1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)bt_page.c 8.3 (Berkeley) 7/14/94";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 #include <sys/types.h>
37
38 #include <stdio.h>
39
40 #include <db.h>
41 #include "btree.h"
42
43 /*
44 * __bt_free --
45 * Put a page on the freelist.
46 *
47 * Parameters:
48 * t: tree
49 * h: page to free
50 *
51 * Returns:
52 * RET_ERROR, RET_SUCCESS
53 *
54 * Side-effect:
55 * mpool_put's the page.
56 */
57 int
__bt_free(BTREE * t,PAGE * h)58 __bt_free(BTREE *t, PAGE *h)
59 {
60 /* Insert the page at the head of the free list. */
61 h->prevpg = P_INVALID;
62 h->nextpg = t->bt_free;
63 t->bt_free = h->pgno;
64 F_SET(t, B_METADIRTY);
65
66 /* Make sure the page gets written back. */
67 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
68 }
69
70 /*
71 * __bt_new --
72 * Get a new page, preferably from the freelist.
73 *
74 * Parameters:
75 * t: tree
76 * npg: storage for page number.
77 *
78 * Returns:
79 * Pointer to a page, NULL on error.
80 */
81 PAGE *
__bt_new(BTREE * t,pgno_t * npg)82 __bt_new(BTREE *t, pgno_t *npg)
83 {
84 PAGE *h;
85
86 if (t->bt_free != P_INVALID &&
87 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
88 *npg = t->bt_free;
89 t->bt_free = h->nextpg;
90 F_SET(t, B_METADIRTY);
91 return (h);
92 }
93 return (mpool_new(t->bt_mp, npg, MPOOL_PAGE_NEXT));
94 }
95