1 /* $NetBSD: bt_page.c,v 1.10 2003/08/07 16:42:41 agc 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. 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 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)bt_page.c 8.3 (Berkeley) 7/14/94"; 36 #else 37 __RCSID("$NetBSD: bt_page.c,v 1.10 2003/08/07 16:42:41 agc Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 44 #include <stdio.h> 45 46 #include <db.h> 47 #include "btree.h" 48 49 /* 50 * __bt_free -- 51 * Put a page on the freelist. 52 * 53 * Parameters: 54 * t: tree 55 * h: page to free 56 * 57 * Returns: 58 * RET_ERROR, RET_SUCCESS 59 * 60 * Side-effect: 61 * mpool_put's the page. 62 */ 63 int 64 __bt_free(t, h) 65 BTREE *t; 66 PAGE *h; 67 { 68 /* Insert the page at the head of the free list. */ 69 h->prevpg = P_INVALID; 70 h->nextpg = t->bt_free; 71 t->bt_free = h->pgno; 72 F_SET(t, B_METADIRTY); 73 74 /* Make sure the page gets written back. */ 75 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 76 } 77 78 /* 79 * __bt_new -- 80 * Get a new page, preferably from the freelist. 81 * 82 * Parameters: 83 * t: tree 84 * npg: storage for page number. 85 * 86 * Returns: 87 * Pointer to a page, NULL on error. 88 */ 89 PAGE * 90 __bt_new(t, npg) 91 BTREE *t; 92 pgno_t *npg; 93 { 94 PAGE *h; 95 96 if (t->bt_free != P_INVALID && 97 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 98 *npg = t->bt_free; 99 t->bt_free = h->nextpg; 100 F_SET(t, B_METADIRTY); 101 return (h); 102 } 103 return (mpool_new(t->bt_mp, npg)); 104 } 105