sbin/hammer/blockmap.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/sbin/hammer/blockmap.c,v 1.2 2008/06/17 04:03:38 dillon Exp $
  35  */
  36
  37 #include "hammer.h"
  38
  39 hammer_off_t
  40 blockmap_lookup(hammer_off_t zone_offset,
  41                 struct hammer_blockmap_layer1 *save_layer1,
  42                 struct hammer_blockmap_layer2 *save_layer2)
  43 {
  44         struct volume_info *root_volume;
  45         hammer_blockmap_t blockmap;
  46         hammer_blockmap_t freemap;
  47         struct hammer_blockmap_layer1 *layer1;
  48         struct hammer_blockmap_layer2 *layer2;
  49         struct buffer_info *buffer = NULL;
  50         hammer_off_t layer1_offset;
  51         hammer_off_t layer2_offset;
  52         hammer_off_t result_offset;
  53         int zone;
  54         int i;
  55
  56         zone = HAMMER_ZONE_DECODE(zone_offset);
  57
  58         assert(zone > HAMMER_ZONE_RAW_VOLUME_INDEX);
  59         assert(zone < HAMMER_MAX_ZONES);
  60         assert(RootVolNo >= 0);
  61         root_volume = get_volume(RootVolNo);
  62         blockmap = &root_volume->ondisk->vol0_blockmap[zone];
  63
  64         if (zone == HAMMER_ZONE_RAW_BUFFER_INDEX) {
  65                 result_offset = zone_offset;
  66         } else if (zone == HAMMER_ZONE_UNDO_INDEX) {
  67                 i = (zone_offset & HAMMER_OFF_SHORT_MASK) /
  68                     HAMMER_LARGEBLOCK_SIZE;
  69                 assert(zone_offset < blockmap->alloc_offset);
  70                 result_offset = root_volume->ondisk->vol0_undo_array[i] +
  71                                 (zone_offset & HAMMER_LARGEBLOCK_MASK64);
  72         } else {
  73                 result_offset = (zone_offset & ~HAMMER_OFF_ZONE_MASK) |
  74                                 HAMMER_ZONE_RAW_BUFFER;
  75         }
  76
  77         assert(HAMMER_ZONE_DECODE(blockmap->alloc_offset) == zone);
  78
  79         /*
  80          * Validate that the big-block is assigned to the zone.  Also
  81          * assign save_layer{1,2}.
  82          */
  83
  84         freemap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_FREEMAP_INDEX];
  85         /*
  86          * Dive layer 1.
  87          */
  88         layer1_offset = freemap->phys_offset +
  89                         HAMMER_BLOCKMAP_LAYER1_OFFSET(zone_offset);
  90         layer1 = get_buffer_data(layer1_offset, &buffer, 0);
  91         assert(layer1->phys_offset != HAMMER_BLOCKMAP_UNAVAIL);
  92         if (save_layer1)
  93                 *save_layer1 = *layer1;
  94
  95         /*
  96          * Dive layer 2, each entry represents a large-block.
  97          */
  98         layer2_offset = layer1->phys_offset +
  99                         HAMMER_BLOCKMAP_LAYER2_OFFSET(zone_offset);
 100         layer2 = get_buffer_data(layer2_offset, &buffer, 0);
 101         if (save_layer2)
 102                 *save_layer2 = *layer2;
 103
 104         assert(layer2->zone == zone);
 105
 106         if (buffer)
 107                 rel_buffer(buffer);
 108         rel_volume(root_volume);
 109         return(result_offset);
 110 }
 111