1 /* $OpenBSD: bt_page.c,v 1.5 1999/02/15 05:11:23 millert 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 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)bt_page.c 8.3 (Berkeley) 7/14/94"; 39 #else 40 static char rcsid[] = "$OpenBSD: bt_page.c,v 1.5 1999/02/15 05:11:23 millert Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <sys/types.h> 45 46 #include <stdio.h> 47 48 #include <db.h> 49 #include "btree.h" 50 51 /* 52 * __bt_free -- 53 * Put a page on the freelist. 54 * 55 * Parameters: 56 * t: tree 57 * h: page to free 58 * 59 * Returns: 60 * RET_ERROR, RET_SUCCESS 61 * 62 * Side-effect: 63 * mpool_put's the page. 64 */ 65 int 66 __bt_free(t, h) 67 BTREE *t; 68 PAGE *h; 69 { 70 /* Insert the page at the head of the free list. */ 71 h->prevpg = P_INVALID; 72 h->nextpg = t->bt_free; 73 t->bt_free = h->pgno; 74 F_SET(t, B_METADIRTY); 75 76 /* Make sure the page gets written back. */ 77 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 78 } 79 80 /* 81 * __bt_new -- 82 * Get a new page, preferably from the freelist. 83 * 84 * Parameters: 85 * t: tree 86 * npg: storage for page number. 87 * 88 * Returns: 89 * Pointer to a page, NULL on error. 90 */ 91 PAGE * 92 __bt_new(t, npg) 93 BTREE *t; 94 pgno_t *npg; 95 { 96 PAGE *h; 97 98 if (t->bt_free != P_INVALID && 99 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 100 *npg = t->bt_free; 101 t->bt_free = h->nextpg; 102 F_SET(t, B_METADIRTY); 103 return (h); 104 } 105 return (mpool_new(t->bt_mp, npg, MPOOL_PAGE_NEXT)); 106 } 107