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 "utils.h"
  32
  33 /* we write the mirror info to stdout unless they are dumping the data
  34  * to stdout
  35  * */
  36 static FILE *info_file;
  37
  38 static struct extent_buffer * debug_read_block(struct btrfs_root *root,
  39                 u64 bytenr, u32 blocksize, u64 copy)
  40 {
  41         int ret;
  42         struct extent_buffer *eb;
  43         u64 length;
  44         struct btrfs_multi_bio *multi = NULL;
  45         struct btrfs_device *device;
  46         int num_copies;
  47         int mirror_num = 1;
  48
  49         eb = btrfs_find_create_tree_block(root, bytenr, blocksize);
  50         if (!eb)
  51                 return NULL;
  52
  53         length = blocksize;
  54         while (1) {
  55                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
  56                                       eb->start, &length, &multi,
  57                                       mirror_num, NULL);
  58                 if (ret) {
  59                         fprintf(info_file,
  60                                 "Error: fails to map mirror%d logical %llu: %s\n",
  61                                 mirror_num, (unsigned long long)eb->start,
  62                                 strerror(-ret));
  63                         free_extent_buffer(eb);
  64                         return NULL;
  65                 }
  66                 device = multi->stripes[0].dev;
  67                 eb->fd = device->fd;
  68                 device->total_ios++;
  69                 eb->dev_bytenr = multi->stripes[0].physical;
  70
  71                 fprintf(info_file, "mirror %d logical %Lu physical %Lu "
  72                         "device %s\n", mirror_num, (unsigned long long)bytenr,
  73                         (unsigned long long)eb->dev_bytenr, device->name);
  74                 kfree(multi);
  75
  76                 if (!copy || mirror_num == copy) {
  77                         ret = read_extent_from_disk(eb, 0, eb->len);
  78                         if (ret) {
  79                                 fprintf(info_file,
  80                                         "Error: failed to read extent: mirror %d logical %llu: %s\n",
  81                                         mirror_num, (unsigned long long)eb->start,
  82                                         strerror(-ret));
  83                                 free_extent_buffer(eb);
  84                                 eb = NULL;
  85                                 break;
  86                         }
  87                 }
  88
  89                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
  90                                               eb->start, eb->len);
  91                 if (num_copies == 1)
  92                         break;
  93
  94                 mirror_num++;
  95                 if (mirror_num > num_copies)
  96                         break;
  97         }
  98         return eb;
  99 }
 100
 101 static void print_usage(void) __attribute__((noreturn));
 102 static void print_usage(void)
 103 {
 104         fprintf(stderr, "usage: btrfs-map-logical [options] device\n");
 105         fprintf(stderr, "\t-l Logical extent to map\n");
 106         fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
 107         fprintf(stderr, "\t-o Output file to hold the extent\n");
 108         fprintf(stderr, "\t-b Number of bytes to read\n");
 109         exit(1);
 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         u64 copy = 0;
 122         u64 bytes = 0;
 123         int out_fd = 0;
 124
 125         while(1) {
 126                 int c;
 127                 static const struct option long_options[] = {
 128                         /* { "byte-count", 1, NULL, 'b' }, */
 129                         { "logical", 1, NULL, 'l' },
 130                         { "copy", 1, NULL, 'c' },
 131                         { "output", 1, NULL, 'o' },
 132                         { "bytes", 1, NULL, 'b' },
 133                         { NULL, 0, NULL, 0}
 134                 };
 135
 136                 c = getopt_long(ac, av, "l:c:o:b:", long_options, NULL);
 137                 if (c < 0)
 138                         break;
 139                 switch(c) {
 140                         case 'l':
 141                                 logical = arg_strtou64(optarg);
 142                                 break;
 143                         case 'c':
 144                                 copy = arg_strtou64(optarg);
 145                                 break;
 146                         case 'b':
 147                                 bytes = arg_strtou64(optarg);
 148                                 break;
 149                         case 'o':
 150                                 output_file = strdup(optarg);
 151                                 break;
 152                         default:
 153                                 print_usage();
 154                 }
 155         }
 156         set_argv0(av);
 157         ac = ac - optind;
 158         if (check_argc_min(ac, 1))
 159                 print_usage();
 160         if (logical == 0)
 161                 print_usage();
 162
 163         dev = av[optind];
 164
 165         radix_tree_init();
 166         cache_tree_init(&root_cache);
 167
 168         root = open_ctree(dev, 0, 0);
 169         if (!root) {
 170                 fprintf(stderr, "Open ctree failed\n");
 171                 exit(1);
 172         }
 173
 174         info_file = stdout;
 175         if (output_file) {
 176                 if (strcmp(output_file, "-") == 0) {
 177                         out_fd = 1;
 178                         info_file = stderr;
 179                 } else {
 180                         out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
 181                         if (out_fd < 0)
 182                                 goto close;
 183                         ret = ftruncate(out_fd, 0);
 184                         if (ret) {
 185                                 ret = 1;
 186                                 close(out_fd);
 187                                 goto close;
 188                         }
 189                         info_file = stdout;
 190                 }
 191         }
 192
 193         if (bytes == 0)
 194                 bytes = root->sectorsize;
 195
 196         bytes = (bytes + root->sectorsize - 1) / root->sectorsize;
 197         bytes *= root->sectorsize;
 198
 199         while (bytes > 0) {
 200                 eb = debug_read_block(root, logical, root->sectorsize, copy);
 201                 if (eb && output_file) {
 202                         ret = write(out_fd, eb->data, eb->len);
 203                         if (ret < 0 || ret != eb->len) {
 204                                 ret = 1;
 205                                 fprintf(stderr, "output file write failed\n");
 206                                 goto out_close_fd;
 207                         }
 208                 }
 209                 free_extent_buffer(eb);
 210                 logical += root->sectorsize;
 211                 bytes -= root->sectorsize;
 212         }
 213
 214 out_close_fd:
 215         if (output_file && out_fd != 1)
 216                 close(out_fd);
 217 close:
 218         close_ctree(root);
 219         return ret;
 220 }