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 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23 #include <getopt.h>
  24 #include "kerncompat.h"
  25 #include "ctree.h"
  26 #include "volumes.h"
  27 #include "disk-io.h"
  28 #include "print-tree.h"
  29 #include "transaction.h"
  30 #include "list.h"
  31 #include "version.h"
  32 #include "utils.h"
  33
  34 /* we write the mirror info to stdout unless they are dumping the data
  35  * to stdout
  36  * */
  37 static FILE *info_file;
  38
  39 static struct extent_buffer * debug_read_block(struct btrfs_root *root,
  40                 u64 bytenr, u32 blocksize, u64 copy)
  41 {
  42         int ret;
  43         struct extent_buffer *eb;
  44         u64 length;
  45         struct btrfs_multi_bio *multi = NULL;
  46         struct btrfs_device *device;
  47         int num_copies;
  48         int mirror_num = 1;
  49
  50         eb = btrfs_find_create_tree_block(root, bytenr, blocksize);
  51         if (!eb)
  52                 return NULL;
  53
  54         length = blocksize;
  55         while (1) {
  56                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
  57                                       eb->start, &length, &multi,
  58                                       mirror_num, NULL);
  59                 if (ret) {
  60                         fprintf(info_file,
  61                                 "Error: fails to map mirror%d logical %llu: %s\n",
  62                                 mirror_num, (unsigned long long)eb->start,
  63                                 strerror(-ret));
  64                         free_extent_buffer(eb);
  65                         return NULL;
  66                 }
  67                 device = multi->stripes[0].dev;
  68                 eb->fd = device->fd;
  69                 device->total_ios++;
  70                 eb->dev_bytenr = multi->stripes[0].physical;
  71
  72                 fprintf(info_file, "mirror %d logical %Lu physical %Lu "
  73                         "device %s\n", mirror_num, (unsigned long long)bytenr,
  74                         (unsigned long long)eb->dev_bytenr, device->name);
  75                 kfree(multi);
  76
  77                 if (!copy || mirror_num == copy) {
  78                         ret = read_extent_from_disk(eb, 0, eb->len);
  79                         if (ret) {
  80                                 fprintf(info_file,
  81                                         "Error: failed to read extent: mirror %d logical %llu: %s\n",
  82                                         mirror_num, (unsigned long long)eb->start,
  83                                         strerror(-ret));
  84                                 free_extent_buffer(eb);
  85                                 eb = NULL;
  86                                 break;
  87                         }
  88                 }
  89
  90                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  91                                               eb->start, eb->len);
  92                 if (num_copies == 1)
  93                         break;
  94
  95                 mirror_num++;
  96                 if (mirror_num > num_copies)
  97                         break;
  98         }
  99         return eb;
 100 }
 101
 102 static void print_usage(void) __attribute__((noreturn));
 103 static void print_usage(void)
 104 {
 105         fprintf(stderr, "usage: btrfs-map-logical [options] device\n");
 106         fprintf(stderr, "\t-l Logical extent to map\n");
 107         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
 108         fprintf(stderr, "\t-o Output file to hold the extent\n");
 109         fprintf(stderr, "\t-b Number of bytes to read\n");
 110         exit(1);
 111 }
 112
 113 int main(int ac, char **av)
 114 {
 115         struct cache_tree root_cache;
 116         struct btrfs_root *root;
 117         struct extent_buffer *eb;
 118         char *dev;
 119         char *output_file = NULL;
 120         u64 logical = 0;
 121         int ret = 0;
 122         u64 copy = 0;
 123         u64 bytes = 0;
 124         int out_fd = 0;
 125
 126         while(1) {
 127                 int c;
 128                 int option_index = 0;
 129                 static const struct option long_options[] = {
 130                         /* { "byte-count", 1, NULL, 'b' }, */
 131                         { "logical", 1, NULL, 'l' },
 132                         { "copy", 1, NULL, 'c' },
 133                         { "output", 1, NULL, 'o' },
 134                         { "bytes", 1, NULL, 'b' },
 135                         { NULL, 0, NULL, 0}
 136                 };
 137
 138                 c = getopt_long(ac, av, "l:c:o:b:", long_options,
 139                                 &option_index);
 140                 if (c < 0)
 141                         break;
 142                 switch(c) {
 143                         case 'l':
 144                                 logical = arg_strtou64(optarg);
 145                                 break;
 146                         case 'c':
 147                                 copy = arg_strtou64(optarg);
 148                                 break;
 149                         case 'b':
 150                                 bytes = arg_strtou64(optarg);
 151                                 break;
 152                         case 'o':
 153                                 output_file = strdup(optarg);
 154                                 break;
 155                         default:
 156                                 print_usage();
 157                 }
 158         }
 159         set_argv0(av);
 160         ac = ac - optind;
 161         if (check_argc_min(ac, 1))
 162                 print_usage();
 163         if (logical == 0)
 164                 print_usage();
 165
 166         dev = av[optind];
 167
 168         radix_tree_init();
 169         cache_tree_init(&root_cache);
 170
 171         root = open_ctree(dev, 0, 0);
 172         if (!root) {
 173                 fprintf(stderr, "Open ctree failed\n");
 174                 exit(1);
 175         }
 176
 177         info_file = stdout;
 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                         ret = ftruncate(out_fd, 0);
 187                         if (ret) {
 188                                 ret = 1;
 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_read_block(root, logical, root->sectorsize, copy);
 204                 if (eb && output_file) {
 205                         ret = write(out_fd, eb->data, eb->len);
 206                         if (ret < 0 || ret != eb->len) {
 207                                 ret = 1;
 208                                 fprintf(stderr, "output file write failed\n");
 209                                 goto out_close_fd;
 210                         }
 211                 }
 212                 free_extent_buffer(eb);
 213                 logical += root->sectorsize;
 214                 bytes -= root->sectorsize;
 215         }
 216
 217 out_close_fd:
 218         if (output_file && out_fd != 1)
 219                 close(out_fd);
 220 close:
 221         close_ctree(root);
 222         return ret;
 223 }