sys/vfs/hammer/hammer_freemap.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   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  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/vfs/hammer/hammer_freemap.c,v 1.1 2008/02/10 09:51:01 dillon Exp $
  35  */
  36
  37 /*
  38  * HAMMER freemap - bigblock allocator
  39  */
  40 #include "hammer.h"
  41
  42 hammer_off_t
  43 hammer_freemap_alloc(hammer_mount_t hmp, int *errorp)
  44 {
  45         hammer_volume_t root_volume;
  46         hammer_volume_ondisk_t ondisk;
  47         hammer_off_t raw_offset;
  48
  49         root_volume = hammer_get_root_volume(hmp, errorp);
  50         if (*errorp)
  51                 return(0);
  52         ondisk = root_volume->ondisk;
  53
  54         hammer_modify_volume(root_volume, &ondisk->vol0_free_off,
  55                              sizeof(ondisk->vol0_free_off));
  56         raw_offset = ondisk->vol0_free_off;
  57         ondisk->vol0_free_off += HAMMER_LARGEBLOCK_SIZE;
  58         KKASSERT(ondisk->vol0_free_off <= root_volume->maxbuf_off);
  59         hammer_rel_volume(root_volume, 0);
  60         return(raw_offset);
  61 }
  62