btrfs-progs: convert-tests: Add test for backup superblock migration
[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
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 }