1/*	$NetBSD: bt_page.c,v 1.12 2008/09/10 17:52:35 joerg Exp $	*/
2
3/*-
4 * Copyright (c) 1990, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if HAVE_NBTOOL_CONFIG_H
33#include "nbtool_config.h"
34#endif
35
36#include <sys/cdefs.h>
37__RCSID("$NetBSD: bt_page.c,v 1.12 2008/09/10 17:52:35 joerg Exp $");
38
39#include "namespace.h"
40#include <sys/types.h>
41
42#include <assert.h>
43#include <stdio.h>
44
45#include <db.h>
46#include "btree.h"
47
48/*
49 * __bt_free --
50 *	Put a page on the freelist.
51 *
52 * Parameters:
53 *	t:	tree
54 *	h:	page to free
55 *
56 * Returns:
57 *	RET_ERROR, RET_SUCCESS
58 *
59 * Side-effect:
60 *	mpool_put's the page.
61 */
62int
63__bt_free(BTREE *t, PAGE *h)
64{
65	/* Insert the page at the head of the free list. */
66	h->prevpg = P_INVALID;
67	h->nextpg = t->bt_free;
68	t->bt_free = h->pgno;
69	F_SET(t, B_METADIRTY);
70
71	/* Make sure the page gets written back. */
72	return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
73}
74
75/*
76 * __bt_new --
77 *	Get a new page, preferably from the freelist.
78 *
79 * Parameters:
80 *	t:	tree
81 *	npg:	storage for page number.
82 *
83 * Returns:
84 *	Pointer to a page, NULL on error.
85 */
86PAGE *
87__bt_new(BTREE *t, pgno_t *npg)
88{
89	PAGE *h;
90
91	if (t->bt_free != P_INVALID &&
92	    (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
93		*npg = t->bt_free;
94		t->bt_free = h->nextpg;
95		F_SET(t, B_METADIRTY);
96		return (h);
97	}
98	return (mpool_new(t->bt_mp, npg));
99}
100