ibalance.c

reiserfsprogs-3.6.19.tar.gz 源码 给有需要的人！

   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;

    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 **/
    /* 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 = get_blkh_nr_items (B_BLK_HEAD(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]);
	    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);

	    /* insert insert_num keys and node-pointers into L[h] */
	    bi.bi_bh = tb->L[h];
	    bi.bi_parent = tb->FL[h];
	    bi.bi_position = get_left_neighbor_position (tb, h);
	    internal_insert_childs (tb->tb_fs, &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.bi_bh = tb->L[h];
	    bi.bi_parent = tb->FL[h];
	    bi.bi_position = get_left_neighbor_position (tb, h);
	    internal_insert_childs (tb->tb_fs, &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);

	    set_dc(dc, MAX_CHILD_SIZE(insert_ptr[k]->b_size) - 
		   get_blkh_free_space (B_BLK_HEAD(insert_ptr[k])), 
		   insert_ptr[k]->b_blocknr);
	/*	       
	    set_dc_child_size (dc, MAX_CHILD_SIZE(insert_ptr[k]->b_size) -
			       get_blkh_free_space (B_BLK_HEAD(insert_ptr[k])));
	    set_dc_child_blocknr (dc, insert_ptr[k]->b_blocknr);
	*/
	    mark_buffer_dirty (tbSh);

	    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 = get_blkh_nr_items (B_BLK_HEAD (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 (INTERNAL_SHIFT_FROM_S_TO_R, tb, h, tb->rnum[h] - insert_num);

		/* insert insert_num keys and node-pointers into R[h] */
		bi.bi_bh = tb->R[h];
		bi.bi_parent = tb->FR[h];
		bi.bi_position = get_right_neighbor_position (tb, h);
		internal_insert_childs (tb->tb_fs, &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.bi_bh = tb->R[h];
		bi.bi_parent = tb->FR[h];
		bi.bi_position = get_right_neighbor_position (tb, h);
		internal_insert_childs (tb->tb_fs, &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);
		set_dc(dc, MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]->b_size) -
		       get_blkh_free_space (B_BLK_HEAD(insert_ptr[insert_num-k-1])),
		       insert_ptr[insert_num-k-1]->b_blocknr);
		/*
		set_dc_child_size (dc, MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]->b_size) -
				   get_blkh_free_space (B_BLK_HEAD(insert_ptr[insert_num-k-1])));
		set_dc_child_blocknr (dc, insert_ptr[insert_num-k-1]->b_blocknr);
		*/
		mark_buffer_dirty (tb->R[h]);
		    
		insert_num -= (k + 1);
	    }
    }

    /** Fill new node that appears instead of S[h] **/
    if ( ! tb->blknum[h] )
    { /* node S[h] is empty now */
	/* Mark buffer as invalid and put it to head of free list. */
	reiserfs_invalidate_buffer(tb, tbSh, 1);/* do not preserve, internal node*/
	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 reiserfs_super_block * sb;

	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);
	set_blkh_level (B_BLK_HEAD(tbSh), h + 1);
	
	/* Put the unique node-pointer to S[h] that points to S[h-1]. */

	dc = B_N_CHILD(tbSh, 0);

	set_dc(dc, MAX_CHILD_SIZE (tbSh_1->b_size) - 
	       get_blkh_free_space (B_BLK_HEAD(tbSh_1)),
	       tbSh_1->b_blocknr);
	/*
	set_dc_child_size (dc, MAX_CHILD_SIZE (tbSh_1->b_size) - get_blkh_free_space (B_BLK_HEAD(tbSh_1)));
	set_dc_child_blocknr (dc, tbSh_1->b_blocknr);
	*/
	tb->insert_size[h] -= DC_SIZE;
	set_blkh_free_space (B_BLK_HEAD(tbSh),
			     get_blkh_free_space (B_BLK_HEAD(tbSh)) - DC_SIZE);

	mark_buffer_dirty (tbSh);
	
	/* put new root into path structure */
	PATH_OFFSET_PBUFFER(tb->tb_path, ILLEGAL_PATH_ELEMENT_OFFSET) = tbSh;
	
	/* Change root in structure super block. */
	sb = tb->tb_fs->fs_ondisk_sb;
	set_sb_root_block (sb, tbSh->b_blocknr);
	set_sb_tree_height (sb, get_sb_tree_height (sb) + 1);
	
	mark_buffer_dirty (tb->tb_fs->fs_super_bh);
	tb->tb_fs->fs_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.bi_bh = S_new;
	dest_bi.bi_parent = 0;
	dest_bi.bi_position = 0;
	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 = get_blkh_nr_items (B_BLK_HEAD(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 (tb->tb_fs, &dest_bi, &src_bi, 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 (tb->tb_fs, &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 (tb->tb_fs, &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 (tb->tb_fs, &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 (tb->tb_fs, &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);
	    set_dc(dc, MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]->b_size) -
		   get_blkh_free_space (B_BLK_HEAD(insert_ptr[insert_num-k-1])),
		   insert_ptr[insert_num-k-1]->b_blocknr);
	    /*
	    set_dc_child_size (dc, MAX_CHILD_SIZE(insert_ptr[insert_num-k-1]->b_size) -
			       get_blkh_free_space (B_BLK_HEAD(insert_ptr[insert_num-k-1])));
	    set_dc_child_blocknr (dc, insert_ptr[insert_num-k-1]->b_blocknr);
	    */
	    mark_buffer_dirty (S_new);
			
	    insert_num -= (k + 1);
	}
	/* new_insert_ptr = node_pointer to S_new */
	new_insert_ptr = S_new;
	/*
	  S_new->b_count --;
	*/
	/*brelse(S_new);*/
    }

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

    if ( -1 <= child_pos && child_pos <= n && insert_num > 0 ) {
	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);
	if (child_pos == -1) {
	    /* this is a little different from original do_balance:
	       here we insert the minimal keys in the tree, that has never happened when file system works */
	    if (tb->CFL[h-1] || insert_num != 1 || h != 1)
		die ("balance_internal: invalid child_pos");
	    /* insert_child (tb->S[h], tb->S[h-1], child_pos, insert_num, B_N_ITEM_HEAD(tb->S[0],0), insert_ptr);*/
	    internal_insert_childs (tb->tb_fs, &bi, child_pos, insert_num,
			B_N_PITEM_HEAD (PATH_PLAST_BUFFER (tb->tb_path), 0), insert_ptr);
	} else
	    internal_insert_childs (tb->tb_fs, &bi, 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;
}