path: root/storage/xtradb/include/fsp0fsp.h

/*****************************************************************************

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Copyright (c) 2013, 2016, MariaDB Corporation. All Rights Reserved.

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
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

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*****************************************************************************/

/**************************************************//**
@file include/fsp0fsp.h
File space management

Created 12/18/1995 Heikki Tuuri
*******************************************************/

#ifndef fsp0fsp_h
#define fsp0fsp_h

#include "univ.i"

#ifndef UNIV_INNOCHECKSUM

#include "mtr0mtr.h"
#include "fut0lst.h"
#include "ut0byte.h"
#include "page0types.h"
#include "fsp0types.h"

#endif /* !UNIV_INNOCHECKSUM */

/* @defgroup fsp_flags InnoDB Tablespace Flag Constants @{ */

/** Width of the POST_ANTELOPE flag */
#define FSP_FLAGS_WIDTH_POST_ANTELOPE	1
/** Number of flag bits used to indicate the tablespace zip page size */
#define FSP_FLAGS_WIDTH_ZIP_SSIZE	4
/** Width of the ATOMIC_BLOBS flag.  The ability to break up a long
column into an in-record prefix and an externally stored part is available
to the two Barracuda row formats COMPRESSED and DYNAMIC. */
#define FSP_FLAGS_WIDTH_ATOMIC_BLOBS	1
/** Number of flag bits used to indicate the tablespace page size */
#define FSP_FLAGS_WIDTH_PAGE_SSIZE	4
/** Width of the DATA_DIR flag.  This flag indicates that the tablespace
is found in a remote location, not the default data directory. */
#define FSP_FLAGS_WIDTH_DATA_DIR	1
/** Number of flag bits used to indicate the page compression and compression level */
#define FSP_FLAGS_WIDTH_PAGE_COMPRESSION  1
#define FSP_FLAGS_WIDTH_PAGE_COMPRESSION_LEVEL 4

/** Number of flag bits used to indicate atomic writes for this tablespace */
#define FSP_FLAGS_WIDTH_ATOMIC_WRITES  2

/** Width of all the currently known tablespace flags */
#define FSP_FLAGS_WIDTH		(FSP_FLAGS_WIDTH_POST_ANTELOPE	\
				+ FSP_FLAGS_WIDTH_ZIP_SSIZE	\
				+ FSP_FLAGS_WIDTH_ATOMIC_BLOBS	\
				+ FSP_FLAGS_WIDTH_PAGE_SSIZE	\
				+ FSP_FLAGS_WIDTH_DATA_DIR      \
				+ FSP_FLAGS_WIDTH_PAGE_COMPRESSION \
				+ FSP_FLAGS_WIDTH_PAGE_COMPRESSION_LEVEL \
				+ FSP_FLAGS_WIDTH_ATOMIC_WRITES )

/** A mask of all the known/used bits in tablespace flags */
#define FSP_FLAGS_MASK		(~(~0 << FSP_FLAGS_WIDTH))

/** Zero relative shift position of the POST_ANTELOPE field */
#define FSP_FLAGS_POS_POST_ANTELOPE	0
/** Zero relative shift position of the ZIP_SSIZE field */
#define FSP_FLAGS_POS_ZIP_SSIZE		(FSP_FLAGS_POS_POST_ANTELOPE	\
					+ FSP_FLAGS_WIDTH_POST_ANTELOPE)
/** Zero relative shift position of the ATOMIC_BLOBS field */
#define FSP_FLAGS_POS_ATOMIC_BLOBS	(FSP_FLAGS_POS_ZIP_SSIZE	\
					+ FSP_FLAGS_WIDTH_ZIP_SSIZE)
/** Note that these need to be before the page size to be compatible with
dictionary */
/** Zero relative shift position of the PAGE_COMPRESSION field */
#define FSP_FLAGS_POS_PAGE_COMPRESSION	(FSP_FLAGS_POS_ATOMIC_BLOBS	\
					+ FSP_FLAGS_WIDTH_ATOMIC_BLOBS)
/** Zero relative shift position of the PAGE_COMPRESSION_LEVEL field */
#define FSP_FLAGS_POS_PAGE_COMPRESSION_LEVEL	(FSP_FLAGS_POS_PAGE_COMPRESSION	\
					+ FSP_FLAGS_WIDTH_PAGE_COMPRESSION)
/** Zero relative shift position of the ATOMIC_WRITES field */
#define FSP_FLAGS_POS_ATOMIC_WRITES	(FSP_FLAGS_POS_PAGE_COMPRESSION_LEVEL	\
					+ FSP_FLAGS_WIDTH_PAGE_COMPRESSION_LEVEL)
/** Zero relative shift position of the PAGE_SSIZE field */
#define FSP_FLAGS_POS_PAGE_SSIZE	(FSP_FLAGS_POS_ATOMIC_WRITES	\
					+ FSP_FLAGS_WIDTH_ATOMIC_WRITES)
/** Zero relative shift position of the start of the DATA DIR bits */
#define FSP_FLAGS_POS_DATA_DIR		(FSP_FLAGS_POS_PAGE_SSIZE	\
					+ FSP_FLAGS_WIDTH_PAGE_SSIZE)
#define FSP_FLAGS_POS_DATA_DIR_ORACLE	(FSP_FLAGS_POS_ATOMIC_BLOBS	\
					+ FSP_FLAGS_WIDTH_ATOMIC_BLOBS  \
					+ FSP_FLAGS_WIDTH_PAGE_SSIZE)
/** Zero relative shift position of the start of the UNUSED bits */
#define FSP_FLAGS_POS_UNUSED		(FSP_FLAGS_POS_DATA_DIR\
                    + FSP_FLAGS_WIDTH_DATA_DIR)

/** Bit mask of the POST_ANTELOPE field */
#define FSP_FLAGS_MASK_POST_ANTELOPE				\
		((~(~0U << FSP_FLAGS_WIDTH_POST_ANTELOPE))	\
		<< FSP_FLAGS_POS_POST_ANTELOPE)
/** Bit mask of the ZIP_SSIZE field */
#define FSP_FLAGS_MASK_ZIP_SSIZE				\
		((~(~0U << FSP_FLAGS_WIDTH_ZIP_SSIZE))		\
		<< FSP_FLAGS_POS_ZIP_SSIZE)
/** Bit mask of the ATOMIC_BLOBS field */
#define FSP_FLAGS_MASK_ATOMIC_BLOBS				\
		((~(~0U << FSP_FLAGS_WIDTH_ATOMIC_BLOBS))	\
		<< FSP_FLAGS_POS_ATOMIC_BLOBS)
/** Bit mask of the PAGE_SSIZE field */
#define FSP_FLAGS_MASK_PAGE_SSIZE				\
		((~(~0U << FSP_FLAGS_WIDTH_PAGE_SSIZE))		\
		<< FSP_FLAGS_POS_PAGE_SSIZE)
/** Bit mask of the DATA_DIR field */
#define FSP_FLAGS_MASK_DATA_DIR					\
		((~(~0U << FSP_FLAGS_WIDTH_DATA_DIR))		\
		<< FSP_FLAGS_POS_DATA_DIR)
/** Bit mask of the DATA_DIR field */
#define FSP_FLAGS_MASK_DATA_DIR_ORACLE				\
		((~(~0U << FSP_FLAGS_WIDTH_DATA_DIR))		\
		<< FSP_FLAGS_POS_DATA_DIR_ORACLE)
/** Bit mask of the PAGE_COMPRESSION field */
#define FSP_FLAGS_MASK_PAGE_COMPRESSION			\
		((~(~0U << FSP_FLAGS_WIDTH_PAGE_COMPRESSION))	\
		<< FSP_FLAGS_POS_PAGE_COMPRESSION)
/** Bit mask of the PAGE_COMPRESSION_LEVEL field */
#define FSP_FLAGS_MASK_PAGE_COMPRESSION_LEVEL		\
		((~(~0U << FSP_FLAGS_WIDTH_PAGE_COMPRESSION_LEVEL))	\
		<< FSP_FLAGS_POS_PAGE_COMPRESSION_LEVEL)
/** Bit mask of the ATOMIC_WRITES field */
#define FSP_FLAGS_MASK_ATOMIC_WRITES		\
		((~(~0U << FSP_FLAGS_WIDTH_ATOMIC_WRITES))	\
		<< FSP_FLAGS_POS_ATOMIC_WRITES)
/** Return the value of the POST_ANTELOPE field */
#define FSP_FLAGS_GET_POST_ANTELOPE(flags)			\
		((flags & FSP_FLAGS_MASK_POST_ANTELOPE)		\
		>> FSP_FLAGS_POS_POST_ANTELOPE)
/** Return the value of the ZIP_SSIZE field */
#define FSP_FLAGS_GET_ZIP_SSIZE(flags)				\
		((flags & FSP_FLAGS_MASK_ZIP_SSIZE)		\
		>> FSP_FLAGS_POS_ZIP_SSIZE)
/** Return the value of the ATOMIC_BLOBS field */
#define FSP_FLAGS_HAS_ATOMIC_BLOBS(flags)			\
		((flags & FSP_FLAGS_MASK_ATOMIC_BLOBS)		\
		>> FSP_FLAGS_POS_ATOMIC_BLOBS)
/** Return the value of the PAGE_SSIZE field */
#define FSP_FLAGS_GET_PAGE_SSIZE(flags)				\
		((flags & FSP_FLAGS_MASK_PAGE_SSIZE)		\
		>> FSP_FLAGS_POS_PAGE_SSIZE)
/** Return the value of the DATA_DIR field */
#define FSP_FLAGS_HAS_DATA_DIR(flags)				\
		((flags & FSP_FLAGS_MASK_DATA_DIR)		\
		>> FSP_FLAGS_POS_DATA_DIR)
#define FSP_FLAGS_HAS_DATA_DIR_ORACLE(flags)			\
		((flags & FSP_FLAGS_MASK_DATA_DIR_ORACLE)	\
		>> FSP_FLAGS_POS_DATA_DIR_ORACLE)
/** Return the contents of the UNUSED bits */
#define FSP_FLAGS_GET_UNUSED(flags)				\
		(flags >> FSP_FLAGS_POS_UNUSED)
/** Return the value of the PAGE_COMPRESSION field */
#define FSP_FLAGS_GET_PAGE_COMPRESSION(flags)			\
		((flags & FSP_FLAGS_MASK_PAGE_COMPRESSION)	\
		>> FSP_FLAGS_POS_PAGE_COMPRESSION)
/** Return the value of the PAGE_COMPRESSION_LEVEL field */
#define FSP_FLAGS_GET_PAGE_COMPRESSION_LEVEL(flags)		\
		((flags & FSP_FLAGS_MASK_PAGE_COMPRESSION_LEVEL) \
		>> FSP_FLAGS_POS_PAGE_COMPRESSION_LEVEL)
/** Return the value of the ATOMIC_WRITES field */
#define FSP_FLAGS_GET_ATOMIC_WRITES(flags)			\
		((flags & FSP_FLAGS_MASK_ATOMIC_WRITES) 	\
		>> FSP_FLAGS_POS_ATOMIC_WRITES)

/** Set a PAGE_SSIZE into the correct bits in a given
tablespace flags. */
#define FSP_FLAGS_SET_PAGE_SSIZE(flags, ssize)			\
		(flags | (ssize << FSP_FLAGS_POS_PAGE_SSIZE))

/** Set a PAGE_COMPRESSION into the correct bits in a given
tablespace flags. */
#define FSP_FLAGS_SET_PAGE_COMPRESSION(flags, compression)	\
		(flags | (compression << FSP_FLAGS_POS_PAGE_COMPRESSION))

/** Set a PAGE_COMPRESSION_LEVEL into the correct bits in a given
tablespace flags. */
#define FSP_FLAGS_SET_PAGE_COMPRESSION_LEVEL(flags, level)	\
		(flags | (level << FSP_FLAGS_POS_PAGE_COMPRESSION_LEVEL))

/** Set a ATOMIC_WRITES into the correct bits in a given
tablespace flags. */
#define FSP_FLAGS_SET_ATOMIC_WRITES(flags, atomics)		\
		(flags | (atomics << FSP_FLAGS_POS_ATOMIC_WRITES))

/* @} */

/* @defgroup Tablespace Header Constants (moved from fsp0fsp.c) @{ */

/** Offset of the space header within a file page */
#define FSP_HEADER_OFFSET	FIL_PAGE_DATA

/* The data structures in files are defined just as byte strings in C */
typedef	byte	fsp_header_t;
typedef	byte	xdes_t;

/*			SPACE HEADER
			============

File space header data structure: this data structure is contained in the
first page of a space. The space for this header is reserved in every extent
descriptor page, but used only in the first. */

/*-------------------------------------*/
#define FSP_SPACE_ID		0	/* space id */
#define FSP_NOT_USED		4	/* this field contained a value up to
					which we know that the modifications
					in the database have been flushed to
					the file space; not used now */
#define	FSP_SIZE		8	/* Current size of the space in
					pages */
#define	FSP_FREE_LIMIT		12	/* Minimum page number for which the
					free list has not been initialized:
					the pages >= this limit are, by
					definition, free; note that in a
					single-table tablespace where size
					< 64 pages, this number is 64, i.e.,
					we have initialized the space
					about the first extent, but have not
					physically allocted those pages to the
					file */
#define	FSP_SPACE_FLAGS		16	/* fsp_space_t.flags, similar to
					dict_table_t::flags */
#define	FSP_FRAG_N_USED		20	/* number of used pages in the
					FSP_FREE_FRAG list */
#define	FSP_FREE		24	/* list of free extents */
#define	FSP_FREE_FRAG		(24 + FLST_BASE_NODE_SIZE)
					/* list of partially free extents not
					belonging to any segment */
#define	FSP_FULL_FRAG		(24 + 2 * FLST_BASE_NODE_SIZE)
					/* list of full extents not belonging
					to any segment */
#define FSP_SEG_ID		(24 + 3 * FLST_BASE_NODE_SIZE)
					/* 8 bytes which give the first unused
					segment id */
#define FSP_SEG_INODES_FULL	(32 + 3 * FLST_BASE_NODE_SIZE)
					/* list of pages containing segment
					headers, where all the segment inode
					slots are reserved */
#define FSP_SEG_INODES_FREE	(32 + 4 * FLST_BASE_NODE_SIZE)
					/* list of pages containing segment
					headers, where not all the segment
					header slots are reserved */
/*-------------------------------------*/
/* File space header size */
#define	FSP_HEADER_SIZE		(32 + 5 * FLST_BASE_NODE_SIZE)

#define	FSP_FREE_ADD		4	/* this many free extents are added
					to the free list from above
					FSP_FREE_LIMIT at a time */
/* @} */

#ifndef UNIV_INNOCHECKSUM

/* @defgroup File Segment Inode Constants (moved from fsp0fsp.c) @{ */

/*			FILE SEGMENT INODE
			==================

Segment inode which is created for each segment in a tablespace. NOTE: in
purge we assume that a segment having only one currently used page can be
freed in a few steps, so that the freeing cannot fill the file buffer with
bufferfixed file pages. */

typedef	byte	fseg_inode_t;

#define FSEG_INODE_PAGE_NODE	FSEG_PAGE_DATA
					/* the list node for linking
					segment inode pages */

#define FSEG_ARR_OFFSET		(FSEG_PAGE_DATA + FLST_NODE_SIZE)
/*-------------------------------------*/
#define	FSEG_ID			0	/* 8 bytes of segment id: if this is 0,
					it means that the header is unused */
#define FSEG_NOT_FULL_N_USED	8
					/* number of used segment pages in
					the FSEG_NOT_FULL list */
#define	FSEG_FREE		12
					/* list of free extents of this
					segment */
#define	FSEG_NOT_FULL		(12 + FLST_BASE_NODE_SIZE)
					/* list of partially free extents */
#define	FSEG_FULL		(12 + 2 * FLST_BASE_NODE_SIZE)
					/* list of full extents */
#define	FSEG_MAGIC_N		(12 + 3 * FLST_BASE_NODE_SIZE)
					/* magic number used in debugging */
#define	FSEG_FRAG_ARR		(16 + 3 * FLST_BASE_NODE_SIZE)
					/* array of individual pages
					belonging to this segment in fsp
					fragment extent lists */
#define FSEG_FRAG_ARR_N_SLOTS	(FSP_EXTENT_SIZE / 2)
					/* number of slots in the array for
					the fragment pages */
#define	FSEG_FRAG_SLOT_SIZE	4	/* a fragment page slot contains its
					page number within space, FIL_NULL
					means that the slot is not in use */
/*-------------------------------------*/
#define FSEG_INODE_SIZE					\
	(16 + 3 * FLST_BASE_NODE_SIZE			\
	 + FSEG_FRAG_ARR_N_SLOTS * FSEG_FRAG_SLOT_SIZE)

#define FSP_SEG_INODES_PER_PAGE(zip_size)		\
	(((zip_size ? zip_size : UNIV_PAGE_SIZE)	\
	  - FSEG_ARR_OFFSET - 10) / FSEG_INODE_SIZE)
				/* Number of segment inodes which fit on a
				single page */

#define FSEG_MAGIC_N_VALUE	97937874

#define	FSEG_FILLFACTOR		8	/* If this value is x, then if
					the number of unused but reserved
					pages in a segment is less than
					reserved pages * 1/x, and there are
					at least FSEG_FRAG_LIMIT used pages,
					then we allow a new empty extent to
					be added to the segment in
					fseg_alloc_free_page. Otherwise, we
					use unused pages of the segment. */

#define FSEG_FRAG_LIMIT		FSEG_FRAG_ARR_N_SLOTS
					/* If the segment has >= this many
					used pages, it may be expanded by
					allocating extents to the segment;
					until that only individual fragment
					pages are allocated from the space */

#define	FSEG_FREE_LIST_LIMIT	40	/* If the reserved size of a segment
					is at least this many extents, we
					allow extents to be put to the free
					list of the extent: at most
					FSEG_FREE_LIST_MAX_LEN many */
#define	FSEG_FREE_LIST_MAX_LEN	4
/* @} */

/* @defgroup Extent Descriptor Constants (moved from fsp0fsp.c) @{ */

/*			EXTENT DESCRIPTOR
			=================

File extent descriptor data structure: contains bits to tell which pages in
the extent are free and which contain old tuple version to clean. */

/*-------------------------------------*/
#define	XDES_ID			0	/* The identifier of the segment
					to which this extent belongs */
#define XDES_FLST_NODE		8	/* The list node data structure
					for the descriptors */
#define	XDES_STATE		(FLST_NODE_SIZE + 8)
					/* contains state information
					of the extent */
#define	XDES_BITMAP		(FLST_NODE_SIZE + 12)
					/* Descriptor bitmap of the pages
					in the extent */
/*-------------------------------------*/

#define	XDES_BITS_PER_PAGE	2	/* How many bits are there per page */
#define	XDES_FREE_BIT		0	/* Index of the bit which tells if
					the page is free */
#define	XDES_CLEAN_BIT		1	/* NOTE: currently not used!
					Index of the bit which tells if
					there are old versions of tuples
					on the page */
/* States of a descriptor */
#define	XDES_FREE		1	/* extent is in free list of space */
#define	XDES_FREE_FRAG		2	/* extent is in free fragment list of
					space */
#define	XDES_FULL_FRAG		3	/* extent is in full fragment list of
					space */
#define	XDES_FSEG		4	/* extent belongs to a segment */

/** File extent data structure size in bytes. */
#define	XDES_SIZE							\
	(XDES_BITMAP							\
	+ UT_BITS_IN_BYTES(FSP_EXTENT_SIZE * XDES_BITS_PER_PAGE))

/** File extent data structure size in bytes for MAX page size. */
#define	XDES_SIZE_MAX							\
	(XDES_BITMAP							\
	+ UT_BITS_IN_BYTES(FSP_EXTENT_SIZE_MAX * XDES_BITS_PER_PAGE))

/** File extent data structure size in bytes for MIN page size. */
#define	XDES_SIZE_MIN							\
	(XDES_BITMAP							\
	+ UT_BITS_IN_BYTES(FSP_EXTENT_SIZE_MIN * XDES_BITS_PER_PAGE))

/** Offset of the descriptor array on a descriptor page */
#define	XDES_ARR_OFFSET		(FSP_HEADER_OFFSET + FSP_HEADER_SIZE)

/* @} */

/**********************************************************************//**
Initializes the file space system. */
UNIV_INTERN
void
fsp_init(void);
/*==========*/
/**********************************************************************//**
Gets the size of the system tablespace from the tablespace header.  If
we do not have an auto-extending data file, this should be equal to
the size of the data files.  If there is an auto-extending data file,
this can be smaller.
@return	size in pages */
UNIV_INTERN
ulint
fsp_header_get_tablespace_size(void);
/*================================*/
/**********************************************************************//**
Reads the file space size stored in the header page.
@return	tablespace size stored in the space header */
UNIV_INTERN
ulint
fsp_get_size_low(
/*=============*/
	page_t*	page);	/*!< in: header page (page 0 in the tablespace) */
/**********************************************************************//**
Reads the space id from the first page of a tablespace.
@return	space id, ULINT UNDEFINED if error */
UNIV_INTERN
ulint
fsp_header_get_space_id(
/*====================*/
	const page_t*	page);	/*!< in: first page of a tablespace */
/**********************************************************************//**
Reads the space flags from the first page of a tablespace.
@return	flags */
UNIV_INTERN
ulint
fsp_header_get_flags(
/*=================*/
	const page_t*	page);	/*!< in: first page of a tablespace */
/**********************************************************************//**
Reads the compressed page size from the first page of a tablespace.
@return	compressed page size in bytes, or 0 if uncompressed */
UNIV_INTERN
ulint
fsp_header_get_zip_size(
/*====================*/
	const page_t*	page);	/*!< in: first page of a tablespace */
/**********************************************************************//**
Writes the space id and flags to a tablespace header.  The flags contain
row type, physical/compressed page size, and logical/uncompressed page
size of the tablespace. */
UNIV_INTERN
void
fsp_header_init_fields(
/*===================*/
	page_t*	page,		/*!< in/out: first page in the space */
	ulint	space_id,	/*!< in: space id */
	ulint	flags);		/*!< in: tablespace flags (FSP_SPACE_FLAGS):
				0, or table->flags if newer than COMPACT */
/**********************************************************************//**
Initializes the space header of a new created space and creates also the
insert buffer tree root if space == 0. */
UNIV_INTERN
void
fsp_header_init(
/*============*/
	ulint	space,		/*!< in: space id */
	ulint	size,		/*!< in: current size in blocks */
	mtr_t*	mtr);		/*!< in/out: mini-transaction */
/**********************************************************************//**
Increases the space size field of a space. */
UNIV_INTERN
void
fsp_header_inc_size(
/*================*/
	ulint	space,		/*!< in: space id */
	ulint	size_inc,	/*!< in: size increment in pages */
	mtr_t*	mtr);		/*!< in/out: mini-transaction */
/**********************************************************************//**
Creates a new segment.
@return the block where the segment header is placed, x-latched, NULL
if could not create segment because of lack of space */
UNIV_INTERN
buf_block_t*
fseg_create(
/*========*/
	ulint	space,	/*!< in: space id */
	ulint	page,	/*!< in: page where the segment header is placed: if
			this is != 0, the page must belong to another segment,
			if this is 0, a new page will be allocated and it
			will belong to the created segment */
	ulint	byte_offset, /*!< in: byte offset of the created segment header
			on the page */
	mtr_t*	mtr);	/*!< in/out: mini-transaction */
/**********************************************************************//**
Creates a new segment.
@return the block where the segment header is placed, x-latched, NULL
if could not create segment because of lack of space */
UNIV_INTERN
buf_block_t*
fseg_create_general(
/*================*/
	ulint	space,	/*!< in: space id */
	ulint	page,	/*!< in: page where the segment header is placed: if
			this is != 0, the page must belong to another segment,
			if this is 0, a new page will be allocated and it
			will belong to the created segment */
	ulint	byte_offset, /*!< in: byte offset of the created segment header
			on the page */
	ibool	has_done_reservation, /*!< in: TRUE if the caller has already
			done the reservation for the pages with
			fsp_reserve_free_extents (at least 2 extents: one for
			the inode and the other for the segment) then there is
			no need to do the check for this individual
			operation */
	mtr_t*	mtr);	/*!< in/out: mini-transaction */
/**********************************************************************//**
Calculates the number of pages reserved by a segment, and how many pages are
currently used.
@return	number of reserved pages */
UNIV_INTERN
ulint
fseg_n_reserved_pages(
/*==================*/
	fseg_header_t*	header,	/*!< in: segment header */
	ulint*		used,	/*!< out: number of pages used (<= reserved) */
	mtr_t*		mtr);	/*!< in/out: mini-transaction */
/**********************************************************************//**
Allocates a single free page from a segment. This function implements
the intelligent allocation strategy which tries to minimize
file space fragmentation.
@param[in/out] seg_header	segment header
@param[in] hint			hint of which page would be desirable
@param[in] direction		if the new page is needed because
				of an index page split, and records are
				inserted there in order, into which
				direction they go alphabetically: FSP_DOWN,
				FSP_UP, FSP_NO_DIR
@param[in/out] mtr		mini-transaction
@return	X-latched block, or NULL if no page could be allocated */
#define fseg_alloc_free_page(seg_header, hint, direction, mtr)		\
	fseg_alloc_free_page_general(seg_header, hint, direction,	\
				     FALSE, mtr, mtr)
/**********************************************************************//**
Allocates a single free page from a segment. This function implements
the intelligent allocation strategy which tries to minimize file space
fragmentation.
@retval NULL if no page could be allocated
@retval block, rw_lock_x_lock_count(&block->lock) == 1 if allocation succeeded
(init_mtr == mtr, or the page was not previously freed in mtr)
@retval block (not allocated or initialized) otherwise */
UNIV_INTERN
buf_block_t*
fseg_alloc_free_page_general(
/*=========================*/
	fseg_header_t*	seg_header,/*!< in/out: segment header */
	ulint		hint,	/*!< in: hint of which page would be
				desirable */
	byte		direction,/*!< in: if the new page is needed because
				of an index page split, and records are
				inserted there in order, into which
				direction they go alphabetically: FSP_DOWN,
				FSP_UP, FSP_NO_DIR */
	ibool		has_done_reservation, /*!< in: TRUE if the caller has
				already done the reservation for the page
				with fsp_reserve_free_extents, then there
				is no need to do the check for this individual
				page */
	mtr_t*		mtr,	/*!< in/out: mini-transaction */
	mtr_t*		init_mtr)/*!< in/out: mtr or another mini-transaction
				in which the page should be initialized.
				If init_mtr!=mtr, but the page is already
				latched in mtr, do not initialize the page. */
	MY_ATTRIBUTE((warn_unused_result, nonnull));
/**********************************************************************//**
Reserves free pages from a tablespace. All mini-transactions which may
use several pages from the tablespace should call this function beforehand
and reserve enough free extents so that they certainly will be able
to do their operation, like a B-tree page split, fully. Reservations
must be released with function fil_space_release_free_extents!

The alloc_type below has the following meaning: FSP_NORMAL means an
operation which will probably result in more space usage, like an
insert in a B-tree; FSP_UNDO means allocation to undo logs: if we are
deleting rows, then this allocation will in the long run result in
less space usage (after a purge); FSP_CLEANING means allocation done
in a physical record delete (like in a purge) or other cleaning operation
which will result in less space usage in the long run. We prefer the latter
two types of allocation: when space is scarce, FSP_NORMAL allocations
will not succeed, but the latter two allocations will succeed, if possible.
The purpose is to avoid dead end where the database is full but the
user cannot free any space because these freeing operations temporarily
reserve some space.

Single-table tablespaces whose size is < 32 pages are a special case. In this
function we would liberally reserve several 64 page extents for every page
split or merge in a B-tree. But we do not want to waste disk space if the table
only occupies < 32 pages. That is why we apply different rules in that special
case, just ensuring that there are 3 free pages available.
@return	TRUE if we were able to make the reservation */
UNIV_INTERN
ibool
fsp_reserve_free_extents(
/*=====================*/
	ulint*	n_reserved,/*!< out: number of extents actually reserved; if we
			return TRUE and the tablespace size is < 64 pages,
			then this can be 0, otherwise it is n_ext */
	ulint	space,	/*!< in: space id */
	ulint	n_ext,	/*!< in: number of extents to reserve */
	ulint	alloc_type,/*!< in: FSP_NORMAL, FSP_UNDO, or FSP_CLEANING */
	mtr_t*	mtr);	/*!< in: mini-transaction */
/**********************************************************************//**
This function should be used to get information on how much we still
will be able to insert new data to the database without running out the
tablespace. Only free extents are taken into account and we also subtract
the safety margin required by the above function fsp_reserve_free_extents.
@return	available space in kB */
UNIV_INTERN
ullint
fsp_get_available_space_in_free_extents(
/*====================================*/
	ulint	space);	/*!< in: space id */
/**********************************************************************//**
Frees a single page of a segment. */
UNIV_INTERN
void
fseg_free_page(
/*===========*/
	fseg_header_t*	seg_header, /*!< in: segment header */
	ulint		space,	/*!< in: space id */
	ulint		page,	/*!< in: page offset */
	mtr_t*		mtr);	/*!< in/out: mini-transaction */
/**********************************************************************//**
Checks if a single page of a segment is free.
@return	true if free */
UNIV_INTERN
bool
fseg_page_is_free(
/*==============*/
	fseg_header_t*	seg_header,	/*!< in: segment header */
	ulint		space,		/*!< in: space id */
	ulint		page)		/*!< in: page offset */
	MY_ATTRIBUTE((nonnull, warn_unused_result));
/**********************************************************************//**
Frees part of a segment. This function can be used to free a segment
by repeatedly calling this function in different mini-transactions.
Doing the freeing in a single mini-transaction might result in
too big a mini-transaction.
@return	TRUE if freeing completed */
UNIV_INTERN
ibool
fseg_free_step(
/*===========*/
	fseg_header_t*	header,	/*!< in, own: segment header; NOTE: if the header
				resides on the first page of the frag list
				of the segment, this pointer becomes obsolete
				after the last freeing step */
	mtr_t*		mtr);	/*!< in/out: mini-transaction */
/**********************************************************************//**
Frees part of a segment. Differs from fseg_free_step because this function
leaves the header page unfreed.
@return	TRUE if freeing completed, except the header page */
UNIV_INTERN
ibool
fseg_free_step_not_header(
/*======================*/
	fseg_header_t*	header,	/*!< in: segment header which must reside on
				the first fragment page of the segment */
	mtr_t*		mtr);	/*!< in/out: mini-transaction */
/***********************************************************************//**
Checks if a page address is an extent descriptor page address.
@return	TRUE if a descriptor page */
UNIV_INLINE
ibool
fsp_descr_page(
/*===========*/
	ulint	zip_size,/*!< in: compressed page size in bytes;
			0 for uncompressed pages */
	ulint	page_no);/*!< in: page number */
/***********************************************************//**
Parses a redo log record of a file page init.
@return	end of log record or NULL */
UNIV_INTERN
byte*
fsp_parse_init_file_page(
/*=====================*/
	byte*		ptr,	/*!< in: buffer */
	byte*		end_ptr, /*!< in: buffer end */
	buf_block_t*	block);	/*!< in: block or NULL */
/*******************************************************************//**
Validates the file space system and its segments.
@return	TRUE if ok */
UNIV_INTERN
ibool
fsp_validate(
/*=========*/
	ulint	space);	/*!< in: space id */
/*******************************************************************//**
Prints info of a file space. */
UNIV_INTERN
void
fsp_print(
/*======*/
	ulint	space);	/*!< in: space id */
#ifdef UNIV_DEBUG
/*******************************************************************//**
Validates a segment.
@return	TRUE if ok */
UNIV_INTERN
ibool
fseg_validate(
/*==========*/
	fseg_header_t*	header, /*!< in: segment header */
	mtr_t*		mtr);	/*!< in/out: mini-transaction */
#endif /* UNIV_DEBUG */
#ifdef UNIV_BTR_PRINT
/*******************************************************************//**
Writes info of a segment. */
UNIV_INTERN
void
fseg_print(
/*=======*/
	fseg_header_t*	header, /*!< in: segment header */
	mtr_t*		mtr);	/*!< in/out: mini-transaction */
#endif /* UNIV_BTR_PRINT */

/********************************************************************//**
Validate and return the tablespace flags, which are stored in the
tablespace header at offset FSP_SPACE_FLAGS.  They should be 0 for
ROW_FORMAT=COMPACT and ROW_FORMAT=REDUNDANT. The newer row formats,
COMPRESSED and DYNAMIC, use a file format > Antelope so they should
have a file format number plus the DICT_TF_COMPACT bit set.
@return	true if check ok */
UNIV_INLINE
bool
fsp_flags_is_valid(
/*===============*/
	ulint	flags)		/*!< in: tablespace flags */
	MY_ATTRIBUTE((warn_unused_result, const));
/********************************************************************//**
Determine if the tablespace is compressed from dict_table_t::flags.
@return	TRUE if compressed, FALSE if not compressed */
UNIV_INLINE
ibool
fsp_flags_is_compressed(
/*====================*/
	ulint	flags);	/*!< in: tablespace flags */

/********************************************************************//**
Calculates the descriptor index within a descriptor page.
@return	descriptor index */
UNIV_INLINE
ulint
xdes_calc_descriptor_index(
/*=======================*/
	ulint	zip_size,	/*!< in: compressed page size in bytes;
				0 for uncompressed pages */
	ulint	offset);	/*!< in: page offset */

/**********************************************************************//**
Gets a descriptor bit of a page.
@return	TRUE if free */
UNIV_INLINE
ibool
xdes_get_bit(
/*=========*/
	const xdes_t*	descr,	/*!< in: descriptor */
	ulint		bit,	/*!< in: XDES_FREE_BIT or XDES_CLEAN_BIT */
	ulint		offset);/*!< in: page offset within extent:
				0 ... FSP_EXTENT_SIZE - 1 */

/********************************************************************//**
Calculates the page where the descriptor of a page resides.
@return	descriptor page offset */
UNIV_INLINE
ulint
xdes_calc_descriptor_page(
/*======================*/
	ulint	zip_size,	/*!< in: compressed page size in bytes;
				0 for uncompressed pages */
	ulint	offset);	/*!< in: page offset */

#endif /* !UNIV_INNOCHECKSUM */

/********************************************************************//**
Extract the zip size from tablespace flags.  A tablespace has only one
physical page size whether that page is compressed or not.
@return	compressed page size of the file-per-table tablespace in bytes,
or zero if the table is not compressed.  */
UNIV_INLINE
ulint
fsp_flags_get_zip_size(
/*====================*/
	ulint	flags);		/*!< in: tablespace flags */
/********************************************************************//**
Extract the page size from tablespace flags.
@return	page size of the tablespace in bytes */
UNIV_INLINE
ulint
fsp_flags_get_page_size(
/*====================*/
	ulint	flags);		/*!< in: tablespace flags */

/*********************************************************************/
/* @return offset into fsp header where crypt data is stored */
UNIV_INTERN
ulint
fsp_header_get_crypt_offset(
/*========================*/
	ulint zip_size,		/*!< in: zip_size */
	ulint* max_size);	/*!< out: free space after offset */

#define fsp_page_is_free(space,page,mtr) \
	fsp_page_is_free_func(space,page,mtr, __FILE__, __LINE__)

/**********************************************************************//**
Checks if a single page is free.
@return	true if free */
UNIV_INTERN
bool
fsp_page_is_free_func(
/*==============*/
	ulint		space,		/*!< in: space id */
	ulint		page,		/*!< in: page offset */
	mtr_t*		mtr,		/*!< in/out: mini-transaction */
	const char *file,
	ulint line);

#ifndef UNIV_NONINL
#include "fsp0fsp.ic"
#endif

#endif