MDEV-12353 preparation: Clean up page directory operations

page_mem_free(): Define in the same file with the only caller
page_cur_delete_rec().

page_dir_slot_set_rec(): Add const qualifier to a parameter.

page_dir_delete_slot(): Merge with the only caller page_dir_balance_slot().

page_dir_add_slot(): Merge with the only caller page_dir_split_slot().

page_dir_split_slot(), page_dir_balance_slot(): Define in the
same compilation unit with the callers, and simplify the code.

4 files changed, 147 insertions, 293 deletions

diff --git a/storage/innobase/include/page0page.h b/storage/innobase/include/page0page.h
index cce4a92ae8b..2e022cddc03 100644
--- a/storage/innobase/include/page0page.h
+++ b/storage/innobase/include/page0page.h
@@ -679,8 +679,8 @@ UNIV_INLINE
 void
 page_dir_slot_set_rec(
 /*==================*/
-	page_dir_slot_t* slot,	/*!< in: directory slot */
-	rec_t*		 rec);	/*!< in: record on the page */
+	page_dir_slot_t*slot,	/*!< in: directory slot */
+	const rec_t*	rec);	/*!< in: record on the page */
 /***************************************************************//**
 Gets the number of records owned by a directory slot.
 @return number of records */
@@ -957,20 +957,6 @@ page_mem_alloc_heap(
 	ulint*		heap_no);/*!< out: this contains the heap number
 				of the allocated record
 				if allocation succeeds */
-/************************************************************//**
-Puts a record to free list. */
-UNIV_INLINE
-void
-page_mem_free(
-/*==========*/
-	page_t*			page,	/*!< in/out: index page */
-	page_zip_des_t*		page_zip,/*!< in/out: compressed page,
-					 or NULL */
-	rec_t*			rec,	/*!< in: pointer to the (origin of)
-					record */
-	const dict_index_t*	index,	/*!< in: index of rec */
-	const ulint*		offsets);/*!< in: array returned by
-					 rec_get_offsets() */
 
 /** Read the PAGE_DIRECTION field from a byte.
 @param[in]	ptr	pointer to PAGE_DIRECTION_B
@@ -1164,28 +1150,6 @@ page_move_rec_list_start(
 	dict_index_t*	index,		/*!< in: record descriptor */
 	mtr_t*		mtr)		/*!< in: mtr */
 	MY_ATTRIBUTE((nonnull(1, 2, 4, 5)));
-/****************************************************************//**
-Splits a directory slot which owns too many records. */
-void
-page_dir_split_slot(
-/*================*/
-	page_t*		page,	/*!< in: index page */
-	page_zip_des_t*	page_zip,/*!< in/out: compressed page whose
-				uncompressed part will be written, or NULL */
-	ulint		slot_no)/*!< in: the directory slot */
-	MY_ATTRIBUTE((nonnull(1)));
-/*************************************************************//**
-Tries to balance the given directory slot with too few records
-with the upper neighbor, so that there are at least the minimum number
-of records owned by the slot; this may result in the merging of
-two slots. */
-void
-page_dir_balance_slot(
-/*==================*/
-	page_t*		page,	/*!< in/out: index page */
-	page_zip_des_t*	page_zip,/*!< in/out: compressed page, or NULL */
-	ulint		slot_no)/*!< in: the directory slot */
-	MY_ATTRIBUTE((nonnull(1)));
 /**********************************************************//**
 Parses a log record of a record list end or start deletion.
 @return end of log record or NULL */
diff --git a/storage/innobase/include/page0page.ic b/storage/innobase/include/page0page.ic
index 5ab50b7bb8e..2359e61aad0 100644
--- a/storage/innobase/include/page0page.ic
+++ b/storage/innobase/include/page0page.ic
@@ -559,8 +559,8 @@ UNIV_INLINE
 void
 page_dir_slot_set_rec(
 /*==================*/
-	page_dir_slot_t* slot,	/*!< in: directory slot */
-	rec_t*		 rec)	/*!< in: record on the page */
+	page_dir_slot_t*slot,	/*!< in: directory slot */
+	const rec_t*	rec)	/*!< in: record on the page */
 {
 	ut_ad(page_rec_check(rec));
 
@@ -1001,48 +1001,6 @@ page_get_max_insert_size_after_reorganize(
 	return(free_space - occupied);
 }
 
-/************************************************************//**
-Puts a record to free list. */
-UNIV_INLINE
-void
-page_mem_free(
-/*==========*/
-	page_t*			page,		/*!< in/out: index page */
-	page_zip_des_t*		page_zip,	/*!< in/out: compressed page,
-						or NULL */
-	rec_t*			rec,		/*!< in: pointer to the
-						(origin of) record */
-	const dict_index_t*	index,		/*!< in: index of rec */
-	const ulint*		offsets)	/*!< in: array returned by
-						rec_get_offsets() */
-{
-	rec_t*		free;
-	ulint		garbage;
-
-	ut_ad(rec_offs_validate(rec, index, offsets));
-	free = page_header_get_ptr(page, PAGE_FREE);
-
-	if (srv_immediate_scrub_data_uncompressed) {
-		/* scrub record */
-		memset(rec, 0, rec_offs_data_size(offsets));
-	}
-
-	page_rec_set_next(rec, free);
-	page_header_set_ptr(page, page_zip, PAGE_FREE, rec);
-
-	garbage = page_header_get_field(page, PAGE_GARBAGE);
-
-	page_header_set_field(page, page_zip, PAGE_GARBAGE,
-			      garbage + rec_offs_size(offsets));
-
-	if (page_zip) {
-		page_zip_dir_delete(page_zip, rec, index, offsets, free);
-	} else {
-		page_header_set_field(page, page_zip, PAGE_N_RECS,
-				      ulint(page_get_n_recs(page)) - 1);
-	}
-}
-
 /** Read the PAGE_DIRECTION field from a byte.
 @param[in]	ptr	pointer to PAGE_DIRECTION_B
 @return	the value of the PAGE_DIRECTION field */
diff --git a/storage/innobase/page/page0cur.cc b/storage/innobase/page/page0cur.cc
index 4fdfafa5d0a..efd9618fad5 100644
--- a/storage/innobase/page/page0cur.cc
+++ b/storage/innobase/page/page0cur.cc
@@ -1243,6 +1243,118 @@ page_direction_increment(
 		1U + page_header_get_field(page, PAGE_N_DIRECTION));
 }
 
+/** Split a directory slot which owns too many records.
+@param[in,out]	page		index page
+@param[in,out]	page_zip	ROW_FORMAT=COMPRESSED page, or NULL
+@param[in]	s		the slot that needs to be split */
+static void page_dir_split_slot(page_t* page, page_zip_des_t* page_zip,
+				ulint s)
+{
+	ut_ad(!page_zip || page_is_comp(page));
+	ut_ad(s);
+
+	page_dir_slot_t* slot = page_dir_get_nth_slot(page, s);
+	const ulint n_owned = PAGE_DIR_SLOT_MAX_N_OWNED + 1;
+
+	ut_ad(page_dir_slot_get_n_owned(slot) == n_owned);
+	compile_time_assert((PAGE_DIR_SLOT_MAX_N_OWNED + 1) / 2
+			    >= PAGE_DIR_SLOT_MIN_N_OWNED);
+
+	/* 1. We loop to find a record approximately in the middle of the
+	records owned by the slot. */
+
+	const rec_t* rec = page_dir_slot_get_rec(slot + PAGE_DIR_SLOT_SIZE);
+
+	for (ulint i = n_owned / 2; i--; ) {
+		rec = page_rec_get_next_const(rec);
+	}
+
+	/* 2. Add a directory slot immediately below this one. */
+	const ulint n_slots = page_dir_get_n_slots(page);
+	page_dir_set_n_slots(page, page_zip, n_slots + 1);
+	page_dir_slot_t* last_slot = page_dir_get_nth_slot(page, n_slots);
+	memmove(last_slot, last_slot + PAGE_DIR_SLOT_SIZE, slot - last_slot);
+
+	/* 3. We store the appropriate values to the new slot. */
+
+	page_dir_slot_set_rec(slot, rec);
+	page_dir_slot_set_n_owned(slot, page_zip, n_owned / 2);
+
+	/* 4. Finally, we update the number of records field of the
+	original slot */
+
+	page_dir_slot_set_n_owned(slot - PAGE_DIR_SLOT_SIZE,
+				  page_zip, n_owned - (n_owned / 2));
+}
+
+/** Try to balance an underfilled directory slot with an adjacent one,
+so that there are at least the minimum number of records owned by the slot;
+this may result in merging the two slots.
+@param[in,out]	page		index page
+@param[in,out]	page_zip	ROW_FORMAT=COMPRESSED page, or NULL
+@param[in]	s		the slot to be balanced */
+static void page_dir_balance_slot(page_t* page, page_zip_des_t* page_zip,
+				  ulint s)
+{
+	ut_ad(!page_zip || page_is_comp(page));
+	ut_ad(s > 0);
+
+	const ulint n_slots = page_dir_get_n_slots(page);
+
+	if (UNIV_UNLIKELY(s + 1 == n_slots)) {
+		/* The last directory slot cannot be balanced. */
+		return;
+	}
+
+	ut_ad(s < n_slots);
+
+	page_dir_slot_t* slot = page_dir_get_nth_slot(page, s);
+	page_dir_slot_t* up_slot = slot - PAGE_DIR_SLOT_SIZE;
+	const ulint up_n_owned = page_dir_slot_get_n_owned(up_slot);
+
+	ut_ad(page_dir_slot_get_n_owned(slot)
+	      == PAGE_DIR_SLOT_MIN_N_OWNED - 1);
+
+	if (up_n_owned <= PAGE_DIR_SLOT_MIN_N_OWNED) {
+		compile_time_assert(2 * PAGE_DIR_SLOT_MIN_N_OWNED - 1
+				    <= PAGE_DIR_SLOT_MAX_N_OWNED);
+		/* Merge the slots. */
+		ulint n_owned = page_dir_slot_get_n_owned(slot);
+		page_dir_slot_set_n_owned(slot, page_zip, 0);
+		page_dir_slot_set_n_owned(up_slot, page_zip,
+					  n_owned
+					  + page_dir_slot_get_n_owned(up_slot));
+		/* Shift the slots */
+		page_dir_slot_t* last_slot = page_dir_get_nth_slot(
+			page, n_slots - 1);
+		memmove(last_slot + PAGE_DIR_SLOT_SIZE, last_slot,
+			slot - last_slot);
+		mach_write_to_2(last_slot, 0);
+		page_dir_set_n_slots(page, page_zip, n_slots - 1);
+		return;
+	}
+
+	/* Transfer one record to the underfilled slot */
+	rec_t* old_rec = const_cast<rec_t*>(page_dir_slot_get_rec(slot));
+	rec_t* new_rec;
+
+	if (page_is_comp(page)) {
+		new_rec = rec_get_next_ptr(old_rec, TRUE);
+
+		rec_set_n_owned_new(old_rec, page_zip, 0);
+		rec_set_n_owned_new(new_rec, page_zip,
+				    PAGE_DIR_SLOT_MIN_N_OWNED);
+	} else {
+		new_rec = rec_get_next_ptr(old_rec, FALSE);
+
+		rec_set_n_owned_old(old_rec, 0);
+		rec_set_n_owned_old(new_rec, PAGE_DIR_SLOT_MIN_N_OWNED);
+	}
+
+	page_dir_slot_set_rec(slot, new_rec);
+	page_dir_slot_set_n_owned(up_slot, page_zip, up_n_owned - 1);
+}
+
 /***********************************************************//**
 Inserts a record next to page cursor on an uncompressed page.
 Returns pointer to inserted record if succeed, i.e., enough
@@ -2280,6 +2392,36 @@ page_cur_parse_delete_rec(
 	return(ptr);
 }
 
+/** Prepend a record to the PAGE_FREE list.
+@param[in,out]	page		index page
+@param[in,out]	page_zip	ROW_FORMAT=COMPRESSED page, or NULL
+@param[in,out]	rec		record being deleted
+@param[in]	index		the index that the page belongs to
+@param[in]	offsets		rec_get_offsets(rec, index) */
+static void page_mem_free(page_t* page, page_zip_des_t* page_zip, rec_t* rec,
+			  const dict_index_t* index, const ulint* offsets)
+{
+	ut_ad(rec_offs_validate(rec, index, offsets));
+	const rec_t* free = page_header_get_ptr(page, PAGE_FREE);
+
+	if (srv_immediate_scrub_data_uncompressed) {
+		/* scrub record */
+		memset(rec, 0, rec_offs_data_size(offsets));
+	}
+
+	page_rec_set_next(rec, free);
+	page_header_set_ptr(page, page_zip, PAGE_FREE, rec);
+	page_header_set_field(page, page_zip, PAGE_GARBAGE,
+			      rec_offs_size(offsets)
+			      + page_header_get_field(page, PAGE_GARBAGE));
+	if (page_zip) {
+		page_zip_dir_delete(page_zip, rec, index, offsets, free);
+	} else {
+		page_header_set_field(page, page_zip, PAGE_N_RECS,
+				      ulint(page_get_n_recs(page)) - 1);
+	}
+}
+
 /***********************************************************//**
 Deletes a record at the page cursor. The cursor is moved to the next
 record after the deleted one. */
@@ -2351,11 +2493,6 @@ page_cur_delete_rec(
 	cur_dir_slot = page_dir_get_nth_slot(page, cur_slot_no);
 	cur_n_owned = page_dir_slot_get_n_owned(cur_dir_slot);
 
-	/* 0. Write the log record */
-	if (mtr != 0) {
-		page_cur_delete_rec_write_log(current_rec, index, mtr);
-	}
-
 	/* 1. Reset the last insert info in the page header and increment
 	the modify clock for the frame */
 
@@ -2368,6 +2505,7 @@ page_cur_delete_rec(
 
 	if (mtr != 0) {
 		buf_block_modify_clock_inc(page_cur_get_block(cursor));
+		page_cur_delete_rec_write_log(current_rec, index, mtr);
 	}
 
 	/* 2. Find the next and the previous record. Note that the cursor is
diff --git a/storage/innobase/page/page0page.cc b/storage/innobase/page/page0page.cc
index c4c5d1727ee..15ce614391c 100644
--- a/storage/innobase/page/page0page.cc
+++ b/storage/innobase/page/page0page.cc
@@ -1386,212 +1386,6 @@ page_move_rec_list_start(
 	return(TRUE);
 }
 
-/**************************************************************//**
-Used to delete n slots from the directory. This function updates
-also n_owned fields in the records, so that the first slot after
-the deleted ones inherits the records of the deleted slots. */
-UNIV_INLINE
-void
-page_dir_delete_slot(
-/*=================*/
-	page_t*		page,	/*!< in/out: the index page */
-	page_zip_des_t*	page_zip,/*!< in/out: compressed page, or NULL */
-	ulint		slot_no)/*!< in: slot to be deleted */
-{
-	page_dir_slot_t*	slot;
-	ulint			n_owned;
-	ulint			i;
-	ulint			n_slots;
-
-	ut_ad(!page_zip || page_is_comp(page));
-	ut_ad(slot_no > 0);
-	ut_ad(slot_no + 1 < page_dir_get_n_slots(page));
-
-	n_slots = page_dir_get_n_slots(page);
-
-	/* 1. Reset the n_owned fields of the slots to be
-	deleted */
-	slot = page_dir_get_nth_slot(page, slot_no);
-	n_owned = page_dir_slot_get_n_owned(slot);
-	page_dir_slot_set_n_owned(slot, page_zip, 0);
-
-	/* 2. Update the n_owned value of the first non-deleted slot */
-
-	slot = page_dir_get_nth_slot(page, slot_no + 1);
-	page_dir_slot_set_n_owned(slot, page_zip,
-				  n_owned + page_dir_slot_get_n_owned(slot));
-
-	/* 3. Destroy the slot by copying slots */
-	for (i = slot_no + 1; i < n_slots; i++) {
-		rec_t*	rec = (rec_t*)
-			page_dir_slot_get_rec(page_dir_get_nth_slot(page, i));
-		page_dir_slot_set_rec(page_dir_get_nth_slot(page, i - 1), rec);
-	}
-
-	/* 4. Zero out the last slot, which will be removed */
-	mach_write_to_2(page_dir_get_nth_slot(page, n_slots - 1), 0);
-
-	/* 5. Update the page header */
-	page_header_set_field(page, page_zip, PAGE_N_DIR_SLOTS, n_slots - 1);
-}
-
-/**************************************************************//**
-Used to add n slots to the directory. Does not set the record pointers
-in the added slots or update n_owned values: this is the responsibility
-of the caller. */
-UNIV_INLINE
-void
-page_dir_add_slot(
-/*==============*/
-	page_t*		page,	/*!< in/out: the index page */
-	page_zip_des_t*	page_zip,/*!< in/out: comprssed page, or NULL */
-	ulint		start)	/*!< in: the slot above which the new slots
-				are added */
-{
-	page_dir_slot_t*	slot;
-	ulint			n_slots;
-
-	n_slots = page_dir_get_n_slots(page);
-
-	ut_ad(start < n_slots - 1);
-
-	/* Update the page header */
-	page_dir_set_n_slots(page, page_zip, n_slots + 1);
-
-	/* Move slots up */
-	slot = page_dir_get_nth_slot(page, n_slots);
-	memmove(slot, slot + PAGE_DIR_SLOT_SIZE,
-		(n_slots - 1 - start) * PAGE_DIR_SLOT_SIZE);
-}
-
-/****************************************************************//**
-Splits a directory slot which owns too many records. */
-void
-page_dir_split_slot(
-/*================*/
-	page_t*		page,	/*!< in/out: index page */
-	page_zip_des_t*	page_zip,/*!< in/out: compressed page whose
-				uncompressed part will be written, or NULL */
-	ulint		slot_no)/*!< in: the directory slot */
-{
-	rec_t*			rec;
-	page_dir_slot_t*	new_slot;
-	page_dir_slot_t*	prev_slot;
-	page_dir_slot_t*	slot;
-	ulint			i;
-	ulint			n_owned;
-
-	ut_ad(!page_zip || page_is_comp(page));
-	ut_ad(slot_no > 0);
-
-	slot = page_dir_get_nth_slot(page, slot_no);
-
-	n_owned = page_dir_slot_get_n_owned(slot);
-	ut_ad(n_owned == PAGE_DIR_SLOT_MAX_N_OWNED + 1);
-
-	/* 1. We loop to find a record approximately in the middle of the
-	records owned by the slot. */
-
-	prev_slot = page_dir_get_nth_slot(page, slot_no - 1);
-	rec = (rec_t*) page_dir_slot_get_rec(prev_slot);
-
-	for (i = 0; i < n_owned / 2; i++) {
-		rec = page_rec_get_next(rec);
-	}
-
-	ut_ad(n_owned / 2 >= PAGE_DIR_SLOT_MIN_N_OWNED);
-
-	/* 2. We add one directory slot immediately below the slot to be
-	split. */
-
-	page_dir_add_slot(page, page_zip, slot_no - 1);
-
-	/* The added slot is now number slot_no, and the old slot is
-	now number slot_no + 1 */
-
-	new_slot = page_dir_get_nth_slot(page, slot_no);
-	slot = page_dir_get_nth_slot(page, slot_no + 1);
-
-	/* 3. We store the appropriate values to the new slot. */
-
-	page_dir_slot_set_rec(new_slot, rec);
-	page_dir_slot_set_n_owned(new_slot, page_zip, n_owned / 2);
-
-	/* 4. Finally, we update the number of records field of the
-	original slot */
-
-	page_dir_slot_set_n_owned(slot, page_zip, n_owned - (n_owned / 2));
-}
-
-/*************************************************************//**
-Tries to balance the given directory slot with too few records with the upper
-neighbor, so that there are at least the minimum number of records owned by
-the slot; this may result in the merging of two slots. */
-void
-page_dir_balance_slot(
-/*==================*/
-	page_t*		page,	/*!< in/out: index page */
-	page_zip_des_t*	page_zip,/*!< in/out: compressed page, or NULL */
-	ulint		slot_no)/*!< in: the directory slot */
-{
-	page_dir_slot_t*	slot;
-	page_dir_slot_t*	up_slot;
-	ulint			n_owned;
-	ulint			up_n_owned;
-	rec_t*			old_rec;
-	rec_t*			new_rec;
-
-	ut_ad(!page_zip || page_is_comp(page));
-	ut_ad(slot_no > 0);
-
-	slot = page_dir_get_nth_slot(page, slot_no);
-
-	/* The last directory slot cannot be balanced with the upper
-	neighbor, as there is none. */
-
-	if (UNIV_UNLIKELY(slot_no + 1 == page_dir_get_n_slots(page))) {
-
-		return;
-	}
-
-	up_slot = page_dir_get_nth_slot(page, slot_no + 1);
-
-	n_owned = page_dir_slot_get_n_owned(slot);
-	up_n_owned = page_dir_slot_get_n_owned(up_slot);
-
-	ut_ad(n_owned == PAGE_DIR_SLOT_MIN_N_OWNED - 1);
-
-	/* If the upper slot has the minimum value of n_owned, we will merge
-	the two slots, therefore we assert: */
-	ut_ad(2 * PAGE_DIR_SLOT_MIN_N_OWNED - 1 <= PAGE_DIR_SLOT_MAX_N_OWNED);
-
-	if (up_n_owned > PAGE_DIR_SLOT_MIN_N_OWNED) {
-
-		/* In this case we can just transfer one record owned
-		by the upper slot to the property of the lower slot */
-		old_rec = (rec_t*) page_dir_slot_get_rec(slot);
-
-		if (page_is_comp(page)) {
-			new_rec = rec_get_next_ptr(old_rec, TRUE);
-
-			rec_set_n_owned_new(old_rec, page_zip, 0);
-			rec_set_n_owned_new(new_rec, page_zip, n_owned + 1);
-		} else {
-			new_rec = rec_get_next_ptr(old_rec, FALSE);
-
-			rec_set_n_owned_old(old_rec, 0);
-			rec_set_n_owned_old(new_rec, n_owned + 1);
-		}
-
-		page_dir_slot_set_rec(slot, new_rec);
-
-		page_dir_slot_set_n_owned(up_slot, page_zip, up_n_owned -1);
-	} else {
-		/* In this case we may merge the two slots */
-		page_dir_delete_slot(page, page_zip, slot_no);
-	}
-}
-
 /************************************************************//**
 Returns the nth record of the record list.
 This is the inverse function of page_rec_get_n_recs_before().