/*
 * Copyright 1996-2004 by Hans Reiser, licensing governed by
 * reiserfsprogs/README
 */

#include "includes.h"

/* modes of internal_shift_left, internal_shift_right and internal_insert_childs */
#define INTERNAL_SHIFT_FROM_S_TO_L 0
#define INTERNAL_SHIFT_FROM_R_TO_S 1
#define INTERNAL_SHIFT_FROM_L_TO_S 2
#define INTERNAL_SHIFT_FROM_S_TO_R 3
#define INTERNAL_INSERT_TO_S 4
#define INTERNAL_INSERT_TO_L 5
#define INTERNAL_INSERT_TO_R 6

static void internal_define_dest_src_infos(int shift_mode,
					   struct tree_balance *tb,
					   int h,
					   struct buffer_info *dest_bi,
					   struct buffer_info *src_bi,
					   int *d_key, struct buffer_head **cf)
{
	/* define dest, src, dest parent, dest position */
	switch (shift_mode) {
	case INTERNAL_SHIFT_FROM_S_TO_L:	/* used in internal_shift_left */
		buffer_info_init_tbSh(tb, src_bi, h);
		buffer_info_init_left(tb, dest_bi, h);
		*d_key = tb->lkey[h];
		*cf = tb->CFL[h];
		break;
	case INTERNAL_SHIFT_FROM_L_TO_S:
		buffer_info_init_left(tb, src_bi, h);
		buffer_info_init_tbSh(tb, dest_bi, h);
		*d_key = tb->lkey[h];
		*cf = tb->CFL[h];
		break;

	case INTERNAL_SHIFT_FROM_R_TO_S:	/* used in internal_shift_left */
		buffer_info_init_right(tb, src_bi, h);
		buffer_info_init_tbSh(tb, dest_bi, h);
		*d_key = tb->rkey[h];
		*cf = tb->CFR[h];
		break;
	case INTERNAL_SHIFT_FROM_S_TO_R:
		buffer_info_init_tbSh(tb, src_bi, h);
		buffer_info_init_right(tb, dest_bi, h);
		*d_key = tb->rkey[h];
		*cf = tb->CFR[h];
		break;

	case INTERNAL_INSERT_TO_L:
		buffer_info_init_left(tb, dest_bi, h);
		break;

	case INTERNAL_INSERT_TO_S:
		buffer_info_init_tbSh(tb, dest_bi, h);
		break;

	case INTERNAL_INSERT_TO_R:
		buffer_info_init_right(tb, dest_bi, h);
		break;

	default:
		reiserfs_panic("internal_define_dest_src_infos",
			       "shift type is unknown (%d)", shift_mode);
	}
}

/* Insert 'count' node pointers into buffer cur before position 'to' + 1.
 * Insert count items into buffer cur before position to.
 * Items and node pointers are specified by inserted and bh respectively.
 */
static void internal_insert_childs(struct buffer_info *cur_bi,
				   int to, int count,
				   struct item_head *inserted,
				   struct buffer_head **bh)
{
	struct buffer_head *cur = cur_bi->bi_bh;
	struct block_head *blkh;
	int nr;
	struct reiserfs_key *key;
	struct disk_child new_dc[2];
	struct disk_child *dc;
	int i;
	int from;

	if (count <= 0)
		return;

	blkh = B_BLK_HEAD(cur);
	nr = get_blkh_nr_items(blkh);

	/* prepare space for count disk_child */
	dc = B_N_CHILD(cur, to + 1);

	memmove(dc + count, dc, (nr + 1 - (to + 1)) * DC_SIZE);

	/* make disk child array for insertion */
	for (i = 0; i < count; i++) {
		set_dc(new_dc + i, MAX_CHILD_SIZE(bh[i]->b_size) -
		       get_blkh_free_space(B_BLK_HEAD(bh[i])),
		       bh[i]->b_blocknr);
		/*
		   set_dc_child_size (new_dc + i,
		   MAX_CHILD_SIZE(bh[i]->b_size) -
		   get_blkh_free_space (B_BLK_HEAD (bh[i])));
		   set_dc_child_blocknr (new_dc + i, bh[i]->b_blocknr); */
	}
	memcpy(dc, new_dc, DC_SIZE * count);

	/* prepare space for 'count' items  */
	from = ((to == -1) ? 0 : to);
	key = internal_key(cur, from);

	memmove(key + count, key,
		(nr - from /*to */ ) * KEY_SIZE + (nr + 1 + count) * DC_SIZE);

	/* copy keys */
	memcpy(key, inserted, KEY_SIZE);
	if (count > 1)
		memcpy(key + 1, inserted + 1, KEY_SIZE);

	/* sizes, item number */
	set_blkh_nr_items(blkh, nr + count);
	set_blkh_free_space(blkh,
			    get_blkh_free_space(blkh) - count * (DC_SIZE +
								 KEY_SIZE));

	mark_buffer_dirty(cur);

	if (cur_bi->bi_parent) {
		dc = B_N_CHILD(cur_bi->bi_parent, cur_bi->bi_position);
		set_dc_child_size(dc,
				  get_dc_child_size(dc) + count * (DC_SIZE +
								   KEY_SIZE));
		mark_buffer_dirty(cur_bi->bi_parent);
	}

}

/* Delete del_num items and node pointers from buffer cur starting from *
 * the first_i'th item and first_p'th pointers respectively.		*/
static void internal_delete_pointers_items(struct buffer_info *cur_bi,
					   int first_p, int first_i,
					   int del_num)
{
	struct buffer_head *cur = cur_bi->bi_bh;
	int nr;
	struct block_head *blkh;
	struct reiserfs_key *key;
	struct disk_child *dc;

	if (del_num == 0)
		return;

	blkh = B_BLK_HEAD(cur);
	nr = get_blkh_nr_items(blkh);

	if (first_p == 0 && del_num == nr + 1) {
		make_empty_node(cur_bi);
		return;
	}

	/* deleting */
	dc = B_N_CHILD(cur, first_p);

	memmove(dc, dc + del_num, (nr + 1 - first_p - del_num) * DC_SIZE);
	key = internal_key(cur, first_i);
	memmove(key, key + del_num,
		(nr - first_i - del_num) * KEY_SIZE + (nr + 1 -
						       del_num) * DC_SIZE);

	/* sizes, item number */
	set_blkh_nr_items(blkh, get_blkh_nr_items(blkh) - del_num);
	set_blkh_free_space(blkh, get_blkh_free_space(blkh) +
			    del_num * (KEY_SIZE + DC_SIZE));

	mark_buffer_dirty(cur);

	if (cur_bi->bi_parent) {
		dc = B_N_CHILD(cur_bi->bi_parent, cur_bi->bi_position);
		set_dc_child_size(dc,
				  get_dc_child_size(dc) - del_num * (KEY_SIZE +
								     DC_SIZE));
		mark_buffer_dirty(cur_bi->bi_parent);
	}
}

/* delete n node pointers and items starting from given position */
static void internal_delete_childs(struct buffer_info *cur_bi, int from, int n)
{
	int i_from = 0;

	if (from)
		i_from = from - 1;

	/* delete n pointers starting from `from' position in CUR;
	   delete n keys starting from 'i_from' position in CUR;
	 */
	internal_delete_pointers_items(cur_bi, from, i_from, n);
}

/* copy cpy_num node pointers and cpy_num - 1 items from buffer src to buffer dest
* last_first == FIRST_TO_LAST means, that we copy first items from src to tail of dest
 * last_first == LAST_TO_FIRST means, that we copy last items from src to head of dest
 */
static void internal_copy_pointers_items(struct buffer_info *dest_bi,
					 struct buffer_head *src,
					 int last_first, int cpy_num)
{
	/* ATTENTION! Number of node pointers in DEST is equal to number of items in DEST *
	 * as delimiting key have already inserted to buffer dest.*/
	struct buffer_head *dest = dest_bi->bi_bh;
	int nr_dest, nr_src;
	int dest_order, src_order;
	struct block_head *blkh;
	struct reiserfs_key *key;
	struct disk_child *dc;

	nr_src = B_NR_ITEMS(src);

	if (cpy_num == 0)
		return;

	/* coping */
	blkh = B_BLK_HEAD(dest);
	nr_dest = get_blkh_nr_items(blkh);

	/*dest_order = (last_first == LAST_TO_FIRST) ? 0 : nr_dest; */
	/*src_order = (last_first == LAST_TO_FIRST) ? (nr_src - cpy_num + 1) : 0; */
	(last_first == LAST_TO_FIRST) ? (dest_order = 0, src_order =
					 nr_src - cpy_num + 1) : (dest_order =
								  nr_dest,
								  src_order =
								  0);

	/* prepare space for cpy_num pointers */
	dc = B_N_CHILD(dest, dest_order);

	memmove(dc + cpy_num, dc, (nr_dest - dest_order) * DC_SIZE);

	/* insert pointers */
	memcpy(dc, B_N_CHILD(src, src_order), DC_SIZE * cpy_num);

	/* prepare space for cpy_num - 1 item headers */
	key = internal_key(dest, dest_order);
	memmove(key + cpy_num - 1, key,
		KEY_SIZE * (nr_dest - dest_order) + DC_SIZE * (nr_dest +
							       cpy_num));

	/* insert headers */
	memcpy(key, internal_key(src, src_order), KEY_SIZE * (cpy_num - 1));

	/* sizes, item number */
	set_blkh_nr_items(blkh, get_blkh_nr_items(blkh) + cpy_num - 1);
	set_blkh_free_space(blkh, get_blkh_free_space(blkh) -
			    (KEY_SIZE * (cpy_num - 1) + DC_SIZE * cpy_num));

	mark_buffer_dirty(dest);
	if (dest_bi->bi_parent) {
		dc = B_N_CHILD(dest_bi->bi_parent, dest_bi->bi_position);
		set_dc_child_size(dc,
				  get_dc_child_size(dc) + KEY_SIZE * (cpy_num -
								      1) +
				  DC_SIZE * cpy_num);
		mark_buffer_dirty(dest_bi->bi_parent);
	}

}

/* Copy cpy_num node pointers and cpy_num - 1 items from buffer src to buffer dest.
 * Delete cpy_num - del_par items and node pointers from buffer src.
 * last_first == FIRST_TO_LAST means, that we copy/delete first items from src.
 * last_first == LAST_TO_FIRST means, that we copy/delete last items from src.
 */
static void internal_move_pointers_items(struct buffer_info *dest_bi,
					 struct buffer_info *src_bi,
					 int last_first, int cpy_num,
					 int del_par)
{
	int first_pointer;
	int first_item;

	internal_copy_pointers_items(dest_bi, src_bi->bi_bh, last_first,
				     cpy_num);

	if (last_first == FIRST_TO_LAST) {	/* shift_left occurs */
		first_pointer = 0;
		first_item = 0;
		/* delete cpy_num - del_par pointers and keys starting for pointers with first_pointer,
		   for key - with first_item */
		internal_delete_pointers_items(src_bi, first_pointer,
					       first_item, cpy_num - del_par);
	} else {		/* shift_right occurs */
		int i, j;

		i = (cpy_num - del_par ==
		     (j =
		      B_NR_ITEMS(src_bi->bi_bh)) + 1) ? 0 : j - cpy_num +
		    del_par;

		internal_delete_pointers_items(src_bi,
					       j + 1 - cpy_num + del_par, i,
					       cpy_num - del_par);
	}
}

/* Insert n_src'th key of buffer src before n_dest'th key of buffer dest. */
static void internal_insert_key(struct buffer_info *dest_bi, int dest_position_before,	/* insert key before key with n_dest number */
				struct buffer_head *src, int src_position)
{
	struct buffer_head *dest = dest_bi->bi_bh;
	int nr;
	struct block_head *blkh;
	struct reiserfs_key *key;

	blkh = B_BLK_HEAD(dest);
	nr = get_blkh_nr_items(blkh);

	/* prepare space for inserting key */
	key = internal_key(dest, dest_position_before);
	memmove(key + 1, key,
		(nr - dest_position_before) * KEY_SIZE + (nr + 1) * DC_SIZE);

	/* insert key */
	memcpy(key, internal_key(src, src_position), KEY_SIZE);

	/* Change dirt, free space, item number fields. */
	set_blkh_nr_items(blkh, get_blkh_nr_items(blkh) + 1);
	set_blkh_free_space(blkh, get_blkh_free_space(blkh) - KEY_SIZE);

	mark_buffer_dirty(dest);

	if (dest_bi->bi_parent) {
		struct disk_child *dc;

		dc = B_N_CHILD(dest_bi->bi_parent, dest_bi->bi_position);
		set_dc_child_size(dc, get_dc_child_size(dc) + KEY_SIZE);
		mark_buffer_dirty(dest_bi->bi_parent);
	}
}

/* Insert d_key'th (delimiting) key from buffer cfl to tail of dest.
 * Copy pointer_amount node pointers and pointer_amount - 1 items from buffer src to buffer dest.
 * Replace  d_key'th key in buffer cfl.
 * Delete pointer_amount items and node pointers from buffer src.
 */
/* this can be invoked both to shift from S to L and from R to S */
static void internal_shift_left(int mode,	/* INTERNAL_FROM_S_TO_L | INTERNAL_FROM_R_TO_S */
				struct tree_balance *tb, int h,
				int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;

	internal_define_dest_src_infos(mode, tb, h, &dest_bi, &src_bi,
				       &d_key_position, &cf);

	/*printk("pointer_amount = %d\n",pointer_amount); */

	if (pointer_amount) {
		/* insert delimiting key from common father of dest and src to node dest into position B_NR_ITEM(dest) */
		internal_insert_key(&dest_bi, B_NR_ITEMS(dest_bi.bi_bh), cf,
				    d_key_position);

		if (B_NR_ITEMS(src_bi.bi_bh) == pointer_amount - 1) {
			if (src_bi.bi_position /*src->b_item_order */  == 0)
				replace_key(tb->tb_fs, cf, d_key_position,
					    src_bi.
					    bi_parent /*src->b_parent */ , 0);
		} else
			replace_key(tb->tb_fs, cf, d_key_position, src_bi.bi_bh,
				    pointer_amount - 1);
	}
	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, FIRST_TO_LAST,
				     pointer_amount, 0);

}

/* Insert delimiting key to L[h].
 * Copy n node pointers and n - 1 items from buffer S[h] to L[h].
 * Delete n - 1 items and node pointers from buffer S[h].
 */
/* it always shifts from S[h] to L[h] */
static void internal_shift1_left(struct tree_balance *tb,
				 int h, int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;

	internal_define_dest_src_infos(INTERNAL_SHIFT_FROM_S_TO_L, tb, h,
				       &dest_bi, &src_bi, &d_key_position, &cf);

	if (pointer_amount > 0)	/* insert lkey[h]-th key  from CFL[h] to left neighbor L[h] */
		internal_insert_key(&dest_bi, B_NR_ITEMS(dest_bi.bi_bh), cf,
				    d_key_position);

	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, FIRST_TO_LAST,
				     pointer_amount, 1);
}

/* Insert d_key'th (delimiting) key from buffer cfr to head of dest.
 * Copy n node pointers and n - 1 items from buffer src to buffer dest.
 * Replace  d_key'th key in buffer cfr.
 * Delete n items and node pointers from buffer src.
 */
static void internal_shift_right(int mode,	/* INTERNAL_FROM_S_TO_R | INTERNAL_FROM_L_TO_S */
				 struct tree_balance *tb, int h,
				 int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;
	int nr;

	internal_define_dest_src_infos(mode, tb, h, &dest_bi, &src_bi,
				       &d_key_position, &cf);

	nr = B_NR_ITEMS(src_bi.bi_bh);

	if (pointer_amount > 0) {
		/* insert delimiting key from common father of dest and src to dest node into position 0 */
		internal_insert_key(&dest_bi, 0, cf, d_key_position);
		if (nr == pointer_amount - 1) {
			/* when S[h] disappers replace left delemiting key as well */
			if (tb->CFL[h])
				replace_key(tb->tb_fs, cf, d_key_position,
					    tb->CFL[h], tb->lkey[h]);
		} else
			replace_key(tb->tb_fs, cf, d_key_position, src_bi.bi_bh,
				    nr - pointer_amount);
	}

	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, LAST_TO_FIRST,
				     pointer_amount, 0);
}

/* Insert delimiting key to R[h].
 * Copy n node pointers and n - 1 items from buffer S[h] to R[h].
 * Delete n - 1 items and node pointers from buffer S[h].
 */
/* it always shift from S[h] to R[h] */
static void internal_shift1_right(struct tree_balance *tb,
				  int h, int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;

	internal_define_dest_src_infos(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
				       &dest_bi, &src_bi, &d_key_position, &cf);

	if (pointer_amount > 0)	/* insert rkey from CFR[h] to right neighbor R[h] */
		internal_insert_key(&dest_bi, 0, cf, d_key_position);

	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, LAST_TO_FIRST,
				     pointer_amount, 1);
}

/* Delete insert_num node pointers together with their left items
 * and balance current node.*/
static void balance_internal_when_delete(struct tree_balance *tb,
					 int h, int child_pos)
{
	int insert_num;
	int n;
	struct buffer_head *tbSh = PATH_H_PBUFFER(tb->tb_path, h);
	struct buffer_info bi;

	insert_num = tb->insert_size[h] / ((int)(DC_SIZE + KEY_SIZE));

	/* delete child-node-pointer(s) together with their left item(s) */
	buffer_info_init_tbSh(tb, &bi, h);
	internal_delete_childs(&bi, child_pos, -insert_num);

	n = B_NR_ITEMS(tbSh);

	if (tb->lnum[h] == 0 && tb->rnum[h] == 0) {
		if (tb->blknum[h] == 0) {
			/* node S[h] (root of the tree) is empty now */
			struct buffer_head *new_root;
			struct reiserfs_super_block *sb;

			/* choose a new root */
			if (!tb->L[h - 1] || !B_NR_ITEMS(tb->L[h - 1]))
				new_root = tb->R[h - 1];
			else
				new_root = tb->L[h - 1];

			/* update super block's tree height and pointer to a root block */
			sb = tb->tb_fs->fs_ondisk_sb;
			set_sb_root_block(sb, new_root->b_blocknr);
			set_sb_tree_height(sb, get_sb_tree_height(sb) - 1);

			mark_buffer_dirty(tb->tb_fs->fs_super_bh);
			tb->tb_fs->fs_dirt = 1;

			/* mark buffer S[h] not uptodate and put it in free list */
			reiserfs_invalidate_buffer(tb, tbSh);
			return;
		}
		return;
	}

	if (tb->L[h] && tb->lnum[h] == -B_NR_ITEMS(tb->L[h]) - 1) {	/* join S[h] with L[h] */
		internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h, n + 1);	/*tb->L[h], tb->CFL[h], tb->lkey[h], tb->S[h], n+1); */
		reiserfs_invalidate_buffer(tb, tbSh);	/* preserve not needed, internal, 1 mean free block */

		return;
	}

	if (tb->R[h] && tb->rnum[h] == -B_NR_ITEMS(tb->R[h]) - 1) {	/* join S[h] with R[h] */
		internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h, n + 1);
		reiserfs_invalidate_buffer(tb, tbSh);
		return;
	}

	if (tb->lnum[h] < 0) {	/* borrow from left neighbor L[h] */
		internal_shift_right(INTERNAL_SHIFT_FROM_L_TO_S, tb, h,
				     -tb->lnum[h]);
		return;
	}

	if (tb->rnum[h] < 0) {	/* borrow from right neighbor R[h] */
		internal_shift_left(INTERNAL_SHIFT_FROM_R_TO_S, tb, h, -tb->rnum[h]);	/*tb->S[h], tb->CFR[h], tb->rkey[h], tb->R[h], -tb->rnum[h]); */
		return;
	}

	if (tb->lnum[h] > 0) {	/* split S[h] into two parts and put them into neighbors */
		internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h, tb->lnum[h]);	/*tb->L[h], tb->CFL[h], tb->lkey[h], tb->S[h], tb->lnum[h]); */
		internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
				     tb->rnum[h]);
		reiserfs_invalidate_buffer(tb, tbSh);

		return;
	}
	reiserfs_panic("balance_internal_when_delete",
		       "unexpected tb->lnum[%d]==%d or tb->rnum[%d]==%d", h,
		       tb->lnum[h], h, tb->rnum[h]);
}

/* Replace delimiting key of buffers L[h] and S[h] by the given key.*/
void replace_lkey(struct tree_balance *tb, int h, struct item_head *key)
{
	if (B_NR_ITEMS(PATH_H_PBUFFER(tb->tb_path, h)) == 0)
		return;

	memcpy(internal_key(tb->CFL[h], tb->lkey[h]), key, KEY_SIZE);

	mark_buffer_dirty(tb->CFL[h]);
}

/* Replace delimiting key of buffers S[h] and R[h] by the given key.*/
void replace_rkey(struct tree_balance *tb, int h, struct item_head *key)
{
	memcpy(internal_key(tb->CFR[h], tb->rkey[h]), key, KEY_SIZE);

	mark_buffer_dirty(tb->CFR[h]);
}

int balance_internal(struct tree_balance *tb,	/* tree_balance structure               */
		     int h,	/* level of the tree                    */
		     int child_pos, struct item_head *insert_key,	/* key for insertion on higher level    */
		     struct buffer_head **insert_ptr)
{				/* node for insertion on higher level */
	/* if inserting/pasting
	   {
	   child_pos is the position of the node-pointer in S[h] that      *
	   pointed to S[h-1] before balancing of the h-1 level;            *
	   this means that new pointers and items must be inserted AFTER *
	   child_pos
	   }
	   else
	   {
	   it is the position of the leftmost pointer that must be deleted (together with
	   its corresponding key to the left of the pointer)
	   as a result of the previous level's balancing.
	   }
	 */
	struct buffer_head *tbSh = PATH_H_PBUFFER(tb->tb_path, h);
	struct buffer_info bi;
	int order;		/* we return this: it is 0 if there is no S[h], else it is tb->S[h]->b_item_order */
	int insert_num, n, k;
	struct buffer_head *S_new;
	struct item_head new_insert_key;
	struct buffer_head *new_insert_ptr = NULL;
	struct item_head *new_insert_key_addr = insert_key;

	order =
	    (tbSh) ? PATH_H_POSITION(tb->tb_path,
				     h + 1) /*tb->S[h]->b_item_order */ : 0;

	/* Using insert_size[h] calculate the number insert_num of items
	   that must be inserted to or deleted from S[h]. */
	insert_num = tb->insert_size[h] / ((int)(KEY_SIZE + DC_SIZE));

	/* Check whether insert_num is proper * */
	/* Make balance in case insert_num < 0 */
	if (insert_num < 0) {
		balance_internal_when_delete(tb, h, child_pos);
		return order;
	}

	k = 0;
	if (tb->lnum[h] > 0) {
		/* shift lnum[h] items from S[h] to the left neighbor L[h].
		   check how many of new items fall into L[h] or CFL[h] after shifting */
		n = get_blkh_nr_items(B_BLK_HEAD(tb->L[h]));	/* number of items in L[h] */
		if (tb->lnum[h] <= child_pos) {
			/* new items don't fall into L[h] or CFL[h] */
			internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h,
					    tb->lnum[h]);
			child_pos -= tb->lnum[h];
		} else if (tb->lnum[h] > child_pos + insert_num) {
			/* all new items fall into L[h] */
			internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h,
					    tb->lnum[h] - insert_num);

			/* insert insert_num keys and node-pointers into L[h] */
			buffer_info_init_left(tb, &bi, h);
			internal_insert_childs(&bi, n + child_pos + 1,
					       insert_num, insert_key,
					       insert_ptr);

			insert_num = 0;
		} else {
			struct disk_child *dc;

			/* some items fall into L[h] or CFL[h], but some don't fall */
			internal_shift1_left(tb, h, child_pos + 1);
			/* calculate number of new items that fall into L[h] */
			k = tb->lnum[h] - child_pos - 1;

			buffer_info_init_left(tb, &bi, h);
			internal_insert_childs(&bi, n + child_pos + 1, k,
					       insert_key, insert_ptr);

			replace_lkey(tb, h, insert_key + k);

			/* replace the first node-ptr in S[h] by node-ptr to insert_ptr[k] */
			dc = B_N_CHILD(tbSh, 0);

			set_dc(dc, MAX_CHILD_SIZE(insert_ptr[k]->b_size) -
			       get_blkh_free_space(B_BLK_HEAD(insert_ptr[k])),
			       insert_ptr[k]->b_blocknr);
			/*
			   set_dc_child_size (dc, MAX_CHILD_SIZE(insert_ptr[k]->b_size) -
			   get_blkh_free_space (B_BLK_HEAD(insert_ptr[k])));
			   set_dc_child_blocknr (dc, insert_ptr[k]->b_blocknr);
			 */
			mark_buffer_dirty(tbSh);

			k++;
			insert_key += k;
			insert_ptr += k;
			insert_num -= k;
			child_pos = 0;
		}
	}
	/* tb->lnum[h] > 0 */
	if (tb->rnum[h] > 0) {
		/*shift rnum[h] items from S[h] to the right neighbor R[h] */
		/* check how many of new items fall into R or CFR after shifting */
		n = get_blkh_nr_items(B_BLK_HEAD(tbSh));	/* number of items in S[h] */
		if (n - tb->rnum[h] >= child_pos)
			/* new items fall into S[h] */
			/*internal_shift_right(tb,h,tbSh,tb->CFR[h],tb->rkey[h],tb->R[h],tb->rnum[h]); */
			internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
					     tb->rnum[h]);
		else if (n + insert_num - tb->rnum[h] < child_pos) {
			/* all new items fall into R[h] */
			internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
					     tb->rnum[h] - insert_num);

			/* insert insert_num keys and node-pointers into R[h] */
			buffer_info_init_right(tb, &bi, h);
			internal_insert_childs(&bi,
					       child_pos - n - insert_num +
					       tb->rnum[h] - 1,
					       insert_num, insert_key,
					       insert_ptr);
			insert_num = 0;
		} else {
			struct disk_child *dc;

			/* one of the items falls into CFR[h] */
			internal_shift1_right(tb, h, n - child_pos + 1);
			/* calculate number of new items that fall into R[h] */
			k = tb->rnum[h] - n + child_pos - 1;

			buffer_info_init_right(tb, &bi, h);
			internal_insert_childs(&bi, 0, k, insert_key + 1,
					       insert_ptr + 1);

			replace_rkey(tb, h, insert_key + insert_num - k - 1);

			/* replace the first node-ptr in R[h] by node-ptr insert_ptr[insert_num-k-1] */
			dc = B_N_CHILD(tb->R[h], 0);
			set_dc(dc,
			       MAX_CHILD_SIZE(insert_ptr[insert_num - k - 1]->
					      b_size) -
			       get_blkh_free_space(B_BLK_HEAD
						   (insert_ptr
						    [insert_num - k - 1])),
			       insert_ptr[insert_num - k - 1]->b_blocknr);
			/*
			   set_dc_child_size (dc, MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]->b_size) -
			   get_blkh_free_space (B_BLK_HEAD(insert_ptr[insert_num-k-1])));
			   set_dc_child_blocknr (dc, insert_ptr[insert_num-k-1]->b_blocknr);
			 */
			mark_buffer_dirty(tb->R[h]);

			insert_num -= (k + 1);
		}
	}

    /** Fill new node that appears instead of S[h] **/
	if (!tb->blknum[h]) {	/* node S[h] is empty now */
		/* Mark buffer as invalid and put it to head of free list. */
		reiserfs_invalidate_buffer(tb, tbSh);	/* do not preserve, internal node */
		return order;
	}

	if (!tbSh) {
		/* create new root */
		struct disk_child *dc;
		struct buffer_head *tbSh_1 = PATH_H_PBUFFER(tb->tb_path, h - 1);
		struct reiserfs_super_block *sb;

		if (tb->blknum[h] != 1)
			reiserfs_panic(0, "balance_internal",
				       "One new node required for creating the new root");
		/* S[h] = empty buffer from the list FEB. */
		tbSh = get_FEB(tb);
		set_blkh_level(B_BLK_HEAD(tbSh), h + 1);

		/* Put the unique node-pointer to S[h] that points to S[h-1]. */

		dc = B_N_CHILD(tbSh, 0);

		set_dc(dc, MAX_CHILD_SIZE(tbSh_1->b_size) -
		       get_blkh_free_space(B_BLK_HEAD(tbSh_1)),
		       tbSh_1->b_blocknr);
		/*
		   set_dc_child_size (dc, MAX_CHILD_SIZE (tbSh_1->b_size) - get_blkh_free_space (B_BLK_HEAD(tbSh_1)));
		   set_dc_child_blocknr (dc, tbSh_1->b_blocknr);
		 */
		tb->insert_size[h] -= DC_SIZE;
		set_blkh_free_space(B_BLK_HEAD(tbSh),
				    get_blkh_free_space(B_BLK_HEAD(tbSh)) -
				    DC_SIZE);

		mark_buffer_dirty(tbSh);

		/* put new root into path structure */
		PATH_OFFSET_PBUFFER(tb->tb_path, ILLEGAL_PATH_ELEMENT_OFFSET) =
		    tbSh;

		/* Change root in structure super block. */
		sb = tb->tb_fs->fs_ondisk_sb;
		set_sb_root_block(sb, tbSh->b_blocknr);
		set_sb_tree_height(sb, get_sb_tree_height(sb) + 1);

		mark_buffer_dirty(tb->tb_fs->fs_super_bh);
		tb->tb_fs->fs_dirt = 1;
	}

	if (tb->blknum[h] == 2) {
		int snum;
		struct buffer_info dest_bi, src_bi;

		/* S_new = free buffer from list FEB */
		S_new = get_FEB(tb);

		set_blkh_level(B_BLK_HEAD(S_new), h + 1);

		buffer_info_init_bh(tb, &dest_bi, S_new);
		buffer_info_init_tbSh(tb, &src_bi, h);

		n = get_blkh_nr_items(B_BLK_HEAD(tbSh));	/* number of items in S[h] */
		snum = (insert_num + n + 1) / 2;
		if (n - snum >= child_pos) {
			/* new items don't fall into S_new */
			/*  store the delimiting key for the next level */
			/* new_insert_key = (n - snum)'th key in S[h] */
			memcpy(&new_insert_key, internal_key(tbSh, n - snum),
			       KEY_SIZE);
			/* last parameter is del_par */
			internal_move_pointers_items(&dest_bi, &src_bi,
						     LAST_TO_FIRST,
						     snum, 0);
		} else if (n + insert_num - snum < child_pos) {
			/* all new items fall into S_new */
			/*  store the delimiting key for the next level */
			/* new_insert_key = (n + insert_item - snum)'th key in S[h] */
			memcpy(&new_insert_key,
			       internal_key(tbSh, n + insert_num - snum),
			       KEY_SIZE);
			/* last parameter is del_par */
			internal_move_pointers_items(&dest_bi, &src_bi,
						     LAST_TO_FIRST,
						     snum - insert_num, 0);
			/*                  internal_move_pointers_items(S_new,tbSh,1,snum - insert_num,0); */

			/* insert insert_num keys and node-pointers into S_new */
			internal_insert_childs(&dest_bi,
					       child_pos - n - insert_num +
					       snum - 1,
					       insert_num, insert_key,
					       insert_ptr);

			insert_num = 0;
		} else {
			struct disk_child *dc;

			/* some items fall into S_new, but some don't fall */
			/* last parameter is del_par */
			internal_move_pointers_items(&dest_bi, &src_bi,
						     LAST_TO_FIRST,
						     n - child_pos + 1, 1);
			/*                  internal_move_pointers_items(S_new,tbSh,1,n - child_pos + 1,1); */
			/* calculate number of new items that fall into S_new */
			k = snum - n + child_pos - 1;

			internal_insert_childs(&dest_bi, 0, k, insert_key + 1,
					       insert_ptr + 1);

			/* new_insert_key = insert_key[insert_num - k - 1] */
			memcpy(&new_insert_key, insert_key + insert_num - k - 1,
			       KEY_SIZE);
			/* replace first node-ptr in S_new by node-ptr to insert_ptr[insert_num-k-1] */

			dc = B_N_CHILD(S_new, 0);
			set_dc(dc,
			       MAX_CHILD_SIZE(insert_ptr[insert_num - k - 1]->
					      b_size) -
			       get_blkh_free_space(B_BLK_HEAD
						   (insert_ptr
						    [insert_num - k - 1])),
			       insert_ptr[insert_num - k - 1]->b_blocknr);
			/*
			   set_dc_child_size (dc, MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]->b_size) -
			   get_blkh_free_space (B_BLK_HEAD(insert_ptr[insert_num-k-1])));
			   set_dc_child_blocknr (dc, insert_ptr[insert_num-k-1]->b_blocknr);
			 */
			mark_buffer_dirty(S_new);

			insert_num -= (k + 1);
		}
		/* new_insert_ptr = node_pointer to S_new */
		new_insert_ptr = S_new;
		/*
		   S_new->b_count --;
		 */
		/*brelse(S_new); */
	}

	n = get_blkh_nr_items(B_BLK_HEAD(tbSh));	/*number of items in S[h] */

	if (-1 <= child_pos && child_pos <= n && insert_num > 0) {
		buffer_info_init_tbSh(tb, &bi, h);
		if (child_pos == -1) {
			/* this is a little different from original do_balance:
			   here we insert the minimal keys in the tree, that has never happened when file system works */
			if (tb->CFL[h - 1] || insert_num != 1 || h != 1)
				die("balance_internal: invalid child_pos");
			/* insert_child (tb->S[h], tb->S[h-1], child_pos, insert_num, B_N_ITEM_HEAD(tb->S[0],0), insert_ptr); */
			internal_insert_childs(&bi, child_pos, insert_num,
					       item_head(PATH_PLAST_BUFFER
							      (tb->tb_path), 0),
					       insert_ptr);
		} else
			internal_insert_childs(&bi, child_pos, insert_num,
					       insert_key, insert_ptr);
	}

	insert_ptr[0] = new_insert_ptr;
	if (new_insert_ptr)
		memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);

	return order;
}