MDEV-12548 Initial implementation of Mariabackup for MariaDB 10.2

InnoDB I/O and buffer pool interfaces and the redo log format
have been changed between MariaDB 10.1 and 10.2, and the backup
code has to be adjusted accordingly.

The code has been simplified, and many memory leaks have been fixed.
Instead of the file name xtrabackup_logfile, the file name ib_logfile0
is being used for the copy of the redo log. Unnecessary InnoDB startup and
shutdown and some unnecessary threads have been removed.

Some help was provided by Vladislav Vaintroub.

Parameters have been cleaned up and aligned with those of MariaDB 10.2.

The --dbug option has been added, so that in debug builds,
--dbug=d,ib_log can be specified to enable diagnostic messages
for processing redo log entries.

By default, innodb_doublewrite=OFF, so that --prepare works faster.
If more crash-safety for --prepare is needed, double buffering
can be enabled.

The parameter innodb_log_checksums=OFF can be used to ignore redo log
checksums in --backup.

Some messages have been cleaned up.
Unless --export is specified, Mariabackup will not deal with undo log.
The InnoDB mini-transaction redo log is not only about user-level
transactions; it is actually about mini-transactions. To avoid confusion,
call it the redo log, not transaction log.

We disable any undo log processing in --prepare.

Because MariaDB 10.2 supports indexed virtual columns, the
undo log processing would need to be able to evaluate virtual column
expressions. To reduce the amount of code dependencies, we will not
process any undo log in prepare.

This means that the --export option must be disabled for now.

This also means that the following options are redundant
and have been removed:
	xtrabackup --apply-log-only
	innobackupex --redo-only

In addition to disabling any undo log processing, we will disable any
further changes to data pages during --prepare, including the change
buffer merge. This means that restoring incremental backups should
reliably work even when change buffering is being used on the server.
Because of this, preparing a backup will not generate any further
redo log, and the redo log file can be safely deleted. (If the
--export option is enabled in the future, it must generate redo log
when processing undo logs and buffered changes.)

In --prepare, we cannot easily know if a partial backup was used,
especially when restoring a series of incremental backups. So, we
simply warn about any missing files, and ignore the redo log for them.

FIXME: Enable the --export option.

FIXME: Improve the handling of the MLOG_INDEX_LOAD record, and write
a test that initiates a backup while an ALGORITHM=INPLACE operation
is creating indexes or rebuilding a table. An error should be detected
when preparing the backup.

FIXME: In --incremental --prepare, xtrabackup_apply_delta() should
ensure that if FSP_SIZE is modified, the file size will be adjusted
accordingly.

1 files changed, 10 insertions, 40 deletions

diff --git a/extra/mariabackup/xtrabackup.h b/extra/mariabackup/xtrabackup.h
index eafc848fd43..b883194ef86 100644
--- a/extra/mariabackup/xtrabackup.h
+++ b/extra/mariabackup/xtrabackup.h
@@ -26,26 +26,14 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 #include "xbstream.h"
 #include "changed_page_bitmap.h"
 
-#ifdef __WIN__
-#define XB_FILE_UNDEFINED INVALID_HANDLE_VALUE
-#else
-#define XB_FILE_UNDEFINED (-1)
-#endif
+struct xb_delta_info_t
+{
+	xb_delta_info_t(page_size_t page_size, ulint space_id)
+	: page_size(page_size), space_id(space_id) {}
 
-typedef struct {
-	ulint	page_size;
-	ulint	zip_size;
-	ulint	space_id;
-} xb_delta_info_t;
-
-/* ======== Datafiles iterator ======== */
-typedef struct {
-	fil_system_t	*system;
-	fil_space_t	*space;
-	fil_node_t	*node;
-	ibool		started;
-	os_ib_mutex_t	mutex;
-} datafiles_iter_t;
+	page_size_t	page_size;
+	ulint		space_id;
+};
 
 /* value of the --incremental option */
 extern lsn_t incremental_lsn;
@@ -84,15 +72,11 @@ extern ibool		xtrabackup_compress;
 
 extern my_bool		xtrabackup_backup;
 extern my_bool		xtrabackup_prepare;
-extern my_bool		xtrabackup_apply_log_only;
 extern my_bool		xtrabackup_copy_back;
 extern my_bool		xtrabackup_move_back;
 extern my_bool		xtrabackup_decrypt_decompress;
 
 extern char		*innobase_data_file_path;
-extern char		*innobase_doublewrite_file;
-extern longlong		innobase_log_file_size;
-extern long		innobase_log_files_in_group;
 extern longlong		innobase_page_size;
 
 extern int		xtrabackup_parallel;
@@ -108,9 +92,7 @@ extern "C"{
 }
 #endif
 extern my_bool		xtrabackup_export;
-extern char		*xtrabackup_incremental_basedir;
 extern char		*xtrabackup_extra_lsndir;
-extern char		*xtrabackup_incremental_dir;
 extern ulint		xtrabackup_log_copy_interval;
 extern char		*xtrabackup_stream_str;
 extern long		xtrabackup_throttle;
@@ -166,14 +148,9 @@ void xtrabackup_io_throttling(void);
 my_bool xb_write_delta_metadata(const char *filename,
 				const xb_delta_info_t *info);
 
-datafiles_iter_t *datafiles_iter_new(fil_system_t *f_system);
-fil_node_t *datafiles_iter_next(datafiles_iter_t *it);
-void datafiles_iter_free(datafiles_iter_t *it);
-
-/***********************************************************************
-Reads the space flags from a given data file and returns the compressed
-page size, or 0 if the space is not compressed. */
-ulint xb_get_zip_size(pfs_os_file_t file);
+/** @return the tablespace flags from a given data file
+@retval	ULINT_UNDEFINED	if the file is not readable */
+ulint xb_get_space_flags(pfs_os_file_t file);
 
 /************************************************************************
 Checks if a table specified as a name in the form "database/name" (InnoDB 5.6)
@@ -204,17 +181,10 @@ bool
 check_if_param_set(const char *param);
 
 #if defined(HAVE_OPENSSL)
-extern my_bool opt_use_ssl;
 extern my_bool opt_ssl_verify_server_cert;
-#if !defined(HAVE_YASSL)
-extern char *opt_server_public_key;
-#endif
 #endif
 
 
-void
-xtrabackup_backup_func(void);
-
 my_bool
 xb_get_one_option(int optid,
 		  const struct my_option *opt __attribute__((unused)),