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 1.1 2008/02/23 03:01:06 dillon Exp $
  35  */
  36
  37 #include "hammer.h"
  38
  39 hammer_off_t
  40 blockmap_lookup(hammer_off_t bmap_off,
  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 rootmap;
  46         struct hammer_blockmap_layer1 *layer1;
  47         struct hammer_blockmap_layer2 *layer2;
  48         struct buffer_info *buffer = NULL;
  49         hammer_off_t layer1_offset;
  50         hammer_off_t layer2_offset;
  51         hammer_off_t result_offset;
  52         int zone;
  53
  54         zone = HAMMER_ZONE_DECODE(bmap_off);
  55         assert(zone >= HAMMER_ZONE_BTREE_INDEX && zone < HAMMER_MAX_ZONES);
  56         assert(RootVolNo >= 0);
  57         root_volume = get_volume(RootVolNo);
  58         rootmap = &root_volume->ondisk->vol0_blockmap[zone];
  59         assert(rootmap->phys_offset != 0);
  60         assert(HAMMER_ZONE_DECODE(rootmap->phys_offset) ==
  61                  HAMMER_ZONE_RAW_BUFFER_INDEX);
  62         assert(HAMMER_ZONE_DECODE(rootmap->alloc_offset) == zone);
  63
  64         if (bmap_off >= rootmap->alloc_offset) {
  65                 panic("hammer_blockmap_lookup: %016llx beyond EOF %016llx",
  66                       bmap_off, rootmap->alloc_offset);
  67                 result_offset = 0;
  68                 goto done;
  69         }
  70
  71         /*
  72          * Dive layer 1.
  73          */
  74         layer1_offset = rootmap->phys_offset +
  75                         HAMMER_BLOCKMAP_LAYER1_OFFSET(bmap_off);
  76         layer1 = get_buffer_data(layer1_offset, &buffer, 0);
  77         assert(layer1->phys_offset);
  78         if (save_layer1)
  79                 *save_layer1 = *layer1;
  80
  81         /*
  82          * Dive layer 2, each entry represents a large-block.
  83          */
  84         layer2_offset = layer1->phys_offset +
  85                         HAMMER_BLOCKMAP_LAYER2_OFFSET(bmap_off);
  86         layer2 = get_buffer_data(layer2_offset, &buffer, 0);
  87         if (save_layer2)
  88                 *save_layer2 = *layer2;
  89
  90         assert(layer2->u.phys_offset);
  91
  92         result_offset = layer2->u.phys_offset +
  93                         (bmap_off & HAMMER_LARGEBLOCK_MASK64);
  94 done:
  95         if (buffer)
  96                 rel_buffer(buffer);
  97         rel_volume(root_volume);
  98         return(result_offset);
  99 }
 100