btrfs-select-super.c

   1 /*
   2  * Copyright (C) 2007 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 <unistd.h>
  22 #include <fcntl.h>
  23 #include <sys/stat.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 static void print_usage(void)
  34 {
  35         fprintf(stderr, "usage: btrfs-select-super -s number dev\n");
  36         fprintf(stderr, "%s\n", PACKAGE_STRING);
  37         exit(1);
  38 }
  39
  40 int main(int argc, char **argv)
  41 {
  42         struct btrfs_root *root;
  43         int ret;
  44         u64 num = 0;
  45         u64 bytenr = 0;
  46
  47         while(1) {
  48                 int c;
  49                 c = getopt(argc, argv, "s:");
  50                 if (c < 0)
  51                         break;
  52                 switch(c) {
  53                         case 's':
  54                                 num = arg_strtou64(optarg);
  55                                 if (num >= BTRFS_SUPER_MIRROR_MAX) {
  56                                         fprintf(stderr,
  57                                                 "ERROR: super mirror should be less than: %d\n",
  58                                                 BTRFS_SUPER_MIRROR_MAX);
  59                                         exit(1);
  60                                 }
  61                                 bytenr = btrfs_sb_offset(((int)num));
  62                                 break;
  63                         default:
  64                                 print_usage();
  65                 }
  66         }
  67         set_argv0(argv);
  68         if (check_argc_exact(argc - optind, 1))
  69                 print_usage();
  70
  71         if (bytenr == 0) {
  72                 fprintf(stderr, "Please select the super copy with -s\n");
  73                 print_usage();
  74         }
  75
  76         radix_tree_init();
  77
  78         if((ret = check_mounted(argv[optind])) < 0) {
  79                 error("cannot check mount status: %s", strerror(-ret));
  80                 return ret;
  81         } else if(ret) {
  82                 error("%s is currently mounted, aborting", argv[optind]);
  83                 return -EBUSY;
  84         }
  85
  86         root = open_ctree(argv[optind], bytenr, 1);
  87
  88         if (!root) {
  89                 fprintf(stderr, "Open ctree failed\n");
  90                 return 1;
  91         }
  92
  93         /* make the super writing code think we've read the first super */
  94         root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
  95         ret = write_all_supers(root);
  96
  97         /* we don't close the ctree or anything, because we don't want a real
  98          * transaction commit.  We just want the super copy we pulled off the
  99          * disk to overwrite all the other copies
 100          */
 101         printf("using SB copy %llu, bytenr %llu\n", (unsigned long long)num,
 102                (unsigned long long)bytenr);
 103         close_ctree(root);
 104         btrfs_close_all_devices();
 105         return ret;
 106 }