ibalance.c

嵌入式系统设计与实验教材二源码linux内核移植与编译

  /*&&&&&&&&&&&&&&&&&&&&&&&&*/
  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",