1 /* $NetBSD: bt_page.c,v 1.9 1997/10/10 21:08:53 is 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)bt_page.c 8.3 (Berkeley) 7/14/94"; 40 #else 41 __RCSID("$NetBSD: bt_page.c,v 1.9 1997/10/10 21:08:53 is Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include <sys/types.h> 47 48 #include <stdio.h> 49 50 #include <db.h> 51 #include "btree.h" 52 53 /* 54 * __bt_free -- 55 * Put a page on the freelist. 56 * 57 * Parameters: 58 * t: tree 59 * h: page to free 60 * 61 * Returns: 62 * RET_ERROR, RET_SUCCESS 63 * 64 * Side-effect: 65 * mpool_put's the page. 66 */ 67 int 68 __bt_free(t, h) 69 BTREE *t; 70 PAGE *h; 71 { 72 /* Insert the page at the head of the free list. */ 73 h->prevpg = P_INVALID; 74 h->nextpg = t->bt_free; 75 t->bt_free = h->pgno; 76 F_SET(t, B_METADIRTY); 77 78 /* Make sure the page gets written back. */ 79 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 80 } 81 82 /* 83 * __bt_new -- 84 * Get a new page, preferably from the freelist. 85 * 86 * Parameters: 87 * t: tree 88 * npg: storage for page number. 89 * 90 * Returns: 91 * Pointer to a page, NULL on error. 92 */ 93 PAGE * 94 __bt_new(t, npg) 95 BTREE *t; 96 pgno_t *npg; 97 { 98 PAGE *h; 99 100 if (t->bt_free != P_INVALID && 101 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 102 *npg = t->bt_free; 103 t->bt_free = h->nextpg; 104 F_SET(t, B_METADIRTY); 105 return (h); 106 } 107 return (mpool_new(t->bt_mp, npg)); 108 } 109