1 /*- 2 * Copyright (c) 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)bt_page.c 8.3 (Berkeley) 7/14/94 34 */ 35 36 #include <sys/types.h> 37 38 #include <stdio.h> 39 40 #include <db.h> 41 #include "btree.h" 42 43 /* 44 * __bt_free -- 45 * Put a page on the freelist. 46 * 47 * Parameters: 48 * t: tree 49 * h: page to free 50 * 51 * Returns: 52 * RET_ERROR, RET_SUCCESS 53 * 54 * Side-effect: 55 * mpool_put's the page. 56 */ 57 int 58 __bt_free(t, h) 59 BTREE *t; 60 PAGE *h; 61 { 62 /* Insert the page at the head of the free list. */ 63 h->prevpg = P_INVALID; 64 h->nextpg = t->bt_free; 65 t->bt_free = h->pgno; 66 F_SET(t, B_METADIRTY); 67 68 /* Make sure the page gets written back. */ 69 return (mpool_put(t->bt_mp, h, MPOOL_DIRTY)); 70 } 71 72 /* 73 * __bt_new -- 74 * Get a new page, preferably from the freelist. 75 * 76 * Parameters: 77 * t: tree 78 * npg: storage for page number. 79 * 80 * Returns: 81 * Pointer to a page, NULL on error. 82 */ 83 PAGE * 84 __bt_new(t, npg) 85 BTREE *t; 86 pgno_t *npg; 87 { 88 PAGE *h; 89 90 if (t->bt_free != P_INVALID && 91 (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) { 92 *npg = t->bt_free; 93 t->bt_free = h->nextpg; 94 F_SET(t, B_METADIRTY); 95 return (h); 96 } 97 return (mpool_new(t->bt_mp, npg)); 98 } 99