/*
   * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   */

  /*
   * Now we have all buffers that must be used in balancing of the tree
   * Further calculations can not cause schedule(), and thus the buffer
   * tree will be stable until the balancing will be finished
   * balance the tree according to the analysis made before,
   * and using buffers obtained after all above.
   */

  #include <linux/uaccess.h>

  #include <linux/time.h>

  #include "reiserfs.h"

  #include <linux/buffer_head.h>

  #include <linux/kernel.h>

  static inline void buffer_info_init_left(struct tree_balance *tb,
                                           struct buffer_info *bi)
  {
  	bi->tb          = tb;
  	bi->bi_bh       = tb->L[0];
  	bi->bi_parent   = tb->FL[0];
  	bi->bi_position = get_left_neighbor_position(tb, 0);
  }
  
  static inline void buffer_info_init_right(struct tree_balance *tb,
                                            struct buffer_info *bi)
  {
  	bi->tb          = tb;
  	bi->bi_bh       = tb->R[0];
  	bi->bi_parent   = tb->FR[0];
  	bi->bi_position = get_right_neighbor_position(tb, 0);
  }
  
  static inline void buffer_info_init_tbS0(struct tree_balance *tb,
                                           struct buffer_info *bi)
  {
  	bi->tb          = tb;
  	bi->bi_bh        = PATH_PLAST_BUFFER(tb->tb_path);
  	bi->bi_parent   = PATH_H_PPARENT(tb->tb_path, 0);
  	bi->bi_position = PATH_H_POSITION(tb->tb_path, 1);
  }
  
  static inline void buffer_info_init_bh(struct tree_balance *tb,
                                         struct buffer_info *bi,
                                         struct buffer_head *bh)
  {
  	bi->tb          = tb;
  	bi->bi_bh       = bh;
  	bi->bi_parent   = NULL;
  	bi->bi_position = 0;
  }

  inline void do_balance_mark_leaf_dirty(struct tree_balance *tb,
  				       struct buffer_head *bh, int flag)

  {

  	journal_mark_dirty(tb->transaction_handle, bh);

  }
  
  #define do_balance_mark_internal_dirty do_balance_mark_leaf_dirty
  #define do_balance_mark_sb_dirty do_balance_mark_leaf_dirty

  /*
   * summary:
   *  if deleting something ( tb->insert_size[0] < 0 )
   *    return(balance_leaf_when_delete()); (flag d handled here)
   *  else
   *    if lnum is larger than 0 we put items into the left node
   *    if rnum is larger than 0 we put items into the right node
   *    if snum1 is larger than 0 we put items into the new node s1
   *    if snum2 is larger than 0 we put items into the new node s2
   * Note that all *num* count new items being created.

   */

  static void balance_leaf_when_delete_del(struct tree_balance *tb)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int item_pos = PATH_LAST_POSITION(tb->tb_path);
  	struct buffer_info bi;
  #ifdef CONFIG_REISERFS_CHECK
  	struct item_head *ih = item_head(tbS0, item_pos);
  #endif
  
  	RFALSE(ih_item_len(ih) + IH_SIZE != -tb->insert_size[0],
  	       "vs-12013: mode Delete, insert size %d, ih to be deleted %h",
  	       -tb->insert_size[0], ih);
  
  	buffer_info_init_tbS0(tb, &bi);
  	leaf_delete_items(&bi, 0, item_pos, 1, -1);
  
  	if (!item_pos && tb->CFL[0]) {
  		if (B_NR_ITEMS(tbS0)) {
  			replace_key(tb, tb->CFL[0], tb->lkey[0], tbS0, 0);
  		} else {
  			if (!PATH_H_POSITION(tb->tb_path, 1))
  				replace_key(tb, tb->CFL[0], tb->lkey[0],
  					    PATH_H_PPARENT(tb->tb_path, 0), 0);
  		}
  	}
  
  	RFALSE(!item_pos && !tb->CFL[0],
  	       "PAP-12020: tb->CFL[0]==%p, tb->L[0]==%p", tb->CFL[0],
  	       tb->L[0]);
  }
  
  /* cut item in S[0] */
  static void balance_leaf_when_delete_cut(struct tree_balance *tb)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int item_pos = PATH_LAST_POSITION(tb->tb_path);
  	struct item_head *ih = item_head(tbS0, item_pos);
  	int pos_in_item = tb->tb_path->pos_in_item;
  	struct buffer_info bi;
  	buffer_info_init_tbS0(tb, &bi);
  
  	if (is_direntry_le_ih(ih)) {
  		/*
  		 * UFS unlink semantics are such that you can only
  		 * delete one directory entry at a time.
  		 *
  		 * when we cut a directory tb->insert_size[0] means
  		 * number of entries to be cut (always 1)
  		 */
  		tb->insert_size[0] = -1;
  		leaf_cut_from_buffer(&bi, item_pos, pos_in_item,
  				     -tb->insert_size[0]);
  
  		RFALSE(!item_pos && !pos_in_item && !tb->CFL[0],
  		       "PAP-12030: can not change delimiting key. CFL[0]=%p",
  		       tb->CFL[0]);
  
  		if (!item_pos && !pos_in_item && tb->CFL[0])
  			replace_key(tb, tb->CFL[0], tb->lkey[0], tbS0, 0);
  	} else {
  		leaf_cut_from_buffer(&bi, item_pos, pos_in_item,
  				     -tb->insert_size[0]);
  
  		RFALSE(!ih_item_len(ih),
  		       "PAP-12035: cut must leave non-zero dynamic "
  		       "length of item");
  	}
  }
  
  static int balance_leaf_when_delete_left(struct tree_balance *tb)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n = B_NR_ITEMS(tbS0);
  
  	/* L[0] must be joined with S[0] */
  	if (tb->lnum[0] == -1) {
  		/* R[0] must be also joined with S[0] */
  		if (tb->rnum[0] == -1) {
  			if (tb->FR[0] == PATH_H_PPARENT(tb->tb_path, 0)) {
  				/*
  				 * all contents of all the
  				 * 3 buffers will be in L[0]
  				 */
  				if (PATH_H_POSITION(tb->tb_path, 1) == 0 &&
  				    1 < B_NR_ITEMS(tb->FR[0]))
  					replace_key(tb, tb->CFL[0],
  						    tb->lkey[0], tb->FR[0], 1);
  
  				leaf_move_items(LEAF_FROM_S_TO_L, tb, n, -1,
  						NULL);
  				leaf_move_items(LEAF_FROM_R_TO_L, tb,
  						B_NR_ITEMS(tb->R[0]), -1,
  						NULL);
  
  				reiserfs_invalidate_buffer(tb, tbS0);
  				reiserfs_invalidate_buffer(tb, tb->R[0]);
  
  				return 0;
  			}
  
  			/* all contents of all the 3 buffers will be in R[0] */
  			leaf_move_items(LEAF_FROM_S_TO_R, tb, n, -1, NULL);
  			leaf_move_items(LEAF_FROM_L_TO_R, tb,
  					B_NR_ITEMS(tb->L[0]), -1, NULL);
  
  			/* right_delimiting_key is correct in R[0] */
  			replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
  
  			reiserfs_invalidate_buffer(tb, tbS0);
  			reiserfs_invalidate_buffer(tb, tb->L[0]);
  
  			return -1;
  		}
  
  		RFALSE(tb->rnum[0] != 0,
  		       "PAP-12045: rnum must be 0 (%d)", tb->rnum[0]);
  		/* all contents of L[0] and S[0] will be in L[0] */
  		leaf_shift_left(tb, n, -1);
  
  		reiserfs_invalidate_buffer(tb, tbS0);
  
  		return 0;
  	}
  
  	/*
  	 * a part of contents of S[0] will be in L[0] and
  	 * the rest part of S[0] will be in R[0]
  	 */
  
  	RFALSE((tb->lnum[0] + tb->rnum[0] < n) ||
  	       (tb->lnum[0] + tb->rnum[0] > n + 1),
  	       "PAP-12050: rnum(%d) and lnum(%d) and item "
  	       "number(%d) in S[0] are not consistent",
  	       tb->rnum[0], tb->lnum[0], n);
  	RFALSE((tb->lnum[0] + tb->rnum[0] == n) &&
  	       (tb->lbytes != -1 || tb->rbytes != -1),
  	       "PAP-12055: bad rbytes (%d)/lbytes (%d) "
  	       "parameters when items are not split",
  	       tb->rbytes, tb->lbytes);
  	RFALSE((tb->lnum[0] + tb->rnum[0] == n + 1) &&
  	       (tb->lbytes < 1 || tb->rbytes != -1),
  	       "PAP-12060: bad rbytes (%d)/lbytes (%d) "
  	       "parameters when items are split",
  	       tb->rbytes, tb->lbytes);
  
  	leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
  	leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
  
  	reiserfs_invalidate_buffer(tb, tbS0);
  
  	return 0;
  }

  /*
   * Balance leaf node in case of delete or cut: insert_size[0] < 0

   *
   * lnum, rnum can have values >= -1
   *	-1 means that the neighbor must be joined with S
   *	 0 means that nothing should be done with the neighbor

   *	>0 means to shift entirely or partly the specified number of items
   *         to the neighbor

   */

  static int balance_leaf_when_delete(struct tree_balance *tb, int flag)

  {

  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int item_pos = PATH_LAST_POSITION(tb->tb_path);

  	struct buffer_info bi;
  	int n;
  	struct item_head *ih;

  	RFALSE(tb->FR[0] && B_LEVEL(tb->FR[0]) != DISK_LEAF_NODE_LEVEL + 1,
  	       "vs- 12000: level: wrong FR %z", tb->FR[0]);
  	RFALSE(tb->blknum[0] > 1,
  	       "PAP-12005: tb->blknum == %d, can not be > 1", tb->blknum[0]);
  	RFALSE(!tb->blknum[0] && !PATH_H_PPARENT(tb->tb_path, 0),
  	       "PAP-12010: tree can not be empty");

  	ih = item_head(tbS0, item_pos);

  	buffer_info_init_tbS0(tb, &bi);

  	/* Delete or truncate the item */

  	BUG_ON(flag != M_DELETE && flag != M_CUT);
  	if (flag == M_DELETE)
  		balance_leaf_when_delete_del(tb);
  	else /* M_CUT */
  		balance_leaf_when_delete_cut(tb);

  	/*
  	 * the rule is that no shifting occurs unless by shifting
  	 * a node can be freed
  	 */

  	n = B_NR_ITEMS(tbS0);

  	/* L[0] takes part in balancing */
  	if (tb->lnum[0])
  		return balance_leaf_when_delete_left(tb);

  	if (tb->rnum[0] == -1) {
  		/* all contents of R[0] and S[0] will be in R[0] */
  		leaf_shift_right(tb, n, -1);
  		reiserfs_invalidate_buffer(tb, tbS0);
  		return 0;
  	}

  	RFALSE(tb->rnum[0],
  	       "PAP-12065: bad rnum parameter must be 0 (%d)", tb->rnum[0]);

  	return 0;

  }

  static unsigned int balance_leaf_insert_left(struct tree_balance *tb,
  					     struct item_head *const ih,
  					     const char * const body)

  {

  	int ret;

  	struct buffer_info bi;
  	int n = B_NR_ITEMS(tb->L[0]);

  	unsigned body_shift_bytes = 0;

  	if (tb->item_pos == tb->lnum[0] - 1 && tb->lbytes != -1) {
  		/* part of new item falls into L[0] */
  		int new_item_len, shift;
  		int version;
  
  		ret = leaf_shift_left(tb, tb->lnum[0] - 1, -1);
  
  		/* Calculate item length to insert to S[0] */
  		new_item_len = ih_item_len(ih) - tb->lbytes;
  
  		/* Calculate and check item length to insert to L[0] */
  		put_ih_item_len(ih, ih_item_len(ih) - new_item_len);

  		RFALSE(ih_item_len(ih) <= 0,
  		       "PAP-12080: there is nothing to insert into L[0]: "
  		       "ih_item_len=%d", ih_item_len(ih));
  
  		/* Insert new item into L[0] */
  		buffer_info_init_left(tb, &bi);
  		leaf_insert_into_buf(&bi, n + tb->item_pos - ret, ih, body,
  			     min_t(int, tb->zeroes_num, ih_item_len(ih)));
  
  		version = ih_version(ih);
  
  		/*
  		 * Calculate key component, item length and body to
  		 * insert into S[0]
  		 */
  		shift = 0;
  		if (is_indirect_le_ih(ih))
  			shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
  
  		add_le_ih_k_offset(ih, tb->lbytes << shift);
  
  		put_ih_item_len(ih, new_item_len);
  		if (tb->lbytes > tb->zeroes_num) {

  			body_shift_bytes = tb->lbytes - tb->zeroes_num;

  			tb->zeroes_num = 0;
  		} else
  			tb->zeroes_num -= tb->lbytes;
  
  		RFALSE(ih_item_len(ih) <= 0,
  		       "PAP-12085: there is nothing to insert into S[0]: "
  		       "ih_item_len=%d", ih_item_len(ih));
  	} else {
  		/* new item in whole falls into L[0] */
  		/* Shift lnum[0]-1 items to L[0] */
  		ret = leaf_shift_left(tb, tb->lnum[0] - 1, tb->lbytes);
  
  		/* Insert new item into L[0] */
  		buffer_info_init_left(tb, &bi);
  		leaf_insert_into_buf(&bi, n + tb->item_pos - ret, ih, body,
  				     tb->zeroes_num);
  		tb->insert_size[0] = 0;
  		tb->zeroes_num = 0;
  	}

  	return body_shift_bytes;

  }

  static void balance_leaf_paste_left_shift_dirent(struct tree_balance *tb,

  						 struct item_head * const ih,
  						 const char * const body)

  {
  	int n = B_NR_ITEMS(tb->L[0]);
  	struct buffer_info bi;
  
  	RFALSE(tb->zeroes_num,
  	       "PAP-12090: invalid parameter in case of a directory");
  
  	/* directory item */
  	if (tb->lbytes > tb->pos_in_item) {
  		/* new directory entry falls into L[0] */
  		struct item_head *pasted;
  		int ret, l_pos_in_item = tb->pos_in_item;
  
  		/*
  		 * Shift lnum[0] - 1 items in whole.
  		 * Shift lbytes - 1 entries from given directory item
  		 */
  		ret = leaf_shift_left(tb, tb->lnum[0], tb->lbytes - 1);
  		if (ret && !tb->item_pos) {
  			pasted = item_head(tb->L[0], B_NR_ITEMS(tb->L[0]) - 1);
  			l_pos_in_item += ih_entry_count(pasted) -
  					 (tb->lbytes - 1);
  		}
  
  		/* Append given directory entry to directory item */
  		buffer_info_init_left(tb, &bi);
  		leaf_paste_in_buffer(&bi, n + tb->item_pos - ret,
  				     l_pos_in_item, tb->insert_size[0],
  				     body, tb->zeroes_num);
  
  		/*
  		 * previous string prepared space for pasting new entry,
  		 * following string pastes this entry
  		 */
  
  		/*
  		 * when we have merge directory item, pos_in_item
  		 * has been changed too
  		 */
  
  		/* paste new directory entry. 1 is entry number */
  		leaf_paste_entries(&bi, n + tb->item_pos - ret,
  				   l_pos_in_item, 1,
  				   (struct reiserfs_de_head *) body,
  				   body + DEH_SIZE, tb->insert_size[0]);
  		tb->insert_size[0] = 0;
  	} else {
  		/* new directory item doesn't fall into L[0] */
  		/*
  		 * Shift lnum[0]-1 items in whole. Shift lbytes
  		 * directory entries from directory item number lnum[0]
  		 */
  		leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
  	}
  
  	/* Calculate new position to append in item body */
  	tb->pos_in_item -= tb->lbytes;
  }

  static unsigned int balance_leaf_paste_left_shift(struct tree_balance *tb,
  						  struct item_head * const ih,
  						  const char * const body)

  {

  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);

  	int n = B_NR_ITEMS(tb->L[0]);

  	struct buffer_info bi;

  	int body_shift_bytes = 0;

  
  	if (is_direntry_le_ih(item_head(tbS0, tb->item_pos))) {
  		balance_leaf_paste_left_shift_dirent(tb, ih, body);

  		return 0;

  	}
  
  	RFALSE(tb->lbytes <= 0,
  	       "PAP-12095: there is nothing to shift to L[0]. "
  	       "lbytes=%d", tb->lbytes);
  	RFALSE(tb->pos_in_item != ih_item_len(item_head(tbS0, tb->item_pos)),
  	       "PAP-12100: incorrect position to paste: "
  	       "item_len=%d, pos_in_item=%d",
  	       ih_item_len(item_head(tbS0, tb->item_pos)), tb->pos_in_item);
  
  	/* appended item will be in L[0] in whole */
  	if (tb->lbytes >= tb->pos_in_item) {
  		struct item_head *tbS0_pos_ih, *tbL0_ih;
  		struct item_head *tbS0_0_ih;
  		struct reiserfs_key *left_delim_key;
  		int ret, l_n, version, temp_l;
  
  		tbS0_pos_ih = item_head(tbS0, tb->item_pos);
  		tbS0_0_ih = item_head(tbS0, 0);
  
  		/*
  		 * this bytes number must be appended
  		 * to the last item of L[h]
  		 */
  		l_n = tb->lbytes - tb->pos_in_item;
  
  		/* Calculate new insert_size[0] */
  		tb->insert_size[0] -= l_n;
  
  		RFALSE(tb->insert_size[0] <= 0,
  		       "PAP-12105: there is nothing to paste into "
  		       "L[0]. insert_size=%d", tb->insert_size[0]);
  
  		ret = leaf_shift_left(tb, tb->lnum[0],
  				      ih_item_len(tbS0_pos_ih));
  
  		tbL0_ih = item_head(tb->L[0], n + tb->item_pos - ret);
  
  		/* Append to body of item in L[0] */
  		buffer_info_init_left(tb, &bi);
  		leaf_paste_in_buffer(&bi, n + tb->item_pos - ret,
  				     ih_item_len(tbL0_ih), l_n, body,
  				     min_t(int, l_n, tb->zeroes_num));
  
  		/*
  		 * 0-th item in S0 can be only of DIRECT type
  		 * when l_n != 0
  		 */
  		temp_l = l_n;
  
  		RFALSE(ih_item_len(tbS0_0_ih),
  		       "PAP-12106: item length must be 0");
  		RFALSE(comp_short_le_keys(&tbS0_0_ih->ih_key,
  		       leaf_key(tb->L[0], n + tb->item_pos - ret)),
  		       "PAP-12107: items must be of the same file");
  
  		if (is_indirect_le_ih(tbL0_ih)) {
  			int shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
  			temp_l = l_n << shift;
  		}
  		/* update key of first item in S0 */
  		version = ih_version(tbS0_0_ih);
  		add_le_key_k_offset(version, &tbS0_0_ih->ih_key, temp_l);
  
  		/* update left delimiting key */
  		left_delim_key = internal_key(tb->CFL[0], tb->lkey[0]);
  		add_le_key_k_offset(version, left_delim_key, temp_l);
  
  		/*
  		 * Calculate new body, position in item and
  		 * insert_size[0]
  		 */
  		if (l_n > tb->zeroes_num) {

  			body_shift_bytes = l_n - tb->zeroes_num;

  			tb->zeroes_num = 0;
  		} else
  			tb->zeroes_num -= l_n;
  		tb->pos_in_item = 0;
  
  		RFALSE(comp_short_le_keys(&tbS0_0_ih->ih_key,
  					  leaf_key(tb->L[0],
  						 B_NR_ITEMS(tb->L[0]) - 1)) ||
  		       !op_is_left_mergeable(leaf_key(tbS0, 0), tbS0->b_size) ||
  		       !op_is_left_mergeable(left_delim_key, tbS0->b_size),
  		       "PAP-12120: item must be merge-able with left "
  		       "neighboring item");
  	} else {
  		/* only part of the appended item will be in L[0] */
  
  		/* Calculate position in item for append in S[0] */
  		tb->pos_in_item -= tb->lbytes;
  
  		RFALSE(tb->pos_in_item <= 0,
  		       "PAP-12125: no place for paste. pos_in_item=%d",
  		       tb->pos_in_item);
  
  		/*
  		 * Shift lnum[0] - 1 items in whole.
  		 * Shift lbytes - 1 byte from item number lnum[0]
  		 */
  		leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
  	}

  	return body_shift_bytes;

  }
  
  
  /* appended item will be in L[0] in whole */
  static void balance_leaf_paste_left_whole(struct tree_balance *tb,

  					  struct item_head * const ih,
  					  const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);

  	int n = B_NR_ITEMS(tb->L[0]);

  	struct buffer_info bi;
  	struct item_head *pasted;
  	int ret;

  	/* if we paste into first item of S[0] and it is left mergable */
  	if (!tb->item_pos &&
  	    op_is_left_mergeable(leaf_key(tbS0, 0), tbS0->b_size)) {
  		/*
  		 * then increment pos_in_item by the size of the
  		 * last item in L[0]
  		 */
  		pasted = item_head(tb->L[0], n - 1);
  		if (is_direntry_le_ih(pasted))
  			tb->pos_in_item += ih_entry_count(pasted);
  		else
  			tb->pos_in_item += ih_item_len(pasted);
  	}
  
  	/*
  	 * Shift lnum[0] - 1 items in whole.
  	 * Shift lbytes - 1 byte from item number lnum[0]
  	 */
  	ret = leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
  
  	/* Append to body of item in L[0] */
  	buffer_info_init_left(tb, &bi);
  	leaf_paste_in_buffer(&bi, n + tb->item_pos - ret, tb->pos_in_item,
  			     tb->insert_size[0], body, tb->zeroes_num);
  
  	/* if appended item is directory, paste entry */
  	pasted = item_head(tb->L[0], n + tb->item_pos - ret);
  	if (is_direntry_le_ih(pasted))
  		leaf_paste_entries(&bi, n + tb->item_pos - ret,
  				   tb->pos_in_item, 1,
  				   (struct reiserfs_de_head *)body,
  				   body + DEH_SIZE, tb->insert_size[0]);
  
  	/*
  	 * if appended item is indirect item, put unformatted node
  	 * into un list
  	 */
  	if (is_indirect_le_ih(pasted))
  		set_ih_free_space(pasted, 0);

  	tb->insert_size[0] = 0;
  	tb->zeroes_num = 0;
  }

  static unsigned int balance_leaf_paste_left(struct tree_balance *tb,
  					    struct item_head * const ih,
  					    const char * const body)

  {
  	/* we must shift the part of the appended item */
  	if (tb->item_pos == tb->lnum[0] - 1 && tb->lbytes != -1)

  		return balance_leaf_paste_left_shift(tb, ih, body);

  	else
  		balance_leaf_paste_left_whole(tb, ih, body);

  	return 0;

  }

  /* Shift lnum[0] items from S[0] to the left neighbor L[0] */

  static unsigned int balance_leaf_left(struct tree_balance *tb,
  				      struct item_head * const ih,
  				      const char * const body, int flag)

  {
  	if (tb->lnum[0] <= 0)

  		return 0;

  
  	/* new item or it part falls to L[0], shift it too */
  	if (tb->item_pos < tb->lnum[0]) {
  		BUG_ON(flag != M_INSERT && flag != M_PASTE);
  
  		if (flag == M_INSERT)

  			return balance_leaf_insert_left(tb, ih, body);

  		else /* M_PASTE */

  			return balance_leaf_paste_left(tb, ih, body);

  	} else
  		/* new item doesn't fall into L[0] */
  		leaf_shift_left(tb, tb->lnum[0], tb->lbytes);

  	return 0;

  }

  static void balance_leaf_insert_right(struct tree_balance *tb,

  				      struct item_head * const ih,
  				      const char * const body)

  {
  
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n = B_NR_ITEMS(tbS0);
  	struct buffer_info bi;

  	int ret;

  	/* new item or part of it doesn't fall into R[0] */
  	if (n - tb->rnum[0] >= tb->item_pos) {
  		leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
  		return;
  	}
  
  	/* new item or its part falls to R[0] */
  
  	/* part of new item falls into R[0] */
  	if (tb->item_pos == n - tb->rnum[0] + 1 && tb->rbytes != -1) {
  		loff_t old_key_comp, old_len, r_zeroes_number;
  		const char *r_body;
  		int version, shift;
  		loff_t offset;

  		leaf_shift_right(tb, tb->rnum[0] - 1, -1);
  
  		version = ih_version(ih);
  
  		/* Remember key component and item length */
  		old_key_comp = le_ih_k_offset(ih);
  		old_len = ih_item_len(ih);
  
  		/*
  		 * Calculate key component and item length to insert
  		 * into R[0]
  		 */
  		shift = 0;
  		if (is_indirect_le_ih(ih))
  			shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
  		offset = le_ih_k_offset(ih) + ((old_len - tb->rbytes) << shift);
  		set_le_ih_k_offset(ih, offset);
  		put_ih_item_len(ih, tb->rbytes);
  
  		/* Insert part of the item into R[0] */
  		buffer_info_init_right(tb, &bi);
  		if ((old_len - tb->rbytes) > tb->zeroes_num) {
  			r_zeroes_number = 0;
  			r_body = body + (old_len - tb->rbytes) - tb->zeroes_num;
  		} else {
  			r_body = body;
  			r_zeroes_number = tb->zeroes_num -
  					  (old_len - tb->rbytes);
  			tb->zeroes_num -= r_zeroes_number;
  		}
  
  		leaf_insert_into_buf(&bi, 0, ih, r_body, r_zeroes_number);
  
  		/* Replace right delimiting key by first key in R[0] */
  		replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
  
  		/*
  		 * Calculate key component and item length to
  		 * insert into S[0]
  		 */
  		set_le_ih_k_offset(ih, old_key_comp);
  		put_ih_item_len(ih, old_len - tb->rbytes);
  
  		tb->insert_size[0] -= tb->rbytes;
  
  	} else {
  		/* whole new item falls into R[0] */
  
  		/* Shift rnum[0]-1 items to R[0] */
  		ret = leaf_shift_right(tb, tb->rnum[0] - 1, tb->rbytes);
  
  		/* Insert new item into R[0] */
  		buffer_info_init_right(tb, &bi);
  		leaf_insert_into_buf(&bi, tb->item_pos - n + tb->rnum[0] - 1,
  				     ih, body, tb->zeroes_num);
  
  		if (tb->item_pos - n + tb->rnum[0] - 1 == 0)
  			replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
  
  		tb->zeroes_num = tb->insert_size[0] = 0;
  	}

  }

  
  static void balance_leaf_paste_right_shift_dirent(struct tree_balance *tb,

  				     struct item_head * const ih,
  				     const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	struct buffer_info bi;

  	int entry_count;

  	RFALSE(tb->zeroes_num,

  	       "PAP-12145: invalid parameter in case of a directory");
  	entry_count = ih_entry_count(item_head(tbS0, tb->item_pos));

  	/* new directory entry falls into R[0] */
  	if (entry_count - tb->rbytes < tb->pos_in_item) {
  		int paste_entry_position;

  		RFALSE(tb->rbytes - 1 >= entry_count || !tb->insert_size[0],
  		       "PAP-12150: no enough of entries to shift to R[0]: "
  		       "rbytes=%d, entry_count=%d", tb->rbytes, entry_count);

  		/*
  		 * Shift rnum[0]-1 items in whole.
  		 * Shift rbytes-1 directory entries from directory
  		 * item number rnum[0]
  		 */
  		leaf_shift_right(tb, tb->rnum[0], tb->rbytes - 1);

  		/* Paste given directory entry to directory item */
  		paste_entry_position = tb->pos_in_item - entry_count +
  				       tb->rbytes - 1;
  		buffer_info_init_right(tb, &bi);
  		leaf_paste_in_buffer(&bi, 0, paste_entry_position,
  				     tb->insert_size[0], body, tb->zeroes_num);

  		/* paste entry */
  		leaf_paste_entries(&bi, 0, paste_entry_position, 1,
  				   (struct reiserfs_de_head *) body,
  				   body + DEH_SIZE, tb->insert_size[0]);

  		/* change delimiting keys */
  		if (paste_entry_position == 0)
  			replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);

  		tb->insert_size[0] = 0;
  		tb->pos_in_item++;
  	} else {
  		/* new directory entry doesn't fall into R[0] */
  		leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
  	}
  }

  static void balance_leaf_paste_right_shift(struct tree_balance *tb,

  				     struct item_head * const ih,
  				     const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n_shift, n_rem, r_zeroes_number, version;
  	unsigned long temp_rem;
  	const char *r_body;
  	struct buffer_info bi;

  	/* we append to directory item */
  	if (is_direntry_le_ih(item_head(tbS0, tb->item_pos))) {
  		balance_leaf_paste_right_shift_dirent(tb, ih, body);
  		return;
  	}

  	/* regular object */

  	/*
  	 * Calculate number of bytes which must be shifted
  	 * from appended item
  	 */
  	n_shift = tb->rbytes - tb->insert_size[0];
  	if (n_shift < 0)
  		n_shift = 0;

  	RFALSE(tb->pos_in_item != ih_item_len(item_head(tbS0, tb->item_pos)),

  	       "PAP-12155: invalid position to paste. ih_item_len=%d, "

  	       "pos_in_item=%d", tb->pos_in_item,
  	       ih_item_len(item_head(tbS0, tb->item_pos)));

  	leaf_shift_right(tb, tb->rnum[0], n_shift);

  	/*
  	 * Calculate number of bytes which must remain in body
  	 * after appending to R[0]
  	 */
  	n_rem = tb->insert_size[0] - tb->rbytes;
  	if (n_rem < 0)
  		n_rem = 0;

  	temp_rem = n_rem;

  	version = ih_version(item_head(tb->R[0], 0));

  	if (is_indirect_le_key(version, leaf_key(tb->R[0], 0))) {
  		int shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
  		temp_rem = n_rem << shift;
  	}

  	add_le_key_k_offset(version, leaf_key(tb->R[0], 0), temp_rem);
  	add_le_key_k_offset(version, internal_key(tb->CFR[0], tb->rkey[0]),
  			    temp_rem);

  	do_balance_mark_internal_dirty(tb, tb->CFR[0], 0);

  	/* Append part of body into R[0] */
  	buffer_info_init_right(tb, &bi);
  	if (n_rem > tb->zeroes_num) {
  		r_zeroes_number = 0;
  		r_body = body + n_rem - tb->zeroes_num;
  	} else {
  		r_body = body;
  		r_zeroes_number = tb->zeroes_num - n_rem;
  		tb->zeroes_num -= r_zeroes_number;
  	}

  	leaf_paste_in_buffer(&bi, 0, n_shift, tb->insert_size[0] - n_rem,
  			     r_body, r_zeroes_number);
  
  	if (is_indirect_le_ih(item_head(tb->R[0], 0)))
  		set_ih_free_space(item_head(tb->R[0], 0), 0);
  
  	tb->insert_size[0] = n_rem;
  	if (!n_rem)
  		tb->pos_in_item++;
  }
  
  static void balance_leaf_paste_right_whole(struct tree_balance *tb,

  				     struct item_head * const ih,
  				     const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n = B_NR_ITEMS(tbS0);
  	struct item_head *pasted;
  	struct buffer_info bi;
  
  							buffer_info_init_right(tb, &bi);
  	leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
  
  	/* append item in R[0] */
  	if (tb->pos_in_item >= 0) {
  		buffer_info_init_right(tb, &bi);
  		leaf_paste_in_buffer(&bi, tb->item_pos - n + tb->rnum[0],
  				     tb->pos_in_item, tb->insert_size[0], body,
  				     tb->zeroes_num);
  	}
  
  	/* paste new entry, if item is directory item */
  	pasted = item_head(tb->R[0], tb->item_pos - n + tb->rnum[0]);
  	if (is_direntry_le_ih(pasted) && tb->pos_in_item >= 0) {
  		leaf_paste_entries(&bi, tb->item_pos - n + tb->rnum[0],
  				   tb->pos_in_item, 1,
  				   (struct reiserfs_de_head *)body,
  				   body + DEH_SIZE, tb->insert_size[0]);
  
  		if (!tb->pos_in_item) {
  
  			RFALSE(tb->item_pos - n + tb->rnum[0],
  			       "PAP-12165: directory item must be first "
  			       "item of node when pasting is in 0th position");

  			/* update delimiting keys */
  			replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
  		}
  	}
  
  	if (is_indirect_le_ih(pasted))
  		set_ih_free_space(pasted, 0);
  	tb->zeroes_num = tb->insert_size[0] = 0;
  }
  
  static void balance_leaf_paste_right(struct tree_balance *tb,

  				     struct item_head * const ih,
  				     const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n = B_NR_ITEMS(tbS0);
  
  	/* new item doesn't fall into R[0] */
  	if (n - tb->rnum[0] > tb->item_pos) {
  		leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
  		return;
  	}
  
  	/* pasted item or part of it falls to R[0] */
  
  	if (tb->item_pos == n - tb->rnum[0] && tb->rbytes != -1)
  		/* we must shift the part of the appended item */
  		balance_leaf_paste_right_shift(tb, ih, body);
  	else
  		/* pasted item in whole falls into R[0] */
  		balance_leaf_paste_right_whole(tb, ih, body);

  }

  /* shift rnum[0] items from S[0] to the right neighbor R[0] */

  static void balance_leaf_right(struct tree_balance *tb,
  			       struct item_head * const ih,
  			       const char * const body, int flag)

  {
  	if (tb->rnum[0] <= 0)
  		return;
  
  	BUG_ON(flag != M_INSERT && flag != M_PASTE);
  
  	if (flag == M_INSERT)
  		balance_leaf_insert_right(tb, ih, body);
  	else /* M_PASTE */
  		balance_leaf_paste_right(tb, ih, body);

  }

  static void balance_leaf_new_nodes_insert(struct tree_balance *tb,

  					  struct item_head * const ih,
  					  const char * const body,

  					  struct item_head *insert_key,
  					  struct buffer_head **insert_ptr,
  					  int i)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n = B_NR_ITEMS(tbS0);
  	struct buffer_info bi;

  	int shift;
  
  	/* new item or it part don't falls into S_new[i] */
  	if (n - tb->snum[i] >= tb->item_pos) {
  		leaf_move_items(LEAF_FROM_S_TO_SNEW, tb,
  				tb->snum[i], tb->sbytes[i], tb->S_new[i]);
  		return;
  	}

  	/* new item or it's part falls to first new node S_new[i] */

  	/* part of new item falls into S_new[i] */
  	if (tb->item_pos == n - tb->snum[i] + 1 && tb->sbytes[i] != -1) {
  		int old_key_comp, old_len, r_zeroes_number;
  		const char *r_body;
  		int version;
  
  		/* Move snum[i]-1 items from S[0] to S_new[i] */
  		leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i] - 1, -1,
  				tb->S_new[i]);
  
  		/* Remember key component and item length */
  		version = ih_version(ih);
  		old_key_comp = le_ih_k_offset(ih);
  		old_len = ih_item_len(ih);
  
  		/*
  		 * Calculate key component and item length to insert
  		 * into S_new[i]
  		 */
  		shift = 0;
  		if (is_indirect_le_ih(ih))
  			shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
  		set_le_ih_k_offset(ih,
  				   le_ih_k_offset(ih) +
  				   ((old_len - tb->sbytes[i]) << shift));
  
  		put_ih_item_len(ih, tb->sbytes[i]);
  
  		/* Insert part of the item into S_new[i] before 0-th item */
  		buffer_info_init_bh(tb, &bi, tb->S_new[i]);
  
  		if ((old_len - tb->sbytes[i]) > tb->zeroes_num) {
  			r_zeroes_number = 0;
  			r_body = body + (old_len - tb->sbytes[i]) -
  					 tb->zeroes_num;
  		} else {
  			r_body = body;
  			r_zeroes_number = tb->zeroes_num - (old_len -
  					  tb->sbytes[i]);
  			tb->zeroes_num -= r_zeroes_number;
  		}
  
  		leaf_insert_into_buf(&bi, 0, ih, r_body, r_zeroes_number);
  
  		/*
  		 * Calculate key component and item length to
  		 * insert into S[i]
  		 */
  		set_le_ih_k_offset(ih, old_key_comp);
  		put_ih_item_len(ih, old_len - tb->sbytes[i]);
  		tb->insert_size[0] -= tb->sbytes[i];
  	} else {
  		/* whole new item falls into S_new[i] */
  
  		/*
  		 * Shift snum[0] - 1 items to S_new[i]
  		 * (sbytes[i] of split item)
  		 */
  		leaf_move_items(LEAF_FROM_S_TO_SNEW, tb,
  				tb->snum[i] - 1, tb->sbytes[i], tb->S_new[i]);
  
  		/* Insert new item into S_new[i] */
  		buffer_info_init_bh(tb, &bi, tb->S_new[i]);
  		leaf_insert_into_buf(&bi, tb->item_pos - n + tb->snum[i] - 1,
  				     ih, body, tb->zeroes_num);
  
  		tb->zeroes_num = tb->insert_size[0] = 0;
  	}

  }

  /* we append to directory item */
  static void balance_leaf_new_nodes_paste_dirent(struct tree_balance *tb,

  					 struct item_head * const ih,
  					 const char * const body,

  					 struct item_head *insert_key,
  					 struct buffer_head **insert_ptr,
  					 int i)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	struct item_head *aux_ih = item_head(tbS0, tb->item_pos);
  	int entry_count = ih_entry_count(aux_ih);
  	struct buffer_info bi;
  
  	if (entry_count - tb->sbytes[i] < tb->pos_in_item &&
  	    tb->pos_in_item <= entry_count) {
  		/* new directory entry falls into S_new[i] */
  
  		RFALSE(!tb->insert_size[0],
  		       "PAP-12215: insert_size is already 0");
  		RFALSE(tb->sbytes[i] - 1 >= entry_count,
  		       "PAP-12220: there are no so much entries (%d), only %d",
  		       tb->sbytes[i] - 1, entry_count);
  
  		/*
  		 * Shift snum[i]-1 items in whole.
  		 * Shift sbytes[i] directory entries
  		 * from directory item number snum[i]
  		 */
  		leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i],
  				tb->sbytes[i] - 1, tb->S_new[i]);
  
  		/*
  		 * Paste given directory entry to
  		 * directory item
  		 */
  		buffer_info_init_bh(tb, &bi, tb->S_new[i]);
  		leaf_paste_in_buffer(&bi, 0, tb->pos_in_item - entry_count +
  				     tb->sbytes[i] - 1, tb->insert_size[0],
  				     body, tb->zeroes_num);
  
  		/* paste new directory entry */
  		leaf_paste_entries(&bi, 0, tb->pos_in_item - entry_count +
  				   tb->sbytes[i] - 1, 1,
  				   (struct reiserfs_de_head *) body,
  				   body + DEH_SIZE, tb->insert_size[0]);
  
  		tb->insert_size[0] = 0;
  		tb->pos_in_item++;
  	} else {
  		/* new directory entry doesn't fall into S_new[i] */
  		leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i],
  				tb->sbytes[i], tb->S_new[i]);
  	}
  
  }
  
  static void balance_leaf_new_nodes_paste_shift(struct tree_balance *tb,

  					 struct item_head * const ih,
  					 const char * const body,

  					 struct item_head *insert_key,
  					 struct buffer_head **insert_ptr,
  					 int i)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);

  	struct item_head *aux_ih = item_head(tbS0, tb->item_pos);
  	int n_shift, n_rem, r_zeroes_number, shift;
  	const char *r_body;
  	struct item_head *tmp;
  	struct buffer_info bi;
  
  	RFALSE(ih, "PAP-12210: ih must be 0");
  
  	if (is_direntry_le_ih(aux_ih)) {
  		balance_leaf_new_nodes_paste_dirent(tb, ih, body, insert_key,
  						    insert_ptr, i);
  		return;
  	}
  
  	/* regular object */
  
  
  	RFALSE(tb->pos_in_item != ih_item_len(item_head(tbS0, tb->item_pos)) ||
  	       tb->insert_size[0] <= 0,
  	       "PAP-12225: item too short or insert_size <= 0");
  
  	/*
  	 * Calculate number of bytes which must be shifted from appended item
  	 */
  	n_shift = tb->sbytes[i] - tb->insert_size[0];
  	if (n_shift < 0)
  		n_shift = 0;
  	leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i], n_shift,
  			tb->S_new[i]);
  
  	/*
  	 * Calculate number of bytes which must remain in body after
  	 * append to S_new[i]
  	 */
  	n_rem = tb->insert_size[0] - tb->sbytes[i];
  	if (n_rem < 0)
  		n_rem = 0;
  
  	/* Append part of body into S_new[0] */
  	buffer_info_init_bh(tb, &bi, tb->S_new[i]);
  	if (n_rem > tb->zeroes_num) {
  		r_zeroes_number = 0;
  		r_body = body + n_rem - tb->zeroes_num;
  	} else {
  		r_body = body;
  		r_zeroes_number = tb->zeroes_num - n_rem;
  		tb->zeroes_num -= r_zeroes_number;
  	}
  
  	leaf_paste_in_buffer(&bi, 0, n_shift, tb->insert_size[0] - n_rem,
  			     r_body, r_zeroes_number);
  
  	tmp = item_head(tb->S_new[i], 0);
  	shift = 0;
  	if (is_indirect_le_ih(tmp)) {
  		set_ih_free_space(tmp, 0);
  		shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
  	}
  	add_le_ih_k_offset(tmp, n_rem << shift);
  
  	tb->insert_size[0] = n_rem;
  	if (!n_rem)
  		tb->pos_in_item++;
  }
  
  static void balance_leaf_new_nodes_paste_whole(struct tree_balance *tb,

  					       struct item_head * const ih,
  					       const char * const body,

  					       struct item_head *insert_key,
  					       struct buffer_head **insert_ptr,
  					       int i)
  
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);

  	int n = B_NR_ITEMS(tbS0);

  	int leaf_mi;
  	struct item_head *pasted;

  	struct buffer_info bi;

  
  #ifdef CONFIG_REISERFS_CHECK

  	struct item_head *ih_check = item_head(tbS0, tb->item_pos);
  
  	if (!is_direntry_le_ih(ih_check) &&
  	    (tb->pos_in_item != ih_item_len(ih_check) ||
  	    tb->insert_size[0] <= 0))
  		reiserfs_panic(tb->tb_sb,
  			     "PAP-12235",
  			     "pos_in_item must be equal to ih_item_len");
  #endif
  
  	leaf_mi = leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i],
  				  tb->sbytes[i], tb->S_new[i]);
  
  	RFALSE(leaf_mi,
  	       "PAP-12240: unexpected value returned by leaf_move_items (%d)",
  	       leaf_mi);
  
  	/* paste into item */
  	buffer_info_init_bh(tb, &bi, tb->S_new[i]);
  	leaf_paste_in_buffer(&bi, tb->item_pos - n + tb->snum[i],
  			     tb->pos_in_item, tb->insert_size[0],
  			     body, tb->zeroes_num);
  
  	pasted = item_head(tb->S_new[i], tb->item_pos - n +
  			   tb->snum[i]);
  	if (is_direntry_le_ih(pasted))
  		leaf_paste_entries(&bi, tb->item_pos - n + tb->snum[i],
  				   tb->pos_in_item, 1,
  				   (struct reiserfs_de_head *)body,
  				   body + DEH_SIZE, tb->insert_size[0]);

  	/* if we paste to indirect item update ih_free_space */
  	if (is_indirect_le_ih(pasted))
  		set_ih_free_space(pasted, 0);

  	tb->zeroes_num = tb->insert_size[0] = 0;
  
  }
  static void balance_leaf_new_nodes_paste(struct tree_balance *tb,

  					 struct item_head * const ih,
  					 const char * const body,

  					 struct item_head *insert_key,
  					 struct buffer_head **insert_ptr,
  					 int i)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	int n = B_NR_ITEMS(tbS0);
  
  	/* pasted item doesn't fall into S_new[i] */
  	if (n - tb->snum[i] > tb->item_pos) {
  		leaf_move_items(LEAF_FROM_S_TO_SNEW, tb,
  				tb->snum[i], tb->sbytes[i], tb->S_new[i]);
  		return;
  	}

  	/* pasted item or part if it falls to S_new[i] */
  
  	if (tb->item_pos == n - tb->snum[i] && tb->sbytes[i] != -1)
  		/* we must shift part of the appended item */
  		balance_leaf_new_nodes_paste_shift(tb, ih, body, insert_key,
  						   insert_ptr, i);
  	else
  		/* item falls wholly into S_new[i] */
  		balance_leaf_new_nodes_paste_whole(tb, ih, body, insert_key,
  						   insert_ptr, i);

  }

  /* Fill new nodes that appear in place of S[0] */
  static void balance_leaf_new_nodes(struct tree_balance *tb,

  				   struct item_head * const ih,
  				   const char * const body,

  				   struct item_head *insert_key,
  				   struct buffer_head **insert_ptr,
  				   int flag)
  {
  	int i;
  	for (i = tb->blknum[0] - 2; i >= 0; i--) {

  		BUG_ON(flag != M_INSERT && flag != M_PASTE);

  
  		RFALSE(!tb->snum[i],
  		       "PAP-12200: snum[%d] == %d. Must be > 0", i,
  		       tb->snum[i]);
  
  		/* here we shift from S to S_new nodes */
  
  		tb->S_new[i] = get_FEB(tb);
  
  		/* initialized block type and tree level */
  		set_blkh_level(B_BLK_HEAD(tb->S_new[i]), DISK_LEAF_NODE_LEVEL);

  		if (flag == M_INSERT)

  			balance_leaf_new_nodes_insert(tb, ih, body, insert_key,
  						      insert_ptr, i);

  		else /* M_PASTE */

  			balance_leaf_new_nodes_paste(tb, ih, body, insert_key,
  						     insert_ptr, i);

  
  		memcpy(insert_key + i, leaf_key(tb->S_new[i], 0), KEY_SIZE);
  		insert_ptr[i] = tb->S_new[i];
  
  		RFALSE(!buffer_journaled(tb->S_new[i])
  		       || buffer_journal_dirty(tb->S_new[i])
  		       || buffer_dirty(tb->S_new[i]),
  		       "PAP-12247: S_new[%d] : (%b)",

  		       i, tb->S_new[i]);

  	}
  }

  static void balance_leaf_finish_node_insert(struct tree_balance *tb,

  					    struct item_head * const ih,
  					    const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	struct buffer_info bi;

  	buffer_info_init_tbS0(tb, &bi);
  	leaf_insert_into_buf(&bi, tb->item_pos, ih, body, tb->zeroes_num);
  
  	/* If we insert the first key change the delimiting key */
  	if (tb->item_pos == 0) {
  		if (tb->CFL[0])	/* can be 0 in reiserfsck */
  			replace_key(tb, tb->CFL[0], tb->lkey[0], tbS0, 0);
  
  	}
  }
  
  static void balance_leaf_finish_node_paste_dirent(struct tree_balance *tb,

  						  struct item_head * const ih,
  						  const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	struct item_head *pasted = item_head(tbS0, tb->item_pos);
  	struct buffer_info bi;
  
  	if (tb->pos_in_item >= 0 && tb->pos_in_item <= ih_entry_count(pasted)) {
  		RFALSE(!tb->insert_size[0],
  		       "PAP-12260: insert_size is 0 already");
  
  		/* prepare space */
  		buffer_info_init_tbS0(tb, &bi);
  		leaf_paste_in_buffer(&bi, tb->item_pos, tb->pos_in_item,
  				     tb->insert_size[0], body, tb->zeroes_num);
  
  		/* paste entry */
  		leaf_paste_entries(&bi, tb->item_pos, tb->pos_in_item, 1,
  				   (struct reiserfs_de_head *)body,
  				   body + DEH_SIZE, tb->insert_size[0]);
  
  		if (!tb->item_pos && !tb->pos_in_item) {
  			RFALSE(!tb->CFL[0] || !tb->L[0],
  			       "PAP-12270: CFL[0]/L[0] must  be specified");
  			if (tb->CFL[0])
  				replace_key(tb, tb->CFL[0], tb->lkey[0],
  					    tbS0, 0);
  		}
  
  		tb->insert_size[0] = 0;
  	}

  }

  static void balance_leaf_finish_node_paste(struct tree_balance *tb,

  					   struct item_head * const ih,
  					   const char * const body)

  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
  	struct buffer_info bi;

  	struct item_head *pasted = item_head(tbS0, tb->item_pos);

  	/* when directory, may be new entry already pasted */
  	if (is_direntry_le_ih(pasted)) {
  		balance_leaf_finish_node_paste_dirent(tb, ih, body);
  		return;
  	}
  
  	/* regular object */
  
  	if (tb->pos_in_item == ih_item_len(pasted)) {
  		RFALSE(tb->insert_size[0] <= 0,
  		       "PAP-12275: insert size must not be %d",
  		       tb->insert_size[0]);
  		buffer_info_init_tbS0(tb, &bi);
  		leaf_paste_in_buffer(&bi, tb->item_pos,
  				     tb->pos_in_item, tb->insert_size[0], body,
  				     tb->zeroes_num);
  
  		if (is_indirect_le_ih(pasted))
  			set_ih_free_space(pasted, 0);
  
  		tb->insert_size[0] = 0;
  	}
  #ifdef CONFIG_REISERFS_CHECK
  	else if (tb->insert_size[0]) {
  		print_cur_tb("12285");
  		reiserfs_panic(tb->tb_sb, "PAP-12285",
  		    "insert_size must be 0 (%d)", tb->insert_size[0]);
  	}
  #endif

  }

  /*
   * if the affected item was not wholly shifted then we
   * perform all necessary operations on that part or whole
   * of the affected item which remains in S
   */
  static void balance_leaf_finish_node(struct tree_balance *tb,

  				      struct item_head * const ih,
  				      const char * const body, int flag)

  {
  	/* if we must insert or append into buffer S[0] */
  	if (0 <= tb->item_pos && tb->item_pos < tb->s0num) {
  		if (flag == M_INSERT)
  			balance_leaf_finish_node_insert(tb, ih, body);
  		else /* M_PASTE */
  			balance_leaf_finish_node_paste(tb, ih, body);
  	}
  }

  /**
   * balance_leaf - reiserfs tree balancing algorithm
   * @tb: tree balance state
   * @ih: item header of inserted item (little endian)
   * @body: body of inserted item or bytes to paste
   * @flag: i - insert, d - delete, c - cut, p - paste (see do_balance)
   * passed back:
   * @insert_key: key to insert new nodes
   * @insert_ptr: array of nodes to insert at the next level
   *
   * In our processing of one level we sometimes determine what must be
   * inserted into the next higher level.  This insertion consists of a
   * key or two keys and their corresponding pointers.
   */
  static int balance_leaf(struct tree_balance *tb, struct item_head *ih,
  			const char *body, int flag,
  			struct item_head *insert_key,
  			struct buffer_head **insert_ptr)
  {
  	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);

  
  	PROC_INFO_INC(tb->tb_sb, balance_at[0]);
  
  	/* Make balance in case insert_size[0] < 0 */
  	if (tb->insert_size[0] < 0)
  		return balance_leaf_when_delete(tb, flag);
  
  	tb->item_pos = PATH_LAST_POSITION(tb->tb_path),
  	tb->pos_in_item = tb->tb_path->pos_in_item,
  	tb->zeroes_num = 0;
  	if (flag == M_INSERT && !body)
  		tb->zeroes_num = ih_item_len(ih);
  
  	/*
  	 * for indirect item pos_in_item is measured in unformatted node
  	 * pointers. Recalculate to bytes
  	 */
  	if (flag != M_INSERT
  	    && is_indirect_le_ih(item_head(tbS0, tb->item_pos)))
  		tb->pos_in_item *= UNFM_P_SIZE;

  	body += balance_leaf_left(tb, ih, body, flag);

  
  	/* tb->lnum[0] > 0 */
  	/* Calculate new item position */
  	tb->item_pos -= (tb->lnum[0] - ((tb->lbytes != -1) ? 1 : 0));

  	balance_leaf_right(tb, ih, body, flag);

  	/* tb->rnum[0] > 0 */
  	RFALSE(tb->blknum[0] > 3,

  	       "PAP-12180: blknum can not be %d. It must be <= 3", tb->blknum[0]);

  	RFALSE(tb->blknum[0] < 0,

  	       "PAP-12185: blknum can not be %d. It must be >= 0", tb->blknum[0]);

  	/*
  	 * if while adding to a node we discover that it is possible to split
  	 * it in two, and merge the left part into the left neighbor and the
  	 * right part into the right neighbor, eliminating the node
  	 */

  	if (tb->blknum[0] == 0) {	/* node S[0] is empty now */
  
  		RFALSE(!tb->lnum[0] || !tb->rnum[0],
  		       "PAP-12190: lnum and rnum must not be zero");

  		/*
  		 * if insertion was done before 0-th position in R[0], right
  		 * delimiting key of the tb->L[0]'s and left delimiting key are
  		 * not set correctly
  		 */

  		if (tb->CFL[0]) {
  			if (!tb->CFR[0])

  				reiserfs_panic(tb->tb_sb, "vs-12195",
  					       "CFR not initialized");

  			copy_key(internal_key(tb->CFL[0], tb->lkey[0]),
  				 internal_key(tb->CFR[0], tb->rkey[0]));

  			do_balance_mark_internal_dirty(tb, tb->CFL[0], 0);
  		}

  		reiserfs_invalidate_buffer(tb, tbS0);
  		return 0;
  	}

  	balance_leaf_new_nodes(tb, ih, body, insert_key, insert_ptr, flag);

  	balance_leaf_finish_node(tb, ih, body, flag);

  #ifdef CONFIG_REISERFS_CHECK

  	if (flag == M_PASTE && tb->insert_size[0]) {
  		print_cur_tb("12290");
  		reiserfs_panic(tb->tb_sb,

  			       "PAP-12290", "insert_size is still not 0 (%d)",

  			       tb->insert_size[0]);
  	}

  #endif
  
  	/* Leaf level of the tree is balanced (end of balance_leaf) */

  	return 0;

  }

  
  /* Make empty node */

  void make_empty_node(struct buffer_info *bi)

  {

  	struct block_head *blkh;

  	RFALSE(bi->bi_bh == NULL, "PAP-12295: pointer to the buffer is NULL");

  	blkh = B_BLK_HEAD(bi->bi_bh);
  	set_blkh_nr_item(blkh, 0);
  	set_blkh_free_space(blkh, MAX_CHILD_SIZE(bi->bi_bh));

  	if (bi->bi_parent)
  		B_N_CHILD(bi->bi_parent, bi->bi_position)->dc_size = 0;	/* Endian safe if 0 */

  }

  /* Get first empty buffer */

  struct buffer_head *get_FEB(struct tree_balance *tb)

  {

  	int i;

  	struct buffer_info bi;

  	for (i = 0; i < MAX_FEB_SIZE; i++)

  		if (tb->FEB[i] != NULL)

  			break;
  
  	if (i == MAX_FEB_SIZE)

  		reiserfs_panic(tb->tb_sb, "vs-12300", "FEB list is empty");

  	buffer_info_init_bh(tb, &bi, tb->FEB[i]);

  	make_empty_node(&bi);

  	set_buffer_uptodate(tb->FEB[i]);
  	tb->used[i] = tb->FEB[i];

  	tb->FEB[i] = NULL;

  	return tb->used[i];

  }

  /* This is now used because reiserfs_free_block has to be able to schedule. */

  static void store_thrown(struct tree_balance *tb, struct buffer_head *bh)

  {

  	int i;
  
  	if (buffer_dirty(bh))

  		reiserfs_warning(tb->tb_sb, "reiserfs-12320",
  				 "called with dirty buffer");

  	for (i = 0; i < ARRAY_SIZE(tb->thrown); i++)

  		if (!tb->thrown[i]) {
  			tb->thrown[i] = bh;
  			get_bh(bh);	/* free_thrown puts this */
  			return;
  		}

  	reiserfs_warning(tb->tb_sb, "reiserfs-12321",
  			 "too many thrown buffers");

  }

  static void free_thrown(struct tree_balance *tb)
  {
  	int i;
  	b_blocknr_t blocknr;

  	for (i = 0; i < ARRAY_SIZE(tb->thrown); i++) {

  		if (tb->thrown[i]) {
  			blocknr = tb->thrown[i]->b_blocknr;
  			if (buffer_dirty(tb->thrown[i]))

  				reiserfs_warning(tb->tb_sb, "reiserfs-12322",
  						 "called with dirty buffer %d",

  						 blocknr);
  			brelse(tb->thrown[i]);	/* incremented in store_thrown */
  			reiserfs_free_block(tb->transaction_handle, NULL,
  					    blocknr, 0);
  		}

  	}

  }

  void reiserfs_invalidate_buffer(struct tree_balance *tb, struct buffer_head *bh)

  {

  	struct block_head *blkh;
  	blkh = B_BLK_HEAD(bh);
  	set_blkh_level(blkh, FREE_LEVEL);
  	set_blkh_nr_item(blkh, 0);
  
  	clear_buffer_dirty(bh);
  	store_thrown(tb, bh);

  }
  
  /* Replace n_dest'th key in buffer dest by n_src'th key of buffer src.*/

  void replace_key(struct tree_balance *tb, struct buffer_head *dest, int n_dest,
  		 struct buffer_head *src, int n_src)

  {

  	RFALSE(dest == NULL || src == NULL,
  	       "vs-12305: source or destination buffer is 0 (src=%p, dest=%p)",
  	       src, dest);
  	RFALSE(!B_IS_KEYS_LEVEL(dest),
  	       "vs-12310: invalid level (%z) for destination buffer. dest must be leaf",
  	       dest);
  	RFALSE(n_dest < 0 || n_src < 0,
  	       "vs-12315: src(%d) or dest(%d) key number < 0", n_src, n_dest);
  	RFALSE(n_dest >= B_NR_ITEMS(dest) || n_src >= B_NR_ITEMS(src),
  	       "vs-12320: src(%d(%d)) or dest(%d(%d)) key number is too big",
  	       n_src, B_NR_ITEMS(src), n_dest, B_NR_ITEMS(dest));
  
  	if (B_IS_ITEMS_LEVEL(src))
  		/* source buffer contains leaf node */

  		memcpy(internal_key(dest, n_dest), item_head(src, n_src),

  		       KEY_SIZE);
  	else

  		memcpy(internal_key(dest, n_dest), internal_key(src, n_src),

  		       KEY_SIZE);
  
  	do_balance_mark_internal_dirty(tb, dest, 0);

  }

  int get_left_neighbor_position(struct tree_balance *tb, int h)

  {

  	int Sh_position = PATH_H_POSITION(tb->tb_path, h + 1);

  	RFALSE(PATH_H_PPARENT(tb->tb_path, h) == NULL || tb->FL[h] == NULL,

  	       "vs-12325: FL[%d](%p) or F[%d](%p) does not exist",
  	       h, tb->FL[h], h, PATH_H_PPARENT(tb->tb_path, h));

  	if (Sh_position == 0)
  		return B_NR_ITEMS(tb->FL[h]);
  	else
  		return Sh_position - 1;

  }

  int get_right_neighbor_position(struct tree_balance *tb, int h)

  {

  	int Sh_position = PATH_H_POSITION(tb->tb_path, h + 1);

  	RFALSE(PATH_H_PPARENT(tb->tb_path, h) == NULL || tb->FR[h] == NULL,

  	       "vs-12330: F[%d](%p) or FR[%d](%p) does not exist",
  	       h, PATH_H_PPARENT(tb->tb_path, h), h, tb->FR[h]);

  	if (Sh_position == B_NR_ITEMS(PATH_H_PPARENT(tb->tb_path, h)))
  		return 0;
  	else
  		return Sh_position + 1;

  }

  #ifdef CONFIG_REISERFS_CHECK

  int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value);
  static void check_internal_node(struct super_block *s, struct buffer_head *bh,
  				char *mes)

  {

  	struct disk_child *dc;
  	int i;

  	RFALSE(!bh, "PAP-12336: bh == 0");

  	if (!bh || !B_IS_IN_TREE(bh))
  		return;

  	RFALSE(!buffer_dirty(bh) &&
  	       !(buffer_journaled(bh) || buffer_journal_dirty(bh)),
  	       "PAP-12337: buffer (%b) must be dirty", bh);
  	dc = B_N_CHILD(bh, 0);

  	for (i = 0; i <= B_NR_ITEMS(bh); i++, dc++) {
  		if (!is_reusable(s, dc_block_number(dc), 1)) {
  			print_cur_tb(mes);

  			reiserfs_panic(s, "PAP-12338",
  				       "invalid child pointer %y in %b",

  				       dc, bh);
  		}
  	}

  }

  static int locked_or_not_in_tree(struct tree_balance *tb,
  				  struct buffer_head *bh, char *which)

  {
  	if ((!buffer_journal_prepared(bh) && buffer_locked(bh)) ||
  	    !B_IS_IN_TREE(bh)) {

  		reiserfs_warning(tb->tb_sb, "vs-12339", "%s (%b)", which, bh);

  		return 1;
  	}
  	return 0;
  }

  static int check_before_balancing(struct tree_balance *tb)

  {

  	int retval = 0;

  	if (REISERFS_SB(tb->tb_sb)->cur_tb) {

  		reiserfs_panic(tb->tb_sb, "vs-12335", "suspect that schedule "
  			       "occurred based on cur_tb not being null at "
  			       "this point in code. do_balance cannot properly "

  			       "handle concurrent tree accesses on a same "
  			       "mount point.");

  	}

  	/*
  	 * double check that buffers that we will modify are unlocked.
  	 * (fix_nodes should already have prepped all of these for us).
  	 */

  	if (tb->lnum[0]) {

  		retval |= locked_or_not_in_tree(tb, tb->L[0], "L[0]");
  		retval |= locked_or_not_in_tree(tb, tb->FL[0], "FL[0]");
  		retval |= locked_or_not_in_tree(tb, tb->CFL[0], "CFL[0]");

  		check_leaf(tb->L[0]);

  	}

  	if (tb->rnum[0]) {

  		retval |= locked_or_not_in_tree(tb, tb->R[0], "R[0]");
  		retval |= locked_or_not_in_tree(tb, tb->FR[0], "FR[0]");
  		retval |= locked_or_not_in_tree(tb, tb->CFR[0], "CFR[0]");

  		check_leaf(tb->R[0]);
  	}

  	retval |= locked_or_not_in_tree(tb, PATH_PLAST_BUFFER(tb->tb_path),
  					"S[0]");

  	check_leaf(PATH_PLAST_BUFFER(tb->tb_path));

  	return retval;
  }

  static void check_after_balance_leaf(struct tree_balance *tb)

  {

  	if (tb->lnum[0]) {
  		if (B_FREE_SPACE(tb->L[0]) !=
  		    MAX_CHILD_SIZE(tb->L[0]) -
  		    dc_size(B_N_CHILD
  			    (tb->FL[0], get_left_neighbor_position(tb, 0)))) {
  			print_cur_tb("12221");

  			reiserfs_panic(tb->tb_sb, "PAP-12355",
  				       "shift to left was incorrect");

  		}
  	}
  	if (tb->rnum[0]) {
  		if (B_FREE_SPACE(tb->R[0]) !=
  		    MAX_CHILD_SIZE(tb->R[0]) -
  		    dc_size(B_N_CHILD
  			    (tb->FR[0], get_right_neighbor_position(tb, 0)))) {
  			print_cur_tb("12222");

  			reiserfs_panic(tb->tb_sb, "PAP-12360",
  				       "shift to right was incorrect");

  		}
  	}
  	if (PATH_H_PBUFFER(tb->tb_path, 1) &&
  	    (B_FREE_SPACE(PATH_H_PBUFFER(tb->tb_path, 0)) !=
  	     (MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, 0)) -
  	      dc_size(B_N_CHILD(PATH_H_PBUFFER(tb->tb_path, 1),
  				PATH_H_POSITION(tb->tb_path, 1)))))) {
  		int left = B_FREE_SPACE(PATH_H_PBUFFER(tb->tb_path, 0));
  		int right = (MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, 0)) -
  			     dc_size(B_N_CHILD(PATH_H_PBUFFER(tb->tb_path, 1),
  					       PATH_H_POSITION(tb->tb_path,
  							       1))));
  		print_cur_tb("12223");

  		reiserfs_warning(tb->tb_sb, "reiserfs-12363",

  				 "B_FREE_SPACE (PATH_H_PBUFFER(tb->tb_path,0)) = %d; "
  				 "MAX_CHILD_SIZE (%d) - dc_size( %y, %d ) [%d] = %d",
  				 left,
  				 MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, 0)),
  				 PATH_H_PBUFFER(tb->tb_path, 1),
  				 PATH_H_POSITION(tb->tb_path, 1),
  				 dc_size(B_N_CHILD
  					 (PATH_H_PBUFFER(tb->tb_path, 1),
  					  PATH_H_POSITION(tb->tb_path, 1))),
  				 right);

  		reiserfs_panic(tb->tb_sb, "PAP-12365", "S is incorrect");

  	}

  }

  static void check_leaf_level(struct tree_balance *tb)

  {

  	check_leaf(tb->L[0]);
  	check_leaf(tb->R[0]);
  	check_leaf(PATH_PLAST_BUFFER(tb->tb_path));
  }

  static void check_internal_levels(struct tree_balance *tb)
  {
  	int h;
  
  	/* check all internal nodes */
  	for (h = 1; tb->insert_size[h]; h++) {
  		check_internal_node(tb->tb_sb, PATH_H_PBUFFER(tb->tb_path, h),
  				    "BAD BUFFER ON PATH");
  		if (tb->lnum[h])
  			check_internal_node(tb->tb_sb, tb->L[h], "BAD L");
  		if (tb->rnum[h])
  			check_internal_node(tb->tb_sb, tb->R[h], "BAD R");
  	}

  
  }
  
  #endif

  /*
   * Now we have all of the buffers that must be used in balancing of
   * the tree.  We rely on the assumption that schedule() will not occur
   * while do_balance works. ( Only interrupt handlers are acceptable.)
   * We balance the tree according to the analysis made before this,
   * using buffers already obtained.  For SMP support it will someday be
   * necessary to add ordered locking of tb.
   */

  /*
   * Some interesting rules of balancing:
   * we delete a maximum of two nodes per level per balancing: we never
   * delete R, when we delete two of three nodes L, S, R then we move
   * them into R.
   *
   * we only delete L if we are deleting two nodes, if we delete only
   * one node we delete S
   *
   * if we shift leaves then we shift as much as we can: this is a
   * deliberate policy of extremism in node packing which results in
   * higher average utilization after repeated random balance operations
   * at the cost of more memory copies and more balancing as a result of
   * small insertions to full nodes.
   *
   * if we shift internal nodes we try to evenly balance the node
   * utilization, with consequent less balancing at the cost of lower
   * utilization.
   *
   * one could argue that the policy for directories in leaves should be
   * that of internal nodes, but we will wait until another day to
   * evaluate this....  It would be nice to someday measure and prove
   * these assumptions as to what is optimal....
   */

  static inline void do_balance_starts(struct tree_balance *tb)

  {

  	/* use print_cur_tb() to see initial state of struct tree_balance */

  	/* store_print_tb (tb); */

  	/* do not delete, just comment it out */

  	/*
  	print_tb(flag, PATH_LAST_POSITION(tb->tb_path),
  		 tb->tb_path->pos_in_item, tb, "check");
  	*/

  	RFALSE(check_before_balancing(tb), "PAP-12340: locked buffers in TB");

  #ifdef CONFIG_REISERFS_CHECK

  	REISERFS_SB(tb->tb_sb)->cur_tb = tb;

  #endif
  }

  static inline void do_balance_completed(struct tree_balance *tb)

  {

  #ifdef CONFIG_REISERFS_CHECK

  	check_leaf_level(tb);
  	check_internal_levels(tb);

  	REISERFS_SB(tb->tb_sb)->cur_tb = NULL;

  #endif

  	/*
  	 * reiserfs_free_block is no longer schedule safe.  So, we need to
  	 * put the buffers we want freed on the thrown list during do_balance,
  	 * and then free them now

  	 */

  	REISERFS_SB(tb->tb_sb)->s_do_balance++;

  	/* release all nodes hold to perform the balancing */
  	unfix_nodes(tb);

  	free_thrown(tb);

  }

  /*
   * do_balance - balance the tree
   *
   * @tb: tree_balance structure
   * @ih: item header of inserted item
   * @body: body of inserted item or bytes to paste
   * @flag: 'i' - insert, 'd' - delete, 'c' - cut, 'p' paste
   *
   * Cut means delete part of an item (includes removing an entry from a
   * directory).
   *
   * Delete means delete whole item.
   *
   * Insert means add a new item into the tree.
   *
   * Paste means to append to the end of an existing file or to
   * insert a directory entry.
   */
  void do_balance(struct tree_balance *tb, struct item_head *ih,
  		const char *body, int flag)
  {
  	int child_pos;		/* position of a child node in its parent */
  	int h;			/* level of the tree being processed */
  
  	/*
  	 * in our processing of one level we sometimes determine what
  	 * must be inserted into the next higher level.  This insertion
  	 * consists of a key or two keys and their corresponding
  	 * pointers
  	 */
  	struct item_head insert_key[2];
  
  	/* inserted node-ptrs for the next level */
  	struct buffer_head *insert_ptr[2];

  
  	tb->tb_mode = flag;
  	tb->need_balance_dirty = 0;
  
  	if (FILESYSTEM_CHANGED_TB(tb)) {

  		reiserfs_panic(tb->tb_sb, "clm-6000", "fs generation has "
  			       "changed");

  	}
  	/* if we have no real work to do  */
  	if (!tb->insert_size[0]) {

  		reiserfs_warning(tb->tb_sb, "PAP-12350",
  				 "insert_size == 0, mode == %c", flag);

  		unfix_nodes(tb);
  		return;
  	}

  	atomic_inc(&fs_generation(tb->tb_sb));

  	do_balance_starts(tb);

  	/*
  	 * balance_leaf returns 0 except if combining L R and S into
  	 * one node.  see balance_internal() for explanation of this
  	 * line of code.
  	 */

  	child_pos = PATH_H_B_ITEM_ORDER(tb->tb_path, 0) +
  	    balance_leaf(tb, ih, body, flag, insert_key, insert_ptr);

  
  #ifdef CONFIG_REISERFS_CHECK

  	check_after_balance_leaf(tb);

  #endif

  	/* Balance internal level of the tree. */
  	for (h = 1; h < MAX_HEIGHT && tb->insert_size[h]; h++)

  		child_pos = balance_internal(tb, h, child_pos, insert_key,
  					     insert_ptr);

  	do_balance_completed(tb);

  }