e021221e286d20218c84a9c7e7605c55e4526a0b
[platform/upstream/btrfs-progs.git] / 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 #include "help.h"
33
34 static void print_usage(void)
35 {
36         printf("usage: btrfs-select-super -s number dev\n");
37         printf("\t-s super   copy of superbloc to overwrite the primary one (values: 1, 2)\n");
38         exit(1);
39 }
40
41 int main(int argc, char **argv)
42 {
43         struct btrfs_root *root;
44         int ret;
45         u64 num = 0;
46         u64 bytenr = 0;
47
48         while(1) {
49                 int c;
50                 c = getopt(argc, argv, "s:");
51                 if (c < 0)
52                         break;
53                 switch(c) {
54                         case 's':
55                                 num = arg_strtou64(optarg);
56                                 if (num >= BTRFS_SUPER_MIRROR_MAX) {
57                                         fprintf(stderr,
58                                                 "ERROR: super mirror should be less than: %d\n",
59                                                 BTRFS_SUPER_MIRROR_MAX);
60                                         exit(1);
61                                 }
62                                 bytenr = btrfs_sb_offset(((int)num));
63                                 break;
64                         default:
65                                 print_usage();
66                 }
67         }
68         set_argv0(argv);
69         if (check_argc_exact(argc - optind, 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(argv[optind])) < 0) {
80                 error("cannot check mount status: %s", strerror(-ret));
81                 return ret;
82         } else if(ret) {
83                 error("%s is currently mounted, aborting", argv[optind]);
84                 return -EBUSY;
85         }
86
87         root = open_ctree(argv[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->fs_info);
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         close_ctree(root);
105         btrfs_close_all_devices();
106         return ret;
107 }