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ibalance.c

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

#include <asm/uaccess.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/reiserfs_fs.h>
#include <linux/buffer_head.h>

/* 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)
{
      memset(dest_bi, 0, sizeof(struct buffer_info));
      memset(src_bi, 0, sizeof(struct buffer_info));
      /* 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 reiserfs_key *ih;
      struct disk_child new_dc[2];
      struct disk_child *dc;
      int i;

      if (count <= 0)
            return;

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

      RFALSE(count > 2, "too many children (%d) are to be inserted", count);
      RFALSE(B_FREE_SPACE(cur) < count * (KEY_SIZE + DC_SIZE),
             "no enough free space (%d), needed %d bytes",
             B_FREE_SPACE(cur), count * (KEY_SIZE + DC_SIZE));

      /* 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++) {
            put_dc_size(&(new_dc[i]),
                      MAX_CHILD_SIZE(bh[i]) - B_FREE_SPACE(bh[i]));
            put_dc_block_number(&(new_dc[i]), 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 */
      set_blkh_nr_item(blkh, blkh_nr_item(blkh) + count);
      set_blkh_free_space(blkh,
                      blkh_free_space(blkh) - count * (DC_SIZE +
                                               KEY_SIZE));

      do_balance_mark_internal_dirty(cur_bi->tb, cur, 0);

      /*&&&&&&&&&&&&&&&&&&&&&&&& */
      check_internal(cur);
      /*&&&&&&&&&&&&&&&&&&&&&&&& */

      if (cur_bi->bi_parent) {
            struct disk_child *t_dc =
                B_N_CHILD(cur_bi->bi_parent, cur_bi->bi_position);
            put_dc_size(t_dc,
                      dc_size(t_dc) + (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 reiserfs_key *key;
      struct disk_child *dc;

      RFALSE(cur == NULL, "buffer is 0");
      RFALSE(del_num < 0,
             "negative number of items (%d) can not be deleted", del_num);
      RFALSE(first_p < 0 || first_p + del_num > B_NR_ITEMS(cur) + 1
             || first_i < 0,
             "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);
      if (del_num == 0)
            return;

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

      if (first_p == 0 && del_num == nr + 1) {
            RFALSE(first_i != 0,
                   "1st deleted key must have order 0, not %d", first_i);
            make_empty_node(cur_bi);
            return;
      }

      RFALSE(first_i + del_num > B_NR_ITEMS(cur),
             "first_i = %d del_num = %d "
             "no so many keys (%d) in the node (%b)(%z)",
             first_i, del_num, first_i + del_num, cur, cur);

      /* 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 */
      set_blkh_nr_item(blkh, blkh_nr_item(blkh) - del_num);
      set_blkh_free_space(blkh,
                      blkh_free_space(blkh) +
                      (del_num * (KEY_SIZE + DC_SIZE)));

      do_balance_mark_internal_dirty(cur_bi->tb, cur, 0);
      /*&&&&&&&&&&&&&&&&&&&&&&& */
      check_internal(cur);
      /*&&&&&&&&&&&&&&&&&&&&&&& */

      if (cur_bi->bi_parent) {
            struct disk_child *t_dc;
            t_dc = B_N_CHILD(cur_bi->bi_parent, cur_bi->bi_position);
            put_dc_size(t_dc,
                      dc_size(t_dc) - (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 reiserfs_key *key;
      struct disk_child *dc;

      nr_src = B_NR_ITEMS(src);

      RFALSE(dest == NULL || src == NULL,
             "src (%p) or dest (%p) buffer is 0", src, dest);
      RFALSE(last_first != FIRST_TO_LAST && last_first != LAST_TO_FIRST,
             "invalid last_first parameter (%d)", last_first);
      RFALSE(nr_src < cpy_num - 1,
             "no so many items (%d) in src (%d)", cpy_num, nr_src);
      RFALSE(cpy_num < 0, "cpy_num less than 0 (%d)", cpy_num);
      RFALSE(cpy_num - 1 + B_NR_ITEMS(dest) > (int)MAX_NR_KEY(dest),
             "cpy_num (%d) + item number in dest (%d) can not be > MAX_NR_KEY(%d)",
             cpy_num, B_NR_ITEMS(dest), MAX_NR_KEY(dest));

      if (cpy_num == 0)
            return;

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

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

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

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

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

      /* prepare space for cpy_num - 1 item headers */
      key = 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 */
      set_blkh_nr_item(blkh, blkh_nr_item(blkh) + (cpy_num - 1));
      set_blkh_free_space(blkh,
                      blkh_free_space(blkh) - (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) {
            struct disk_child *t_dc;
            t_dc = B_N_CHILD(dest_bi->bi_parent, dest_bi->bi_position);
            put_dc_size(t_dc,
                      dc_size(t_dc) + (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 reiserfs_key *key;

      RFALSE(dest == NULL || src == NULL,
             "source(%p) or dest(%p) buffer is 0", src, dest);
      RFALSE(dest_position_before < 0 || src_position < 0,
             "source(%d) or dest(%d) key number less than 0",
             src_position, dest_position_before);
      RFALSE(dest_position_before > B_NR_ITEMS(dest) ||
             src_position >= B_NR_ITEMS(src),
             "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));
      RFALSE(B_FREE_SPACE(dest) < KEY_SIZE,
             "no enough free space (%d) in dest buffer", B_FREE_SPACE(dest));

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

      /* 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. */

      set_blkh_nr_item(blkh, blkh_nr_item(blkh) + 1);
      set_blkh_free_space(blkh, blkh_free_space(blkh) - KEY_SIZE);

      do_balance_mark_internal_dirty(dest_bi->tb, dest, 0);

      if (dest_bi->bi_parent) {
            struct disk_child *t_dc;
            t_dc = B_N_CHILD(dest_bi->bi_parent, dest_bi->bi_position);
            put_dc_size(t_dc, dc_size(t_dc) + 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) {
                  RFALSE(src_bi.bi_bh != PATH_H_PBUFFER(tb->tb_path, h) /*tb->S[h] */ ||
                         dest_bi.bi_bh != tb->R[h],
                         "src (%p) must be == tb->S[h](%p) when it disappears",
                         src_bi.bi_bh, PATH_H_PBUFFER(tb->tb_path, h));
                  /* 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);

      RFALSE(tb->blknum[h] > 1,
             "tb->blknum[%d]=%d when insert_size < 0", h, tb->blknum[h]);

      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;

                  RFALSE(n
                         || B_FREE_SPACE(tbSh) !=
                         MAX_CHILD_SIZE(tbSh) - DC_SIZE,
                         "buffer must have only 0 keys (%d)", n);
                  RFALSE(bi.bi_parent, "root has parent (%p)",
                         bi.bi_parent);

                  /* 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 */
                  PUT_SB_ROOT_BLOCK(tb->tb_sb, new_root->b_blocknr);
                  //REISERFS_SB(tb->tb_sb)->s_rs->s_tree_height --;
                  PUT_SB_TREE_HEIGHT(tb->tb_sb,
                                 SB_TREE_HEIGHT(tb->tb_sb) - 1);

                  do_balance_mark_sb_dirty(tb,
                                     REISERFS_SB(tb->tb_sb)->s_sbh,
                                     1);
                  /*&&&&&&&&&&&&&&&&&&&&&& */
                  if (h > 1)
                        /* use check_internal if new root is an internal node */
                        check_internal(new_root);
                  /*&&&&&&&&&&&&&&&&&&&&&& */

                  /* 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] */

            RFALSE(tb->rnum[h] != 0,
                   "invalid tb->rnum[%d]==%d when joining S[h] with L[h]",
                   h, tb->rnum[h]);

            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] */
            RFALSE(tb->lnum[h] != 0,
                   "invalid tb->lnum[%d]==%d when joining S[h] with R[h]",
                   h, tb->lnum[h]);

            internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h, n + 1);

            reiserfs_invalidate_buffer(tb, tbSh);
            return;
      }

      if (tb->lnum[h] < 0) {  /* borrow from left neighbor L[h] */
            RFALSE(tb->rnum[h] != 0,
                   "wrong tb->rnum[%d]==%d when borrow from L[h]", h,
                   tb->rnum[h]);
            /*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] */
            RFALSE(tb->lnum[h] != 0,
                   "invalid tb->lnum[%d]==%d when borrow from R[h]",
                   h, tb->lnum[h]);
            internal_shift_left(INTERNAL_SHIFT_FROM_R_TO_S, tb, h, -tb->rnum[h]);   /*tb->S[h], tb->CFR[h], tb->rkey[h], tb->R[h], -tb->rnum[h]); */
            return;
      }

      if (tb->lnum[h] > 0) {  /* split S[h] into two parts and put them into neighbors */
            RFALSE(tb->rnum[h] == 0 || tb->lnum[h] + tb->rnum[h] != n + 1,
                   "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);

            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.*/
static void replace_lkey(struct tree_balance *tb, int h, struct item_head *key)
{
      RFALSE(tb->L[h] == NULL || tb->CFL[h] == NULL,
             "L[h](%p) and CFL[h](%p) must exist in replace_lkey",
             tb->L[h], tb->CFL[h]);

      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.*/
static void replace_rkey(struct tree_balance *tb, int h, struct item_head *key)
{
      RFALSE(tb->R[h] == NULL || tb->CFR[h] == NULL,
             "R[h](%p) and CFR[h](%p) must exist in replace_rkey",
             tb->R[h], tb->CFR[h]);
      RFALSE(B_NR_ITEMS(tb->R[h]) == 0,
             "R[h] can not be empty if it exists (item number=%d)",
             B_NR_ITEMS(tb->R[h]));

      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;

      RFALSE(h < 1, "h (%d) can not be < 1 on internal level", h);

      PROC_INFO_INC(tb->tb_sb, balance_at[h]);

      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 * */
      RFALSE(insert_num < -2 || insert_num > 2,
             "incorrect number of items inserted to the internal node (%d)",
             insert_num);
      RFALSE(h > 1 && (insert_num > 1 || insert_num < -1),
             "incorrect number of items (%d) inserted to the internal node on a level (h=%d) higher than last internal level",
             insert_num, h);

      /* 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);
                  put_dc_size(dc,
                            MAX_CHILD_SIZE(insert_ptr[k]) -
                            B_FREE_SPACE(insert_ptr[k]));
                  put_dc_block_number(dc, 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);
                  put_dc_size(dc,
                            MAX_CHILD_SIZE(insert_ptr
                                       [insert_num - k - 1]) -
                            B_FREE_SPACE(insert_ptr
                                     [insert_num - k - 1]));
                  put_dc_block_number(dc,
                                  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] **/
      RFALSE(tb->blknum[h] > 2, "blknum can not be > 2 for internal level");
      RFALSE(tb->blknum[h] < 0, "blknum can not be < 0");

      if (!tb->blknum[h]) {   /* node S[h] is empty now */
            RFALSE(!tbSh, "S[h] is equal NULL");

            /* 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);
            struct block_head *blkh;

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

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

            dc = B_N_CHILD(tbSh, 0);
            put_dc_block_number(dc, tbSh_1->b_blocknr);
            put_dc_size(dc,
                      (MAX_CHILD_SIZE(tbSh_1) - B_FREE_SPACE(tbSh_1)));

            tb->insert_size[h] -= DC_SIZE;
            set_blkh_free_space(blkh, blkh_free_space(blkh) - 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. */
            PUT_SB_ROOT_BLOCK(tb->tb_sb, tbSh->b_blocknr);
            PUT_SB_TREE_HEIGHT(tb->tb_sb, SB_TREE_HEIGHT(tb->tb_sb) + 1);
            do_balance_mark_sb_dirty(tb, REISERFS_SB(tb->tb_sb)->s_sbh, 1);
      }

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

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

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

            dest_bi.tb = tb;
            dest_bi.bi_bh = S_new;
            dest_bi.bi_parent = NULL;
            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);
                  put_dc_size(dc,
                            (MAX_CHILD_SIZE
                             (insert_ptr[insert_num - k - 1]) -
                             B_FREE_SPACE(insert_ptr
                                      [insert_num - k - 1])));
                  put_dc_block_number(dc,
                                  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;

            RFALSE(!buffer_journaled(S_new) || buffer_journal_dirty(S_new)
                   || buffer_dirty(S_new), "cm-00001: bad S_new (%b)",
                   S_new);

            // S_new is released in unfix_nodes
      }

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

      if (0 <= child_pos && child_pos <= n && insert_num > 0) {
            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_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;
}

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