1 /* $NetBSD: bt_page.c,v 1.15 2016/09/24 21:31:25 christos 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 1.15 2016/09/24 21:31:25 christos 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 */
62 int
__bt_free(BTREE * t,PAGE * h)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 */
86 PAGE *
__bt_new(BTREE * t,pgno_t * npg)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