MDEV-21951: mariabackup SST fail if data-directory have lost+found directory

To fix this, it is necessary to add an option to exclude the
database with the name "lost+found" from processing (the database
name will be checked by the check_if_skip_database_by_path() or
by the check_if_skip_database() function, and as a result
"lost+found" will be skipped).

In addition, it is necessary to slightly modify the verification
logic in the check_if_skip_database() function.

Also added a new test galera_sst_mariabackup_lost_found.test

extra/mariabackup/xtrabackup.cc

@@ -2371,7 +2371,7 @@ check_if_skip_database(
 	if (databases_exclude_hash &&
 		find_filter_in_hashtable(name, databases_exclude_hash,
 					 &database) &&
-		!database->has_tables) {
+		(!database->has_tables || !databases_include_hash)) {
 		/* Database is found and there are no tables specified,
 		   skip entire db. */
 		return DATABASE_SKIP;

mysql-test/suite/galera/r/galera_sst_mariabackup_lost_found.result

@@ -0,0 +1,37 @@
+connection node_1;
+connection node_2;
+connection node_2;
+Shutting down server ...
+connection node_1;
+CREATE DATABASE `lost+found`;
+USE `lost+found`;
+CREATE TABLE t1(id INT);
+INSERT INTO t1 VALUES (1), (2);
+SELECT * FROM `lost+found`.t1;
+id
+1
+2
+CREATE DATABASE `#mysql50#not_lost+found`;
+USE `#mysql50#not_lost+found`;
+CREATE TABLE t1(id INT);
+INSERT INTO t1 VALUES (1), (2);
+SELECT * FROM `#mysql50#not_lost+found`.t1;
+id
+1
+2
+Cleaning var directory ...
+connection node_2;
+Starting server ...
+SELECT * FROM `lost+found`.t1;
+id
+1
+2
+SELECT * FROM `#mysql50#not_lost+found`.t1;
+id
+1
+2
+connection node_1;
+DROP DATABASE `lost+found`;
+DROP DATABASE `#mysql50#not_lost+found`;
+disconnect node_2;
+disconnect node_1;

mysql-test/suite/galera/t/galera_sst_mariabackup_lost_found.cnf

@@ -0,0 +1,15 @@
+!include ../galera_2nodes.cnf
+
+[mysqld]
+wsrep_sst_method=mariabackup
+wsrep_sst_auth="root:"
+
+[mysqld.1]
+wsrep_provider_options='base_port=@mysqld.1.#galera_port;gcache.size=1;pc.ignore_sb=true'
+
+[mysqld.2]
+wsrep_provider_options='base_port=@mysqld.2.#galera_port;gcache.size=1;pc.ignore_sb=true'
+
+[sst]
+transferfmt=@ENV.MTR_GALERA_TFMT
+streamfmt=xbstream

mysql-test/suite/galera/t/galera_sst_mariabackup_lost_found.test

@@ -0,0 +1,71 @@
+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+--source include/have_mariabackup.inc
+
+# Save original auto_increment_offset values.
+--let $node_1=node_1
+--let $node_2=node_2
+--source include/auto_increment_offset_save.inc
+
+--connection node_2
+
+#--connection node_2
+#--source suite/galera/include/galera_unload_provider.inc
+
+--echo Shutting down server ...
+--source include/shutdown_mysqld.inc
+
+--connection node_1
+--let $wait_condition = SELECT VARIABLE_VALUE = 1 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_size'
+--source include/wait_condition.inc
+
+CREATE DATABASE `lost+found`;
+USE `lost+found`;
+CREATE TABLE t1(id INT);
+INSERT INTO t1 VALUES (1), (2);
+SELECT * FROM `lost+found`.t1;
+
+CREATE DATABASE `#mysql50#not_lost+found`;
+USE `#mysql50#not_lost+found`;
+CREATE TABLE t1(id INT);
+INSERT INTO t1 VALUES (1), (2);
+SELECT * FROM `#mysql50#not_lost+found`.t1;
+
+#
+# Force SST
+#
+--echo Cleaning var directory ...
+--remove_file $MYSQLTEST_VARDIR/mysqld.2/data/grastate.dat
+--remove_files_wildcard $MYSQLTEST_VARDIR/mysqld.2/data/mtr
+--remove_files_wildcard $MYSQLTEST_VARDIR/mysqld.2/data/performance_schema
+--remove_files_wildcard $MYSQLTEST_VARDIR/mysqld.2/data/test
+--remove_files_wildcard $MYSQLTEST_VARDIR/mysqld.2/data/mysql
+--remove_files_wildcard $MYSQLTEST_VARDIR/mysqld.2/data
+
+--connection node_2
+
+--echo Starting server ...
+let $restart_noprint=2;
+--source include/start_mysqld.inc
+
+--let $wait_condition = SELECT VARIABLE_VALUE = 2 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_size';
+--source include/wait_condition.inc
+
+--let $wait_condition = SELECT VARIABLE_VALUE = 'ON' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_ready';
+--source include/wait_condition.inc
+
+SELECT * FROM `lost+found`.t1;
+SELECT * FROM `#mysql50#not_lost+found`.t1;
+
+--connection node_1
+
+DROP DATABASE `lost+found`;
+DROP DATABASE `#mysql50#not_lost+found`;
+
+# rmdir $MYSQLD_DATADIR/lost+found;
+# rmdir $MYSQLD_DATADIR/not_lost+found;
+
+# Restore original auto_increment_offset values.
+--source include/auto_increment_offset_restore.inc
+
+--source include/galera_end.inc

scripts/wsrep_sst_mariabackup.sh

@@ -712,9 +712,11 @@ if ${INNOBACKUPEX_BIN} /tmp --help 2>/dev/null | grep -q -- '--version-check'; t
     disver="--no-version-check"
 fi
 
+iopts+=" --databases-exclude=\"lost+found\""
+
 if [[ ${FORCE_FTWRL:-0} -eq 1 ]];then 
     wsrep_log_info "Forcing FTWRL due to environment variable FORCE_FTWRL equal to $FORCE_FTWRL"
-    iopts+=" --no-backup-locks "
+    iopts+=" --no-backup-locks"
 fi
 
 INNOEXTRA=$WSREP_SST_OPT_MYSQLD