InnoDB: Failing assertion: node->is_open() in fil_space_t::flush_low

--source include/have_innodb.inc

--source include/have_partition.inc

CREATE TABLE t1 (

  pk INT,

  a TEXT,

  b TEXT,

  c TEXT,

  d TEXT,

  PRIMARY KEY(pk),

  FULLTEXT INDEX (a)

) ENGINE=InnoDB;

CREATE TABLE t2 (f INT) ENGINE=InnoDB;

ALTER TABLE t1 ADD FULLTEXT INDEX (b), ADD FULLTEXT INDEX (c);

FLUSH TABLE t1 WITH READ LOCK;

UNLOCK TABLES;

ALTER TABLE t1 ADD FULLTEXT INDEX (d);

ALTER TABLE t1 PARTITION BY HASH(pk) PARTITIONS 13;

FLUSH TABLE t2 WITH READ LOCK;

# Cleanup

UNLOCK TABLES;

DROP TABLE t1, t2;

2020-10-29 00:04:22 0x7ffb2cb08700  InnoDB: Assertion failure in file /data/src/10.5/storage/innobase/fil/fil0fil.cc line 517

InnoDB: Failing assertion: node->is_open()

#5  0x00007ffb3374e859 in __GI_abort () at abort.c:79

#6  0x00005590f1bae1a0 in ut_dbg_assertion_failed (expr=0x5590f231d714 "node->is_open()", file=0x5590f231d4b0 "/data/src/10.5/storage/innobase/fil/fil0fil.cc", line=517) at /data/src/10.5/storage/innobase/ut/ut0dbg.cc:60

#7  0x00005590f1cba900 in fil_space_t::flush_low (this=0x7ffaf0225b48) at /data/src/10.5/storage/innobase/fil/fil0fil.cc:517

#8  0x00005590f1b3514b in fil_space_t::flush (this=0x7ffaf0225b48) at /data/src/10.5/storage/innobase/include/fil0fil.h:1466

#9  0x00005590f1b34520 in row_quiesce_table_start (table=0x7ffaf0205b88, trx=0x7ffb2ddb21e8) at /data/src/10.5/storage/innobase/row/row0quiesce.cc:548

#10 0x00005590f192f638 in ha_innobase::external_lock (this=0x7ffaf005e1d0, thd=0x7ffaf0000db8, lock_type=0) at /data/src/10.5/storage/innobase/handler/ha_innodb.cc:15656

#11 0x00005590f14b04e2 in handler::ha_external_lock (this=0x7ffaf005e1d0, thd=0x7ffaf0000db8, lock_type=0) at /data/src/10.5/sql/handler.cc:6669

#12 0x00005590f15f66d7 in lock_external (thd=0x7ffaf0000db8, tables=0x7ffaf00fa638, count=1) at /data/src/10.5/sql/lock.cc:393

#13 0x00005590f15f637e in mysql_lock_tables (thd=0x7ffaf0000db8, sql_lock=0x7ffaf00fa618, flags=4096) at /data/src/10.5/sql/lock.cc:338

#14 0x00005590f15f6232 in mysql_lock_tables (thd=0x7ffaf0000db8, tables=0x7ffaf00146d0, count=1, flags=4096) at /data/src/10.5/sql/lock.cc:301

#15 0x00005590f1090922 in lock_tables (thd=0x7ffaf0000db8, tables=0x7ffaf0013ff8, count=1, flags=4096) at /data/src/10.5/sql/sql_base.cc:5472

#16 0x00005590f108fda0 in open_and_lock_tables (thd=0x7ffaf0000db8, options=..., tables=0x7ffaf0013ff8, derived=false, flags=4096, prelocking_strategy=0x7ffb2cb06cf0) at /data/src/10.5/sql/sql_base.cc:5183

#17 0x00005590f131f478 in open_and_lock_tables (thd=0x7ffaf0000db8, tables=0x7ffaf0013ff8, derived=false, flags=4096, prelocking_strategy=0x7ffb2cb06cf0) at /data/src/10.5/sql/sql_base.h:276

#18 0x00005590f13205d8 in flush_tables_with_read_lock (thd=0x7ffaf0000db8, all_tables=0x7ffaf0013ff8) at /data/src/10.5/sql/sql_reload.cc:576

#19 0x00005590f113b8cb in mysql_execute_command (thd=0x7ffaf0000db8) at /data/src/10.5/sql/sql_parse.cc:5391

#20 0x00005590f1143dbe in mysql_parse (thd=0x7ffaf0000db8, rawbuf=0x7ffaf0013f20 "FLUSH TABLE t2 WITH READ LOCK", length=29, parser_state=0x7ffb2cb07510, is_com_multi=false, is_next_command=false) at /data/src/10.5/sql/sql_parse.cc:8010

#21 0x00005590f1130112 in dispatch_command (command=COM_QUERY, thd=0x7ffaf0000db8, packet=0x7ffaf0009099 "FLUSH TABLE t2 WITH READ LOCK", packet_length=29, is_com_multi=false, is_next_command=false) at /data/src/10.5/sql/sql_parse.cc:1871

#22 0x00005590f112e906 in do_command (thd=0x7ffaf0000db8) at /data/src/10.5/sql/sql_parse.cc:1352

#23 0x00005590f12dae63 in do_handle_one_connection (connect=0x5590f3f6aae8, put_in_cache=true) at /data/src/10.5/sql/sql_connect.cc:1410

#24 0x00005590f12dabc6 in handle_one_connection (arg=0x5590f3f84568) at /data/src/10.5/sql/sql_connect.cc:1312

#25 0x00005590f183814f in pfs_spawn_thread (arg=0x5590f3f6a728) at /data/src/10.5/storage/perfschema/pfs.cc:2201

#26 0x00007ffb33c77609 in start_thread (arg=<optimized out>) at pthread_create.c:477

#27 0x00007ffb3384b293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

commit 118e258aaac5da75a2ac4556201aaea3688fac67

Author: Marko Mäkelä <marko.makela@mariadb.com>

Date:   Mon Oct 26 16:04:12 2020 +0200

    MDEV-23855: Shrink fil_space_t