Code clean-up related to MDEV-13167

xdes_get_descriptor_const(): New function, to get read-only access to
the allocation descriptor.

fseg_page_is_free(): Only acquire a shared latch on the tablespace,
not an exclusive latch. Calculate the descriptor page address before
acquiring the tablespace latch. If the page number is out of bounds,
return without fetching any page. Access only one descriptor page.

fsp_page_is_free(), fsp_page_is_free_func(): Remove.
Use fseg_page_is_free() instead.

fsp_init_file_page(): Move the debug parameter into a separate function.

btr_validate_level(): Remove the unused variable "seg".

storage/innobase/btr/btr0btr.cc

@@ -4846,7 +4846,6 @@ btr_validate_level(
 	bool		ret	= true;
 	mtr_t		mtr;
 	mem_heap_t*	heap	= mem_heap_create(256);
-	fseg_header_t*	seg;
 	ulint*		offsets	= NULL;
 	ulint*		offsets2= NULL;
 #ifdef UNIV_ZIP_DEBUG
@@ -4870,7 +4869,6 @@ btr_validate_level(
 
 	block = btr_root_block_get(index, RW_SX_LATCH, &mtr);
 	page = buf_block_get_frame(block);
-	seg = page + PAGE_HEADER + PAGE_BTR_SEG_TOP;
 
 #ifdef UNIV_DEBUG
 	if (dict_index_is_spatial(index)) {
@@ -4879,7 +4877,7 @@ btr_validate_level(
 	}
 #endif
 
-	const fil_space_t*	space	= fil_space_get(index->space);
+	fil_space_t*		space	= fil_space_get(index->space);
 	const page_size_t	table_page_size(
 		dict_table_page_size(index->table));
 	const page_size_t	space_page_size(space->flags);
@@ -4897,9 +4895,7 @@ btr_validate_level(
 	while (level != btr_page_get_level(page, &mtr)) {
 		const rec_t*	node_ptr;
 
-		if (fseg_page_is_free(seg,
-				      block->page.id.space(),
-				      block->page.id.page_no())) {
+		if (fseg_page_is_free(space, block->page.id.page_no())) {
 
 			btr_validate_report1(index, level, block);
 
@@ -4959,11 +4955,6 @@ btr_validate_level(
 	/* Now we are on the desired level. Loop through the pages on that
 	level. */
 
-	if (level == 0) {
-		/* Leaf pages are managed in their own file segment. */
-		seg -= PAGE_BTR_SEG_TOP - PAGE_BTR_SEG_LEAF;
-	}
-
 loop:
 	mem_heap_empty(heap);
 	offsets = offsets2 = NULL;
@@ -4982,9 +4973,7 @@ btr_validate_level(
 
 	ut_a(block->page.id.space() == index->space);
 
-	if (fseg_page_is_free(seg,
-			      block->page.id.space(),
-			      block->page.id.page_no())) {
+	if (fseg_page_is_free(space, block->page.id.page_no())) {
 
 		btr_validate_report1(index, level, block);
 

storage/innobase/fil/fil0crypt.cc

@@ -1723,7 +1723,7 @@ btr_scrub_get_block_and_allocation_status(
 
 	mtr_start(&local_mtr);
 
-	*allocation_status = fsp_page_is_free(space->id, offset, &local_mtr) ?
+	*allocation_status = fseg_page_is_free(space, offset) ?
 		BTR_SCRUB_PAGE_FREE :
 		BTR_SCRUB_PAGE_ALLOCATED;
 

storage/innobase/fsp/fsp0fsp.cc

@@ -506,6 +506,51 @@ xdes_get_descriptor(
 		       sp_header, space, offset, mtr));
 }
 
+/** Get the extent descriptor of a page.
+The page where the extent descriptor resides is x-locked. If the page
+offset is equal to the free limit of the space, we will add new
+extents from above the free limit to the space free list, if not free
+limit == space size. This adding is necessary to make the descriptor
+defined, as they are uninitialized above the free limit.
+@param[in]	space		tablespace
+@param[in]	page		descriptor page offset
+@param[in]	offset		page offset
+@param[in]	page_size	page size
+@param[in,out]	mtr		mini-transaction
+@return	the extent descriptor
+@retval	NULL	if the descriptor is not available */
+MY_ATTRIBUTE((warn_unused_result))
+static
+const xdes_t*
+xdes_get_descriptor_const(
+	const fil_space_t*	space,
+	page_no_t		page,
+	page_no_t		offset,
+	const page_size_t&	page_size,
+	mtr_t*			mtr)
+{
+	ut_ad(mtr_memo_contains(mtr, &space->latch, MTR_MEMO_S_LOCK));
+	ut_ad(offset < space->free_limit);
+	ut_ad(offset < space->size_in_header);
+
+	if (buf_block_t* block = buf_page_get(page_id_t(space->id, page),
+					      page_size, RW_S_LATCH, mtr)) {
+		buf_block_dbg_add_level(block, SYNC_FSP_PAGE);
+
+		ut_ad(page != 0 || space->free_limit == mach_read_from_4(
+			      FSP_FREE_LIMIT + FSP_HEADER_OFFSET
+			      + block->frame));
+		ut_ad(page != 0 || space->size_in_header == mach_read_from_4(
+			      FSP_SIZE + FSP_HEADER_OFFSET
+			      + block->frame));
+
+		return(block->frame + XDES_ARR_OFFSET + XDES_SIZE
+		       * xdes_calc_descriptor_index(page_size, offset));
+	}
+
+	return(NULL);
+}
+
 /** Get a pointer to the extent descriptor. The page where the
 extent descriptor resides is x-locked.
 @param[in]	space		tablespace
@@ -611,25 +656,31 @@ fsp_space_modify_check(
 #endif /* UNIV_DEBUG */
 
 /** Initialize a file page.
-@param[in]	space	tablespace
 @param[in,out]	block	file page
 @param[in,out]	mtr	mini-transaction */
-MY_ATTRIBUTE((nonnull))
 static
 void
-fsp_init_file_page(
-	const fil_space_t*	space MY_ATTRIBUTE((unused)),
-	buf_block_t*		block,
-	mtr_t*			mtr)
+fsp_init_file_page(buf_block_t* block, mtr_t* mtr)
 {
-	ut_d(fsp_space_modify_check(space, mtr));
-	ut_ad(space->id == block->page.id.space());
 	fsp_init_file_page_low(block);
 
 	mlog_write_initial_log_record(buf_block_get_frame(block),
 				      MLOG_INIT_FILE_PAGE2, mtr);
 }
 
+#ifdef UNIV_DEBUG
+static
+void
+fsp_init_file_page(const fil_space_t* space, buf_block_t* block, mtr_t* mtr)
+{
+	ut_d(fsp_space_modify_check(space, mtr));
+	ut_ad(space->id == block->page.id.space());
+	fsp_init_file_page(block, mtr);
+}
+#else /* UNIV_DEBUG */
+# define fsp_init_file_page(space, block, mtr) fsp_init_file_page(block, mtr)
+#endif
+
 /***********************************************************//**
 Parses a redo log record of a file page init.
 @return end of log record or NULL */
@@ -3149,39 +3200,31 @@ fseg_free_page_func(
 	DBUG_VOID_RETURN;
 }
 
-/**********************************************************************//**
-Checks if a single page of a segment is free.
-@return true if free */
+/** Determine whether a page is free.
+@param[in,out]	space	tablespace
+@param[in]	page	page number
+@return whether the page is marked as free */
 bool
-fseg_page_is_free(
-/*==============*/
-	fseg_header_t*	seg_header,	/*!< in: segment header */
-	ulint		space_id,	/*!< in: space id */
-	ulint		page)		/*!< in: page offset */
+fseg_page_is_free(fil_space_t* space, unsigned page)
 {
+	bool		is_free;
 	mtr_t		mtr;
-	ibool		is_free;
-	xdes_t*		descr;
-	fseg_inode_t*	seg_inode;
-
-	mtr_start(&mtr);
-	const fil_space_t*	space = mtr_x_lock_space(space_id, &mtr);
-	const page_size_t	page_size(space->flags);
-
-	seg_inode = fseg_inode_get(seg_header, space_id, page_size, &mtr);
-
-	ut_a(seg_inode);
-	ut_ad(mach_read_from_4(seg_inode + FSEG_MAGIC_N)
-	      == FSEG_MAGIC_N_VALUE);
-	ut_ad(!((page_offset(seg_inode) - FSEG_ARR_OFFSET) % FSEG_INODE_SIZE));
-
-	descr = xdes_get_descriptor(space, page, page_size, &mtr);
-	ut_a(descr);
+	page_size_t	page_size(space->flags);
+	page_no_t	dpage = xdes_calc_descriptor_page(page_size, page);
 
-	is_free = xdes_mtr_get_bit(
-		descr, XDES_FREE_BIT, page % FSP_EXTENT_SIZE, &mtr);
+	mtr.start();
+	mtr_s_lock(&space->latch, &mtr);
 
-	mtr_commit(&mtr);
+	if (page >= space->free_limit || page >= space->size_in_header) {
+		is_free = true;
+	} else if (const xdes_t* descr = xdes_get_descriptor_const(
+			   space, dpage, page, page_size, &mtr)) {
+		is_free = xdes_get_bit(descr, XDES_FREE_BIT,
+				       page % FSP_EXTENT_SIZE);
+	} else {
+		is_free = true;
+	}
+	mtr.commit();
 
 	return(is_free);
 }
@@ -3563,28 +3606,3 @@ fseg_header::to_stream(std::ostream&	out) const
 	return(out);
 }
 #endif /* UNIV_DEBUG */
-
-/**********************************************************************//**
-Checks if a single page is free.
-@return	true if free */
-UNIV_INTERN
-bool
-fsp_page_is_free_func(
-/*==============*/
-	ulint		space_id,	/*!< in: space id */
-	ulint		page_no,	/*!< in: page offset */
-	mtr_t*		mtr,		/*!< in/out: mini-transaction */
-	const char *file,
-	unsigned line)
-{
-	ut_ad(mtr);
-
-	fil_space_t*		space = mtr_x_lock_space(space_id, mtr);
-	const page_size_t	page_size(space->flags);
-
-	xdes_t* descr = xdes_get_descriptor(space, page_no, page_size, mtr);
-	ut_a(descr);
-
-	return xdes_mtr_get_bit(
-		descr, XDES_FREE_BIT, page_no % FSP_EXTENT_SIZE, mtr);
-}

storage/innobase/include/fsp0fsp.h

 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2017, MariaDB Corporation. All Rights Reserved.
+Copyright (c) 2013, 2017, MariaDB Corporation.
 
 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
@@ -588,15 +588,12 @@ fseg_free_page_func(
 # define fseg_free_page(header, space_id, page, ahi, mtr)	\
 	fseg_free_page_func(header, space_id, page, mtr)
 #endif /* BTR_CUR_HASH_ADAPT */
-/**********************************************************************//**
-Checks if a single page of a segment is free.
-@return true if free */
+/** Determine whether a page is free.
+@param[in,out]	space	tablespace
+@param[in]	page	page number
+@return whether the page is marked as free */
 bool
-fseg_page_is_free(
-/*==============*/
-	fseg_header_t*	seg_header,	/*!< in: segment header */
-	ulint		space_id,	/*!< in: space id */
-	ulint		page)		/*!< in: page offset */
+fseg_page_is_free(fil_space_t* space, unsigned page)
 	MY_ATTRIBUTE((nonnull, warn_unused_result));
 /**********************************************************************//**
 Frees part of a segment. This function can be used to free a segment
@@ -834,22 +831,6 @@ xdes_calc_descriptor_page(
 	const page_size_t&	page_size,
 	ulint			offset);
 
-/**********************************************************************//**
-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,
-	unsigned line);
-
-#define fsp_page_is_free(space,page,mtr)				\
-	fsp_page_is_free_func(space,page,mtr, __FILE__, __LINE__)
-
 #endif /* UNIV_INNOCHECKSUM */
 
 #include "fsp0fsp.ic"