btrfs-corrupt-block.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_corrupt_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, (unsigned long long)bytenr,
  67                         (unsigned long long)eb->dev_bytenr, device->name);
  68                 kfree(multi);
  69
  70                 if (!copy || mirror_num == copy) {
  71                         ret = read_extent_from_disk(eb);
  72                         printf("corrupting %llu copy %d\n", eb->start,
  73                                mirror_num);
  74                         memset(eb->data, 0, eb->len);
  75                         write_extent_to_disk(eb);
  76                         fsync(eb->fd);
  77                 }
  78
  79                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  80                                               eb->start, eb->len);
  81                 if (num_copies == 1)
  82                         break;
  83
  84                 mirror_num++;
  85                 if (mirror_num > num_copies)
  86                         break;
  87         }
  88         return eb;
  89 }
  90
  91 static void print_usage(void)
  92 {
  93         fprintf(stderr, "usage: btrfs-map-logical [options] mount_point\n");
  94         fprintf(stderr, "\t-l Logical extent to map\n");
  95         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
  96         fprintf(stderr, "\t-o Output file to hold the extent\n");
  97         fprintf(stderr, "\t-b Number of bytes to read\n");
  98         exit(1);
  99 }
 100
 101 static struct option long_options[] = {
 102         /* { "byte-count", 1, NULL, 'b' }, */
 103         { "logical", 1, NULL, 'l' },
 104         { "copy", 1, NULL, 'c' },
 105         { "bytes", 1, NULL, 'b' },
 106         { 0, 0, 0, 0}
 107 };
 108
 109 int main(int ac, char **av)
 110 {
 111         struct cache_tree root_cache;
 112         struct btrfs_root *root;
 113         struct extent_buffer *eb;
 114         char *dev;
 115         char *output_file = NULL;
 116         u64 logical = 0;
 117         int ret = 0;
 118         int option_index = 0;
 119         int copy = 0;
 120         u64 bytes = 4096;
 121         int out_fd = 0;
 122         int err;
 123
 124         while(1) {
 125                 int c;
 126                 c = getopt_long(ac, av, "l:c:", long_options,
 127                                 &option_index);
 128                 if (c < 0)
 129                         break;
 130                 switch(c) {
 131                         case 'l':
 132                                 logical = atoll(optarg);
 133                                 if (logical == 0) {
 134                                         fprintf(stderr,
 135                                                 "invalid extent number\n");
 136                                         print_usage();
 137                                 }
 138                                 break;
 139                         case 'c':
 140                                 copy = atoi(optarg);
 141                                 if (copy == 0) {
 142                                         fprintf(stderr,
 143                                                 "invalid copy number\n");
 144                                         print_usage();
 145                                 }
 146                                 break;
 147                         case 'b':
 148                                 bytes = atoll(optarg);
 149                                 if (bytes == 0) {
 150                                         fprintf(stderr,
 151                                                 "invalid byte count\n");
 152                                         print_usage();
 153                                 }
 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, 1);
 173         if (!root) {
 174                 fprintf(stderr, "Open ctree failed\n");
 175                 exit(1);
 176         }
 177
 178         info_file = stdout;
 179         if (output_file) {
 180                 if (strcmp(output_file, "-") == 0) {
 181                         out_fd = 1;
 182                         info_file = stderr;
 183                 } else {
 184                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 185                         if (out_fd < 0)
 186                                 goto close;
 187                         err = ftruncate(out_fd, 0);
 188                         if (err) {
 189                                 close(out_fd);
 190                                 goto close;
 191                         }
 192                         info_file = stdout;
 193                 }
 194         }
 195
 196         if (bytes == 0)
 197                 bytes = root->sectorsize;
 198
 199         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 200         bytes *= root->sectorsize;
 201
 202         while (bytes > 0) {
 203                 eb = debug_corrupt_block(root, logical, root->sectorsize, copy);
 204                 if (eb && output_file) {
 205                         err = write(out_fd, eb->data, eb->len);
 206                         if (err < 0 || err != eb->len) {
 207                                 fprintf(stderr, "output file write failed\n");
 208                                 goto out_close_fd;
 209                         }
 210                 }
 211                 free_extent_buffer(eb);
 212                 logical += root->sectorsize;
 213                 bytes -= root->sectorsize;
 214         }
 215
 216 out_close_fd:
 217         if (output_file && out_fd != 1)
 218                 close(out_fd);
 219 close:
 220         return ret;
 221 }