btrfs-map-logical.c

   1 /*
   2  * Copyright (C) 2009 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #define _XOPEN_SOURCE 500
  20 #define _GNU_SOURCE 1
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <fcntl.h>
  24 #include <unistd.h>
  25 #include <getopt.h>
  26 #include "kerncompat.h"
  27 #include "ctree.h"
  28 #include "volumes.h"
  29 #include "disk-io.h"
  30 #include "print-tree.h"
  31 #include "transaction.h"
  32 #include "list.h"
  33 #include "version.h"
  34
  35 /* we write the mirror info to stdout unless they are dumping the data
  36  * to stdout
  37  * */
  38 static FILE *info_file;
  39
  40 struct extent_buffer *debug_read_block(struct btrfs_root *root, u64 bytenr,
  41                                      u32 blocksize, int copy)
  42 {
  43         int ret;
  44         int dev_nr;
  45         struct extent_buffer *eb;
  46         u64 length;
  47         struct btrfs_multi_bio *multi = NULL;
  48         struct btrfs_device *device;
  49         int num_copies;
  50         int mirror_num = 1;
  51
  52         eb = btrfs_find_create_tree_block(root, bytenr, blocksize);
  53         if (!eb)
  54                 return NULL;
  55
  56         dev_nr = 0;
  57         length = blocksize;
  58         while (1) {
  59                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
  60                                       eb->start, &length, &multi, mirror_num);
  61                 BUG_ON(ret);
  62                 device = multi->stripes[0].dev;
  63                 eb->fd = device->fd;
  64                 device->total_ios++;
  65                 eb->dev_bytenr = multi->stripes[0].physical;
  66
  67                 fprintf(info_file, "mirror %d logical %Lu physical %Lu "
  68                         "device %s\n", mirror_num, bytenr, eb->dev_bytenr,
  69                         device->name);
  70                 kfree(multi);
  71
  72                 if (!copy || mirror_num == copy)
  73                         ret = read_extent_from_disk(eb);
  74
  75                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  76                                               eb->start, eb->len);
  77                 if (num_copies == 1)
  78                         break;
  79
  80                 mirror_num++;
  81                 if (mirror_num > num_copies)
  82                         break;
  83         }
  84         return eb;
  85 }
  86
  87 static void print_usage(void)
  88 {
  89         fprintf(stderr, "usage: btrfs-map-logical [options] mount_point\n");
  90         fprintf(stderr, "\t-l Logical extent to map\n");
  91         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
  92         fprintf(stderr, "\t-o Output file to hold the extent\n");
  93         fprintf(stderr, "\t-s Number of bytes to read\n");
  94         exit(1);
  95 }
  96
  97 static struct option long_options[] = {
  98         /* { "byte-count", 1, NULL, 'b' }, */
  99         { "logical", 1, NULL, 'l' },
 100         { "copy", 1, NULL, 'c' },
 101         { "output", 1, NULL, 'c' },
 102         { "bytes", 1, NULL, 'b' },
 103         { 0, 0, 0, 0}
 104 };
 105
 106 int main(int ac, char **av)
 107 {
 108         struct cache_tree root_cache;
 109         struct btrfs_root *root;
 110         struct extent_buffer *eb;
 111         char *dev;
 112         char *output_file = NULL;
 113         u64 logical = 0;
 114         int ret = 0;
 115         int option_index = 0;
 116         int copy = 0;
 117         u64 bytes = 0;
 118         int out_fd = 0;
 119         int err;
 120
 121         while(1) {
 122                 int c;
 123                 c = getopt_long(ac, av, "l:c:o:b:", long_options,
 124                                 &option_index);
 125                 if (c < 0)
 126                         break;
 127                 switch(c) {
 128                         case 'l':
 129                                 logical = atoll(optarg);
 130                                 if (logical == 0) {
 131                                         fprintf(stderr,
 132                                                 "invalid extent number\n");
 133                                         print_usage();
 134                                 }
 135                                 break;
 136                         case 'c':
 137                                 copy = atoi(optarg);
 138                                 if (copy == 0) {
 139                                         fprintf(stderr,
 140                                                 "invalid copy number\n");
 141                                         print_usage();
 142                                 }
 143                                 break;
 144                         case 'b':
 145                                 bytes = atoll(optarg);
 146                                 if (bytes == 0) {
 147                                         fprintf(stderr,
 148                                                 "invalid byte count\n");
 149                                         print_usage();
 150                                 }
 151                                 break;
 152                         case 'o':
 153                                 output_file = strdup(optarg);
 154                                 break;
 155                         default:
 156                                 print_usage();
 157                 }
 158         }
 159         ac = ac - optind;
 160         if (ac == 0)
 161                 print_usage();
 162         if (logical == 0)
 163                 print_usage();
 164         if (copy < 0)
 165                 print_usage();
 166
 167         dev = av[optind];
 168
 169         radix_tree_init();
 170         cache_tree_init(&root_cache);
 171
 172         root = open_ctree(dev, 0, 0);
 173         if (!root) {
 174                 fprintf(stderr, "Open ctree failed\n");
 175                 exit(1);
 176         }
 177
 178         if (output_file) {
 179                 if (strcmp(output_file, "-") == 0) {
 180                         out_fd = 1;
 181                         info_file = stderr;
 182                 } else {
 183                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 184                         if (out_fd < 0)
 185                                 goto close;
 186                         err = ftruncate(out_fd, 0);
 187                         if (err) {
 188                                 close(out_fd);
 189                                 goto close;
 190                         }
 191                         info_file = stdout;
 192                 }
 193         }
 194
 195         if (bytes == 0)
 196                 bytes = root->sectorsize;
 197
 198         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 199         bytes *= root->sectorsize;
 200
 201         while (bytes > 0) {
 202                 eb = debug_read_block(root, logical, root->sectorsize, copy);
 203                 if (eb && output_file) {
 204                         err = write(out_fd, eb->data, eb->len);
 205                         if (err < 0 || err != eb->len) {
 206                                 fprintf(stderr, "output file write failed\n");
 207                                 goto out_close_fd;
 208                         }
 209                 }
 210                 free_extent_buffer(eb);
 211                 logical += root->sectorsize;
 212                 bytes -= root->sectorsize;
 213         }
 214
 215 out_close_fd:
 216         if (output_file && out_fd != 1)
 217                 close(out_fd);
 218 close:
 219         close_ctree(root);
 220         return ret;
 221 }