bt_page.c revision 331722 
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 * 4. 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
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)bt_page.c	8.3 (Berkeley) 7/14/94";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: stable/11/lib/libc/db/btree/bt_page.c 331722 2018-03-29 02:50:57Z eadler $");
35
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 */
57int
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 */
81PAGE *
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