Adding upstream version 1:10.11.6.upstream/1%10.11.6

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1040 insertions, 0 deletions

diff --git a/extra/mariabackup/changed_page_bitmap.cc b/extra/mariabackup/changed_page_bitmap.cc
new file mode 100644
index 00000000..39a07a25
--- /dev/null
+++ b/extra/mariabackup/changed_page_bitmap.cc
@@ -0,0 +1,1040 @@
+/******************************************************
+XtraBackup: hot backup tool for InnoDB
+(c) 2009-2012 Percona Inc.
+Originally Created 3/3/2009 Yasufumi Kinoshita
+Written by Alexey Kopytov, Aleksandr Kuzminsky, Stewart Smith, Vadim Tkachenko,
+Yasufumi Kinoshita, Ignacio Nin and Baron Schwartz.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA
+
+*******************************************************/
+
+/* Changed page bitmap implementation */
+
+#include "changed_page_bitmap.h"
+
+#include "common.h"
+#include "xtrabackup.h"
+#include "srv0srv.h"
+
+/* TODO: copy-pasted shared definitions from the XtraDB bitmap write code.
+Remove these on the first opportunity, i.e. single-binary XtraBackup.  */
+
+/* log0online.h */
+
+/** Single bitmap file information */
+struct log_online_bitmap_file_t {
+	char		name[FN_REFLEN];	/*!< Name with full path */
+	pfs_os_file_t	file;			/*!< Handle to opened file */
+	ib_uint64_t	size;			/*!< Size of the file */
+	ib_uint64_t	offset;			/*!< Offset of the next read,
+						or count of already-read bytes
+						*/
+};
+
+/** A set of bitmap files containing some LSN range */
+struct log_online_bitmap_file_range_t {
+	size_t	count;				/*!< Number of files */
+	/*!< Dynamically-allocated array of info about individual files */
+	struct files_t {
+		char	name[FN_REFLEN];/*!< Name of a file */
+		lsn_t	start_lsn;	/*!< Starting LSN of data in this
+					file */
+		ulong	seq_num;	/*!< Sequence number of this file */
+	}	*files;
+};
+
+/* log0online.c */
+
+/** File name stem for bitmap files. */
+static const char* bmp_file_name_stem = "ib_modified_log_";
+
+/** The bitmap file block size in bytes.  All writes will be multiples of this.
+ */
+enum {
+	MODIFIED_PAGE_BLOCK_SIZE = 4096
+};
+
+/** Offsets in a file bitmap block */
+enum {
+	MODIFIED_PAGE_IS_LAST_BLOCK = 0,/* 1 if last block in the current
+					write, 0 otherwise. */
+	MODIFIED_PAGE_START_LSN = 4,	/* The starting tracked LSN of this and
+					other blocks in the same write */
+	MODIFIED_PAGE_END_LSN = 12,	/* The ending tracked LSN of this and
+					other blocks in the same write */
+	MODIFIED_PAGE_SPACE_ID = 20,	/* The space ID of tracked pages in
+					this block */
+	MODIFIED_PAGE_1ST_PAGE_ID = 24,	/* The page ID of the first tracked
+					page in this block */
+	MODIFIED_PAGE_BLOCK_UNUSED_1 = 28,/* Unused in order to align the start
+					  of bitmap at 8 byte boundary */
+	MODIFIED_PAGE_BLOCK_BITMAP = 32,/* Start of the bitmap itself */
+	MODIFIED_PAGE_BLOCK_UNUSED_2 = MODIFIED_PAGE_BLOCK_SIZE - 8,
+					/* Unused in order to align the end of
+					bitmap at 8 byte boundary */
+	MODIFIED_PAGE_BLOCK_CHECKSUM = MODIFIED_PAGE_BLOCK_SIZE - 4
+					/* The checksum of the current block */
+};
+
+/** Length of the bitmap data in a block */
+enum { MODIFIED_PAGE_BLOCK_BITMAP_LEN
+       = MODIFIED_PAGE_BLOCK_UNUSED_2 - MODIFIED_PAGE_BLOCK_BITMAP };
+
+/** Length of the bitmap data in a block in page ids */
+enum { MODIFIED_PAGE_BLOCK_ID_COUNT = MODIFIED_PAGE_BLOCK_BITMAP_LEN * 8 };
+
+typedef ib_uint64_t	bitmap_word_t;
+
+/****************************************************************//**
+Calculate a bitmap block checksum.  Algorithm borrowed from
+log_block_calc_checksum.
+@return checksum */
+UNIV_INLINE
+ulint
+log_online_calc_checksum(
+/*=====================*/
+	const byte*	block);	/*!<in: bitmap block */
+
+/****************************************************************//**
+Provide a comparisson function for the RB-tree tree (space,
+block_start_page) pairs.  Actual implementation does not matter as
+long as the ordering is full.
+@return -1 if p1 < p2, 0 if p1 == p2, 1 if p1 > p2
+*/
+static
+int
+log_online_compare_bmp_keys(
+/*========================*/
+	const void* p1,	/*!<in: 1st key to compare */
+	const void* p2)	/*!<in: 2nd key to compare */
+{
+	const byte *k1 = (const byte *)p1;
+	const byte *k2 = (const byte *)p2;
+
+	ulint k1_space = mach_read_from_4(k1 + MODIFIED_PAGE_SPACE_ID);
+	ulint k2_space = mach_read_from_4(k2 + MODIFIED_PAGE_SPACE_ID);
+	if (k1_space == k2_space) {
+
+		ulint k1_start_page
+			= mach_read_from_4(k1 + MODIFIED_PAGE_1ST_PAGE_ID);
+		ulint k2_start_page
+			= mach_read_from_4(k2 + MODIFIED_PAGE_1ST_PAGE_ID);
+		return k1_start_page < k2_start_page
+			? -1 : k1_start_page > k2_start_page ? 1 : 0;
+	}
+	return k1_space < k2_space ? -1 : 1;
+}
+
+/****************************************************************//**
+Calculate a bitmap block checksum.  Algorithm borrowed from
+log_block_calc_checksum.
+@return checksum */
+UNIV_INLINE
+ulint
+log_online_calc_checksum(
+/*=====================*/
+	const byte*	block)	/*!<in: bitmap block */
+{
+	ulint	sum;
+	ulint	sh;
+	ulint	i;
+
+	sum = 1;
+	sh = 0;
+
+	for (i = 0; i < MODIFIED_PAGE_BLOCK_CHECKSUM; i++) {
+
+		ulint	b = block[i];
+		sum &= 0x7FFFFFFFUL;
+		sum += b;
+		sum += b << sh;
+		sh++;
+		if (sh > 24) {
+
+			sh = 0;
+		}
+	}
+
+	return sum;
+}
+
+/****************************************************************//**
+Read one bitmap data page and check it for corruption.
+
+@return TRUE if page read OK, FALSE if I/O error */
+static
+ibool
+log_online_read_bitmap_page(
+/*========================*/
+	log_online_bitmap_file_t	*bitmap_file,	/*!<in/out: bitmap
+							file */
+	byte				*page,	/*!<out: read page.  Must be at
+						least MODIFIED_PAGE_BLOCK_SIZE
+						bytes long */
+	ibool				*checksum_ok)	/*!<out: TRUE if page
+							checksum OK */
+{
+	ulint	checksum;
+	ulint	actual_checksum;
+
+	ut_a(bitmap_file->size >= MODIFIED_PAGE_BLOCK_SIZE);
+	ut_a(bitmap_file->offset
+	     <= bitmap_file->size - MODIFIED_PAGE_BLOCK_SIZE);
+	ut_a(bitmap_file->offset % MODIFIED_PAGE_BLOCK_SIZE == 0);
+	if (DB_SUCCESS !=
+	    os_file_read(IORequestRead, bitmap_file->file, page,
+			 bitmap_file->offset, MODIFIED_PAGE_BLOCK_SIZE,
+			 nullptr)) {
+		/* The following call prints an error message */
+		os_file_get_last_error(TRUE);
+		msg("InnoDB: Warning: failed reading changed page bitmap "
+		    "file \'%s\'", bitmap_file->name);
+		return FALSE;
+	}
+
+	bitmap_file->offset += MODIFIED_PAGE_BLOCK_SIZE;
+	ut_ad(bitmap_file->offset <= bitmap_file->size);
+
+	checksum = mach_read_from_4(page + MODIFIED_PAGE_BLOCK_CHECKSUM);
+	actual_checksum = log_online_calc_checksum(page);
+	*checksum_ok = (checksum == actual_checksum);
+
+	return TRUE;
+}
+
+/*********************************************************************//**
+Check the name of a given file if it's a changed page bitmap file and
+return file sequence and start LSN name components if it is.  If is not,
+the values of output parameters are undefined.
+
+@return TRUE if a given file is a changed page bitmap file.  */
+static
+ibool
+log_online_is_bitmap_file(
+/*======================*/
+	const os_file_stat_t*	file_info,		/*!<in: file to
+							check */
+	ulong*			bitmap_file_seq_num,	/*!<out: bitmap file
+							sequence number */
+	lsn_t*			bitmap_file_start_lsn)	/*!<out: bitmap file
+							start LSN */
+{
+	char	stem[FN_REFLEN];
+
+	ut_ad (strlen(file_info->name) < OS_FILE_MAX_PATH);
+
+	return ((file_info->type == OS_FILE_TYPE_FILE
+		 || file_info->type == OS_FILE_TYPE_LINK)
+		&& (sscanf(file_info->name, "%[a-z_]%lu_" LSN_PF ".xdb", stem,
+			   bitmap_file_seq_num, bitmap_file_start_lsn) == 3)
+		&& (!strcmp(stem, bmp_file_name_stem)));
+}
+
+/*********************************************************************//**
+List the bitmap files in srv_data_home and setup their range that contains the
+specified LSN interval.  This range, if non-empty, will start with a file that
+has the greatest LSN equal to or less than the start LSN and will include all
+the files up to the one with the greatest LSN less than the end LSN.  Caller
+must free bitmap_files->files when done if bitmap_files set to non-NULL and
+this function returned TRUE.  Field bitmap_files->count might be set to a
+larger value than the actual count of the files, and space for the unused array
+slots will be allocated but cleared to zeroes.
+
+@return TRUE if succeeded
+*/
+static
+ibool
+log_online_setup_bitmap_file_range(
+/*===============================*/
+	log_online_bitmap_file_range_t	*bitmap_files,	/*!<in/out: bitmap file
+							range */
+	lsn_t				range_start,	/*!<in: start LSN */
+	lsn_t				range_end)	/*!<in: end LSN */
+{
+	os_file_dir_t	bitmap_dir;
+	os_file_stat_t	bitmap_dir_file_info;
+	ulong		first_file_seq_num	= ULONG_MAX;
+	ulong		last_file_seq_num	= 0;
+	lsn_t		first_file_start_lsn	= LSN_MAX;
+
+	xb_ad(range_end >= range_start);
+
+	bitmap_files->count = 0;
+	bitmap_files->files = NULL;
+
+	/* 1st pass: size the info array */
+
+	bitmap_dir = os_file_opendir(srv_data_home);
+	if (UNIV_UNLIKELY(bitmap_dir == IF_WIN(INVALID_HANDLE_VALUE, NULL))) {
+		msg("InnoDB: Error: failed to open bitmap directory \'%s\'",
+		    srv_data_home);
+		return FALSE;
+	}
+
+	while (!os_file_readdir_next_file(srv_data_home, bitmap_dir,
+					  &bitmap_dir_file_info)) {
+
+		ulong	file_seq_num;
+		lsn_t	file_start_lsn;
+
+		if (!log_online_is_bitmap_file(&bitmap_dir_file_info,
+					       &file_seq_num,
+					       &file_start_lsn)
+		    || file_start_lsn >= range_end) {
+
+			continue;
+		}
+
+		if (file_seq_num > last_file_seq_num) {
+
+			last_file_seq_num = file_seq_num;
+		}
+
+		if (file_start_lsn >= range_start
+		    || file_start_lsn == first_file_start_lsn
+		    || first_file_start_lsn > range_start) {
+
+			/* A file that falls into the range */
+
+			if (file_start_lsn < first_file_start_lsn) {
+
+				first_file_start_lsn = file_start_lsn;
+			}
+			if (file_seq_num < first_file_seq_num) {
+
+				first_file_seq_num = file_seq_num;
+			}
+		} else if (file_start_lsn > first_file_start_lsn) {
+
+			/* A file that has LSN closer to the range start
+			but smaller than it, replacing another such file */
+			first_file_start_lsn = file_start_lsn;
+			first_file_seq_num = file_seq_num;
+		}
+	}
+
+	if (UNIV_UNLIKELY(os_file_closedir_failed(bitmap_dir))) {
+		os_file_get_last_error(TRUE);
+		msg("InnoDB: Error: cannot close \'%s\'",srv_data_home);
+		return FALSE;
+	}
+
+	if (first_file_seq_num == ULONG_MAX && last_file_seq_num == 0) {
+
+		bitmap_files->count = 0;
+		return TRUE;
+	}
+
+	bitmap_files->count = last_file_seq_num - first_file_seq_num + 1;
+
+	/* 2nd pass: get the file names in the file_seq_num order */
+
+	bitmap_dir = os_file_opendir(srv_data_home);
+	if (UNIV_UNLIKELY(bitmap_dir == IF_WIN(INVALID_HANDLE_VALUE, NULL))) {
+		msg("InnoDB: Error: failed to open bitmap directory \'%s\'",
+		    srv_data_home);
+		return FALSE;
+	}
+
+	bitmap_files->files =
+		static_cast<log_online_bitmap_file_range_t::files_t *>
+		(malloc(bitmap_files->count * sizeof(bitmap_files->files[0])));
+	memset(bitmap_files->files, 0,
+	       bitmap_files->count * sizeof(bitmap_files->files[0]));
+
+	while (!os_file_readdir_next_file(srv_data_home, bitmap_dir,
+					  &bitmap_dir_file_info)) {
+
+		ulong	file_seq_num;
+		lsn_t	file_start_lsn;
+		size_t	array_pos;
+
+		if (!log_online_is_bitmap_file(&bitmap_dir_file_info,
+					       &file_seq_num,
+					       &file_start_lsn)
+		    || file_start_lsn >= range_end
+		    || file_start_lsn < first_file_start_lsn) {
+
+			continue;
+		}
+
+		array_pos = file_seq_num - first_file_seq_num;
+		if (UNIV_UNLIKELY(array_pos >= bitmap_files->count)) {
+
+			msg("InnoDB: Error: inconsistent bitmap file "
+			    "directory");
+			os_file_closedir(bitmap_dir);
+			free(bitmap_files->files);
+			return FALSE;
+		}
+
+		if (file_seq_num > bitmap_files->files[array_pos].seq_num) {
+
+			bitmap_files->files[array_pos].seq_num = file_seq_num;
+			strncpy(bitmap_files->files[array_pos].name,
+				bitmap_dir_file_info.name, FN_REFLEN - 1);
+			bitmap_files->files[array_pos].name[FN_REFLEN - 1]
+				= '\0';
+			bitmap_files->files[array_pos].start_lsn
+				= file_start_lsn;
+		}
+	}
+
+	if (UNIV_UNLIKELY(os_file_closedir_failed(bitmap_dir))) {
+		os_file_get_last_error(TRUE);
+		msg("InnoDB: Error: cannot close \'%s\'", srv_data_home);
+		free(bitmap_files->files);
+		return FALSE;
+	}
+
+#ifdef UNIV_DEBUG
+	ut_ad(bitmap_files->files[0].seq_num == first_file_seq_num);
+
+	for (size_t i = 1; i < bitmap_files->count; i++) {
+		if (!bitmap_files->files[i].seq_num) {
+
+			break;
+		}
+		ut_ad(bitmap_files->files[i].seq_num
+		      > bitmap_files->files[i - 1].seq_num);
+		ut_ad(bitmap_files->files[i].start_lsn
+		      >= bitmap_files->files[i - 1].start_lsn);
+	}
+#endif
+
+	return TRUE;
+}
+
+/****************************************************************//**
+Open a bitmap file for reading.
+
+@return whether opened successfully */
+static
+bool
+log_online_open_bitmap_file_read_only(
+/*==================================*/
+	const char*			name,		/*!<in: bitmap file
+							name without directory,
+							which is assumed to be
+							srv_data_home */
+	log_online_bitmap_file_t*	bitmap_file)	/*!<out: opened bitmap
+							file */
+{
+	bool	success	= false;
+
+	xb_ad(name[0] != '\0');
+
+	snprintf(bitmap_file->name, FN_REFLEN, "%s%s", srv_data_home, name);
+	bitmap_file->file = os_file_create_simple_no_error_handling(
+		0, bitmap_file->name,
+		OS_FILE_OPEN, OS_FILE_READ_ONLY, true, &success);
+	if (UNIV_UNLIKELY(!success)) {
+
+		/* Here and below assume that bitmap file names do not
+		contain apostrophes, thus no need for ut_print_filename(). */
+		msg("InnoDB: Warning: error opening the changed page "
+		    "bitmap \'%s\'", bitmap_file->name);
+		return success;
+	}
+
+	bitmap_file->size = os_file_get_size(bitmap_file->file);
+	bitmap_file->offset = 0;
+
+#ifdef __linux__
+	posix_fadvise(bitmap_file->file, 0, 0, POSIX_FADV_SEQUENTIAL);
+	posix_fadvise(bitmap_file->file, 0, 0, POSIX_FADV_NOREUSE);
+#endif
+
+	return success;
+}
+
+/****************************************************************//**
+Diagnose one or both of the following situations if we read close to
+the end of bitmap file:
+1) Warn if the remainder of the file is less than one page.
+2) Error if we cannot read any more full pages but the last read page
+did not have the last-in-run flag set.
+
+@return FALSE for the error */
+static
+ibool
+log_online_diagnose_bitmap_eof(
+/*===========================*/
+	const log_online_bitmap_file_t*	bitmap_file,	/*!< in: bitmap file */
+	ibool				last_page_in_run)/*!< in: "last page in
+							run" flag value in the
+							last read page */
+{
+	/* Check if we are too close to EOF to read a full page */
+	if ((bitmap_file->size < MODIFIED_PAGE_BLOCK_SIZE)
+	    || (bitmap_file->offset
+		> bitmap_file->size - MODIFIED_PAGE_BLOCK_SIZE)) {
+
+		if (UNIV_UNLIKELY(bitmap_file->offset != bitmap_file->size)) {
+
+			/* If we are not at EOF and we have less than one page
+			to read, it's junk.  This error is not fatal in
+			itself. */
+
+			msg("InnoDB: Warning: junk at the end of changed "
+			    "page bitmap file \'%s\'.", bitmap_file->name);
+		}
+
+		if (UNIV_UNLIKELY(!last_page_in_run)) {
+
+			/* We are at EOF but the last read page did not finish
+			a run */
+			/* It's a "Warning" here because it's not a fatal error
+			for the whole server */
+			msg("InnoDB: Warning: changed page bitmap "
+			    "file \'%s\' does not contain a complete run "
+			    "at the end.", bitmap_file->name);
+			return FALSE;
+		}
+	}
+	return TRUE;
+}
+
+/* End of copy-pasted definitions */
+
+/** Iterator structure over changed page bitmap */
+struct xb_page_bitmap_range_struct {
+	const xb_page_bitmap	*bitmap;	/* Bitmap with data */
+	ulint			space_id;	/* Space id for this
+					        iterator */
+	ulint			bit_i;		/* Bit index of the iterator
+						position in the current page */
+	const ib_rbt_node_t	*bitmap_node;	/* Current bitmap tree node */
+	const byte		*bitmap_page;	/* Current bitmap page */
+	ulint			current_page_id;/* Current page id */
+};
+
+/****************************************************************//**
+Print a diagnostic message on missing bitmap data for an LSN range.  */
+static
+void
+xb_msg_missing_lsn_data(
+/*====================*/
+	lsn_t	missing_interval_start,	/*!<in: interval start */
+	lsn_t	missing_interval_end)	/*!<in: interval end */
+{
+	msg("mariabackup: warning: changed page data missing for LSNs between "
+	    LSN_PF " and " LSN_PF, missing_interval_start,
+	    missing_interval_end);
+}
+
+/****************************************************************//**
+Scan a bitmap file until data for a desired LSN or EOF is found and check that
+the page before the starting one is not corrupted to ensure that the found page
+indeed contains the very start of the desired LSN data.  The caller must check
+the page LSN values to determine if the bitmap file was scanned until the data
+was found or until EOF.  Page must be at least MODIFIED_PAGE_BLOCK_SIZE big.
+
+@return TRUE if the scan successful without corruption detected
+*/
+static
+ibool
+xb_find_lsn_in_bitmap_file(
+/*=======================*/
+	log_online_bitmap_file_t	*bitmap_file,	/*!<in/out: bitmap
+							file */
+	byte				*page,		/*!<in/out: last read
+							bitmap page */
+	lsn_t				*page_end_lsn,	/*!<out: end LSN of the
+							last read page */
+	lsn_t				lsn)		/*!<in: LSN to find */
+{
+	ibool		last_page_ok		= TRUE;
+	ibool		next_to_last_page_ok	= TRUE;
+
+	xb_ad (bitmap_file->size >= MODIFIED_PAGE_BLOCK_SIZE);
+
+	*page_end_lsn = 0;
+
+	while ((*page_end_lsn <= lsn)
+	       && (bitmap_file->offset
+		   <= bitmap_file->size - MODIFIED_PAGE_BLOCK_SIZE)) {
+
+		next_to_last_page_ok = last_page_ok;
+		if (!log_online_read_bitmap_page(bitmap_file, page,
+						 &last_page_ok)) {
+
+			return FALSE;
+		}
+
+		*page_end_lsn = mach_read_from_8(page + MODIFIED_PAGE_END_LSN);
+	}
+
+	/* We check two pages here because the last read page already contains
+	the required LSN data. If the next to the last one page is corrupted,
+	then we have no way of telling if that page contained the required LSN
+	range data too */
+	return last_page_ok && next_to_last_page_ok;
+}
+
+/****************************************************************//**
+Read the disk bitmap and build the changed page bitmap tree for the
+LSN interval incremental_lsn to log_sys.next_checkpoint_lsn.
+
+@return the built bitmap tree or NULL if unable to read the full interval for
+any reason. */
+xb_page_bitmap*
+xb_page_bitmap_init(void)
+/*=====================*/
+{
+	log_online_bitmap_file_t	bitmap_file;
+	lsn_t				bmp_start_lsn	= incremental_lsn;
+	const lsn_t bmp_end_lsn{log_sys.next_checkpoint_lsn};
+	byte				page[MODIFIED_PAGE_BLOCK_SIZE];
+	lsn_t				current_page_end_lsn;
+	xb_page_bitmap			*result;
+	ibool				last_page_in_run= FALSE;
+	log_online_bitmap_file_range_t	bitmap_files;
+	size_t				bmp_i;
+	ibool				last_page_ok	= TRUE;
+
+	if (UNIV_UNLIKELY(bmp_start_lsn > bmp_end_lsn)) {
+
+		msg("mariabackup: incremental backup LSN " LSN_PF
+		    " is larger than than the last checkpoint LSN " LSN_PF
+		    , bmp_start_lsn, bmp_end_lsn);
+		return NULL;
+	}
+
+	if (!log_online_setup_bitmap_file_range(&bitmap_files, bmp_start_lsn,
+						bmp_end_lsn)) {
+
+		return NULL;
+	}
+
+	/* Only accept no bitmap files returned if start LSN == end LSN */
+	if (bitmap_files.count == 0 && bmp_end_lsn != bmp_start_lsn) {
+
+		return NULL;
+	}
+
+	result = rbt_create(MODIFIED_PAGE_BLOCK_SIZE,
+			    log_online_compare_bmp_keys);
+
+	if (bmp_start_lsn == bmp_end_lsn) {
+
+		/* Empty range - empty bitmap */
+		return result;
+	}
+
+	bmp_i = 0;
+
+	if (UNIV_UNLIKELY(bitmap_files.files[bmp_i].start_lsn
+			  > bmp_start_lsn)) {
+
+		/* The 1st file does not have the starting LSN data */
+		xb_msg_missing_lsn_data(bmp_start_lsn,
+					bitmap_files.files[bmp_i].start_lsn);
+		rbt_free(result);
+		free(bitmap_files.files);
+		return NULL;
+	}
+
+	/* Skip any zero-sized files at the start */
+	while ((bmp_i < bitmap_files.count - 1)
+	       && (bitmap_files.files[bmp_i].start_lsn
+		   == bitmap_files.files[bmp_i + 1].start_lsn)) {
+
+		bmp_i++;
+	}
+
+	/* Is the 1st bitmap file missing? */
+	if (UNIV_UNLIKELY(bitmap_files.files[bmp_i].name[0] == '\0')) {
+
+		/* TODO: this is not the exact missing range */
+		xb_msg_missing_lsn_data(bmp_start_lsn, bmp_end_lsn);
+		rbt_free(result);
+		free(bitmap_files.files);
+		return NULL;
+	}
+
+	/* Open the 1st bitmap file */
+	if (UNIV_UNLIKELY(!log_online_open_bitmap_file_read_only(
+				  bitmap_files.files[bmp_i].name,
+				  &bitmap_file))) {
+
+		rbt_free(result);
+		free(bitmap_files.files);
+		return NULL;
+	}
+
+	/* If the 1st file is truncated, no data.  Not merged with the case
+	below because zero-length file indicates not a corruption but missing
+	subsequent files instead.  */
+	if (UNIV_UNLIKELY(bitmap_file.size < MODIFIED_PAGE_BLOCK_SIZE)) {
+
+		xb_msg_missing_lsn_data(bmp_start_lsn, bmp_end_lsn);
+		rbt_free(result);
+		free(bitmap_files.files);
+		os_file_close(bitmap_file.file);
+		return NULL;
+	}
+
+	/* Find the start of the required LSN range in the file */
+	if (UNIV_UNLIKELY(!xb_find_lsn_in_bitmap_file(&bitmap_file, page,
+						      &current_page_end_lsn,
+						      bmp_start_lsn))) {
+
+		msg("mariabackup: Warning: changed page bitmap file "
+		    "\'%s\' corrupted", bitmap_file.name);
+		rbt_free(result);
+		free(bitmap_files.files);
+		os_file_close(bitmap_file.file);
+		return NULL;
+	}
+
+	last_page_in_run
+		= mach_read_from_4(page + MODIFIED_PAGE_IS_LAST_BLOCK);
+
+	if (UNIV_UNLIKELY(!log_online_diagnose_bitmap_eof(&bitmap_file,
+							  last_page_in_run))) {
+
+		rbt_free(result);
+		free(bitmap_files.files);
+		os_file_close(bitmap_file.file);
+		return NULL;
+	}
+
+	if (UNIV_UNLIKELY(current_page_end_lsn < bmp_start_lsn)) {
+
+		xb_msg_missing_lsn_data(current_page_end_lsn, bmp_start_lsn);
+		rbt_free(result);
+		free(bitmap_files.files);
+		os_file_close(bitmap_file.file);
+		return NULL;
+	}
+
+	/* 1st bitmap page found, add it to the tree.  */
+	rbt_insert(result, page, page);
+
+	/* Read next pages/files until all required data is read */
+	while (last_page_ok
+	       && (current_page_end_lsn < bmp_end_lsn
+		   || (current_page_end_lsn == bmp_end_lsn
+		       && !last_page_in_run))) {
+
+		ib_rbt_bound_t	tree_search_pos;
+
+		/* If EOF, advance the file skipping over any empty files */
+		while (bitmap_file.size < MODIFIED_PAGE_BLOCK_SIZE
+		       || (bitmap_file.offset
+			   > bitmap_file.size - MODIFIED_PAGE_BLOCK_SIZE)) {
+
+			os_file_close(bitmap_file.file);
+
+			if (UNIV_UNLIKELY(
+				!log_online_diagnose_bitmap_eof(
+					&bitmap_file, last_page_in_run))) {
+
+				rbt_free(result);
+				free(bitmap_files.files);
+				return NULL;
+			}
+
+			bmp_i++;
+
+			if (UNIV_UNLIKELY(bmp_i == bitmap_files.count
+					  || (bitmap_files.files[bmp_i].seq_num
+					      == 0))) {
+
+				xb_msg_missing_lsn_data(current_page_end_lsn,
+							bmp_end_lsn);
+				rbt_free(result);
+				free(bitmap_files.files);
+				return NULL;
+			}
+
+			/* Is the next file missing? */
+			if (UNIV_UNLIKELY(bitmap_files.files[bmp_i].name[0]
+					  == '\0')) {
+
+				/* TODO: this is not the exact missing range */
+				xb_msg_missing_lsn_data(bitmap_files.files
+							[bmp_i - 1].start_lsn,
+							bmp_end_lsn);
+				rbt_free(result);
+				free(bitmap_files.files);
+				return NULL;
+			}
+
+			if (UNIV_UNLIKELY(
+				    !log_online_open_bitmap_file_read_only(
+					    bitmap_files.files[bmp_i].name,
+					    &bitmap_file))) {
+
+				rbt_free(result);
+				free(bitmap_files.files);
+				return NULL;
+			}
+		}
+
+		if (UNIV_UNLIKELY(
+			    !log_online_read_bitmap_page(&bitmap_file, page,
+							 &last_page_ok))) {
+
+			rbt_free(result);
+			free(bitmap_files.files);
+			os_file_close(bitmap_file.file);
+			return NULL;
+		}
+
+		if (UNIV_UNLIKELY(!last_page_ok)) {
+
+			msg("mariabackup: warning: changed page bitmap file "
+			    "\'%s\' corrupted.", bitmap_file.name);
+			rbt_free(result);
+			free(bitmap_files.files);
+			os_file_close(bitmap_file.file);
+			return NULL;
+		}
+
+		/* Merge the current page with an existing page or insert a new
+		page into the tree */
+
+		if (!rbt_search(result, &tree_search_pos, page)) {
+
+			/* Merge the bitmap pages */
+			byte	*existing_page
+				= rbt_value(byte, tree_search_pos.last);
+			bitmap_word_t *bmp_word_1	= (bitmap_word_t *)
+				(existing_page + MODIFIED_PAGE_BLOCK_BITMAP);
+			bitmap_word_t *bmp_end = (bitmap_word_t *)
+				(existing_page + MODIFIED_PAGE_BLOCK_UNUSED_2);
+			bitmap_word_t *bmp_word_2	= (bitmap_word_t *)
+				(page + MODIFIED_PAGE_BLOCK_BITMAP);
+			while (bmp_word_1 < bmp_end) {
+
+				*bmp_word_1++ |= *bmp_word_2++;
+			}
+			xb_a (bmp_word_1 == bmp_end);
+		} else {
+
+			/* Add a new page */
+			rbt_add_node(result, &tree_search_pos, page);
+		}
+
+		current_page_end_lsn
+			= mach_read_from_8(page + MODIFIED_PAGE_END_LSN);
+		last_page_in_run
+			= mach_read_from_4(page + MODIFIED_PAGE_IS_LAST_BLOCK);
+	}
+
+	xb_a (current_page_end_lsn >= bmp_end_lsn);
+
+	free(bitmap_files.files);
+	os_file_close(bitmap_file.file);
+
+	return result;
+}
+
+/****************************************************************//**
+Free the bitmap tree. */
+void
+xb_page_bitmap_deinit(
+/*==================*/
+	xb_page_bitmap*	bitmap)	/*!<in/out: bitmap tree */
+{
+	if (bitmap) {
+
+		rbt_free(bitmap);
+	}
+}
+
+/****************************************************************//**
+Advance to the next bitmap page or setup the first bitmap page for the
+given bitmap range.  Assumes that bitmap_range->bitmap_page has been
+already found/bumped by rbt_search()/rbt_next().
+
+@return FALSE if no more bitmap data for the range space ID */
+static
+ibool
+xb_page_bitmap_setup_next_page(
+/*===========================*/
+	xb_page_bitmap_range*	bitmap_range)	/*!<in/out: the bitmap range */
+{
+	ulint	new_space_id;
+	ulint	new_1st_page_id;
+
+	if (bitmap_range->bitmap_node == NULL) {
+
+		bitmap_range->current_page_id = ULINT_UNDEFINED;
+		return FALSE;
+	}
+
+	bitmap_range->bitmap_page = rbt_value(byte, bitmap_range->bitmap_node);
+
+	new_space_id = mach_read_from_4(bitmap_range->bitmap_page
+					+ MODIFIED_PAGE_SPACE_ID);
+	if (new_space_id != bitmap_range->space_id) {
+
+		/* No more data for the current page id. */
+		xb_a(new_space_id > bitmap_range->space_id);
+		bitmap_range->current_page_id = ULINT_UNDEFINED;
+		return FALSE;
+	}
+
+	new_1st_page_id = mach_read_from_4(bitmap_range->bitmap_page +
+					   MODIFIED_PAGE_1ST_PAGE_ID);
+	xb_a (new_1st_page_id >= bitmap_range->current_page_id
+	      || bitmap_range->current_page_id == ULINT_UNDEFINED);
+
+	bitmap_range->current_page_id = new_1st_page_id;
+	bitmap_range->bit_i = 0;
+
+	return TRUE;
+}
+
+/** Find the node with the smallest key that greater than equal to search key.
+@param[in]	tree	red-black tree
+@param[in]	key	search key
+@return	node with the smallest greater-than-or-equal key
+@retval	NULL	if none was found */
+static
+const ib_rbt_node_t*
+rbt_lower_bound(const ib_rbt_t* tree, const void* key)
+{
+	ut_ad(!tree->cmp_arg);
+	const ib_rbt_node_t* ge = NULL;
+
+	for (const ib_rbt_node_t *node = tree->root->left;
+	     node != tree->nil; ) {
+		int	result = tree->compare(node->value, key);
+
+		if (result < 0) {
+			node = node->right;
+		} else {
+			ge = node;
+			if (result == 0) {
+				break;
+			}
+
+			node = node->left;
+		}
+	}
+
+	return(ge);
+}
+
+/****************************************************************//**
+Set up a new bitmap range iterator over a given space id changed
+pages in a given bitmap.
+
+@return bitmap range iterator */
+xb_page_bitmap_range*
+xb_page_bitmap_range_init(
+/*======================*/
+	xb_page_bitmap*	bitmap,		/*!< in: bitmap to iterate over */
+	ulint		space_id)	/*!< in: space id */
+{
+	byte			search_page[MODIFIED_PAGE_BLOCK_SIZE];
+	xb_page_bitmap_range	*result
+		= static_cast<xb_page_bitmap_range *>(malloc(sizeof(*result)));
+
+	memset(result, 0, sizeof(*result));
+	result->bitmap = bitmap;
+	result->space_id = space_id;
+	result->current_page_id = ULINT_UNDEFINED;
+
+	/* Search for the 1st page for the given space id */
+	/* This also sets MODIFIED_PAGE_1ST_PAGE_ID to 0, which is what we
+	want. */
+	memset(search_page, 0, MODIFIED_PAGE_BLOCK_SIZE);
+	mach_write_to_4(search_page + MODIFIED_PAGE_SPACE_ID, space_id);
+
+	result->bitmap_node = rbt_lower_bound(result->bitmap, search_page);
+
+	xb_page_bitmap_setup_next_page(result);
+
+	return result;
+}
+
+/****************************************************************//**
+Get the value of the bitmap->range->bit_i bitmap bit
+
+@return the current bit value */
+static inline
+ibool
+is_bit_set(
+/*=======*/
+	const xb_page_bitmap_range*	bitmap_range)	/*!< in: bitmap
+							range */
+{
+	return ((*(((bitmap_word_t *)(bitmap_range->bitmap_page
+				     + MODIFIED_PAGE_BLOCK_BITMAP))
+		  + (bitmap_range->bit_i >> 6)))
+		& (1ULL << (bitmap_range->bit_i & 0x3F))) ? TRUE : FALSE;
+}
+
+/****************************************************************//**
+Get the next page id that has its bit set or cleared, i.e. equal to
+bit_value.
+
+@return page id */
+ulint
+xb_page_bitmap_range_get_next_bit(
+/*==============================*/
+	xb_page_bitmap_range*	bitmap_range,	/*!< in/out: bitmap range */
+	ibool			bit_value)	/*!< in: bit value */
+{
+	if (UNIV_UNLIKELY(bitmap_range->current_page_id
+			  == ULINT_UNDEFINED)) {
+
+		return ULINT_UNDEFINED;
+	}
+
+	do {
+		while (bitmap_range->bit_i < MODIFIED_PAGE_BLOCK_ID_COUNT) {
+
+			while (is_bit_set(bitmap_range) != bit_value
+			       && (bitmap_range->bit_i
+				   < MODIFIED_PAGE_BLOCK_ID_COUNT)) {
+
+				bitmap_range->current_page_id++;
+				bitmap_range->bit_i++;
+			}
+
+			if (bitmap_range->bit_i
+			    < MODIFIED_PAGE_BLOCK_ID_COUNT) {
+
+				ulint result = bitmap_range->current_page_id;
+				bitmap_range->current_page_id++;
+				bitmap_range->bit_i++;
+				return result;
+			}
+		}
+
+		bitmap_range->bitmap_node
+			= rbt_next(bitmap_range->bitmap,
+				   bitmap_range->bitmap_node);
+
+	} while (xb_page_bitmap_setup_next_page(bitmap_range));
+
+	return ULINT_UNDEFINED;
+}
+
+/****************************************************************//**
+Free the bitmap range iterator. */
+void
+xb_page_bitmap_range_deinit(
+/*========================*/
+	xb_page_bitmap_range*	bitmap_range)	/*! in/out: bitmap range */
+{
+	free(bitmap_range);
+}