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