1 /*-
2 * Copyright (c) 1990, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)bt_page.c 8.3 (Berkeley) 7/14/94
30 * $FreeBSD: head/lib/libc/db/btree/bt_page.c 190498 2009-03-28 07:31:02Z delphij $
31 */
32
33 #include <sys/types.h>
34
35 #include <stdio.h>
36
37 #include <db.h>
38 #include "btree.h"
39
40 /*
41 * __bt_free --
42 * Put a page on the freelist.
43 *
44 * Parameters:
45 * t: tree
46 * h: page to free
47 *
48 * Returns:
49 * RET_ERROR, RET_SUCCESS
50 *
51 * Side-effect:
52 * mpool_put's the page.
53 */
54 int
__bt_free(BTREE * t,PAGE * h)55 __bt_free(BTREE *t, PAGE *h)
56 {
57 /* Insert the page at the head of the free list. */
58 h->prevpg = P_INVALID;
59 h->nextpg = t->bt_free;
60 t->bt_free = h->pgno;
61 F_SET(t, B_METADIRTY);
62
63 /* Make sure the page gets written back. */
64 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
65 }
66
67 /*
68 * __bt_new --
69 * Get a new page, preferably from the freelist.
70 *
71 * Parameters:
72 * t: tree
73 * npg: storage for page number.
74 *
75 * Returns:
76 * Pointer to a page, NULL on error.
77 */
78 PAGE *
__bt_new(BTREE * t,pgno_t * npg)79 __bt_new(BTREE *t, pgno_t *npg)
80 {
81 PAGE *h;
82
83 if (t->bt_free != P_INVALID &&
84 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
85 *npg = t->bt_free;
86 t->bt_free = h->nextpg;
87 F_SET(t, B_METADIRTY);
88 return (h);
89 }
90 return (mpool_new(t->bt_mp, npg, MPOOL_PAGE_NEXT));
91 }
92