Reduce unnecessary inter-module calls for IMPORT TABLESPACE.
Move some IMPORT-related code from fil0fil.cc to row0import.cc.

PageCallback: Remove. Make AbstractCallback the base class.

PageConverter: Define some member functions inline.

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

With a big buffer pool that contains many data pages,
DISCARD TABLESPACE took a long time, because it would scan the
entire buffer pool to remove any pages that belong to the tablespace.
With a large buffer pool, this would take a lot of time, especially
when the table-to-discard is empty.

The minimum amount of work that DISCARD TABLESPACE must do is to
remove the pages of the to-be-discarded table from the
buf_pool->flush_list because any writes to the data file must be
prevented before the file is deleted.

If DISCARD TABLESPACE does not evict the pages from the buffer pool,
then IMPORT TABLESPACE must do it, because we must prevent pre-DISCARD,
not-yet-evicted pages from being mistaken for pages of the imported
tablespace.

It would not be a useful fix to simply move the buffer pool scan to
the IMPORT TABLESPACE step. What we can do is to actively evict those
pages that could be mistaken for imported pages. In this way, when
importing a small table into a big buffer pool, the import should
still run relatively fast.

Import is bypassing the buffer pool when reading pages for the
adjustment phase. In the adjustment phase, if a page exists in
the buffer pool, we could replace it with the page from the imported
file. Unfortunately I did not get this to work properly, so instead
we will simply evict any matching page from the buffer pool.

buf_page_get_gen(): Implement BUF_EVICT_IF_IN_POOL, a new mode
where the requested page will be evicted if it is found. There
must be no unwritten changes for the page.

buf_remove_t: Remove. Instead, use trx!=NULL to signify that a write
to file is desired, and use a separate parameter bool drop_ahi.

buf_LRU_flush_or_remove_pages(), fil_delete_tablespace():
Replace buf_remove_t.

buf_LRU_remove_pages(), buf_LRU_remove_all_pages(): Remove.

PageConverter::m_mtr: A dummy mini-transaction buffer

PageConverter::PageConverter(): Complete the member initialization list.

PageConverter::operator()(): Evict any 'shadow' pages from the
buffer pool so that pre-existing (garbage) pages cannot be mistaken
for pages that exist in the being-imported file.

row_discard_tablespace(): Remove a bogus comment that seems to
refer to IMPORT TABLESPACE, not DISCARD TABLESPACE.

The ALTER TABLE…IMPORT TABLESPACE adjustment code that was introduced by
WL#5522 in MySQL 5.6 is incorrectly invoking rec_get_status() on a
ROW_FORMAT=REDUNDANT record to determine if a record is a leaf page record.
The function rec_get_status(rec) is only to be called on
ROW_FORMAT=COMPACT, DYNAMIC or COMPRESSED records.

When using innodb_page_size=16k, InnoDB tables
that were created in MariaDB 10.1.0 to 10.1.20 with
PAGE_COMPRESSED=1 and
PAGE_COMPRESSION_LEVEL=2 or PAGE_COMPRESSION_LEVEL=3
would fail to load.

fsp_flags_is_valid(): When using innodb_page_size=16k, use a
more strict check for .ibd files, with the assumption that
nobody would try to use different-page-size files.

dict_table_t::thd: Remove. This was only used by btr_root_block_get()
for reporting decryption failures, and it was only assigned by
ha_innobase::open(), and never cleared. This could mean that if a
connection is closed, the pointer would become stale, and the server
could crash while trying to report the error. It could also mean
that an error is being reported to the wrong client. It is better
to use current_thd in this case, even though it could mean that if
the code is invoked from an InnoDB background operation, there would
be no connection to which to send the error message.

Remove dict_table_t::crypt_data and dict_table_t::page_0_read.
These fields were never read.

fil_open_single_table_tablespace(): Remove the parameter "table".

Do not silence uncertain cases, or fix any bugs.

The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.

Do not silence uncertain cases, or fix any bugs.

The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.

Problem was that bpage was referenced after it was already freed
from LRU. Fixed by adding a new variable encrypted that is
passed down to buf_page_check_corrupt() and used in
buf_page_get_gen() to stop processing page read.

This patch should also address following test failures and
bugs:

MDEV-12419: IMPORT should not look up tablespace in
PageConverter::validate(). This is now removed.

MDEV-10099: encryption.innodb_onlinealter_encryption fails
sporadically in buildbot

MDEV-11420: encryption.innodb_encryption-page-compression
failed in buildbot

MDEV-11222: encryption.encrypt_and_grep failed in buildbot on P8

Removed dict_table_t::is_encrypted and dict_table_t::ibd_file_missing
and replaced these with dict_table_t::file_unreadable. Table
ibd file is missing if fil_get_space(space_id) returns NULL
and encrypted if not. Removed dict_table_t::is_corrupted field.

Ported FilSpace class from 10.2 and using that on buf_page_check_corrupt(),
buf_page_decrypt_after_read(), buf_page_encrypt_before_write(),
buf_dblwr_process(), buf_read_page(), dict_stats_save_defrag_stats().

Added test cases when enrypted page could be read while doing
redo log crash recovery. Also added test case for row compressed
blobs.

btr_cur_open_at_index_side_func(),
btr_cur_open_at_rnd_pos_func(): Avoid referencing block that is
NULL.

buf_page_get_zip(): Issue error if page read fails.

buf_page_get_gen(): Use dberr_t for error detection and
do not reference bpage after we hare freed it.

buf_mark_space_corrupt(): remove bpage from LRU also when
it is encrypted.

buf_page_check_corrupt(): @return DB_SUCCESS if page has
been read and is not corrupted,
DB_PAGE_CORRUPTED if page based on checksum check is corrupted,
DB_DECRYPTION_FAILED if page post encryption checksum matches but
after decryption normal page checksum does not match. In read
case only DB_SUCCESS is possible.

buf_page_io_complete(): use dberr_t for error handling.

buf_flush_write_block_low(),
buf_read_ahead_random(),
buf_read_page_async(),
buf_read_ahead_linear(),
buf_read_ibuf_merge_pages(),
buf_read_recv_pages(),
fil_aio_wait():
        Issue error if page read fails.

btr_pcur_move_to_next_page(): Do not reference page if it is
NULL.

Introduced dict_table_t::is_readable() and dict_index_t::is_readable()
that will return true if tablespace exists and pages read from
tablespace are not corrupted or page decryption failed.
Removed buf_page_t::key_version. After page decryption the
key version is not removed from page frame. For unencrypted
pages, old key_version is removed at buf_page_encrypt_before_write()

dict_stats_update_transient_for_index(),
dict_stats_update_transient()
        Do not continue if table decryption failed or table
        is corrupted.

dict0stats.cc: Introduced a dict_stats_report_error function
to avoid code duplication.

fil_parse_write_crypt_data():
        Check that key read from redo log entry is found from
        encryption plugin and if it is not, refuse to start.

PageConverter::validate(): Removed access to fil_space_t as
tablespace is not available during import.

Fixed error code on innodb.innodb test.

Merged test cased innodb-bad-key-change5 and innodb-bad-key-shutdown
to innodb-bad-key-change2.  Removed innodb-bad-key-change5 test.
Decreased unnecessary complexity on some long lasting tests.

Removed fil_inc_pending_ops(), fil_decr_pending_ops(),
fil_get_first_space(), fil_get_next_space(),
fil_get_first_space_safe(), fil_get_next_space_safe()
functions.

fil_space_verify_crypt_checksum(): Fixed bug found using ASAN
where FIL_PAGE_END_LSN_OLD_CHECKSUM field was incorrectly
accessed from row compressed tables. Fixed out of page frame
bug for row compressed tables in
fil_space_verify_crypt_checksum() found using ASAN. Incorrect
function was called for compressed table.

Added new tests for discard, rename table and drop (we should allow them
even when page decryption fails). Alter table rename is not allowed.
Added test for restart with innodb-force-recovery=1 when page read on
redo-recovery cant be decrypted. Added test for corrupted table where
both page data and FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION is corrupted.

Adjusted the test case innodb_bug14147491 so that it does not anymore
expect crash. Instead table is just mostly not usable.

fil0fil.h: fil_space_acquire_low is not visible function
and fil_space_acquire and fil_space_acquire_silent are
inline functions. FilSpace class uses fil_space_acquire_low
directly.

recv_apply_hashed_log_recs() does not return anything.

This is a reduced version of an originally much larger patch.
We will keep the definition of the ulint, lint data types unchanged,
and we will not be replacing fprintf() calls with ib_logf().

On Windows, use the standard format strings instead of nonstandard
extensions.

This patch fixes some errors in format strings.
Most notably, an IMPORT TABLESPACE error message in InnoDB was
displaying the number of columns instead of the mismatching flags.

compatibility problems

Pages that are encrypted contain post encryption checksum on
different location that normal checksum fields. Therefore,
we should before decryption check this checksum to avoid
unencrypting corrupted pages. After decryption we can use
traditional checksum check to detect if page is corrupted
or unencryption was done using incorrect key.

Pages that are page compressed do not contain any checksum,
here we need to fist unencrypt, decompress and finally
use tradional checksum check to detect page corruption
or that we used incorrect key in unencryption.

buf0buf.cc: buf_page_is_corrupted() mofified so that
compressed pages are skipped.

buf0buf.h, buf_block_init(), buf_page_init_low():
removed unnecessary page_encrypted, page_compressed,
stored_checksum, valculated_checksum fields from
buf_page_t

buf_page_get_gen(): use new buf_page_check_corrupt() function
to detect corrupted pages.

buf_page_check_corrupt(): If page was not yet decrypted
check if post encryption checksum still matches.
If page is not anymore encrypted, use buf_page_is_corrupted()
traditional checksum method.

If page is detected as corrupted and it is not encrypted
we print corruption message to error log.
If page is still encrypted or it was encrypted and now
corrupted, we will print message that page is
encrypted to error log.

buf_page_io_complete(): use new buf_page_check_corrupt()
function to detect corrupted pages.

buf_page_decrypt_after_read(): Verify post encryption
checksum before tring to decrypt.

fil0crypt.cc: fil_encrypt_buf() verify post encryption
checksum and ind fil_space_decrypt() return true
if we really decrypted the page.

fil_space_verify_crypt_checksum(): rewrite to use
the method used when calculating post encryption
checksum. We also check if post encryption checksum
matches that traditional checksum check does not
match.

fil0fil.ic: Add missed page type encrypted and page
compressed to fil_get_page_type_name()

Note that this change does not yet fix innochecksum tool,
that will be done in separate MDEV.

Fix test failures caused by buf page corruption injection.

MariaDB 10.0/MySQL 5.6 using innodb-page-size!=16K

The storage format of FSP_SPACE_FLAGS was accidentally broken
already in MariaDB 10.1.0. This fix is bringing the format in
line with other MySQL and MariaDB release series.

Please refer to the comments that were added to fsp0fsp.h
for details.

This is an INCOMPATIBLE CHANGE that affects users of
page_compression and non-default innodb_page_size. Upgrading
to this release will correct the flags in the data files.
If you want to downgrade to earlier MariaDB 10.1.x, please refer
to the test innodb.101_compatibility how to reset the
FSP_SPACE_FLAGS in the files.

NOTE: MariaDB 10.1.0 to 10.1.20 can misinterpret
uncompressed data files with innodb_page_size=4k or 64k as
compressed innodb_page_size=16k files, and then probably fail
when trying to access the pages. See the comments in the
function fsp_flags_convert_from_101() for detailed analysis.

Move PAGE_COMPRESSION to FSP_SPACE_FLAGS bit position 16.
In this way, compressed innodb_page_size=16k tablespaces will not
be mistaken for uncompressed ones by MariaDB 10.1.0 to 10.1.20.

Derive PAGE_COMPRESSION_LEVEL, ATOMIC_WRITES and DATA_DIR from the
dict_table_t::flags when the table is available, in
fil_space_for_table_exists_in_mem() or fil_open_single_table_tablespace().
During crash recovery, fil_load_single_table_tablespace() will use
innodb_compression_level for the PAGE_COMPRESSION_LEVEL.

FSP_FLAGS_MEM_MASK: A bitmap of the memory-only fil_space_t::flags
that are not to be written to FSP_SPACE_FLAGS. Currently, these will
include PAGE_COMPRESSION_LEVEL, ATOMIC_WRITES and DATA_DIR.

Introduce the macro FSP_FLAGS_PAGE_SSIZE(). We only support
one innodb_page_size for the whole instance.

When creating a dummy tablespace for the redo log, use
fil_space_t::flags=0. The flags are never written to the redo log files.

Remove many FSP_FLAGS_SET_ macros.

dict_tf_verify_flags(): Remove. This is basically only duplicating
the logic of dict_tf_to_fsp_flags(), used in a debug assertion.

fil_space_t::mark: Remove. This flag was not used for anything.

fil_space_for_table_exists_in_mem(): Remove the unnecessary parameter
mark_space, and add a parameter for table flags. Check that
fil_space_t::flags match the table flags, and adjust the (memory-only)
flags based on the table flags.

fil_node_open_file(): Remove some redundant or unreachable conditions,
do not use stderr for output, and avoid unnecessary server aborts.

fil_user_tablespace_restore_page(): Convert the flags, so that the
correct page_size will be used when restoring a page from the
doublewrite buffer.

fil_space_get_page_compressed(), fsp_flags_is_page_compressed(): Remove.
It suffices to have fil_space_is_page_compressed().

FSP_FLAGS_WIDTH_DATA_DIR, FSP_FLAGS_WIDTH_PAGE_COMPRESSION_LEVEL,
FSP_FLAGS_WIDTH_ATOMIC_WRITES: Remove, because these flags do not
exist in the FSP_SPACE_FLAGS but only in memory.

fsp_flags_try_adjust(): New function, to adjust the FSP_SPACE_FLAGS
in page 0. Called by fil_open_single_table_tablespace(),
fil_space_for_table_exists_in_mem(), innobase_start_or_create_for_mysql()
except if --innodb-read-only is active.

fsp_flags_is_valid(ulint): Reimplement from the scratch, with
accurate comments. Do not display any details of detected
inconsistencies, because the output could be confusing when
dealing with MariaDB 10.1.x data files.

fsp_flags_convert_from_101(ulint): Convert flags from buggy
MariaDB 10.1.x format, or return ULINT_UNDEFINED if the flags
cannot be in MariaDB 10.1.x format.

fsp_flags_match(): Check the flags when probing files.
Implemented based on fsp_flags_is_valid()
and fsp_flags_convert_from_101().

dict_check_tablespaces_and_store_max_id(): Do not access the
page after committing the mini-transaction.

IMPORT TABLESPACE fixes:

AbstractCallback::init(): Convert the flags.

FetchIndexRootPages::operator(): Check that the tablespace flags match the
table flags. Do not attempt to convert tablespace flags to table flags,
because the conversion would necessarily be lossy.

PageConverter::update_header(): Write back the correct flags.
This takes care of the flags in IMPORT TABLESPACE.

Add error message when used index_id in index page is not found
from configuration file.

MDEV-8772: Assertion failure in file ha_innodb.cc line 20027 when importing page compressed and encrypted tablespace using incorrect keys

Add error handling to decryp function when decrypt fails during
import.

MDEV-8588: Assertion failure in file ha_innodb.cc line 21140 if at least one encrypted table exists and encryption service is not available

Analysis: Problem was that in fil_read_first_page we do find that
table has encryption information and that encryption service
or used key_id is not available. But, then we just printed
fatal error message that causes above assertion.

Fix: When we open single table tablespace if it has encryption
information (crypt_data) store this crypt data to the table
structure. When we open a table and we find out that tablespace
is not available, check has table a encryption information
and from there is encryption service or used key_id is not available.
If it is, add additional warning for SQL-layer.