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 "disk-io.h"
  27 #include "print-tree.h"
  28 #include "transaction.h"
  29 #include "list.h"
  30 #include "utils.h"
  31
  32 static void print_usage(void)
  33 {
  34         fprintf(stderr, "usage: btrfs-select-super -s number dev\n");
  35         fprintf(stderr, "%s\n", PACKAGE_STRING);
  36         exit(1);
  37 }
  38
  39 int main(int ac, char **av)
  40 {
  41         struct btrfs_root *root;
  42         int ret;
  43         u64 num = 0;
  44         u64 bytenr = 0;
  45
  46         while(1) {
  47                 int c;
  48                 c = getopt(ac, av, "s:");
  49                 if (c < 0)
  50                         break;
  51                 switch(c) {
  52                         case 's':
  53                                 num = arg_strtou64(optarg);
  54                                 if (num >= BTRFS_SUPER_MIRROR_MAX) {
  55                                         fprintf(stderr,
  56                                                 "ERROR: super mirror should be less than: %d\n",
  57                                                 BTRFS_SUPER_MIRROR_MAX);
  58                                         exit(1);
  59                                 }
  60                                 bytenr = btrfs_sb_offset(((int)num));
  61                                 break;
  62                         default:
  63                                 print_usage();
  64                 }
  65         }
  66         set_argv0(av);
  67         ac = ac - optind;
  68
  69         if (check_argc_exact(ac, 1))
  70                 print_usage();
  71
  72         if (bytenr == 0) {
  73                 fprintf(stderr, "Please select the super copy with -s\n");
  74                 print_usage();
  75         }
  76
  77         radix_tree_init();
  78
  79         if((ret = check_mounted(av[optind])) < 0) {
  80                 fprintf(stderr, "Could not check mount status: %s\n", strerror(-ret));
  81                 return ret;
  82         } else if(ret) {
  83                 fprintf(stderr, "%s is currently mounted. Aborting.\n", av[optind]);
  84                 return -EBUSY;
  85         }
  86
  87         root = open_ctree(av[optind], bytenr, 1);
  88
  89         if (!root) {
  90                 fprintf(stderr, "Open ctree failed\n");
  91                 return 1;
  92         }
  93
  94         /* make the super writing code think we've read the first super */
  95         root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
  96         ret = write_all_supers(root);
  97
  98         /* we don't close the ctree or anything, because we don't want a real
  99          * transaction commit.  We just want the super copy we pulled off the
 100          * disk to overwrite all the other copies
 101          */
 102         printf("using SB copy %llu, bytenr %llu\n", (unsigned long long)num,
 103                (unsigned long long)bytenr);
 104         return ret;
 105 }