
 			slapi_rdn_free(&rdn);
 
 			rc= slapi_setbit_int(rc,SLAPI_RTN_BIT_FETCH_EXISTING_DN_ENTRY);
@@ -241,7 +250,10 @@ urp_add_operation( Slapi_PBlock *pb )
 		{
 			op_result= LDAP_OPERATIONS_ERROR;
 			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-			rc= -1; /* Ignore this Operation */
+			slapi_log_error(slapi_log_urp, sessionid,
+			                "urp_add (%s): Entry to be added is a loser; "
+			                "urp_annotate_dn failed.\n", basedn);
+			rc = SLAPI_PLUGIN_NOOP; /* Ignore this Operation */
 		}
 		else
 		{
@@ -271,12 +283,12 @@ urp_add_operation( Slapi_PBlock *pb )
 		slapi_entry_get_dn_const(existing_dn_entry));
 		op_result= LDAP_UNWILLING_TO_PERFORM;
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-		rc= -1; /* Ignore this Operation */
+		rc = SLAPI_PLUGIN_NOOP; /* Ignore this Operation */
 		PROFILE_POINT; /* Add Conflict; Entry Exists; Same CSN */
 	}
 
 bailout:
-    return rc;
+	return rc;
 }
 
 /*
@@ -289,11 +301,11 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 {
 	slapi_operation_parameters *op_params = NULL;
 	Slapi_Entry *parent_entry;
-    Slapi_Entry *new_parent_entry;
+	Slapi_Entry *new_parent_entry;
 	Slapi_DN *newsuperior = NULL;
 	Slapi_DN *parentdn = NULL;
-	Slapi_Entry *target_entry;
-    Slapi_Entry *existing_entry;
+	const Slapi_Entry *target_entry;
+	Slapi_Entry *existing_entry;
 	const CSN *target_entry_dncsn;
 	CSN *opcsn= NULL;
 	char *op_uniqueid = NULL;
@@ -304,7 +316,7 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 	char sessionid[REPL_SESSION_ID_SIZE];
 	int r;
 	int op_result= 0;
-    int rc= 0; /* OK */
+	int rc= 0; /* OK */
 	int del_old_replconflict_attr = 0;
 
 	if ( slapi_op_abandoned(pb) )
@@ -312,7 +324,7 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 		return rc;
 	}
 
-   	slapi_pblock_get (pb, SLAPI_MODRDN_TARGET_ENTRY, &target_entry);
+	slapi_pblock_get (pb, SLAPI_MODRDN_TARGET_ENTRY, &target_entry);
 	if(target_entry==NULL)
 	{
 		/* An entry can't be found for the Unique Identifier */
@@ -323,7 +335,7 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 		goto bailout;
 	}
 
-   	get_repl_session_id (pb, sessionid, &opcsn);
+	get_repl_session_id (pb, sessionid, &opcsn);
 	target_entry_dncsn = entry_get_dncsn (target_entry);
 	if ( csn_compare (target_entry_dncsn, opcsn) >= 0 )
 	{
@@ -343,7 +355,7 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 		           slapi_entry_get_dn_const(target_entry));
 		op_result= LDAP_UNWILLING_TO_PERFORM;
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-		rc= -1; /* Ignore the modrdn */
+		rc = SLAPI_PLUGIN_NOOP; /* Ignore the modrdn */
 		PROFILE_POINT; /* ModRDN Conflict; Entry with Target DN Exists; OPCSN is not newer. */
 		goto bailout;
 	}
@@ -385,7 +397,10 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 		}
 		else
 		{
-			rc = -1;
+			slapi_log_error(slapi_log_urp, sessionid,
+			                "urp_modrdn (%s): target entry is a tombstone.\n",
+			                slapi_entry_get_dn_const(target_entry));
+			rc = SLAPI_PLUGIN_NOOP; /* Ignore the modrdn */
 		}
 		PROFILE_POINT; /* ModRDN Conflict; Entry with Target DN Exists; OPCSN is not newer. */
 		goto bailout;
@@ -426,12 +441,12 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 			 * but the uniqueids are not.
 			 * There might be two replicas with the same ReplicaID.
 			 */
-			slapi_log_error(SLAPI_LOG_FATAL, sessionid,
-				"Duplicated CSN for different uniqueids [%s][%s]",
+			slapi_log_error(slapi_log_urp, sessionid,
+				"urp_modrdn: Duplicated CSN for different uniqueids [%s][%s]",
 				existing_uniqueid, op_uniqueid);
 			op_result= LDAP_OPERATIONS_ERROR;
 			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-			rc= -1; /* Abort */
+			rc = SLAPI_PLUGIN_NOOP; /* Ignore this Operation */
 			PROFILE_POINT; /* ModRDN Conflict; Duplicated CSN for Different Entries */
 			goto bailout;
 		}
@@ -454,8 +469,8 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 			mod_namingconflict_attr (op_uniqueid, target_sdn, existing_sdn, opcsn);
 			slapi_pblock_set(pb, SLAPI_MODRDN_NEWRDN, newrdn_with_uniqueid); 
 			slapi_log_error(slapi_log_urp, sessionid,
-					"Naming conflict MODRDN. Rename target entry to %s\n",
-					newrdn_with_uniqueid );
+			  "urp_modrdn: Naming conflict MODRDN. Rename target entry to %s\n",
+			  newrdn_with_uniqueid );
 
 			rc= slapi_setbit_int(rc,SLAPI_RTN_BIT_FETCH_EXISTING_DN_ENTRY);
 			PROFILE_POINT; /* ModRDN Conflict; Entry with Target DN Exists; Rename Operation Entry */
@@ -559,11 +574,11 @@ urp_modrdn_operation( Slapi_PBlock *pb )
 			 * admin intercession
 			 */
 			slapi_log_error( SLAPI_LOG_FATAL, sessionid,
-				 "Parent %s couldn't be found, nor recreated as a glue entry\n",
+				 "urp_modrdn: Parent %s couldn't be found, nor recreated as a glue entry\n",
 				 slapi_sdn_get_dn(newsuperior) );
 			op_result= LDAP_OPERATIONS_ERROR;
 			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-			rc = -1;
+			rc = SLAPI_PLUGIN_FAILURE; /* Ignore this Operation */
 			PROFILE_POINT;
 			goto bailout;
 		}
@@ -590,24 +605,25 @@ bailout:
 int 
 urp_delete_operation( Slapi_PBlock *pb )
 {
-  	Slapi_Entry *deleteentry;
+	const Slapi_Entry *deleteentry;
 	CSN *opcsn= NULL;
 	char sessionid[REPL_SESSION_ID_SIZE];
 	int op_result= 0;
-    int rc= 0; /* OK */
+    int rc = SLAPI_PLUGIN_SUCCESS; /* OK */
 
 	if ( slapi_op_abandoned(pb) )
 	{
 		return rc;
 	}
 
-   	slapi_pblock_get(pb, SLAPI_DELETE_EXISTING_ENTRY, &deleteentry);
+	slapi_pblock_get(pb, SLAPI_DELETE_EXISTING_ENTRY, &deleteentry);
 
+	get_repl_session_id (pb, sessionid, &opcsn);
 	if(deleteentry==NULL) /* uniqueid can't be found */
 	{
 		op_result= LDAP_NO_SUCH_OBJECT;
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-		rc= -1; /* Don't apply the Delete */
+		rc = SLAPI_PLUGIN_FAILURE; /* Don't apply the Delete */
 		PROFILE_POINT; /* Delete Operation; Entry not exist. */
 	}
 	else if(is_tombstone_entry(deleteentry))
@@ -615,7 +631,10 @@ urp_delete_operation( Slapi_PBlock *pb )
 		/* The entry is already a Tombstone, ignore this delete. */
 		op_result= LDAP_SUCCESS;
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-		rc = -1; /* Don't apply the Delete */
+		rc = SLAPI_PLUGIN_NOOP; /* Don't apply the Delete */
+		slapi_log_error(slapi_log_urp, sessionid,
+		                "urp_delete: Entry \"%s\" is already a Tombstone.\n",
+		                slapi_entry_get_dn_const(deleteentry));
 		PROFILE_POINT; /* Delete Operation; Already a Tombstone. */
 	}
 	else /* The entry to be deleted exists and is not a tombstone */
@@ -627,7 +646,7 @@ urp_delete_operation( Slapi_PBlock *pb )
 		{
 			/* Remove possible conflict attributes */
 			del_replconflict_attr (deleteentry, opcsn, 0);
-			rc= 0; /* OK, to delete the entry */
+			rc = SLAPI_PLUGIN_SUCCESS; /* OK, to delete the entry */
 			PROFILE_POINT; /* Delete Operation; OK. */
 		}
 		else
@@ -638,8 +657,11 @@ urp_delete_operation( Slapi_PBlock *pb )
 			/* Turn the Delete into a No-Op */
 			op_result= LDAP_SUCCESS;
 			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &op_result);
-			rc = -1; /* Don't apply the Delete */
-		    PROFILE_POINT; /* Delete Operation; Entry has children. */
+			rc = SLAPI_PLUGIN_NOOP; /* Don't apply the Delete */
+			slapi_log_error(slapi_log_urp, sessionid,
+			 "urp_delete: Turn entry \"%s\" into a glue_absent_parent entry.\n",
+		     slapi_entry_get_dn_const(deleteentry));
+			PROFILE_POINT; /* Delete Operation; Entry has children. */
 		}
 	}
 	return rc;
@@ -785,7 +807,7 @@ urp_fixup_add_entry (Slapi_Entry *e, const char *target_uniqueid, const char *pa
 }
 
 int
-urp_fixup_rename_entry (Slapi_Entry *entry, const char *newrdn, int opflags)
+urp_fixup_rename_entry (const Slapi_Entry *entry, const char *newrdn, int opflags)
 {
 	Slapi_PBlock *newpb;
     Slapi_Operation *op;
@@ -996,7 +1018,7 @@ bailout:
  * a new entry (the operation entry) see urp_add_operation.
  */
 static int
-urp_annotate_dn (char *sessionid, Slapi_Entry *entry, CSN *opcsn, const char *optype)
+urp_annotate_dn (char *sessionid, const Slapi_Entry *entry, CSN *opcsn, const char *optype)
 {
 	int rc = 0; /* Fail */
 	int op_result;
@@ -1179,7 +1201,7 @@ urp_naming_conflict_removal ( Slapi_PBlock *pb, char *sessionid, CSN *opcsn, con
 
 	/* Step 1: Restore the entry's original DN */
 
-	oldrdn = slapi_rdn_new_sdn ( slapi_entry_get_sdn (min_naming_conflict_entry) );
+	oldrdn = slapi_rdn_new_sdn(slapi_entry_get_sdn_const(min_naming_conflict_entry));
 	oldrdnstr = slapi_rdn_get_rdn ( oldrdn );
 
 	/* newrdnstr is the old rdn of the entry minus the nsuniqueid part */
@@ -1192,7 +1214,7 @@ urp_naming_conflict_removal ( Slapi_PBlock *pb, char *sessionid, CSN *opcsn, con
 	 * is done after DB lock was released. The backend modrdn
 	 * will acquire the DB lock if it sees this flag.
 	 */
-	op_result = urp_fixup_rename_entry (min_naming_conflict_entry, newrdnstr, OP_FLAG_ACTION_INVOKE_FOR_REPLOP);
+	op_result = urp_fixup_rename_entry((const Slapi_Entry *)min_naming_conflict_entry, newrdnstr, OP_FLAG_ACTION_INVOKE_FOR_REPLOP);
 	if ( op_result != LDAP_SUCCESS )
 	{
 	    slapi_log_error (slapi_log_urp, sessionid,
@@ -1215,7 +1237,7 @@ urp_naming_conflict_removal ( Slapi_PBlock *pb, char *sessionid, CSN *opcsn, con
 	}
 
 bailout:
-	slapi_entry_free (min_naming_conflict_entry);
+	slapi_entry_free(min_naming_conflict_entry);
 	slapi_rdn_free(&oldrdn);
 	slapi_rdn_free(&newrdn);
 	return op_result;
@@ -1347,7 +1369,7 @@ mod_namingconflict_attr (const char *uniqueid, const Slapi_DN *entrysdn,
 }
 
 static int
-del_replconflict_attr (Slapi_Entry *entry, CSN *opcsn, int opflags)
+del_replconflict_attr (const Slapi_Entry *entry, CSN *opcsn, int opflags)
 {
 	Slapi_Attr *attr;
 	int op_result = 0;

ldap/servers/plugins/replication/urp.h

@@ -59,7 +59,7 @@ int urp_post_modrdn_operation( Slapi_PBlock *pb );
 /* urp internal ops */
 int urp_fixup_add_entry (Slapi_Entry *e, const char *target_uniqueid, const char *parentuniqueid, CSN *opcsn, int opflags);
 int urp_fixup_delete_entry (const char *uniqueid, const char *dn, CSN *opcsn, int opflags);
-int urp_fixup_rename_entry (Slapi_Entry *entry, const char *newrdn, int opflags);
+int urp_fixup_rename_entry (const Slapi_Entry *entry, const char *newrdn, int opflags);
 int urp_fixup_modify_entry (const char *uniqueid, const Slapi_DN *sdn, CSN *opcsn, Slapi_Mods *smods, int opflags);
 
 int is_suffix_dn (Slapi_PBlock *pb, const Slapi_DN *dn, Slapi_DN **parenddn);

ldap/servers/slapd/back-ldbm/ldbm_add.c

@@ -116,6 +116,7 @@ ldbm_back_add( Slapi_PBlock *pb )
 	int is_ruv = 0;				 /* True if the current entry is RUV */
 	CSN *opcsn = NULL;
 	entry_address addr = {0};
+	int not_an_error = 0;
 
 	slapi_pblock_get( pb, SLAPI_PLUGIN_PRIVATE, &li );
 	slapi_pblock_get( pb, SLAPI_ADD_ENTRY, &e );
@@ -266,9 +267,12 @@ ldbm_back_add( Slapi_PBlock *pb )
 		/* Call the Backend Pre Add plugins */
 		slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);
 		rc= plugin_call_plugins(pb, SLAPI_PLUGIN_BE_PRE_ADD_FN);
-		if(rc==-1)
-		{
+		if (rc) {
 			int opreturn = 0;
+			if (SLAPI_PLUGIN_NOOP == rc) {
+				not_an_error = 1;
+				rc = LDAP_SUCCESS;
+			}
 			/* 
 			 * Plugin indicated some kind of failure,
 			 * or that this Operation became a No-Op.
@@ -776,8 +780,13 @@ ldbm_back_add( Slapi_PBlock *pb )
 
 		/* call the transaction pre add plugins just after the to-be-added entry
 		 * is prepared. */
-		if ((retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_ADD_FN))) {
+		retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_ADD_FN);
+		if (retval) {
 			int opreturn = 0;
+			if (SLAPI_PLUGIN_NOOP == retval) {
+				not_an_error = 1;
+				rc = retval = LDAP_SUCCESS;
+			}
 			LDAPDebug1Arg( LDAP_DEBUG_TRACE, "SLAPI_PLUGIN_BE_TXN_PRE_ADD_FN plugin "
 				       "returned error code %d\n", retval );
 			if (!ldap_result_code) {
@@ -1120,7 +1129,9 @@ diskfull_return:
 			/* txn is no longer valid - reset the txn pointer to the parent */
 			slapi_pblock_set(pb, SLAPI_TXN, parent_txn);
 		}
-		rc= SLAPI_FAIL_GENERAL;
+		if (!not_an_error) {
+			rc = SLAPI_FAIL_GENERAL;
+		}
 	}
 	
 common_return:
@@ -1166,6 +1177,11 @@ common_return:
 	done_with_pblock_entry(pb,SLAPI_ADD_PARENT_ENTRY);
 	if(ldap_result_code!=-1)
 	{
+		if (not_an_error) {
+			/* This is mainly used by urp.  Solved conflict is not an error.
+			 * And we don't want the supplier to halt sending the updates. */
+			ldap_result_code = LDAP_SUCCESS;
+		}
 		slapi_send_ldap_result( pb, ldap_result_code, ldap_result_matcheddn, ldap_result_message, 0, NULL );
 	}
 	backentry_free(&originalentry);

ldap/servers/slapd/back-ldbm/ldbm_delete.c

@@ -97,6 +97,7 @@ ldbm_back_delete( Slapi_PBlock *pb )
 	Slapi_DN parentsdn;
 	int opreturn = 0;
 	int free_delete_existing_entry = 0;
+	int not_an_error = 0;
 
 	slapi_pblock_get( pb, SLAPI_BACKEND, &be);
 	slapi_pblock_get( pb, SLAPI_PLUGIN_PRIVATE, &li );
@@ -300,8 +301,11 @@ ldbm_back_delete( Slapi_PBlock *pb )
 				slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);
 		
 				rc = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_PRE_DELETE_FN);
-				if (rc == -1)
+				if (rc)
 				{
+					if (SLAPI_PLUGIN_NOOP == rc) {
+						not_an_error = 1;
+					}
 					/* 
 					 * Plugin indicated some kind of failure,
 					 * or that this Operation became a No-Op.
@@ -569,6 +573,9 @@ ldbm_back_delete( Slapi_PBlock *pb )
 			   instead, have them modify a copy of the entry */
 			retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_DELETE_FN);
 			if (retval) {
+				if (SLAPI_PLUGIN_NOOP == retval) {
+					not_an_error = 1;
+				}
 				LDAPDebug1Arg( LDAP_DEBUG_TRACE,
 				               "SLAPI_PLUGIN_BE_TXN_PRE_DELETE_FN plugin "
 				               "returned error code %d\n", retval );
@@ -1223,8 +1230,12 @@ common_return:
 	}
 
 diskfull_return:
-    if(ldap_result_code!=-1)
-	{
+	if(ldap_result_code!=-1) {
+		if (not_an_error) {
+			/* This is mainly used by urp.  Solved conflict is not an error.
+			 * And we don't want the supplier to halt sending the updates. */
+			ldap_result_code = LDAP_SUCCESS;
+		}
 		slapi_send_ldap_result( pb, ldap_result_code, NULL, ldap_result_message, 0, NULL );
 	}
 	modify_term(&parent_modify_c,be);

ldap/servers/slapd/back-ldbm/ldbm_modify.c

@@ -340,6 +340,7 @@ ldbm_back_modify( Slapi_PBlock *pb )
 	int repl_op;
 	int opreturn = 0;
 	int mod_count = 0;
+	int not_an_error = 0;
 
 	slapi_pblock_get( pb, SLAPI_BACKEND, &be);
 	slapi_pblock_get( pb, SLAPI_PLUGIN_PRIVATE, &li );
@@ -511,7 +512,8 @@ ldbm_back_modify( Slapi_PBlock *pb )
 			slapi_pblock_set( pb, SLAPI_MODIFY_EXISTING_ENTRY, ec->ep_entry );
 			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);
 		
-			if ((opreturn = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_PRE_MODIFY_FN)) ||
+			opreturn = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_PRE_MODIFY_FN);
+			if (opreturn ||
 				(slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code) && ldap_result_code) ||
 				(slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn) && opreturn)) {
 				slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
@@ -521,7 +523,11 @@ ldbm_back_modify( Slapi_PBlock *pb )
 						       "returned error but did not set SLAPI_RESULT_CODE\n");
 					ldap_result_code = LDAP_OPERATIONS_ERROR;
 				}
-				if (!opreturn) {
+				if (SLAPI_PLUGIN_NOOP == opreturn) {
+					not_an_error = 1;
+					rc = opreturn = LDAP_SUCCESS;
+					goto error_return;
+				} else if (!opreturn) {
 					opreturn = -1;
 					slapi_pblock_set(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
 				}
@@ -563,11 +569,16 @@ ldbm_back_modify( Slapi_PBlock *pb )
 		} /* if (0 == retry_count) just once */
 
 		/* call the transaction pre modify plugins just after creating the transaction */
-		if ((retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_MODIFY_FN))) {
+		retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_MODIFY_FN);
+		if (retval) {
 			LDAPDebug1Arg( LDAP_DEBUG_TRACE, "SLAPI_PLUGIN_BE_TXN_PRE_MODIFY_FN plugin "
 						   "returned error code %d\n", retval );
 			slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
 			slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
+			if (SLAPI_PLUGIN_NOOP == retval) {
+				not_an_error = 1;
+				rc = retval = LDAP_SUCCESS;
+			}
 			if (!opreturn) {
 				slapi_pblock_set(pb, SLAPI_PLUGIN_OPRETURN, ldap_result_code ? &ldap_result_code : &retval);
 			}
@@ -796,7 +807,9 @@ error_return:
 			/* txn is no longer valid - reset the txn pointer to the parent */
 			slapi_pblock_set(pb, SLAPI_TXN, parent_txn);
 		}
-	    rc= SLAPI_FAIL_GENERAL;
+		if (!not_an_error) {
+			rc = SLAPI_FAIL_GENERAL;
+		}
 	}
 
 	/* if ec is in cache, remove it, then add back e if we still have it */
@@ -845,6 +858,11 @@ common_return:
 
 	if(ldap_result_code!=-1)
 	{
+		if (not_an_error) {
+			/* This is mainly used by urp.  Solved conflict is not an error.
+			 * And we don't want the supplier to halt sending the updates. */
+			ldap_result_code = LDAP_SUCCESS;
+		}
 		slapi_send_ldap_result( pb, ldap_result_code, NULL, ldap_result_message, 0, NULL );
 	}
 

ldap/servers/slapd/back-ldbm/ldbm_modrdn.c

@@ -120,6 +120,7 @@ ldbm_back_modrdn( Slapi_PBlock *pb )
     char *newrdn = NULL;
     int opreturn = 0;
     int free_modrdn_existing_entry = 0;
+    int not_an_error = 0;
 
     /* sdn & parentsdn need to be initialized before "goto *_return" */
     slapi_sdn_init(&dn_newdn);
@@ -441,8 +442,11 @@ ldbm_back_modrdn( Slapi_PBlock *pb )
                 /* Call the Backend Pre ModRDN plugins */
                 slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);
                 rc= plugin_call_plugins(pb, SLAPI_PLUGIN_BE_PRE_MODRDN_FN);
-                if(rc==-1)
-                {
+                if (rc) {
+                    if (SLAPI_PLUGIN_NOOP == rc) {
+                        not_an_error = 1;
+                        rc = LDAP_SUCCESS;
+                    }
                     /* 
                      * Plugin indicated some kind of failure,
                      * or that this Operation became a No-Op.
@@ -869,9 +873,14 @@ ldbm_back_modrdn( Slapi_PBlock *pb )
         } /* if (0 == retry_count) just once */
 
         /* call the transaction pre modrdn plugins just after creating the transaction */
-        if ((retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_MODRDN_FN))) {
+        retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_MODRDN_FN);
+        if (retval) {
             LDAPDebug1Arg( LDAP_DEBUG_TRACE, "SLAPI_PLUGIN_BE_TXN_PRE_MODRDN_FN plugin "
                            "returned error code %d\n", retval );
+            if (SLAPI_PLUGIN_NOOP == retval) {
+                not_an_error = 1;
+                rc = retval = LDAP_SUCCESS;
+            }
             if (!ldap_result_code) {
                 slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
             }
@@ -1267,7 +1276,9 @@ error_return:
             /* txn is no longer valid - reset the txn pointer to the parent */
             slapi_pblock_set(pb, SLAPI_TXN, parent_txn);
         }
-        retval= SLAPI_FAIL_GENERAL;
+        if (!not_an_error) {
+            retval = SLAPI_FAIL_GENERAL;
+        }
     }
 
 common_return:
@@ -1314,6 +1325,11 @@ common_return:
 
     if (ldap_result_code!=-1)
     {
+		if (not_an_error) {
+			/* This is mainly used by urp.  Solved conflict is not an error.
+			 * And we don't want the supplier to halt sending the updates. */
+			ldap_result_code = LDAP_SUCCESS;
+		}
         slapi_send_ldap_result( pb, ldap_result_code, ldap_result_matcheddn,
                     ldap_result_message, 0,NULL );
     }

ldap/servers/slapd/slapi-plugin.h

@@ -6326,6 +6326,16 @@ time_t slapi_current_time( void );
 #define SLAPI_PLUGIN_EXTENDED_SENT_RESULT	-1
 #define SLAPI_PLUGIN_EXTENDED_NOT_HANDLED	-2
 
+/*
+ * Return values of plugins:
+ */
+#define SLAPI_PLUGIN_SUCCESS  0  /* 0 is treated as success implicitely */
+#define SLAPI_PLUGIN_FAILURE -1  /* common failure */
+#define SLAPI_PLUGIN_NOOP    -2  /* Special in be_pre_op/be_txn_pre_op.
+                                  * Treat as SUCCESS, but skip the backend op.
+                                  * Also, return SUCCESS to the client/supplier.
+                                  * Necessary for the replication conflicts. */
+
 /*
  * the following can be used as the second argument to the
  * slapi_pblock_get() and slapi_pblock_set() calls.