path: root/fs/reiserfs/ibalance.c

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

#include <linux/config.h>
#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 =