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 #include "utils.h"
  35
  36 /* we write the mirror info to stdout unless they are dumping the data
  37  * to stdout
  38  * */
  39 static FILE *info_file;
  40
  41 static struct extent_buffer * debug_read_block(struct btrfs_root *root,
  42                 u64 bytenr, u32 blocksize, u64 copy)
  43 {
  44         int ret;
  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         length = blocksize;
  57         while (1) {
  58                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
  59                                       eb->start, &length, &multi,
  60                                       mirror_num, NULL);
  61                 if (ret) {
  62                         fprintf(info_file,
  63                                 "Error: fails to map mirror%d logical %llu: %s\n",
  64                                 mirror_num, (unsigned long long)eb->start,
  65                                 strerror(-ret));
  66                         free_extent_buffer(eb);
  67                         return NULL;
  68                 }
  69                 device = multi->stripes[0].dev;
  70                 eb->fd = device->fd;
  71                 device->total_ios++;
  72                 eb->dev_bytenr = multi->stripes[0].physical;
  73
  74                 fprintf(info_file, "mirror %d logical %Lu physical %Lu "
  75                         "device %s\n", mirror_num, (unsigned long long)bytenr,
  76                         (unsigned long long)eb->dev_bytenr, device->name);
  77                 kfree(multi);
  78
  79                 if (!copy || mirror_num == copy) {
  80                         ret = read_extent_from_disk(eb, 0, eb->len);
  81                         if (ret) {
  82                                 fprintf(info_file,
  83                                         "Error: failed to read extent: mirror %d logical %llu: %s\n",
  84                                         mirror_num, (unsigned long long)eb->start,
  85                                         strerror(-ret));
  86                                 free_extent_buffer(eb);
  87                                 eb = NULL;
  88                                 break;
  89                         }
  90                 }
  91
  92                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  93                                               eb->start, eb->len);
  94                 if (num_copies == 1)
  95                         break;
  96
  97                 mirror_num++;
  98                 if (mirror_num > num_copies)
  99                         break;
 100         }
 101         return eb;
 102 }
 103
 104 static void print_usage(void) __attribute__((noreturn));
 105 static void print_usage(void)
 106 {
 107         fprintf(stderr, "usage: btrfs-map-logical [options] device\n");
 108         fprintf(stderr, "\t-l Logical extent to map\n");
 109         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
 110         fprintf(stderr, "\t-o Output file to hold the extent\n");
 111         fprintf(stderr, "\t-b Number of bytes to read\n");
 112         exit(1);
 113 }
 114
 115 int main(int ac, char **av)
 116 {
 117         struct cache_tree root_cache;
 118         struct btrfs_root *root;
 119         struct extent_buffer *eb;
 120         char *dev;
 121         char *output_file = NULL;
 122         u64 logical = 0;
 123         int ret = 0;
 124         u64 copy = 0;
 125         u64 bytes = 0;
 126         int out_fd = 0;
 127
 128         while(1) {
 129                 int c;
 130                 int option_index = 0;
 131                 static const struct option long_options[] = {
 132                         /* { "byte-count", 1, NULL, 'b' }, */
 133                         { "logical", 1, NULL, 'l' },
 134                         { "copy", 1, NULL, 'c' },
 135                         { "output", 1, NULL, 'o' },
 136                         { "bytes", 1, NULL, 'b' },
 137                         { NULL, 0, NULL, 0}
 138                 };
 139
 140                 c = getopt_long(ac, av, "l:c:o:b:", long_options,
 141                                 &option_index);
 142                 if (c < 0)
 143                         break;
 144                 switch(c) {
 145                         case 'l':
 146                                 logical = arg_strtou64(optarg);
 147                                 break;
 148                         case 'c':
 149                                 copy = arg_strtou64(optarg);
 150                                 break;
 151                         case 'b':
 152                                 bytes = arg_strtou64(optarg);
 153                                 break;
 154                         case 'o':
 155                                 output_file = strdup(optarg);
 156                                 break;
 157                         default:
 158                                 print_usage();
 159                 }
 160         }
 161         set_argv0(av);
 162         ac = ac - optind;
 163         if (check_argc_min(ac, 1))
 164                 print_usage();
 165         if (logical == 0)
 166                 print_usage();
 167
 168         dev = av[optind];
 169
 170         radix_tree_init();
 171         cache_tree_init(&root_cache);
 172
 173         root = open_ctree(dev, 0, 0);
 174         if (!root) {
 175                 fprintf(stderr, "Open ctree failed\n");
 176                 exit(1);
 177         }
 178
 179         info_file = stdout;
 180         if (output_file) {
 181                 if (strcmp(output_file, "-") == 0) {
 182                         out_fd = 1;
 183                         info_file = stderr;
 184                 } else {
 185                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 186                         if (out_fd < 0)
 187                                 goto close;
 188                         ret = ftruncate(out_fd, 0);
 189                         if (ret) {
 190                                 ret = 1;
 191                                 close(out_fd);
 192                                 goto close;
 193                         }
 194                         info_file = stdout;
 195                 }
 196         }
 197
 198         if (bytes == 0)
 199                 bytes = root->sectorsize;
 200
 201         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 202         bytes *= root->sectorsize;
 203
 204         while (bytes > 0) {
 205                 eb = debug_read_block(root, logical, root->sectorsize, copy);
 206                 if (eb && output_file) {
 207                         ret = write(out_fd, eb->data, eb->len);
 208                         if (ret < 0 || ret != eb->len) {
 209                                 ret = 1;
 210                                 fprintf(stderr, "output file write failed\n");
 211                                 goto out_close_fd;
 212                         }
 213                 }
 214                 free_extent_buffer(eb);
 215                 logical += root->sectorsize;
 216                 bytes -= root->sectorsize;
 217         }
 218
 219 out_close_fd:
 220         if (output_file && out_fd != 1)
 221                 close(out_fd);
 222 close:
 223         close_ctree(root);
 224         return ret;
 225 }