FreeBSD/Linux Kernel Cross Reference
sys/fs/reiserfs/ibalance.c

     /*
      * Copyright 2000-2002 by Hans Reiser, licensing governed by reiserfs/README
      */
     
     #include <linux/config.h>
     #include <asm/uaccess.h>
     #include <linux/string.h>
     #include <linux/sched.h>
     #include <linux/reiserfs_fs.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 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 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 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 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 );
               //tb->tb_sb->u.reiserfs_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, 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] */
   
           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.*/
   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.*/
   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(0, "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, 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);
   
           set_blkh_level( B_BLK_HEAD(S_new), 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);
              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_locked(S_new) || atomic_read (&(S_new->b_count)) != 1) &&
                 (buffer_locked(S_new) || atomic_read(&(S_new->b_count)) > 2 ||
                  !(buffer_journaled(S_new) || buffer_journal_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;
      }
  
    
      

Cache object: ecf59ec47cd5dcc40871e01409ef3773