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

	   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;
    }