MDEV-21398 Deadlock (server hang) or assertion failure in
Diagnostics_area::set_error_status upon ALTER under lock

This failure could only happen if one locked the same table
multiple times and then did an ALTER TABLE on the table.

Major change is to change all instances of
table->m_needs_reopen= true;
to
table->mark_table_for_reopen();

The main fix for the problem was to ensure that we mark all
instances of the table in the locked_table_list and when we
reopen the tables, we first close all tables before reopening
and locking them.

Other things:
- Don't call thd->locked_tables_list.reopen_tables if there
  are no tables marked for reopen. (performance)

MDEV-22111 ERROR 1064 & 1033 and SIGSEGV on CREATE TABLE w/ various charsets on 10.4/5 optimized builds | Assertion `(uint) (table_check_constraints - share->check_constraints) == (uint) (share->table_check_constraints - share->field_check_constraints)' failed

Additional 10.2 specific tests (with JSON)

MDEV-22111 ERROR 1064 & 1033 and SIGSEGV on CREATE TABLE w/ various charsets on 10.4/5 optimized builds | Assertion `(uint) (table_check_constraints - share->check_constraints) == (uint) (share->table_check_constraints - share->field_check_constraints)' failed

The code incorrectly assumed in multiple places that TYPELIB
values cannot have 0x00 bytes inside. In fact they can:

  CREATE TABLE t1 (a ENUM(0x61, 0x0062) CHARACTER SET BINARY);

Note, the TYPELIB value encoding used in FRM is ambiguous about 0x00.

So this fix is partial.

It fixes 0x00 bytes in many (but not all) places:

- In the middle or in the end of a value:
    CREATE TABLE t1 (a ENUM(0x6100) ...);
    CREATE TABLE t1 (a ENUM(0x610062) ...);

- In the beginning of the first value:
    CREATE TABLE t1 (a ENUM(0x0061));
    CREATE TABLE t1 (a ENUM(0x0061), b ENUM('b'));

- In the beginning of the second (and following) value of the *last* ENUM/SET
  in the table:

    CREATE TABLE t1 (a ENUM('a',0x0061));
    CREATE TABLE t1 (a ENUM('a'), b ENUM('b',0x0061));

However, it does not fix 0x00 when:

- 0x00 byte is in the beginning of a value of a non-last ENUM/SET
  causes an error:

   CREATE TABLE t1 (a ENUM('a',0x0061), b ENUM('b'));
   ERROR 1033 (HY000): Incorrect information in file: './test/t1.frm'

  This is an ambuguous case and will be fixed separately.
  We need a new TYPELIB encoding to fix this.

Details:

- unireg.cc

  The function pack_header() incorrectly used strlen() to detect
  a TYPELIB value length. Adding a new function typelib_values_packed_length()
  which uses TYPELIB::type_lengths[n] to detect the n-th value length,
  and reusing the new function in pack_header() and packed_fields_length()

- table.cc
  fix_type_pointers() assumed in multiple places that values cannot have
  0x00 inside and used strlen(TYPELIB::type_names[n]) to set
  the corresponding TYPELIB::type_lengths[n].

  Also, fix_type_pointers() did not check the encoded data for consistency.

  Rewriting fix_type_pointers() code to populate TYPELIB::type_names[n] and
  TYPELIB::type_lengths[n] at the same time, so no additional loop
  with strlen() is needed any more.

  Adding many data consistency tests.

  Fixing the main loop in fix_type_pointers() to use memchr() instead of
  strchr() to handle 0x00 properly.

  Fixing create_key_infos() to return the result in a LEX_STRING rather
  that in a char*.

MDEV-22451: SIGSEGV in __memmove_avx_unaligned_erms/memcpy from _my_b_write on CREATE after RESET MASTER

Merge branch '10.1' into 10.2

ins_node_create_entry_list(): Create dummy empty tuples for
corrupted or incomplete indexes, to avoid dereferencing a NULL
dict_field_t::col pointer in row_build_index_entry_low().

This issue was found by a crash in the test gcol.innodb_virtual_basic
when merging the fix to 10.5.

MDEV-22451: SIGSEGV in __memmove_avx_unaligned_erms/memcpy from _my_b_write on CREATE after RESET MASTER

Analysis:
========
RESET MASTER TO # command deletes all binary log files listed in the index
file, resets the binary log index file to be empty, and creates a new binary
log with number #. When the user provided binary log number is greater than
the max allowed value '2147483647' server fails to generate a new binary log.
The RESET MASTER statement marks the binlog closure status as
'LOG_CLOSE_TO_BE_OPENED' and exits. Statements which follow RESET MASTER
try to write to binary log they find the log_state != LOG_CLOSED and
proceed to write to binary log cache and it results in crash.

Fix:
===
During MYSQL_BIN_LOG open, if generation of new binary log name fails then the
"log_state" needs to be marked as "LOG_CLOSED". With this further statements
will find binary log as closed and they will skip writing to the binary log.

prepare_inplace_alter_table_dict(): In the error handling, relax
a debug assertion for the case that we did not execute
dict_stats_wait_bg_to_stop_using_table() yet.

For no good reason, innodb_encryption_threads was limited to
4,294,967,295. Expectedly, the server would crash if such an
insane value was specified. Let us limit the maximum to 255.

The encryption threads are not doing much useful work.
They are basically only dirtying pages by performing
dummy writes via the redo log. The encryption key rotation
or the in-place addition or removal of encryption
will take place in the page cleaner.

In a quick test on a 20-core CPU (40 threads in total),
the sweet spot on an otherwise idle server seemed to be
innodb_encryption_threads=16 for the test
encryption.encrypt_and_grep. The new limit 255 should be
more than enough for even bigger servers.

fts_indexes field in fts_update_t never used. So replace fts_update_t
with doc_id_t in the code

MDEV-18838 : galera.galera_toi_truncate: Test failure: mysqltest: query 'reap' succeeded - should have failed with errno 1213

Test cleanup.

This is a new test from upstream that did not expect the correct value
of the command slot of the Dump thread when the latter gets killed.

The test is made to expect "Killed" string as the command
in show-processlist as it is supposed to when a thread gets killed.

dict_index_remove_from_cache_low(): Add a missing #ifdef around
dict_index_t::freed().

This is a regression due to MDEV-16376
commit 8dc70c86.
To make dict_index_t::detach_columns() idempotent,
we cleared dict_index_t::n_fields. But, this could
cause trouble with purge after a secondary index
creation failed (not even involving virtual columns).

A better way is to clear the dict_field_t::col pointers
that point to virtual columns that are being freed
due to aborting index creation on an index that depends
on a virtual column.

Note: the v_cols[] of an existing dict_table_t object will
never be modified. If any virtual columns are added or removed,
ha_innobase::commit_inplace_alter_table() would invoke
dict_table_remove_from_cache() and reload the table to dict_sys.
Index creation is a special case where the dict_index_t points
to virtual columns that do not yet exist in dict_table_t.

Removing a wrong DBUG_ASSERT:
When Item_param gets "unfixed" in cleanup(), its "fixed" gets assigned
to false, while item_item keeps the value. So the assert was wrong.

Perhaps, instead of removing the assert, it was possible to reset
item_type to NO_VALUE in cleanup. But this is not very important:
it's implemented in 10.4 in a better way:
Item_param::is_fixed() always returns true and it does not need to be "unfixed".

error is logged

The fix is to set flag in ib::error::~error() and check it in
mariabackup.

ib::error::error() is replaced with ib::warn::warn() in
AIO::linux_create_io_ctx() because of two reasons:

1) if we leave it as is, then mariabackup MTR tests will fail with --mem
option, because Linux AIO can not be used on tmpfs,

2) when Linux AIO can not be initialized, InnoDB falls back to simulated
AIO, so such sutiation is not fatal error, it should be treated as warning.

lock_table_locks_lookup(): Relax the assertion.
Locks must not exist while online secondary index creation is
in progress. However, if CREATE UNIQUE INDEX has not been committed
yet, but the index creation has been completed, concurrent DML
transactions may acquire record locks on the index. Furthermore,
such concurrent DML may cause duplicate key violation, causing
the DDL operation to be rolled back. After that, the online_status
may be ONLINE_INDEX_ABORTED or ONLINE_INDEX_ABORTED_DROPPED.

So, the debug assertion may only forbid the state ONLINE_INDEX_CREATION.

MDEV-18457 Assertion `(bitmap->map +
           (bitmap->full_head_size/6*6)) <= full_head_end failed

The problem was that full_head_size was not calculated correctly
in the case when insert_order was inforced, which is the case
for SHOW commands.

The assert was caused by early cleanup of a user variable participant
in BINLOG @var,@var where it plays twice. That was unexpected by the base
code to clear its value prematurely.

Fixed with relocating the user var destruction after operations with
its value is over.

In commit ad6171b9 (MDEV-22456)
we removed the acquisition of the adaptive hash index latch
from the caller of btr_search_update_hash_ref().
The tests innodb.innodb_buffer_pool_resize_with_chunks
and innodb.innodb_buffer_pool_resize
would occasionally fail starting with 10.3,
due to MDEV-12288 causing more purge activity during the test.

btr_search_update_hash_ref(): After acquiring the adaptive hash index
latch, check that the adaptive hash index is still enabled on the page.

The problem is caused by the operation of netcat streamer and does
not appear on systems where socat is installed. We need to add the
"-N" option for netcat to call shutdown() on the socket when receiving
EOF from STDIN.

Localhost, depending on the platform can return any
127.0.0.1/8 address.

Also clean away dead code that is not used and will never have any use
on the 10.2 branch.

There is a 4 MB hard limit on Travis-CI and build output needs to be less
than that. Silencing the 'make install' step gets rid of a lot of
"Installing.." and "Missing.." and removing all mysql-test files will
make the dh_missing warnings much shorter.

Cherry-picked from 41952c85.

Backported from 30b44aae.

Also, adding 10.2 related changes for MDEV-22579

In commit b1742a5c we forgot
FLUSH TABLES, potentially causing errors for MyISAM system tables.

The rw_lock_stats were incorrectly updated.
While global statistics have limited usefulness, we cannot
remove them from a GA version. This contribution is slightly
improving performance in write workloads.

The code erroneously allowed both:
INSERT INTO t1 (vcol) VALUES (DEFAULT);
INSERT INTO t1 (vcol) VALUES (DEFAULT(non_virtual_column));

The former is OK, but the latter is not.
Adding a new virtual method in Item:

virtual bool vcol_assignment_allowed_value() const { return false; }

Item_null, Item_param and Item_default_value override it.

Item_default_value overrides it in the way to:
- allow DEFAULT
- disallow DEFAULT(col)