db/btree/FreeBSD/bt_page.c

   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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)bt_page.c   8.3 (Berkeley) 7/14/94";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/db/btree/bt_page.c,v 1.5 2009/03/02 23:47:18 delphij Exp $");
  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(BTREE *t, PAGE *h)
  59 {
  60         /* Insert the page at the head of the free list. */
  61         h->prevpg = P_INVALID;
  62         h->nextpg = t->bt_free;
  63         t->bt_free = h->pgno;
  64         F_SET(t, B_METADIRTY);
  65
  66         /* Make sure the page gets written back. */
  67         return (mpool_put(t->bt_mp, h, MPOOL_DIRTY));
  68 }
  69
  70 /*
  71  * __bt_new --
  72  *      Get a new page, preferably from the freelist.
  73  *
  74  * Parameters:
  75  *      t:      tree
  76  *      npg:    storage for page number.
  77  *
  78  * Returns:
  79  *      Pointer to a page, NULL on error.
  80  */
  81 PAGE *
  82 __bt_new(BTREE *t, pgno_t *npg)
  83 {
  84         PAGE *h;
  85
  86         if (t->bt_free != P_INVALID &&
  87             (h = mpool_get(t->bt_mp, t->bt_free, 0)) != NULL) {
  88                 *npg = t->bt_free;
  89                 t->bt_free = h->nextpg;
  90                 F_SET(t, B_METADIRTY);
  91                 return (h);
  92         }
  93         return (mpool_new(t->bt_mp, npg));
  94 }