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 static struct extent_buffer * debug_read_block(struct btrfs_root *root,
  41                 u64 bytenr, 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,
  59                                       mirror_num, NULL);
  60                 if (ret) {
  61                         fprintf(info_file,
  62                                 "Error: fails to map mirror%d logical %llu: %s\n",
  63                                 mirror_num, (unsigned long long)eb->start,
  64                                 strerror(-ret));
  65                         free_extent_buffer(eb);
  66                         return NULL;
  67                 }
  68                 device = multi->stripes[0].dev;
  69                 eb->fd = device->fd;
  70                 device->total_ios++;
  71                 eb->dev_bytenr = multi->stripes[0].physical;
  72
  73                 fprintf(info_file, "mirror %d logical %Lu physical %Lu "
  74                         "device %s\n", mirror_num, (unsigned long long)bytenr,
  75                         (unsigned long long)eb->dev_bytenr, device->name);
  76                 kfree(multi);
  77
  78                 if (!copy || mirror_num == copy)
  79                         ret = read_extent_from_disk(eb, 0, eb->len);
  80
  81                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  82                                               eb->start, eb->len);
  83                 if (num_copies == 1)
  84                         break;
  85
  86                 mirror_num++;
  87                 if (mirror_num > num_copies)
  88                         break;
  89         }
  90         return eb;
  91 }
  92
  93 static void print_usage(void)
  94 {
  95         fprintf(stderr, "usage: btrfs-map-logical [options] device\n");
  96         fprintf(stderr, "\t-l Logical extent to map\n");
  97         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
  98         fprintf(stderr, "\t-o Output file to hold the extent\n");
  99         fprintf(stderr, "\t-b Number of bytes to read\n");
 100         exit(1);
 101 }
 102
 103 static struct option long_options[] = {
 104         /* { "byte-count", 1, NULL, 'b' }, */
 105         { "logical", 1, NULL, 'l' },
 106         { "copy", 1, NULL, 'c' },
 107         { "output", 1, NULL, 'o' },
 108         { "bytes", 1, NULL, 'b' },
 109         { 0, 0, 0, 0}
 110 };
 111
 112 int main(int ac, char **av)
 113 {
 114         struct cache_tree root_cache;
 115         struct btrfs_root *root;
 116         struct extent_buffer *eb;
 117         char *dev;
 118         char *output_file = NULL;
 119         u64 logical = 0;
 120         int ret = 0;
 121         int option_index = 0;
 122         int copy = 0;
 123         u64 bytes = 0;
 124         int out_fd = 0;
 125
 126         while(1) {
 127                 int c;
 128                 c = getopt_long(ac, av, "l:c:o:b:", long_options,
 129                                 &option_index);
 130                 if (c < 0)
 131                         break;
 132                 switch(c) {
 133                         case 'l':
 134                                 logical = atoll(optarg);
 135                                 if (logical == 0) {
 136                                         fprintf(stderr,
 137                                                 "invalid extent number\n");
 138                                         print_usage();
 139                                 }
 140                                 break;
 141                         case 'c':
 142                                 copy = atoi(optarg);
 143                                 if (copy == 0) {
 144                                         fprintf(stderr,
 145                                                 "invalid copy number\n");
 146                                         print_usage();
 147                                 }
 148                                 break;
 149                         case 'b':
 150                                 bytes = atoll(optarg);
 151                                 if (bytes == 0) {
 152                                         fprintf(stderr,
 153                                                 "invalid byte count\n");
 154                                         print_usage();
 155                                 }
 156                                 break;
 157                         case 'o':
 158                                 output_file = strdup(optarg);
 159                                 break;
 160                         default:
 161                                 print_usage();
 162                 }
 163         }
 164         ac = ac - optind;
 165         if (ac == 0)
 166                 print_usage();
 167         if (logical == 0)
 168                 print_usage();
 169         if (copy < 0)
 170                 print_usage();
 171
 172         dev = av[optind];
 173
 174         radix_tree_init();
 175         cache_tree_init(&root_cache);
 176
 177         root = open_ctree(dev, 0, 0);
 178         if (!root) {
 179                 fprintf(stderr, "Open ctree failed\n");
 180                 exit(1);
 181         }
 182
 183         info_file = stdout;
 184         if (output_file) {
 185                 if (strcmp(output_file, "-") == 0) {
 186                         out_fd = 1;
 187                         info_file = stderr;
 188                 } else {
 189                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 190                         if (out_fd < 0)
 191                                 goto close;
 192                         ret = ftruncate(out_fd, 0);
 193                         if (ret) {
 194                                 ret = 1;
 195                                 close(out_fd);
 196                                 goto close;
 197                         }
 198                         info_file = stdout;
 199                 }
 200         }
 201
 202         if (bytes == 0)
 203                 bytes = root->sectorsize;
 204
 205         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 206         bytes *= root->sectorsize;
 207
 208         while (bytes > 0) {
 209                 eb = debug_read_block(root, logical, root->sectorsize, copy);
 210                 if (eb && output_file) {
 211                         ret = write(out_fd, eb->data, eb->len);
 212                         if (ret < 0 || ret != eb->len) {
 213                                 ret = 1;
 214                                 fprintf(stderr, "output file write failed\n");
 215                                 goto out_close_fd;
 216                         }
 217                 }
 218                 free_extent_buffer(eb);
 219                 logical += root->sectorsize;
 220                 bytes -= root->sectorsize;
 221         }
 222
 223 out_close_fd:
 224         if (output_file && out_fd != 1)
 225                 close(out_fd);
 226 close:
 227         close_ctree(root);
 228         return ret;
 229 }