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
  82                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  83                                               eb->start, eb->len);
  84                 if (num_copies == 1)
  85                         break;
  86
  87                 mirror_num++;
  88                 if (mirror_num > num_copies)
  89                         break;
  90         }
  91         return eb;
  92 }
  93
  94 static void print_usage(void) __attribute__((noreturn));
  95 static void print_usage(void)
  96 {
  97         fprintf(stderr, "usage: btrfs-map-logical [options] device\n");
  98         fprintf(stderr, "\t-l Logical extent to map\n");
  99         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
 100         fprintf(stderr, "\t-o Output file to hold the extent\n");
 101         fprintf(stderr, "\t-b Number of bytes to read\n");
 102         exit(1);
 103 }
 104
 105 static struct option long_options[] = {
 106         /* { "byte-count", 1, NULL, 'b' }, */
 107         { "logical", 1, NULL, 'l' },
 108         { "copy", 1, NULL, 'c' },
 109         { "output", 1, NULL, 'o' },
 110         { "bytes", 1, NULL, 'b' },
 111         { NULL, 0, NULL, 0}
 112 };
 113
 114 int main(int ac, char **av)
 115 {
 116         struct cache_tree root_cache;
 117         struct btrfs_root *root;
 118         struct extent_buffer *eb;
 119         char *dev;
 120         char *output_file = NULL;
 121         u64 logical = 0;
 122         int ret = 0;
 123         int option_index = 0;
 124         u64 copy = 0;
 125         u64 bytes = 0;
 126         int out_fd = 0;
 127
 128         while(1) {
 129                 int c;
 130                 c = getopt_long(ac, av, "l:c:o:b:", long_options,
 131                                 &option_index);
 132                 if (c < 0)
 133                         break;
 134                 switch(c) {
 135                         case 'l':
 136                                 logical = arg_strtou64(optarg);
 137                                 break;
 138                         case 'c':
 139                                 copy = arg_strtou64(optarg);
 140                                 break;
 141                         case 'b':
 142                                 bytes = arg_strtou64(optarg);
 143                                 break;
 144                         case 'o':
 145                                 output_file = strdup(optarg);
 146                                 break;
 147                         default:
 148                                 print_usage();
 149                 }
 150         }
 151         ac = ac - optind;
 152         if (ac == 0)
 153                 print_usage();
 154         if (logical == 0)
 155                 print_usage();
 156
 157         dev = av[optind];
 158
 159         radix_tree_init();
 160         cache_tree_init(&root_cache);
 161
 162         root = open_ctree(dev, 0, 0);
 163         if (!root) {
 164                 fprintf(stderr, "Open ctree failed\n");
 165                 exit(1);
 166         }
 167
 168         info_file = stdout;
 169         if (output_file) {
 170                 if (strcmp(output_file, "-") == 0) {
 171                         out_fd = 1;
 172                         info_file = stderr;
 173                 } else {
 174                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 175                         if (out_fd < 0)
 176                                 goto close;
 177                         ret = ftruncate(out_fd, 0);
 178                         if (ret) {
 179                                 ret = 1;
 180                                 close(out_fd);
 181                                 goto close;
 182                         }
 183                         info_file = stdout;
 184                 }
 185         }
 186
 187         if (bytes == 0)
 188                 bytes = root->sectorsize;
 189
 190         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 191         bytes *= root->sectorsize;
 192
 193         while (bytes > 0) {
 194                 eb = debug_read_block(root, logical, root->sectorsize, copy);
 195                 if (eb && output_file) {
 196                         ret = write(out_fd, eb->data, eb->len);
 197                         if (ret < 0 || ret != eb->len) {
 198                                 ret = 1;
 199                                 fprintf(stderr, "output file write failed\n");
 200                                 goto out_close_fd;
 201                         }
 202                 }
 203                 free_extent_buffer(eb);
 204                 logical += root->sectorsize;
 205                 bytes -= root->sectorsize;
 206         }
 207
 208 out_close_fd:
 209         if (output_file && out_fd != 1)
 210                 close(out_fd);
 211 close:
 212         close_ctree(root);
 213         return ret;
 214 }