Do not include base64.h, it was recently removed.

MDEV-11581: Mariadb starts InnoDB encryption threads
when key has not changed or data scrubbing turned off

Background: Key rotation is based on background threads
(innodb-encryption-threads) periodically going through
all tablespaces on fil_system. For each tablespace
current used key version is compared to max key age
(innodb-encryption-rotate-key-age). This process
naturally takes CPU. Similarly, in same time need for
scrubbing is investigated. Currently, key rotation
is fully supported on Amazon AWS key management plugin
only but InnoDB does not have knowledge what key
management plugin is used.

This patch re-purposes innodb-encryption-rotate-key-age=0
to disable key rotation and background data scrubbing.
All new tables are added to special list for key rotation
and key rotation is based on sending a event to
background encryption threads instead of using periodic
checking (i.e. timeout).

fil0fil.cc: Added functions fil_space_acquire_low()
to acquire a tablespace when it could be dropped concurrently.
This function is used from fil_space_acquire() or
fil_space_acquire_silent() that will not print
any messages if we try to acquire space that does not exist.
fil_space_release() to release a acquired tablespace.
fil_space_next() to iterate tablespaces in fil_system
using fil_space_acquire() and fil_space_release().
Similarly, fil_space_keyrotation_next() to iterate new
list fil_system->rotation_list where new tables.
are added if key rotation is disabled.
Removed unnecessary functions fil_get_first_space_safe()
fil_get_next_space_safe()

fil_node_open_file(): After page 0 is read read also
crypt_info if it is not yet read.

btr_scrub_lock_dict_func()
buf_page_check_corrupt()
buf_page_encrypt_before_write()
buf_merge_or_delete_for_page()
lock_print_info_all_transactions()
row_fts_psort_info_init()
row_truncate_table_for_mysql()
row_drop_table_for_mysql()
    Use fil_space_acquire()/release() to access fil_space_t.

buf_page_decrypt_after_read():
    Use fil_space_get_crypt_data() because at this point
    we might not yet have read page 0.

fil0crypt.cc/fil0fil.h: Lot of changes. Pass fil_space_t* directly
to functions needing it and store fil_space_t* to rotation state.
Use fil_space_acquire()/release() when iterating tablespaces
and removed unnecessary is_closing from fil_crypt_t. Use
fil_space_t::is_stopping() to detect when access to
tablespace should be stopped. Removed unnecessary
fil_space_get_crypt_data().

fil_space_create(): Inform key rotation that there could
be something to do if key rotation is disabled and new
table with encryption enabled is created.
Remove unnecessary functions fil_get_first_space_safe()
and fil_get_next_space_safe(). fil_space_acquire()
and fil_space_release() are used instead. Moved
fil_space_get_crypt_data() and fil_space_set_crypt_data()
to fil0crypt.cc.

fsp_header_init(): Acquire fil_space_t*, write crypt_data
and release space.

check_table_options()
	Renamed FIL_SPACE_ENCRYPTION_* TO FIL_ENCRYPTION_*

i_s.cc: Added ROTATING_OR_FLUSHING field to
information_schema.innodb_tablespace_encryption
to show current status of key rotation.

assert that strmov() cannot be used on overlapping strings.
(because strpcpy cannot)

various ed25519/ref10 api simplifications for our specific use case

ED25519 authentication plugin

* define MYSQL_DYNAMIC_PLUGIN only for server plugins
* don't typedef my_bool in mysql.h if plugin.h has already done it
* fix the include guard in plugin.h

so that auth plugins could use various thd services

move most of the code into my_sha.ic, making it independent
from the actual SHAx variant.

just as sql_plugin.cc does

because FLUSH STATUS does not reset them, so their values
are affected by previously run tests since the last server restart.

MDEV-11942 BLACKHOLE is no longer active in 10.1 by default, mysql_upgrade not handling the situation

fix the patch. add tests

Try harder to show the table's engine.

If the table's engine is not loaded, the table won't open.
But we can still read the engine name from frm as a string.

Make SELECT <columns> FROM I_S.TABLES behave identically independently
from whether <columns> require opening the table in engine or
<columns> can be filled with only opening the frm.

In particular, fill_schema_table_from_frm() should not silently skip
frms with unknown engine, but should fill the I_S.TABLES row
with NULLs just like fill_schema_table_by_open() does.

this simplifies the code and avoids unnecessary conversions back and forth.
and it works even if the engine is not installed.

this fixes the crash of innodb.innodb-blob --ps-protocol

has_no_default_value() should only fail the insert in the strict mode.

Additionally, don't check for "all fields are given values" twice,
it'll produce duplicate warnings.

In the 10.1 InnoDB Plugin, a call os_event_free(buf_flush_event) was
misplaced. The event could be signalled by rollback of resurrected
transactions while shutdown was in progress. This bug was caught
by cmake -DWITH_ASAN testing. This call was only present in the
10.1 InnoDB Plugin, not in other versions, or in XtraDB.

That said, the bug affects all InnoDB versions. Shutdown assumes the
cessation of any page-dirtying activity, including the activity of
the background rollback thread. InnoDB only waited for the background
rollback to finish as part of a slow shutdown (innodb_fast_shutdown=0).
The default is a clean shutdown (innodb_fast_shutdown=1). In a scenario
where InnoDB is killed, restarted, and shut down soon enough, the data
files could become corrupted.

logs_empty_and_mark_files_at_shutdown(): Wait for the
rollback to finish, except if innodb_fast_shutdown=2
(crash-like shutdown) was requested.

trx_rollback_or_clean_recovered(): Before choosing the next
recovered transaction to roll back, terminate early if non-slow
shutdown was initiated. Roll back everything on slow shutdown
(innodb_fast_shutdown=0).

srv_innodb_monitor_mutex: Declare as static, because the mutex
is only used within one module.

After each call to os_event_free(), ensure that the freed event
is not reachable via global variables, by setting the relevant
variables to NULL.

If openat is present on the system and it tries to open a symlink with
O_NOFOLLOW, we get errno 40.

If openat is not present on the system, we use the alternative open call, with
slightly different logic. IF the symlink doesn't point to a valid file,
we get errno 20. This test uses an invalid symlink on the table t1.MYD.