MDEV-25265: ALTER TABLE...IMPORT TABLESPACE fails after DROP INDEX

A side effect of the MDEV-24589 bug fix is that if
FLUSH TABLE...FOR EXPORT is initiated before the history of an
earlier DROP INDEX operation has been purged, then the data file
will contain allocated pages that belonged to the dropped indexes.
These pages would never be freed after a subsequent IMPORT TABLESPACE.

We will work around this regression by making IMPORT TABLESPACE
tolerate pages that refer to an unknown index.

6 files changed, 30 insertions, 17 deletions

diff --git a/mysql-test/suite/innodb/r/innodb-wl5522-debug.result b/mysql-test/suite/innodb/r/innodb-wl5522-debug.result
index 8e255e18bec..1030fbd0502 100644
--- a/mysql-test/suite/innodb/r/innodb-wl5522-debug.result
+++ b/mysql-test/suite/innodb/r/innodb-wl5522-debug.result
@@ -8,6 +8,7 @@ call mtr.add_suppression("InnoDB: Cannot calculate statistics for table .*");
 call mtr.add_suppression("InnoDB: Page 0 at offset 0 looks corrupted in file");
 call mtr.add_suppression("InnoDB: Page for tablespace ");
 call mtr.add_suppression("InnoDB: Invalid FSP_SPACE_FLAGS=");
+call mtr.add_suppression("InnoDB: Unknown index id .* on page");
 FLUSH TABLES;
 SET GLOBAL innodb_file_per_table = 1;
 CREATE TABLE t1 (c1 INT) ENGINE = InnoDB;
diff --git a/mysql-test/suite/innodb/t/innodb-alter.test b/mysql-test/suite/innodb/t/innodb-alter.test
index f72935ebc3c..536bf4bff26 100644
--- a/mysql-test/suite/innodb/t/innodb-alter.test
+++ b/mysql-test/suite/innodb/t/innodb-alter.test
@@ -583,10 +583,14 @@ DROP TABLE t1, parent;
 --echo #BUG#21514135 SCHEMA MISMATCH ERROR WHEN IMPORTING TABLESPACE AFTER
 --echo #DROPPING AN INDEX
 --echo #
+
+--disable_query_log
+call mtr.add_suppression("\\[Warning\\] InnoDB: Unknown index id .* on page");
+--enable_query_log
+
 let $source_db = source_db;
 let $dest_db = dest_db;
 
---source include/default_charset.inc
 SET NAMES utf8mb4;
 
 eval CREATE DATABASE $source_db;
diff --git a/mysql-test/suite/innodb/t/innodb-wl5522-debug.test b/mysql-test/suite/innodb/t/innodb-wl5522-debug.test
index 07c2adeb550..a22afc041b0 100644
--- a/mysql-test/suite/innodb/t/innodb-wl5522-debug.test
+++ b/mysql-test/suite/innodb/t/innodb-wl5522-debug.test
@@ -28,6 +28,7 @@ call mtr.add_suppression("InnoDB: Cannot calculate statistics for table .*");
 call mtr.add_suppression("InnoDB: Page 0 at offset 0 looks corrupted in file");
 call mtr.add_suppression("InnoDB: Page for tablespace ");
 call mtr.add_suppression("InnoDB: Invalid FSP_SPACE_FLAGS=");
+call mtr.add_suppression("InnoDB: Unknown index id .* on page");
 FLUSH TABLES;
 
 let MYSQLD_DATADIR =`SELECT @@datadir`;
diff --git a/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result b/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result
index 15227e9d6d3..fccee685caf 100644
--- a/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result
+++ b/mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result
@@ -3,6 +3,12 @@ call mtr.add_suppression("InnoDB: Cannot calculate statistics for table .* becau
 call mtr.add_suppression("InnoDB: Page 0 at offset 0 looks corrupted in file");
 call mtr.add_suppression("InnoDB: Page for tablespace ");
 call mtr.add_suppression("InnoDB: Invalid FSP_SPACE_FLAGS=0x");
+call mtr.add_suppression("InnoDB: Unknown index id .* on page");
+call mtr.add_suppression("InnoDB: Operating system error number");
+call mtr.add_suppression("InnoDB: The error means");
+call mtr.add_suppression("InnoDB: If you are installing InnoDB");
+call mtr.add_suppression("InnoDB: Cannot open datafile .*t1\\.ibd");
+call mtr.add_suppression("InnoDB: Ignoring tablespace for `test`\\.`t1`");
 FLUSH TABLES;
 SET SESSION innodb_strict_mode=1;
 CREATE TABLE t1 (c1 INT) ENGINE = Innodb
diff --git a/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test b/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test
index 9529045785f..282469f0a0c 100644
--- a/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test
+++ b/mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test
@@ -19,6 +19,12 @@ call mtr.add_suppression("InnoDB: Cannot calculate statistics for table .* becau
 call mtr.add_suppression("InnoDB: Page 0 at offset 0 looks corrupted in file");
 call mtr.add_suppression("InnoDB: Page for tablespace ");
 call mtr.add_suppression("InnoDB: Invalid FSP_SPACE_FLAGS=0x");
+call mtr.add_suppression("InnoDB: Unknown index id .* on page");
+call mtr.add_suppression("InnoDB: Operating system error number");
+call mtr.add_suppression("InnoDB: The error means");
+call mtr.add_suppression("InnoDB: If you are installing InnoDB");
+call mtr.add_suppression("InnoDB: Cannot open datafile .*t1\\.ibd");
+call mtr.add_suppression("InnoDB: Ignoring tablespace for `test`\\.`t1`");
 FLUSH TABLES;
 
 let MYSQLD_DATADIR =`SELECT @@datadir`;
diff --git a/storage/innobase/row/row0import.cc b/storage/innobase/row/row0import.cc
index 8376fbb4ba6..ea961823354 100644
--- a/storage/innobase/row/row0import.cc
+++ b/storage/innobase/row/row0import.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2012, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2020, MariaDB Corporation.
+Copyright (c) 2015, 2021, 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
@@ -1880,38 +1880,33 @@ dberr_t
 PageConverter::update_index_page(
 	buf_block_t*	block) UNIV_NOTHROW
 {
-	index_id_t	id;
-	buf_frame_t*	page = block->frame;
 	const page_id_t page_id(block->page.id());
 
 	if (is_free(page_id.page_no())) {
 		return(DB_SUCCESS);
-	} else if ((id = btr_page_get_index_id(page)) != m_index->m_id) {
+	}
+
+	buf_frame_t* page = block->frame;
+	const index_id_t id = btr_page_get_index_id(page);
 
-		row_index_t*	index = find_index(id);
+	if (id != m_index->m_id) {
+		row_index_t* index = find_index(id);
 
 		if (UNIV_UNLIKELY(!index)) {
-			ib::error() << "Page for tablespace " << m_space
-				<< " is index page with id " << id
-				<< " but that index is not found from"
-				<< " configuration file. Current index name "
-				<< m_index->m_name << " and id " <<  m_index->m_id;
-			m_index = 0;
-			return(DB_CORRUPTION);
+			ib::warn() << "Unknown index id " << id
+				   << " on page " << page_id.page_no();
+			return DB_SUCCESS;
 		}
 
-		/* Update current index */
 		m_index = index;
 	}
 
 	/* If the .cfg file is missing and there is an index mismatch
 	then ignore the error. */
-	if (m_cfg->m_missing && (m_index == 0 || m_index->m_srv_index == 0)) {
+	if (m_cfg->m_missing && !m_index->m_srv_index) {
 		return(DB_SUCCESS);
 	}
 
-
-
 	if (m_index && page_id.page_no() == m_index->m_page_no) {
 		byte *b = FIL_PAGE_DATA + PAGE_BTR_SEG_LEAF + FSEG_HDR_SPACE
 			+ page;