MDEV-15249 Crash in MVCC read after IMPORT TABLESPACE

PageConverter::adjust_cluster_record(): Instead of writing
the invalid value DB_ROLL_PTR=0, write a value that indicates
a fresh insert, that is, prevents the DB_ROLL_PTR from being
dereferenced in any circumstances.

It can be argued that IMPORT TABLESPACE should actually
update the dict_index_t::trx_id to prevent older transactions
from accessing the table, similar to what I did on table
rebuild in MySQL 5.6.6 in
https://github.com/mysql/mysql-server/commit/03f81a55f221095d397c375afe8a10c8038da339

mysql-test/suite/innodb/r/mvcc.result

+SET @save_per_table= @@GLOBAL.innodb_file_per_table;
+SET GLOBAL innodb_file_per_table= 1;
+#
+# MDEV-15249 Crash in MVCC read after IMPORT TABLESPACE
+#
+CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;
+INSERT INTO t1 VALUES(0);
+FLUSH TABLES t1 WITH READ LOCK;
+UNLOCK TABLES;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+ALTER TABLE t1 FORCE, ALGORITHM=COPY;
+SELECT * FROM t1;
+ERROR HY000: Table definition has changed, please retry transaction
+COMMIT;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+ALTER TABLE t1 DISCARD TABLESPACE;
+ALTER TABLE t1 IMPORT TABLESPACE;
+# FIXME: Block this with ER_TABLE_DEF_CHANGED
+SELECT * FROM t1;
+a
+COMMIT;
+SELECT * FROM t1;
+a
+0
+DROP TABLE t1;
+SET GLOBAL innodb_file_per_table= @save_per_table;

mysql-test/suite/innodb/t/mvcc.test

+--source include/have_innodb.inc
+
+SET @save_per_table= @@GLOBAL.innodb_file_per_table;
+SET GLOBAL innodb_file_per_table= 1;
+
+let MYSQLD_DATADIR =`SELECT @@datadir`;
+
+--echo #
+--echo # MDEV-15249 Crash in MVCC read after IMPORT TABLESPACE
+--echo #
+
+CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;
+INSERT INTO t1 VALUES(0);
+FLUSH TABLES t1 WITH READ LOCK;
+perl;
+do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
+ib_backup_tablespace("test", "t1");
+EOF
+UNLOCK TABLES;
+
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+
+connect (con1,localhost,root,,);
+ALTER TABLE t1 FORCE, ALGORITHM=COPY;
+
+connection default;
+--error ER_TABLE_DEF_CHANGED
+SELECT * FROM t1;
+COMMIT;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+
+connection con1;
+
+ALTER TABLE t1 DISCARD TABLESPACE;
+
+perl;
+do "$ENV{MTR_SUITE_DIR}/include/innodb-util.pl";
+ib_restore_tablespace("test", "t1");
+EOF
+
+ALTER TABLE t1 IMPORT TABLESPACE;
+disconnect con1;
+
+connection default;
+--echo # FIXME: Block this with ER_TABLE_DEF_CHANGED
+SELECT * FROM t1;
+COMMIT;
+SELECT * FROM t1;
+
+DROP TABLE t1;
+
+SET GLOBAL innodb_file_per_table= @save_per_table;

storage/innobase/include/row0upd.h

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -119,8 +120,7 @@ row_upd_rec_sys_fields(
 	dict_index_t*	index,	/*!< in: clustered index */
 	const ulint*	offsets,/*!< in: rec_get_offsets(rec, index) */
 	const trx_t*	trx,	/*!< in: transaction */
-	roll_ptr_t	roll_ptr);/*!< in: roll ptr of the undo log record,
-				  can be 0 during IMPORT */
+	roll_ptr_t	roll_ptr);/*!< in: DB_ROLL_PTR to the undo log */
 /*********************************************************************//**
 Sets the trx id or roll ptr field of a clustered index entry. */
 UNIV_INTERN

storage/innobase/include/row0upd.ic

 /*****************************************************************************
 
 Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -153,8 +154,7 @@ row_upd_rec_sys_fields(
 	dict_index_t*	index,	/*!< in: clustered index */
 	const ulint*	offsets,/*!< in: rec_get_offsets(rec, index) */
 	const trx_t*	trx,	/*!< in: transaction */
-	roll_ptr_t	roll_ptr)/*!< in: roll ptr of the undo log record,
-				 can be 0 during IMPORT */
+	roll_ptr_t	roll_ptr)/*!< in: DB_ROLL_PTR to the undo log */
 {
 	ut_ad(dict_index_is_clust(index));
 	ut_ad(rec_offs_validate(rec, index, offsets));

storage/innobase/row/row0import.cc

@@ -1798,7 +1798,7 @@ PageConverter::adjust_cluster_record(
 
 		row_upd_rec_sys_fields(
 			rec, m_page_zip_ptr, m_cluster_index, m_offsets,
-			m_trx, 0);
+			m_trx, roll_ptr_t(1) << 55);
 	}
 
 	return(err);

storage/xtradb/include/row0upd.h

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -119,8 +120,7 @@ row_upd_rec_sys_fields(
 	dict_index_t*	index,	/*!< in: clustered index */
 	const ulint*	offsets,/*!< in: rec_get_offsets(rec, index) */
 	const trx_t*	trx,	/*!< in: transaction */
-	roll_ptr_t	roll_ptr);/*!< in: roll ptr of the undo log record,
-				  can be 0 during IMPORT */
+	roll_ptr_t	roll_ptr);/*!< in: DB_ROLL_PTR to the undo log */
 /*********************************************************************//**
 Sets the trx id or roll ptr field of a clustered index entry. */
 UNIV_INTERN

storage/xtradb/include/row0upd.ic

 /*****************************************************************************
 
 Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -153,8 +154,7 @@ row_upd_rec_sys_fields(
 	dict_index_t*	index,	/*!< in: clustered index */
 	const ulint*	offsets,/*!< in: rec_get_offsets(rec, index) */
 	const trx_t*	trx,	/*!< in: transaction */
-	roll_ptr_t	roll_ptr)/*!< in: roll ptr of the undo log record,
-				 can be 0 during IMPORT */
+	roll_ptr_t	roll_ptr)/*!< in: DB_ROLL_PTR to the undo log */
 {
 	ut_ad(dict_index_is_clust(index));
 	ut_ad(rec_offs_validate(rec, index, offsets));

storage/xtradb/row/row0import.cc

@@ -1798,7 +1798,7 @@ PageConverter::adjust_cluster_record(
 
 		row_upd_rec_sys_fields(
 			rec, m_page_zip_ptr, m_cluster_index, m_offsets,
-			m_trx, 0);
+			m_trx, roll_ptr_t(1) << 55);
 	}
 
 	return(err);