ibalance.c

linux 内核源代码

	}

}

/* 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 reiserfs_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);
			//REISERFS_SB(tb->tb_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,
						 REISERFS_SB(tb->tb_sb)->s_sbh,
						 1);
			/*&&&&&&&&&&&&&&&&&&&&&& */
			if (h > 1)
				/* use check_internal if new root is an internal node */
				check_internal(new_root);
			/*&&&&&&&&&&&&&&&&&&&&&& */

			/* 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.*/
static 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.*/
static void replace_rkey(struct tree_balance *tb, int h, struct item_head *key)
{
	RFALSE(tb->R[h] == NULL || tb->CFR[h] == NULL,