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         struct extent_buffer *eb;
  45         u64 length;
  46         struct btrfs_multi_bio *multi = NULL;
  47         struct btrfs_device *device;
  48         int num_copies;
  49         int mirror_num = 1;
  50
  51         eb = btrfs_find_create_tree_block(root, bytenr, blocksize);
  52         if (!eb)
  53                 return NULL;
  54
  55         length = blocksize;
  56         while (1) {
  57                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
  58                                       eb->start, &length, &multi, mirror_num);
  59                 BUG_ON(ret);
  60                 device = multi->stripes[0].dev;
  61                 eb->fd = device->fd;
  62                 device->total_ios++;
  63                 eb->dev_bytenr = multi->stripes[0].physical;
  64
  65                 fprintf(info_file, "mirror %d logical %Lu physical %Lu "
  66                         "device %s\n", mirror_num, bytenr, eb->dev_bytenr,
  67                         device->name);
  68                 kfree(multi);
  69
  70                 if (!copy || mirror_num == copy)
  71                         ret = read_extent_from_disk(eb);
  72
  73                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  74                                               eb->start, eb->len);
  75                 if (num_copies == 1)
  76                         break;
  77
  78                 mirror_num++;
  79                 if (mirror_num > num_copies)
  80                         break;
  81         }
  82         return eb;
  83 }
  84
  85 static void print_usage(void)
  86 {
  87         fprintf(stderr, "usage: btrfs-map-logical [options] mount_point\n");
  88         fprintf(stderr, "\t-l Logical extent to map\n");
  89         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
  90         fprintf(stderr, "\t-o Output file to hold the extent\n");
  91         fprintf(stderr, "\t-b Number of bytes to read\n");
  92         exit(1);
  93 }
  94
  95 static struct option long_options[] = {
  96         /* { "byte-count", 1, NULL, 'b' }, */
  97         { "logical", 1, NULL, 'l' },
  98         { "copy", 1, NULL, 'c' },
  99         { "output", 1, NULL, 'c' },
 100         { "bytes", 1, NULL, 'b' },
 101         { 0, 0, 0, 0}
 102 };
 103
 104 int main(int ac, char **av)
 105 {
 106         struct cache_tree root_cache;
 107         struct btrfs_root *root;
 108         struct extent_buffer *eb;
 109         char *dev;
 110         char *output_file = NULL;
 111         u64 logical = 0;
 112         int ret = 0;
 113         int option_index = 0;
 114         int copy = 0;
 115         u64 bytes = 0;
 116         int out_fd = 0;
 117         int err;
 118
 119         while(1) {
 120                 int c;
 121                 c = getopt_long(ac, av, "l:c:o:b:", long_options,
 122                                 &option_index);
 123                 if (c < 0)
 124                         break;
 125                 switch(c) {
 126                         case 'l':
 127                                 logical = atoll(optarg);
 128                                 if (logical == 0) {
 129                                         fprintf(stderr,
 130                                                 "invalid extent number\n");
 131                                         print_usage();
 132                                 }
 133                                 break;
 134                         case 'c':
 135                                 copy = atoi(optarg);
 136                                 if (copy == 0) {
 137                                         fprintf(stderr,
 138                                                 "invalid copy number\n");
 139                                         print_usage();
 140                                 }
 141                                 break;
 142                         case 'b':
 143                                 bytes = atoll(optarg);
 144                                 if (bytes == 0) {
 145                                         fprintf(stderr,
 146                                                 "invalid byte count\n");
 147                                         print_usage();
 148                                 }
 149                                 break;
 150                         case 'o':
 151                                 output_file = strdup(optarg);
 152                                 break;
 153                         default:
 154                                 print_usage();
 155                 }
 156         }
 157         ac = ac - optind;
 158         if (ac == 0)
 159                 print_usage();
 160         if (logical == 0)
 161                 print_usage();
 162         if (copy < 0)
 163                 print_usage();
 164
 165         dev = av[optind];
 166
 167         radix_tree_init();
 168         cache_tree_init(&root_cache);
 169
 170         root = open_ctree(dev, 0, 0);
 171         if (!root) {
 172                 fprintf(stderr, "Open ctree failed\n");
 173                 exit(1);
 174         }
 175
 176         if (output_file) {
 177                 if (strcmp(output_file, "-") == 0) {
 178                         out_fd = 1;
 179                         info_file = stderr;
 180                 } else {
 181                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 182                         if (out_fd < 0)
 183                                 goto close;
 184                         err = ftruncate(out_fd, 0);
 185                         if (err) {
 186                                 close(out_fd);
 187                                 goto close;
 188                         }
 189                         info_file = stdout;
 190                 }
 191         }
 192
 193         if (bytes == 0)
 194                 bytes = root->sectorsize;
 195
 196         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 197         bytes *= root->sectorsize;
 198
 199         while (bytes > 0) {
 200                 eb = debug_read_block(root, logical, root->sectorsize, copy);
 201                 if (eb && output_file) {
 202                         err = write(out_fd, eb->data, eb->len);
 203                         if (err < 0 || err != eb->len) {
 204                                 fprintf(stderr, "output file write failed\n");
 205                                 goto out_close_fd;
 206                         }
 207                 }
 208                 free_extent_buffer(eb);
 209                 logical += root->sectorsize;
 210                 bytes -= root->sectorsize;
 211         }
 212
 213 out_close_fd:
 214         if (output_file && out_fd != 1)
 215                 close(out_fd);
 216 close:
 217         close_ctree(root);
 218         return ret;
 219 }