MDEV-6927: Share more structures

Merge Facebook commit f981a51a47519b0ba527917887f8adc6df9ae147
authored by Steaphan Greene from https://github.com/facebook/mysql-5.6.

This just moves some structure definitions from inside a
single .cc file to a shared .h file, with a few tweaks to
allow these structures to be shared.

On its own, it should have no actual effect. This is needed later.

storage/innobase/fil/fil0fil.cc

@@ -140,180 +140,9 @@ UNIV_INTERN mysql_pfs_key_t	fil_system_mutex_key;
 UNIV_INTERN mysql_pfs_key_t	fil_space_latch_key;
 #endif /* UNIV_PFS_RWLOCK */
 
-/** File node of a tablespace or the log data space */
-struct fil_node_t {
-	fil_space_t*	space;	/*!< backpointer to the space where this node
-				belongs */
-	char*		name;	/*!< path to the file */
-	ibool		open;	/*!< TRUE if file open */
-	os_file_t	handle;	/*!< OS handle to the file, if file open */
-	os_event_t	sync_event;/*!< Condition event to group and
-				serialize calls to fsync */
-	ibool		is_raw_disk;/*!< TRUE if the 'file' is actually a raw
-				device or a raw disk partition */
-	ulint		size;	/*!< size of the file in database pages, 0 if
-				not known yet; the possible last incomplete
-				megabyte may be ignored if space == 0 */
-	ulint		n_pending;
-				/*!< count of pending i/o's on this file;
-				closing of the file is not allowed if
-				this is > 0 */
-	ulint		n_pending_flushes;
-				/*!< count of pending flushes on this file;
-				closing of the file is not allowed if
-				this is > 0 */
-	ibool		being_extended;
-				/*!< TRUE if the node is currently
-				being extended. */
-	ib_int64_t	modification_counter;/*!< when we write to the file we
-				increment this by one */
-	ib_int64_t	flush_counter;/*!< up to what
-				modification_counter value we have
-				flushed the modifications to disk */
-	UT_LIST_NODE_T(fil_node_t) chain;
-				/*!< link field for the file chain */
-	UT_LIST_NODE_T(fil_node_t) LRU;
-				/*!< link field for the LRU list */
-	ulint		magic_n;/*!< FIL_NODE_MAGIC_N */
-};
-
-/** Value of fil_node_t::magic_n */
-#define	FIL_NODE_MAGIC_N	89389
-
-/** Tablespace or log data space: let us call them by a common name space */
-struct fil_space_t {
-	char*		name;	/*!< space name = the path to the first file in
-				it */
-	ulint		id;	/*!< space id */
-	ib_int64_t	tablespace_version;
-				/*!< in DISCARD/IMPORT this timestamp
-				is used to check if we should ignore
-				an insert buffer merge request for a
-				page because it actually was for the
-				previous incarnation of the space */
-	ibool		mark;	/*!< this is set to TRUE at database startup if
-				the space corresponds to a table in the InnoDB
-				data dictionary; so we can print a warning of
-				orphaned tablespaces */
-	ibool		stop_ios;/*!< TRUE if we want to rename the
-				.ibd file of tablespace and want to
-				stop temporarily posting of new i/o
-				requests on the file */
-	ibool		stop_new_ops;
-				/*!< we set this TRUE when we start
-				deleting a single-table tablespace.
-				When this is set following new ops
-				are not allowed:
-				* read IO request
-				* ibuf merge
-				* file flush
-				Note that we can still possibly have
-				new write operations because we don't
-				check this flag when doing flush
-				batches. */
-	ulint		purpose;/*!< FIL_TABLESPACE, FIL_LOG, or
-				FIL_ARCH_LOG */
-	UT_LIST_BASE_NODE_T(fil_node_t) chain;
-				/*!< base node for the file chain */
-	ulint		size;	/*!< space size in pages; 0 if a single-table
-				tablespace whose size we do not know yet;
-				last incomplete megabytes in data files may be
-				ignored if space == 0 */
-	ulint		flags;	/*!< tablespace flags; see
-				fsp_flags_is_valid(),
-				fsp_flags_get_zip_size() */
-	ulint		n_reserved_extents;
-				/*!< number of reserved free extents for
-				ongoing operations like B-tree page split */
-	ulint		n_pending_flushes; /*!< this is positive when flushing
-				the tablespace to disk; dropping of the
-				tablespace is forbidden if this is positive */
-	ulint		n_pending_ops;/*!< this is positive when we
-				have pending operations against this
-				tablespace. The pending operations can
-				be ibuf merges or lock validation code
-				trying to read a block.
-				Dropping of the tablespace is forbidden
-				if this is positive */
-	hash_node_t	hash;	/*!< hash chain node */
-	hash_node_t	name_hash;/*!< hash chain the name_hash table */
-#ifndef UNIV_HOTBACKUP
-	rw_lock_t	latch;	/*!< latch protecting the file space storage
-				allocation */
-#endif /* !UNIV_HOTBACKUP */
-	UT_LIST_NODE_T(fil_space_t) unflushed_spaces;
-				/*!< list of spaces with at least one unflushed
-				file we have written to */
-	bool		is_in_unflushed_spaces;
-				/*!< true if this space is currently in
-				unflushed_spaces */
-	UT_LIST_NODE_T(fil_space_t) space_list;
-				/*!< list of all spaces */
-	ulint		magic_n;/*!< FIL_SPACE_MAGIC_N */
-};
-
-/** Value of fil_space_t::magic_n */
-#define	FIL_SPACE_MAGIC_N	89472
-
-/** The tablespace memory cache; also the totality of logs (the log
-data space) is stored here; below we talk about tablespaces, but also
-the ib_logfiles form a 'space' and it is handled here */
-struct fil_system_t {
-#ifndef UNIV_HOTBACKUP
-	ib_mutex_t		mutex;		/*!< The mutex protecting the cache */
-#endif /* !UNIV_HOTBACKUP */
-	hash_table_t*	spaces;		/*!< The hash table of spaces in the
-					system; they are hashed on the space
-					id */
-	hash_table_t*	name_hash;	/*!< hash table based on the space
-					name */
-	UT_LIST_BASE_NODE_T(fil_node_t) LRU;
-					/*!< base node for the LRU list of the
-					most recently used open files with no
-					pending i/o's; if we start an i/o on
-					the file, we first remove it from this
-					list, and return it to the start of
-					the list when the i/o ends;
-					log files and the system tablespace are
-					not put to this list: they are opened
-					after the startup, and kept open until
-					shutdown */
-	UT_LIST_BASE_NODE_T(fil_space_t) unflushed_spaces;
-					/*!< base node for the list of those
-					tablespaces whose files contain
-					unflushed writes; those spaces have
-					at least one file node where
-					modification_counter > flush_counter */
-	ulint		n_open;		/*!< number of files currently open */
-	ulint		max_n_open;	/*!< n_open is not allowed to exceed
-					this */
-	ib_int64_t	modification_counter;/*!< when we write to a file we
-					increment this by one */
-	ulint		max_assigned_id;/*!< maximum space id in the existing
-					tables, or assigned during the time
-					mysqld has been up; at an InnoDB
-					startup we scan the data dictionary
-					and set here the maximum of the
-					space id's of the tables there */
-	ib_int64_t	tablespace_version;
-					/*!< a counter which is incremented for
-					every space object memory creation;
-					every space mem object gets a
-					'timestamp' from this; in DISCARD/
-					IMPORT this is used to check if we
-					should ignore an insert buffer merge
-					request */
-	UT_LIST_BASE_NODE_T(fil_space_t) space_list;
-					/*!< list of all file spaces */
-	ibool		space_id_reuse_warned;
-					/* !< TRUE if fil_space_create()
-					has issued a warning about
-					potential space_id reuse */
-};
-
 /** The tablespace memory cache. This variable is NULL before the module is
 initialized. */
-static fil_system_t*	fil_system	= NULL;
+fil_system_t*	fil_system	= NULL;
 
 /** Determine if (i) is a user tablespace id or not. */
 # define fil_is_user_tablespace_id(i) ((i) > srv_undo_tablespaces_open)

storage/innobase/include/fil0fil.h

@@ -33,6 +33,7 @@ Created 10/25/1995 Heikki Tuuri
 #include "dict0types.h"
 #include "ut0byte.h"
 #include "os0file.h"
+#include "hash0hash.h"
 #ifndef UNIV_HOTBACKUP
 #include "sync0rw.h"
 #include "ibuf0types.h"
@@ -190,6 +191,183 @@ struct fsp_open_info {
 #endif /* UNIV_LOG_ARCHIVE */
 };
 
+struct fil_space_t;
+
+/** File node of a tablespace or the log data space */
+struct fil_node_t {
+	fil_space_t*	space;	/*!< backpointer to the space where this node
+				belongs */
+	char*		name;	/*!< path to the file */
+	ibool		open;	/*!< TRUE if file open */
+	os_file_t	handle;	/*!< OS handle to the file, if file open */
+	os_event_t	sync_event;/*!< Condition event to group and
+				serialize calls to fsync */
+	ibool		is_raw_disk;/*!< TRUE if the 'file' is actually a raw
+				device or a raw disk partition */
+	ulint		size;	/*!< size of the file in database pages, 0 if
+				not known yet; the possible last incomplete
+				megabyte may be ignored if space == 0 */
+	ulint		n_pending;
+				/*!< count of pending i/o's on this file;
+				closing of the file is not allowed if
+				this is > 0 */
+	ulint		n_pending_flushes;
+				/*!< count of pending flushes on this file;
+				closing of the file is not allowed if
+				this is > 0 */
+	ibool		being_extended;
+				/*!< TRUE if the node is currently
+				being extended. */
+	ib_int64_t	modification_counter;/*!< when we write to the file we
+				increment this by one */
+	ib_int64_t	flush_counter;/*!< up to what
+				modification_counter value we have
+				flushed the modifications to disk */
+	UT_LIST_NODE_T(fil_node_t) chain;
+				/*!< link field for the file chain */
+	UT_LIST_NODE_T(fil_node_t) LRU;
+				/*!< link field for the LRU list */
+	ulint		magic_n;/*!< FIL_NODE_MAGIC_N */
+};
+
+/** Value of fil_node_t::magic_n */
+#define	FIL_NODE_MAGIC_N	89389
+
+/** Tablespace or log data space: let us call them by a common name space */
+struct fil_space_t {
+	char*		name;	/*!< space name = the path to the first file in
+				it */
+	ulint		id;	/*!< space id */
+	ib_int64_t	tablespace_version;
+				/*!< in DISCARD/IMPORT this timestamp
+				is used to check if we should ignore
+				an insert buffer merge request for a
+				page because it actually was for the
+				previous incarnation of the space */
+	ibool		mark;	/*!< this is set to TRUE at database startup if
+				the space corresponds to a table in the InnoDB
+				data dictionary; so we can print a warning of
+				orphaned tablespaces */
+	ibool		stop_ios;/*!< TRUE if we want to rename the
+				.ibd file of tablespace and want to
+				stop temporarily posting of new i/o
+				requests on the file */
+	ibool		stop_new_ops;
+				/*!< we set this TRUE when we start
+				deleting a single-table tablespace.
+				When this is set following new ops
+				are not allowed:
+				* read IO request
+				* ibuf merge
+				* file flush
+				Note that we can still possibly have
+				new write operations because we don't
+				check this flag when doing flush
+				batches. */
+	ulint		purpose;/*!< FIL_TABLESPACE, FIL_LOG, or
+				FIL_ARCH_LOG */
+	UT_LIST_BASE_NODE_T(fil_node_t) chain;
+				/*!< base node for the file chain */
+	ulint		size;	/*!< space size in pages; 0 if a single-table
+				tablespace whose size we do not know yet;
+				last incomplete megabytes in data files may be
+				ignored if space == 0 */
+	ulint		flags;	/*!< tablespace flags; see
+				fsp_flags_is_valid(),
+				fsp_flags_get_zip_size() */
+	ulint		n_reserved_extents;
+				/*!< number of reserved free extents for
+				ongoing operations like B-tree page split */
+	ulint		n_pending_flushes; /*!< this is positive when flushing
+				the tablespace to disk; dropping of the
+				tablespace is forbidden if this is positive */
+	ulint		n_pending_ops;/*!< this is positive when we
+				have pending operations against this
+				tablespace. The pending operations can
+				be ibuf merges or lock validation code
+				trying to read a block.
+				Dropping of the tablespace is forbidden
+				if this is positive */
+	hash_node_t	hash;	/*!< hash chain node */
+	hash_node_t	name_hash;/*!< hash chain the name_hash table */
+#ifndef UNIV_HOTBACKUP
+	rw_lock_t	latch;	/*!< latch protecting the file space storage
+				allocation */
+#endif /* !UNIV_HOTBACKUP */
+	UT_LIST_NODE_T(fil_space_t) unflushed_spaces;
+				/*!< list of spaces with at least one unflushed
+				file we have written to */
+	bool		is_in_unflushed_spaces;
+				/*!< true if this space is currently in
+				unflushed_spaces */
+	UT_LIST_NODE_T(fil_space_t) space_list;
+				/*!< list of all spaces */
+	ulint		magic_n;/*!< FIL_SPACE_MAGIC_N */
+};
+
+/** Value of fil_space_t::magic_n */
+#define	FIL_SPACE_MAGIC_N	89472
+
+/** The tablespace memory cache; also the totality of logs (the log
+data space) is stored here; below we talk about tablespaces, but also
+the ib_logfiles form a 'space' and it is handled here */
+struct fil_system_t {
+#ifndef UNIV_HOTBACKUP
+	ib_mutex_t		mutex;		/*!< The mutex protecting the cache */
+#endif /* !UNIV_HOTBACKUP */
+	hash_table_t*	spaces;		/*!< The hash table of spaces in the
+					system; they are hashed on the space
+					id */
+	hash_table_t*	name_hash;	/*!< hash table based on the space
+					name */
+	UT_LIST_BASE_NODE_T(fil_node_t) LRU;
+					/*!< base node for the LRU list of the
+					most recently used open files with no
+					pending i/o's; if we start an i/o on
+					the file, we first remove it from this
+					list, and return it to the start of
+					the list when the i/o ends;
+					log files and the system tablespace are
+					not put to this list: they are opened
+					after the startup, and kept open until
+					shutdown */
+	UT_LIST_BASE_NODE_T(fil_space_t) unflushed_spaces;
+					/*!< base node for the list of those
+					tablespaces whose files contain
+					unflushed writes; those spaces have
+					at least one file node where
+					modification_counter > flush_counter */
+	ulint		n_open;		/*!< number of files currently open */
+	ulint		max_n_open;	/*!< n_open is not allowed to exceed
+					this */
+	ib_int64_t	modification_counter;/*!< when we write to a file we
+					increment this by one */
+	ulint		max_assigned_id;/*!< maximum space id in the existing
+					tables, or assigned during the time
+					mysqld has been up; at an InnoDB
+					startup we scan the data dictionary
+					and set here the maximum of the
+					space id's of the tables there */
+	ib_int64_t	tablespace_version;
+					/*!< a counter which is incremented for
+					every space object memory creation;
+					every space mem object gets a
+					'timestamp' from this; in DISCARD/
+					IMPORT this is used to check if we
+					should ignore an insert buffer merge
+					request */
+	UT_LIST_BASE_NODE_T(fil_space_t) space_list;
+					/*!< list of all file spaces */
+	ibool		space_id_reuse_warned;
+					/* !< TRUE if fil_space_create()
+					has issued a warning about
+					potential space_id reuse */
+};
+
+/** The tablespace memory cache. This variable is NULL before the module is
+initialized. */
+extern fil_system_t*	fil_system;
+
 #ifndef UNIV_HOTBACKUP
 /*******************************************************************//**
 Returns the version number of a tablespace, -1 if not found.

storage/xtradb/fil/fil0fil.cc

@@ -140,181 +140,15 @@ UNIV_INTERN mysql_pfs_key_t	fil_system_mutex_key;
 UNIV_INTERN mysql_pfs_key_t	fil_space_latch_key;
 #endif /* UNIV_PFS_RWLOCK */
 
-/** File node of a tablespace or the log data space */
-struct fil_node_t {
-	fil_space_t*	space;	/*!< backpointer to the space where this node
-				belongs */
-	char*		name;	/*!< path to the file */
-	ibool		open;	/*!< TRUE if file open */
-	os_file_t	handle;	/*!< OS handle to the file, if file open */
-	os_event_t	sync_event;/*!< Condition event to group and
-				serialize calls to fsync */
-	ibool		is_raw_disk;/*!< TRUE if the 'file' is actually a raw
-				device or a raw disk partition */
-	ulint		size;	/*!< size of the file in database pages, 0 if
-				not known yet; the possible last incomplete
-				megabyte may be ignored if space == 0 */
-	ulint		n_pending;
-				/*!< count of pending i/o's on this file;
-				closing of the file is not allowed if
-				this is > 0 */
-	ulint		n_pending_flushes;
-				/*!< count of pending flushes on this file;
-				closing of the file is not allowed if
-				this is > 0 */
-	ibool		being_extended;
-				/*!< TRUE if the node is currently
-				being extended. */
-	ib_int64_t	modification_counter;/*!< when we write to the file we
-				increment this by one */
-	ib_int64_t	flush_counter;/*!< up to what
-				modification_counter value we have
-				flushed the modifications to disk */
-	UT_LIST_NODE_T(fil_node_t) chain;
-				/*!< link field for the file chain */
-	UT_LIST_NODE_T(fil_node_t) LRU;
-				/*!< link field for the LRU list */
-	ulint		magic_n;/*!< FIL_NODE_MAGIC_N */
-};
-
 /** Value of fil_node_t::magic_n */
 #define	FIL_NODE_MAGIC_N	89389
 
-/** Tablespace or log data space: let us call them by a common name space */
-struct fil_space_t {
-	char*		name;	/*!< space name = the path to the first file in
-				it */
-	ulint		id;	/*!< space id */
-	ib_int64_t	tablespace_version;
-				/*!< in DISCARD/IMPORT this timestamp
-				is used to check if we should ignore
-				an insert buffer merge request for a
-				page because it actually was for the
-				previous incarnation of the space */
-	ibool		mark;	/*!< this is set to TRUE at database startup if
-				the space corresponds to a table in the InnoDB
-				data dictionary; so we can print a warning of
-				orphaned tablespaces */
-	ibool		stop_ios;/*!< TRUE if we want to rename the
-				.ibd file of tablespace and want to
-				stop temporarily posting of new i/o
-				requests on the file */
-	ibool		stop_new_ops;
-				/*!< we set this TRUE when we start
-				deleting a single-table tablespace.
-				When this is set following new ops
-				are not allowed:
-				* read IO request
-				* ibuf merge
-				* file flush
-				Note that we can still possibly have
-				new write operations because we don't
-				check this flag when doing flush
-				batches. */
-	ulint		purpose;/*!< FIL_TABLESPACE, FIL_LOG, or
-				FIL_ARCH_LOG */
-	UT_LIST_BASE_NODE_T(fil_node_t) chain;
-				/*!< base node for the file chain */
-	ulint		size;	/*!< space size in pages; 0 if a single-table
-				tablespace whose size we do not know yet;
-				last incomplete megabytes in data files may be
-				ignored if space == 0 */
-	ulint		flags;	/*!< tablespace flags; see
-				fsp_flags_is_valid(),
-				fsp_flags_get_zip_size() */
-	ulint		n_reserved_extents;
-				/*!< number of reserved free extents for
-				ongoing operations like B-tree page split */
-	ulint		n_pending_flushes; /*!< this is positive when flushing
-				the tablespace to disk; dropping of the
-				tablespace is forbidden if this is positive */
-	ulint		n_pending_ops;/*!< this is positive when we
-				have pending operations against this
-				tablespace. The pending operations can
-				be ibuf merges or lock validation code
-				trying to read a block.
-				Dropping of the tablespace is forbidden
-				if this is positive */
-	hash_node_t	hash;	/*!< hash chain node */
-	hash_node_t	name_hash;/*!< hash chain the name_hash table */
-#ifndef UNIV_HOTBACKUP
-	prio_rw_lock_t	latch;	/*!< latch protecting the file space storage
-				allocation */
-#endif /* !UNIV_HOTBACKUP */
-	UT_LIST_NODE_T(fil_space_t) unflushed_spaces;
-				/*!< list of spaces with at least one unflushed
-				file we have written to */
-	bool		is_in_unflushed_spaces;
-				/*!< true if this space is currently in
-				unflushed_spaces */
-	ibool		is_corrupt;
-	UT_LIST_NODE_T(fil_space_t) space_list;
-				/*!< list of all spaces */
-	ulint		magic_n;/*!< FIL_SPACE_MAGIC_N */
-};
-
 /** Value of fil_space_t::magic_n */
 #define	FIL_SPACE_MAGIC_N	89472
 
-/** The tablespace memory cache; also the totality of logs (the log
-data space) is stored here; below we talk about tablespaces, but also
-the ib_logfiles form a 'space' and it is handled here */
-struct fil_system_t {
-#ifndef UNIV_HOTBACKUP
-	ib_mutex_t		mutex;		/*!< The mutex protecting the cache */
-#endif /* !UNIV_HOTBACKUP */
-	hash_table_t*	spaces;		/*!< The hash table of spaces in the
-					system; they are hashed on the space
-					id */
-	hash_table_t*	name_hash;	/*!< hash table based on the space
-					name */
-	UT_LIST_BASE_NODE_T(fil_node_t) LRU;
-					/*!< base node for the LRU list of the
-					most recently used open files with no
-					pending i/o's; if we start an i/o on
-					the file, we first remove it from this
-					list, and return it to the start of
-					the list when the i/o ends;
-					log files and the system tablespace are
-					not put to this list: they are opened
-					after the startup, and kept open until
-					shutdown */
-	UT_LIST_BASE_NODE_T(fil_space_t) unflushed_spaces;
-					/*!< base node for the list of those
-					tablespaces whose files contain
-					unflushed writes; those spaces have
-					at least one file node where
-					modification_counter > flush_counter */
-	ulint		n_open;		/*!< number of files currently open */
-	ulint		max_n_open;	/*!< n_open is not allowed to exceed
-					this */
-	ib_int64_t	modification_counter;/*!< when we write to a file we
-					increment this by one */
-	ulint		max_assigned_id;/*!< maximum space id in the existing
-					tables, or assigned during the time
-					mysqld has been up; at an InnoDB
-					startup we scan the data dictionary
-					and set here the maximum of the
-					space id's of the tables there */
-	ib_int64_t	tablespace_version;
-					/*!< a counter which is incremented for
-					every space object memory creation;
-					every space mem object gets a
-					'timestamp' from this; in DISCARD/
-					IMPORT this is used to check if we
-					should ignore an insert buffer merge
-					request */
-	UT_LIST_BASE_NODE_T(fil_space_t) space_list;
-					/*!< list of all file spaces */
-	ibool		space_id_reuse_warned;
-					/* !< TRUE if fil_space_create()
-					has issued a warning about
-					potential space_id reuse */
-};
-
 /** The tablespace memory cache. This variable is NULL before the module is
 initialized. */
-static fil_system_t*	fil_system	= NULL;
+fil_system_t*	fil_system	= NULL;
 
 /** Determine if (i) is a user tablespace id or not. */
 # define fil_is_user_tablespace_id(i) ((i) > srv_undo_tablespaces_open)

storage/xtradb/include/fil0fil.h

@@ -33,6 +33,7 @@ Created 10/25/1995 Heikki Tuuri
 #include "dict0types.h"
 #include "ut0byte.h"
 #include "os0file.h"
+#include "hash0hash.h"
 #ifndef UNIV_HOTBACKUP
 #include "sync0rw.h"
 #include "ibuf0types.h"
@@ -188,6 +189,184 @@ struct fsp_open_info {
 	ulint		flags;		/*!< Tablespace flags */
 };
 
+struct fil_space_t;
+
+/** File node of a tablespace or the log data space */
+struct fil_node_t {
+	fil_space_t*	space;	/*!< backpointer to the space where this node
+				belongs */
+	char*		name;	/*!< path to the file */
+	ibool		open;	/*!< TRUE if file open */
+	os_file_t	handle;	/*!< OS handle to the file, if file open */
+	os_event_t	sync_event;/*!< Condition event to group and
+				serialize calls to fsync */
+	ibool		is_raw_disk;/*!< TRUE if the 'file' is actually a raw
+				device or a raw disk partition */
+	ulint		size;	/*!< size of the file in database pages, 0 if
+				not known yet; the possible last incomplete
+				megabyte may be ignored if space == 0 */
+	ulint		n_pending;
+				/*!< count of pending i/o's on this file;
+				closing of the file is not allowed if
+				this is > 0 */
+	ulint		n_pending_flushes;
+				/*!< count of pending flushes on this file;
+				closing of the file is not allowed if
+				this is > 0 */
+	ibool		being_extended;
+				/*!< TRUE if the node is currently
+				being extended. */
+	ib_int64_t	modification_counter;/*!< when we write to the file we
+				increment this by one */
+	ib_int64_t	flush_counter;/*!< up to what
+				modification_counter value we have
+				flushed the modifications to disk */
+	UT_LIST_NODE_T(fil_node_t) chain;
+				/*!< link field for the file chain */
+	UT_LIST_NODE_T(fil_node_t) LRU;
+				/*!< link field for the LRU list */
+	ulint		magic_n;/*!< FIL_NODE_MAGIC_N */
+};
+
+/** Value of fil_node_t::magic_n */
+#define	FIL_NODE_MAGIC_N	89389
+
+/** Tablespace or log data space: let us call them by a common name space */
+struct fil_space_t {
+	char*		name;	/*!< space name = the path to the first file in
+				it */
+	ulint		id;	/*!< space id */
+	ib_int64_t	tablespace_version;
+				/*!< in DISCARD/IMPORT this timestamp
+				is used to check if we should ignore
+				an insert buffer merge request for a
+				page because it actually was for the
+				previous incarnation of the space */
+	ibool		mark;	/*!< this is set to TRUE at database startup if
+				the space corresponds to a table in the InnoDB
+				data dictionary; so we can print a warning of
+				orphaned tablespaces */
+	ibool		stop_ios;/*!< TRUE if we want to rename the
+				.ibd file of tablespace and want to
+				stop temporarily posting of new i/o
+				requests on the file */
+	ibool		stop_new_ops;
+				/*!< we set this TRUE when we start
+				deleting a single-table tablespace.
+				When this is set following new ops
+				are not allowed:
+				* read IO request
+				* ibuf merge
+				* file flush
+				Note that we can still possibly have
+				new write operations because we don't
+				check this flag when doing flush
+				batches. */
+	ulint		purpose;/*!< FIL_TABLESPACE, FIL_LOG, or
+				FIL_ARCH_LOG */
+	UT_LIST_BASE_NODE_T(fil_node_t) chain;
+				/*!< base node for the file chain */
+	ulint		size;	/*!< space size in pages; 0 if a single-table
+				tablespace whose size we do not know yet;
+				last incomplete megabytes in data files may be
+				ignored if space == 0 */
+	ulint		flags;	/*!< tablespace flags; see
+				fsp_flags_is_valid(),
+				fsp_flags_get_zip_size() */
+	ulint		n_reserved_extents;
+				/*!< number of reserved free extents for
+				ongoing operations like B-tree page split */
+	ulint		n_pending_flushes; /*!< this is positive when flushing
+				the tablespace to disk; dropping of the
+				tablespace is forbidden if this is positive */
+	ulint		n_pending_ops;/*!< this is positive when we
+				have pending operations against this
+				tablespace. The pending operations can
+				be ibuf merges or lock validation code
+				trying to read a block.
+				Dropping of the tablespace is forbidden
+				if this is positive */
+	hash_node_t	hash;	/*!< hash chain node */
+	hash_node_t	name_hash;/*!< hash chain the name_hash table */
+#ifndef UNIV_HOTBACKUP
+	prio_rw_lock_t	latch;	/*!< latch protecting the file space storage
+				allocation */
+#endif /* !UNIV_HOTBACKUP */
+	UT_LIST_NODE_T(fil_space_t) unflushed_spaces;
+				/*!< list of spaces with at least one unflushed
+				file we have written to */
+	bool		is_in_unflushed_spaces;
+				/*!< true if this space is currently in
+				unflushed_spaces */
+	ibool		is_corrupt;
+	UT_LIST_NODE_T(fil_space_t) space_list;
+				/*!< list of all spaces */
+	ulint		magic_n;/*!< FIL_SPACE_MAGIC_N */
+};
+
+/** Value of fil_space_t::magic_n */
+#define	FIL_SPACE_MAGIC_N	89472
+
+/** The tablespace memory cache; also the totality of logs (the log
+data space) is stored here; below we talk about tablespaces, but also
+the ib_logfiles form a 'space' and it is handled here */
+struct fil_system_t {
+#ifndef UNIV_HOTBACKUP
+	ib_mutex_t		mutex;		/*!< The mutex protecting the cache */
+#endif /* !UNIV_HOTBACKUP */
+	hash_table_t*	spaces;		/*!< The hash table of spaces in the
+					system; they are hashed on the space
+					id */
+	hash_table_t*	name_hash;	/*!< hash table based on the space
+					name */
+	UT_LIST_BASE_NODE_T(fil_node_t) LRU;
+					/*!< base node for the LRU list of the
+					most recently used open files with no
+					pending i/o's; if we start an i/o on
+					the file, we first remove it from this
+					list, and return it to the start of
+					the list when the i/o ends;
+					log files and the system tablespace are
+					not put to this list: they are opened
+					after the startup, and kept open until
+					shutdown */
+	UT_LIST_BASE_NODE_T(fil_space_t) unflushed_spaces;
+					/*!< base node for the list of those
+					tablespaces whose files contain
+					unflushed writes; those spaces have
+					at least one file node where
+					modification_counter > flush_counter */
+	ulint		n_open;		/*!< number of files currently open */
+	ulint		max_n_open;	/*!< n_open is not allowed to exceed
+					this */
+	ib_int64_t	modification_counter;/*!< when we write to a file we
+					increment this by one */
+	ulint		max_assigned_id;/*!< maximum space id in the existing
+					tables, or assigned during the time
+					mysqld has been up; at an InnoDB
+					startup we scan the data dictionary
+					and set here the maximum of the
+					space id's of the tables there */
+	ib_int64_t	tablespace_version;
+					/*!< a counter which is incremented for
+					every space object memory creation;
+					every space mem object gets a
+					'timestamp' from this; in DISCARD/
+					IMPORT this is used to check if we
+					should ignore an insert buffer merge
+					request */
+	UT_LIST_BASE_NODE_T(fil_space_t) space_list;
+					/*!< list of all file spaces */
+	ibool		space_id_reuse_warned;
+					/* !< TRUE if fil_space_create()
+					has issued a warning about
+					potential space_id reuse */
+};
+
+/** The tablespace memory cache. This variable is NULL before the module is
+initialized. */
+extern fil_system_t*	fil_system;
+
 #ifndef UNIV_HOTBACKUP
 /*******************************************************************//**
 Returns the version number of a tablespace, -1 if not found.