patch-2.4.1 linux/fs/reiserfs/ibalance.c

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diff -u --recursive --new-file v2.4.0/linux/fs/reiserfs/ibalance.c linux/fs/reiserfs/ibalance.c
@@ -0,0 +1,1140 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+
+#ifdef __KERNEL__
+
+#include <linux/config.h>
+#include <asm/uaccess.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/reiserfs_fs.h>
+
+#else
+
+#include "nokernel.h"
+
+#endif
+
+
+/* this is one and only function that is used outside (do_balance.c) */
+int	balance_internal (
+			  struct tree_balance * ,
+			  int,
+			  int,
+			  struct item_head * ,
+			  struct buffer_head ** 
+			  );
+
+/* 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
+						)
+{
+#ifdef CONFIG_REISERFS_CHECK
+    memset (dest_bi, 0, sizeof (struct buffer_info));
+    memset (src_bi, 0, sizeof (struct buffer_info));
+#endif
+    /* define dest, src, dest parent, dest position */
+    switch (shift_mode) {
+    case INTERNAL_SHIFT_FROM_S_TO_L:	/* used in internal_shift_left */
+	src_bi->tb = tb;
+	src_bi->bi_bh = PATH_H_PBUFFER (tb->tb_path, h);
+	src_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	src_bi->bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = tb->L[h];
+	dest_bi->bi_parent = tb->FL[h];
+	dest_bi->bi_position = get_left_neighbor_position (tb, h);
+	*d_key = tb->lkey[h];
+	*cf = tb->CFL[h];
+	break;
+    case INTERNAL_SHIFT_FROM_L_TO_S:
+	src_bi->tb = tb;
+	src_bi->bi_bh = tb->L[h];
+	src_bi->bi_parent = tb->FL[h];
+	src_bi->bi_position = get_left_neighbor_position (tb, h);
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = PATH_H_PBUFFER (tb->tb_path, h);
+	dest_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	dest_bi->bi_position = PATH_H_POSITION (tb->tb_path, h + 1); /* dest position is analog of dest->b_item_order */
+	*d_key = tb->lkey[h];
+	*cf = tb->CFL[h];
+	break;
+      
+    case INTERNAL_SHIFT_FROM_R_TO_S:	/* used in internal_shift_left */
+	src_bi->tb = tb;
+	src_bi->bi_bh = tb->R[h];
+	src_bi->bi_parent = tb->FR[h];
+	src_bi->bi_position = get_right_neighbor_position (tb, h);
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = PATH_H_PBUFFER (tb->tb_path, h);
+	dest_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	dest_bi->bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+	*d_key = tb->rkey[h];
+	*cf = tb->CFR[h];
+	break;
+
+    case INTERNAL_SHIFT_FROM_S_TO_R:
+	src_bi->tb = tb;
+	src_bi->bi_bh = PATH_H_PBUFFER (tb->tb_path, h);
+	src_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	src_bi->bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = tb->R[h];
+	dest_bi->bi_parent = tb->FR[h];
+	dest_bi->bi_position = get_right_neighbor_position (tb, h);
+	*d_key = tb->rkey[h];
+	*cf = tb->CFR[h];
+	break;
+
+    case INTERNAL_INSERT_TO_L:
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = tb->L[h];
+	dest_bi->bi_parent = tb->FL[h];
+	dest_bi->bi_position = get_left_neighbor_position (tb, h);
+	break;
+	
+    case INTERNAL_INSERT_TO_S:
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = PATH_H_PBUFFER (tb->tb_path, h);
+	dest_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	dest_bi->bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+	break;
+
+    case INTERNAL_INSERT_TO_R:
+	dest_bi->tb = tb;
+	dest_bi->bi_bh = tb->R[h];
+	dest_bi->bi_parent = tb->FR[h];
+	dest_bi->bi_position = get_right_neighbor_position (tb, h);
+	break;
+
+    default:
+	reiserfs_panic (tb->tb_sb, "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 key * ih;
+    struct disk_child new_dc[2];
+    struct disk_child * dc;
+    int i;
+
+    if (count <= 0)
+	return;
+
+    nr = le16_to_cpu ((blkh = B_BLK_HEAD(cur))->blk_nr_item);
+
+#ifdef CONFIG_REISERFS_CHECK
+    if (count > 2)
+	reiserfs_panic (0, "internal_insert_childs", "too many children (%d) are to be inserted", count);
+    if (B_FREE_SPACE (cur) < count * (KEY_SIZE + DC_SIZE))
+	reiserfs_panic (0, "internal_insert_childs", "no enough free space (%d), needed %d bytes", 
+			B_FREE_SPACE (cur), count * (KEY_SIZE + DC_SIZE));
+#endif /* CONFIG_REISERFS_CHECK */
+
+    /* prepare space for count disk_child */
+    dc = B_N_CHILD(cur,to+1);
+
+    memmove (dc + count, dc, (nr+1-(to+1)) * DC_SIZE);
+
+    /* copy to_be_insert disk children */
+    for (i = 0; i < count; i ++) {
+	new_dc[i].dc_size =
+	    cpu_to_le16 (MAX_CHILD_SIZE(bh[i]) - B_FREE_SPACE (bh[i]));
+	new_dc[i].dc_block_number = cpu_to_le32 (bh[i]->b_blocknr);
+    }
+    memcpy (dc, new_dc, DC_SIZE * count);
+
+  
+    /* prepare space for count items  */
+    ih = B_N_PDELIM_KEY (cur, ((to == -1) ? 0 : to));
+
+    memmove (ih + count, ih, (nr - to) * KEY_SIZE + (nr + 1 + count) * DC_SIZE);
+
+    /* copy item headers (keys) */
+    memcpy (ih, inserted, KEY_SIZE);
+    if ( count > 1 )
+	memcpy (ih + 1, inserted + 1, KEY_SIZE);
+
+    /* sizes, item number */
+    blkh->blk_nr_item = cpu_to_le16 (le16_to_cpu (blkh->blk_nr_item) + count);
+    blkh->blk_free_space = cpu_to_le16 (le16_to_cpu (blkh->blk_free_space) - count * (DC_SIZE + KEY_SIZE));
+
+    do_balance_mark_internal_dirty (cur_bi->tb, cur,0);
+
+    /*&&&&&&&&&&&&&&&&&&&&&&&&*/
+    check_internal (cur);
+    /*&&&&&&&&&&&&&&&&&&&&&&&&*/
+
+    if (cur_bi->bi_parent) {
+	B_N_CHILD (cur_bi->bi_parent,cur_bi->bi_position)->dc_size += count * (DC_SIZE + KEY_SIZE);
+	do_balance_mark_internal_dirty(cur_bi->tb, cur_bi->bi_parent, 0);
+
+	/*&&&&&&&&&&&&&&&&&&&&&&&&*/
+	check_internal (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 key * key;
+  struct disk_child * dc;
+
+#ifdef CONFIG_REISERFS_CHECK
+  if (cur == NULL)
+    reiserfs_panic (0, "internal_delete_pointers_items1: buffer is 0");
+	
+  if (del_num < 0)
+    reiserfs_panic (0, "internal_delete_pointers_items2",
+		    "negative number of items (%d) can not be deleted", del_num);
+
+  if (first_p < 0 || first_p + del_num > B_NR_ITEMS (cur) + 1 || first_i < 0)
+    reiserfs_panic (0, "internal_delete_pointers_items3",
+		    "first pointer order (%d) < 0 or "
+		    "no so many pointers (%d), only (%d) or "
+		    "first key order %d < 0", first_p, 
+		    first_p + del_num, B_NR_ITEMS (cur) + 1, first_i);
+#endif /* CONFIG_REISERFS_CHECK */
+  if ( del_num == 0 )
+    return;
+
+  nr = le16_to_cpu ((blkh = B_BLK_HEAD(cur))->blk_nr_item);
+
+  if ( first_p == 0 && del_num == nr + 1 ) {
+#ifdef CONFIG_REISERFS_CHECK
+    if ( first_i != 0 )
+      reiserfs_panic (0, "internal_delete_pointers_items5",
+		      "first deleted key must have order 0, not %d", first_i);
+#endif /* CONFIG_REISERFS_CHECK */
+    make_empty_node (cur_bi);
+    return;
+  }
+
+#ifdef CONFIG_REISERFS_CHECK
+  if (first_i + del_num > B_NR_ITEMS (cur)) {
+    printk("first_i = %d del_num = %d\n",first_i,del_num);
+    reiserfs_panic (0, "internal_delete_pointers_items4: :"
+		    "no so many keys (%d) in the node (%b)(%z)", first_i + del_num, cur, cur);
+  }
+#endif /* CONFIG_REISERFS_CHECK */
+
+
+  /* deleting */
+  dc = B_N_CHILD (cur, first_p);
+
+  memmove (dc, dc + del_num, (nr + 1 - first_p - del_num) * DC_SIZE);
+  key = B_N_PDELIM_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 */
+  blkh->blk_nr_item = cpu_to_le16 (le16_to_cpu (blkh->blk_nr_item) - del_num);
+  blkh->blk_free_space = cpu_to_le16 (le16_to_cpu (blkh->blk_free_space) + del_num * (KEY_SIZE +  DC_SIZE));
+
+  do_balance_mark_internal_dirty (cur_bi->tb, cur, 0);
+  /*&&&&&&&&&&&&&&&&&&&&&&&*/
+  check_internal (cur);
+  /*&&&&&&&&&&&&&&&&&&&&&&&*/
+ 
+  if (cur_bi->bi_parent) {
+    B_N_CHILD (cur_bi->bi_parent, cur_bi->bi_position)->dc_size -= del_num * (KEY_SIZE +  DC_SIZE);
+    do_balance_mark_internal_dirty (cur_bi->tb, cur_bi->bi_parent,0);
+    /*&&&&&&&&&&&&&&&&&&&&&&&&*/
+    check_internal (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;
+
+  i_from = (from == 0) ? 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 key * key;
+  struct disk_child * dc;
+
+  nr_src = B_NR_ITEMS (src);
+
+#ifdef CONFIG_REISERFS_CHECK
+  if ( dest == NULL || src == NULL )
+    reiserfs_panic (0, "internal_copy_pointers_items", "src (%p) or dest (%p) buffer is 0", src, dest);
+
+  if (last_first != FIRST_TO_LAST && last_first != LAST_TO_FIRST)
+    reiserfs_panic (0, "internal_copy_pointers_items",
+		    "invalid last_first parameter (%d)", last_first);
+
+  if ( nr_src < cpy_num - 1 )
+    reiserfs_panic (0, "internal_copy_pointers_items", "no so many items (%d) in src (%d)", cpy_num, nr_src);
+
+  if ( cpy_num < 0 )
+    reiserfs_panic (0, "internal_copy_pointers_items", "cpy_num less than 0 (%d)", cpy_num);
+
+  if (cpy_num - 1 + B_NR_ITEMS(dest) > (int)MAX_NR_KEY(dest))
+    reiserfs_panic (0, "internal_copy_pointers_items",
+		    "cpy_num (%d) + item number in dest (%d) can not be more than MAX_NR_KEY(%d)",
+		    cpy_num, B_NR_ITEMS(dest), MAX_NR_KEY(dest));
+#endif
+
+  if ( cpy_num == 0 )
+    return;
+
+	/* coping */
+  nr_dest = le16_to_cpu ((blkh = B_BLK_HEAD(dest))->blk_nr_item);
+
+  /*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 = B_N_PDELIM_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, B_N_PDELIM_KEY (src, src_order), KEY_SIZE * (cpy_num - 1));
+
+  /* sizes, item number */
+  blkh->blk_nr_item = cpu_to_le16 (le16_to_cpu (blkh->blk_nr_item) + (cpy_num - 1));
+  blkh->blk_free_space = cpu_to_le16 (le16_to_cpu (blkh->blk_free_space) - (KEY_SIZE * (cpy_num - 1) + DC_SIZE * cpy_num));
+
+  do_balance_mark_internal_dirty (dest_bi->tb, dest, 0);
+
+  /*&&&&&&&&&&&&&&&&&&&&&&&&*/
+  check_internal (dest);
+  /*&&&&&&&&&&&&&&&&&&&&&&&&*/
+
+  if (dest_bi->bi_parent) {
+    B_N_CHILD(dest_bi->bi_parent,dest_bi->bi_position)->dc_size +=
+      KEY_SIZE * (cpy_num - 1) + DC_SIZE * cpy_num;
+
+    do_balance_mark_internal_dirty (dest_bi->tb, dest_bi->bi_parent,0);
+    /*&&&&&&&&&&&&&&&&&&&&&&&&*/
+    check_internal (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 key * key;
+
+#ifdef CONFIG_REISERFS_CHECK
+    if (dest == NULL || src == NULL)
+	reiserfs_panic (0, "internal_insert_key", "sourse(%p) or dest(%p) buffer is 0", src, dest);
+
+    if (dest_position_before < 0 || src_position < 0)
+	reiserfs_panic (0, "internal_insert_key", "source(%d) or dest(%d) key number less than 0", 
+			src_position, dest_position_before);
+
+    if (dest_position_before > B_NR_ITEMS (dest) || src_position >= B_NR_ITEMS(src))
+	reiserfs_panic (0, "internal_insert_key", 
+			"invalid position in dest (%d (key number %d)) or in src (%d (key number %d))",
+			dest_position_before, B_NR_ITEMS (dest), src_position, B_NR_ITEMS(src));
+
+    if (B_FREE_SPACE (dest) < KEY_SIZE)
+	reiserfs_panic (0, "internal_insert_key", 
+			"no enough free space (%d) in dest buffer", B_FREE_SPACE (dest));
+#endif
+
+    nr = le16_to_cpu ((blkh=B_BLK_HEAD(dest))->blk_nr_item);
+
+    /* prepare space for inserting key */
+    key = B_N_PDELIM_KEY (dest, dest_position_before);
+    memmove (key + 1, key, (nr - dest_position_before) * KEY_SIZE + (nr + 1) * DC_SIZE);
+
+    /* insert key */
+    memcpy (key, B_N_PDELIM_KEY(src, src_position), KEY_SIZE);
+
+    /* Change dirt, free space, item number fields. */
+    blkh->blk_nr_item = cpu_to_le16 (le16_to_cpu (blkh->blk_nr_item) + 1);
+    blkh->blk_free_space = cpu_to_le16 (le16_to_cpu (blkh->blk_free_space) - KEY_SIZE);
+
+    do_balance_mark_internal_dirty (dest_bi->tb, dest, 0);
+
+    if (dest_bi->bi_parent) {
+	B_N_CHILD(dest_bi->bi_parent,dest_bi->bi_position)->dc_size += KEY_SIZE;
+	do_balance_mark_internal_dirty (dest_bi->tb, dest_bi->bi_parent,0);
+    }
+}
+
+
+
+/* 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, cf, d_key_position, src_bi.bi_parent/*src->b_parent*/, 0);
+    } else
+      replace_key (tb, 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);
+  /*		internal_insert_key (tb->L[h], B_NR_ITEM(tb->L[h]), tb->CFL[h], tb->lkey[h]);*/
+
+  /* last parameter is del_parameter */
+  internal_move_pointers_items (&dest_bi, &src_bi, FIRST_TO_LAST, pointer_amount, 1);
+  /*	internal_move_pointers_items (tb->L[h], tb->S[h], 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) {
+#ifdef CONFIG_REISERFS_CHECK
+      if ( src_bi.bi_bh != PATH_H_PBUFFER (tb->tb_path, h)/*tb->S[h]*/ || dest_bi.bi_bh != tb->R[h])
+	reiserfs_panic (tb->tb_sb, "internal_shift_right", "src (%p) must be == tb->S[h](%p) when it disappears",
+			src_bi.bi_bh, PATH_H_PBUFFER (tb->tb_path, h));
+#endif
+      /* when S[h] disappers replace left delemiting key as well */
+      if (tb->CFL[h])
+	replace_key (tb, cf, d_key_position, tb->CFL[h], tb->lkey[h]);
+    } else
+      replace_key (tb, 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);
+  /*		internal_insert_key (tb->R[h], 0, tb->CFR[h], tb->rkey[h]);*/
+	
+  /* last parameter is del_parameter */
+  internal_move_pointers_items (&dest_bi, &src_bi, LAST_TO_FIRST, pointer_amount, 1);
+  /*	internal_move_pointers_items (tb->R[h], tb->S[h], 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) */
+    bi.tb = tb;
+    bi.bi_bh = tbSh;
+    bi.bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+    bi.bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+
+    internal_delete_childs (&bi, child_pos, -insert_num);
+
+#ifdef CONFIG_REISERFS_CHECK
+    if ( tb->blknum[h] > 1 )
+	reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "tb->blknum[%d]=%d when insert_size < 0",
+			h, tb->blknum[h]);
+#endif /* CONFIG_REISERFS_CHECK */
+
+    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;
+
+#ifdef CONFIG_REISERFS_CHECK
+	    if (n || B_FREE_SPACE (tbSh) != MAX_CHILD_SIZE(tbSh) - DC_SIZE)
+		reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "buffer must have only 0 keys (%d)",
+				n);
+
+	    if (bi.bi_parent)
+		reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "root has parent (%p)", bi.bi_parent);
+#endif /* CONFIG_REISERFS_CHECK */
+		
+	    /* 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];
+	    /* switch super block's tree root block number to the new value */
+	    tb->tb_sb->u.reiserfs_sb.s_rs->s_root_block = cpu_to_le32 (new_root->b_blocknr);
+	    //tb->tb_sb->u.reiserfs_sb.s_rs->s_tree_height --;
+	    tb->tb_sb->u.reiserfs_sb.s_rs->s_tree_height = cpu_to_le16 (SB_TREE_HEIGHT (tb->tb_sb) - 1);
+
+	    do_balance_mark_sb_dirty (tb, tb->tb_sb->u.reiserfs_sb.s_sbh, 1);
+	    /*&&&&&&&&&&&&&&&&&&&&&&*/
+	    if (h > 1)
+		/* use check_internal if new root is an internal node */
+		check_internal (new_root);
+	    /*&&&&&&&&&&&&&&&&&&&&&&*/
+	    tb->tb_sb->s_dirt = 1;
+
+	    /* do what is needed for buffer thrown from tree */
+	    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] */
+
+#ifdef CONFIG_REISERFS_CHECK
+	if ( tb->rnum[h] != 0 )
+	    reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "invalid tb->rnum[%d]==%d when joining S[h] with L[h]",
+			    h, tb->rnum[h]);
+#endif /* CONFIG_REISERFS_CHECK */
+
+	internal_shift_left (INTERNAL_SHIFT_FROM_S_TO_L, tb, h, n + 1);
+	reiserfs_invalidate_buffer(tb, tbSh);
+
+	return;
+    }
+
+    if ( tb->R[h] &&  tb->rnum[h] == -B_NR_ITEMS(tb->R[h]) - 1 ) { /* join S[h] with R[h] */
+#ifdef CONFIG_REISERFS_CHECK
+	if ( tb->lnum[h] != 0 )
+	    reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "invalid tb->lnum[%d]==%d when joining S[h] with R[h]",
+			    h, tb->lnum[h]);
+#endif /* CONFIG_REISERFS_CHECK */
+
+	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] */
+#ifdef CONFIG_REISERFS_CHECK
+	if ( tb->rnum[h] != 0 )
+	    reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "invalid tb->rnum[%d]==%d when borrow from L[h]",
+			    h, tb->rnum[h]);
+#endif /* CONFIG_REISERFS_CHECK */
+	/*internal_shift_right (tb, h, tb->L[h], tb->CFL[h], tb->lkey[h], tb->S[h], -tb->lnum[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] */
+#ifdef CONFIG_REISERFS_CHECK
+	if ( tb->lnum[h] != 0 )
+	    reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", "invalid tb->lnum[%d]==%d when borrow from R[h]",
+			    h, tb->lnum[h]);
+#endif /* CONFIG_REISERFS_CHECK */
+	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 */
+#ifdef CONFIG_REISERFS_CHECK
+	if ( tb->rnum[h] == 0 || tb->lnum[h] + tb->rnum[h] != n + 1 )
+	    reiserfs_panic (tb->tb_sb, "balance_internal_when_delete", 
+			    "invalid tb->lnum[%d]==%d or tb->rnum[%d]==%d when S[h](item number == %d) is split between them",
+			    h, tb->lnum[h], h, tb->rnum[h], n);
+#endif /* CONFIG_REISERFS_CHECK */
+
+	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 (tb->tb_sb, "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
+		      )
+{
+#ifdef CONFIG_REISERFS_CHECK
+  if (tb->L[h] == NULL || tb->CFL[h] == NULL)
+    reiserfs_panic (tb->tb_sb, "replace_lkey: 12255: "
+		    "L[h](%p) and CFL[h](%p) must exist in replace_lkey", tb->L[h], tb->CFL[h]);
+#endif
+
+  if (B_NR_ITEMS(PATH_H_PBUFFER(tb->tb_path, h)) == 0)
+    return;
+
+  memcpy (B_N_PDELIM_KEY(tb->CFL[h],tb->lkey[h]), key, KEY_SIZE);
+
+  do_balance_mark_internal_dirty (tb, tb->CFL[h],0);
+}
+
+
+/* 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
+		      )
+{
+#ifdef CONFIG_REISERFS_CHECK
+  if (tb->R[h] == NULL || tb->CFR[h] == NULL)
+    reiserfs_panic (tb->tb_sb, "replace_rkey: 12260: "
+		    "R[h](%p) and CFR[h](%p) must exist in replace_rkey", tb->R[h], tb->CFR[h]);
+
+  if (B_NR_ITEMS(tb->R[h]) == 0)
+    reiserfs_panic (tb->tb_sb, "replace_rkey: 12265: "
+		    "R[h] can not be empty if it exists (item number=%d)", B_NR_ITEMS(tb->R[h]));
+#endif
+
+  memcpy (B_N_PDELIM_KEY(tb->CFR[h],tb->rkey[h]), key, KEY_SIZE);
+
+  do_balance_mark_internal_dirty (tb, tb->CFR[h], 0);
+}
+
+
+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;
+
+#ifdef CONFIG_REISERFS_CHECK
+    if ( h < 1 )      
+	reiserfs_panic (tb->tb_sb, "balance_internal", "h (%d) can not be < 1 on internal level", h);
+#endif /* CONFIG_REISERFS_CHECK */
+
+    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 **/
+#ifdef CONFIG_REISERFS_CHECK
+    if ( insert_num < -2  ||  insert_num > 2 )
+	reiserfs_panic (tb->tb_sb, "balance_internal",
+			"incorrect number of items inserted to the internal node (%d)", insert_num);
+
+    if ( h > 1  && (insert_num > 1 || insert_num < -1) )
+	reiserfs_panic (tb->tb_sb, "balance_internal",
+			"incorrect number of items (%d) inserted to the internal node on a level (h=%d) higher than last internal level", 
+			insert_num, h);
+#endif /* CONFIG_REISERFS_CHECK */
+
+    /* 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 = B_NR_ITEMS (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]);
+	    /*internal_shift_left (tb->L[h],tb->CFL[h],tb->lkey[h],tbSh,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);
+	    /*			internal_shift_left(tb->L[h],tb->CFL[h],tb->lkey[h],tbSh,
+				tb->lnum[h]-insert_num);
+	    */
+	    /* insert insert_num keys and node-pointers into L[h] */
+	    bi.tb = tb;
+	    bi.bi_bh = tb->L[h];
+	    bi.bi_parent = tb->FL[h];
+	    bi.bi_position = get_left_neighbor_position (tb, h);
+	    internal_insert_childs (&bi,/*tb->L[h], tb->S[h-1]->b_next*/ 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;
+	    bi.tb = tb;
+	    bi.bi_bh = tb->L[h];
+	    bi.bi_parent = tb->FL[h];
+	    bi.bi_position = get_left_neighbor_position (tb, h);
+	    internal_insert_childs (&bi,/*tb->L[h], tb->S[h-1]->b_next,*/ 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);
+	    dc->dc_size = cpu_to_le16 (MAX_CHILD_SIZE(insert_ptr[k]) - B_FREE_SPACE (insert_ptr[k]));
+	    dc->dc_block_number = cpu_to_le32 (insert_ptr[k]->b_blocknr);
+
+	    do_balance_mark_internal_dirty (tb, tbSh, 0);
+
+	    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 = B_NR_ITEMS (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(tb,h,tbSh,tb->CFR[h],tb->rkey[h],tb->R[h],
+	    tb->rnum[h] - insert_num);*/
+		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] */
+		bi.tb = tb;
+		bi.bi_bh = tb->R[h];
+		bi.bi_parent = tb->FR[h];
+		bi.bi_position = get_right_neighbor_position (tb, h);
+		internal_insert_childs (&bi, /*tb->R[h],tb->S[h-1]->b_next*/ 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;
+		bi.tb = tb;
+		bi.bi_bh = tb->R[h];
+		bi.bi_parent = tb->FR[h];
+		bi.bi_position = get_right_neighbor_position (tb, h);
+		internal_insert_childs (&bi, /*tb->R[h], tb->R[h]->b_child,*/ 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);
+		dc->dc_size =
+		    cpu_to_le16 (MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]) -
+				 B_FREE_SPACE (insert_ptr[insert_num-k-1]));
+		dc->dc_block_number = cpu_to_le32 (insert_ptr[insert_num-k-1]->b_blocknr);
+
+		do_balance_mark_internal_dirty (tb, tb->R[h],0);
+
+		insert_num -= (k + 1);
+	    }
+    }
+
+    /** Fill new node that appears instead of S[h] **/
+#ifdef CONFIG_REISERFS_CHECK
+    if ( tb->blknum[h] > 2 )
+	reiserfs_panic(0, "balance_internal", "blknum can not be > 2 for internal level");
+    if ( tb->blknum[h] < 0 )
+	reiserfs_panic(0, "balance_internal", "blknum can not be < 0");
+#endif /* CONFIG_REISERFS_CHECK */
+
+    if ( ! tb->blknum[h] )
+    { /* node S[h] is empty now */
+#ifdef CONFIG_REISERFS_CHECK
+	if ( ! tbSh )
+	    reiserfs_panic(0,"balance_internal", "S[h] is equal NULL");
+#endif /* CONFIG_REISERFS_CHECK */
+
+	/* do what is needed for buffer thrown from tree */
+	reiserfs_invalidate_buffer(tb,tbSh);
+	return order;
+    }
+
+    if ( ! tbSh ) {
+	/* create new root */
+	struct disk_child  * dc;
+	struct buffer_head * tbSh_1 = PATH_H_PBUFFER (tb->tb_path, h - 1);
+
+
+	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);
+	B_BLK_HEAD(tbSh)->blk_level = cpu_to_le16 (h + 1);
+
+	/* Put the unique node-pointer to S[h] that points to S[h-1]. */
+
+	dc = B_N_CHILD(tbSh, 0);
+	dc->dc_block_number = cpu_to_le32 (tbSh_1->b_blocknr);
+	dc->dc_size = cpu_to_le16 (MAX_CHILD_SIZE (tbSh_1) - B_FREE_SPACE (tbSh_1));
+
+	tb->insert_size[h] -= DC_SIZE;
+	B_BLK_HEAD(tbSh)->blk_free_space = cpu_to_le16 (B_FREE_SPACE (tbSh) - DC_SIZE);
+
+	do_balance_mark_internal_dirty (tb, tbSh, 0);
+
+	/*&&&&&&&&&&&&&&&&&&&&&&&&*/
+	check_internal (tbSh);
+	/*&&&&&&&&&&&&&&&&&&&&&&&&*/
+    
+    /* put new root into path structure */
+	PATH_OFFSET_PBUFFER(tb->tb_path, ILLEGAL_PATH_ELEMENT_OFFSET) = tbSh;
+
+	/* Change root in structure super block. */
+	tb->tb_sb->u.reiserfs_sb.s_rs->s_root_block = cpu_to_le32 (tbSh->b_blocknr);
+	tb->tb_sb->u.reiserfs_sb.s_rs->s_tree_height = cpu_to_le16 (SB_TREE_HEIGHT (tb->tb_sb) + 1);
+	do_balance_mark_sb_dirty (tb, tb->tb_sb->u.reiserfs_sb.s_sbh, 1);
+	tb->tb_sb->s_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);
+
+	B_BLK_HEAD(S_new)->blk_level = cpu_to_le16 (h + 1);
+
+	dest_bi.tb = tb;
+	dest_bi.bi_bh = S_new;
+	dest_bi.bi_parent = 0;
+	dest_bi.bi_position = 0;
+	src_bi.tb = tb;
+	src_bi.bi_bh = tbSh;
+	src_bi.bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	src_bi.bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+		
+	n = B_NR_ITEMS (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,B_N_PDELIM_KEY(tbSh,n - snum),
+		    KEY_SIZE);
+	    /* last parameter is del_par */
+	    internal_move_pointers_items (&dest_bi, &src_bi, LAST_TO_FIRST, snum, 0);
+	    /*            internal_move_pointers_items(S_new, tbSh, 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,B_N_PDELIM_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, /*S_new,tb->S[h-1]->b_next,*/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, /*S_new,*/ 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);
+	    dc->dc_size = cpu_to_le16 (MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]) -
+				       B_FREE_SPACE(insert_ptr[insert_num-k-1]));
+	    dc->dc_block_number =	cpu_to_le32 (insert_ptr[insert_num-k-1]->b_blocknr);
+
+	    do_balance_mark_internal_dirty (tb, S_new,0);
+			
+	    insert_num -= (k + 1);
+	}
+	/* new_insert_ptr = node_pointer to S_new */
+	new_insert_ptr = S_new;
+
+#ifdef CONFIG_REISERFS_CHECK
+	if ( buffer_locked(S_new) || atomic_read (&(S_new->b_count)) != 1)
+	    if (buffer_locked(S_new) || atomic_read(&(S_new->b_count)) > 2 ||
+		!(buffer_journaled(S_new) || buffer_journal_dirty(S_new))) {
+		reiserfs_panic (tb->tb_sb, "cm-00001: balance_internal: bad S_new (%b)", S_new);
+	    }
+#endif /* CONFIG_REISERFS_CHECK */
+
+	// S_new is released in unfix_nodes
+    }
+
+    n = B_NR_ITEMS (tbSh); /*number of items in S[h] */
+
+#ifdef REISERFS_FSCK
+    if ( -1 <= child_pos && child_pos <= n && insert_num > 0 ) {
+#else
+	if ( 0 <= child_pos && child_pos <= n && insert_num > 0 ) {
+#endif
+	    bi.tb = tb;
+	    bi.bi_bh = tbSh;
+	    bi.bi_parent = PATH_H_PPARENT (tb->tb_path, h);
+	    bi.bi_position = PATH_H_POSITION (tb->tb_path, h + 1);
+#ifdef REISERFS_FSCK
+	    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, B_N_PITEM_HEAD (PATH_PLAST_BUFFER (tb->tb_path), 0), insert_ptr);
+	    } else
+#endif
+		internal_insert_childs (
+		    &bi,/*tbSh,*/
+		    /*		( tb->S[h-1]->b_parent == tb->S[h] ) ? tb->S[h-1]->b_next :  tb->S[h]->b_child->b_next,*/
+		    child_pos,insert_num,insert_key,insert_ptr
+		    );
+	}
+
+
+	memcpy (new_insert_key_addr,&new_insert_key,KEY_SIZE);
+	insert_ptr[0] = new_insert_ptr;
+
+	return order;
+    }
+
+  
+
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)