btrfs-progs/btrfs-select-super.c

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/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include "kerncompat.h"
#include "ctree.h"
#include "volumes.h"
#include "disk-io.h"
#include "print-tree.h"
#include "transaction.h"
#include "list.h"
#include "common/utils.h"
#include "common/help.h"
static void print_usage(void)
{
printf("usage: btrfs-select-super -s number dev\n");
printf("\t-s super copy of superblock to overwrite the primary one (values: 1, 2)\n");
exit(1);
}
int main(int argc, char **argv)
{
struct btrfs_root *root;
int ret;
u64 num = 0;
u64 bytenr = 0;
while(1) {
int c;
c = getopt(argc, argv, "s:");
if (c < 0)
break;
switch(c) {
case 's':
num = arg_strtou64(optarg);
if (num >= BTRFS_SUPER_MIRROR_MAX) {
fprintf(stderr,
"ERROR: super mirror should be less than: %d\n",
BTRFS_SUPER_MIRROR_MAX);
exit(1);
}
bytenr = btrfs_sb_offset(((int)num));
break;
default:
print_usage();
}
}
set_argv0(argv);
if (check_argc_exact(argc - optind, 1))
return 1;
if (bytenr == 0) {
fprintf(stderr, "Please select the super copy with -s\n");
print_usage();
}
radix_tree_init();
if((ret = check_mounted(argv[optind])) < 0) {
errno = -ret;
error("cannot check mount status: %m");
return ret;
} else if(ret) {
error("%s is currently mounted, aborting", argv[optind]);
return -EBUSY;
}
root = open_ctree(argv[optind], bytenr, 1);
if (!root) {
fprintf(stderr, "Open ctree failed\n");
return 1;
}
/* make the super writing code think we've read the first super */
root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
ret = write_all_supers(root->fs_info);
/* we don't close the ctree or anything, because we don't want a real
* transaction commit. We just want the super copy we pulled off the
* disk to overwrite all the other copies
*/
printf("using SB copy %llu, bytenr %llu\n", (unsigned long long)num,
(unsigned long long)bytenr);
close_ctree(root);
btrfs_close_all_devices();
return ret;
}