1 /* $NetBSD: bt_page.c,v 1.13 2008/09/11 12:58:00 joerg 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 #if HAVE_NBTOOL_CONFIG_H 33 #include "nbtool_config.h" 34 #endif 35 36 #include <sys/cdefs.h> 37 #ifndef __minix 38 __RCSID("$NetBSD: bt_page.c,v 1.13 2008/09/11 12:58:00 joerg Exp $"); 39 #endif 40 41 #ifndef __minix 42 #include "namespace.h" 43 #endif 44 #include <sys/types.h> 45 46 #include <assert.h> 47 #include <stdio.h> 48 49 #include <db.h> 50 #include "btree.h" 51 52 /* 53 * __bt_free -- 54 * Put a page on the freelist. 55 * 56 * Parameters: 57 * t: tree 58 * h: page to free 59 * 60 * Returns: 61 * RET_ERROR, RET_SUCCESS 62 * 63 * Side-effect: 64 * mpool_put's the page. 65 */ 66 int 67 __bt_free(BTREE *t, PAGE *h) 68 { 69 /* Insert the page at the head of the free list. */ 70 h->prevpg = P_INVALID; 71 h->nextpg = t->bt_free; 72 t->bt_free = h->pgno; 73 F_SET(t, B_METADIRTY); 74 75 /* Make sure the page gets written back. */ 76 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 77 } 78 79 /* 80 * __bt_new -- 81 * Get a new page, preferably from the freelist. 82 * 83 * Parameters: 84 * t: tree 85 * npg: storage for page number. 86 * 87 * Returns: 88 * Pointer to a page, NULL on error. 89 */ 90 PAGE * 91 __bt_new(BTREE *t, pgno_t *npg) 92 { 93 PAGE *h; 94 95 if (t->bt_free != P_INVALID && 96 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 97 *npg = t->bt_free; 98 t->bt_free = h->nextpg; 99 F_SET(t, B_METADIRTY); 100 return (h); 101 } 102 return (mpool_new(t->bt_mp, npg)); 103 } 104