mirror of
https://github.com/kdave/btrfs-progs
synced 2024-12-14 10:25:27 +00:00
b4382217f1
Btrfs stores multiple copies of the superblock, and for common power-failure crashes where barriers were not in use, one of the super copies is often valid while the first copy is not. This adds a btrfs-select-super -s N /dev/xxx command, which can overwrite all the super blocks with a copy that you have already determined is valid with btrfsck -s Signed-off-by: Chris Mason <chris.mason@oracle.com>
100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#define _XOPEN_SOURCE 500
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#define _GNU_SOURCE 1
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include "kerncompat.h"
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#include "ctree.h"
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#include "disk-io.h"
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#include "print-tree.h"
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#include "transaction.h"
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#include "list.h"
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#include "version.h"
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#include "utils.h"
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static void print_usage(void)
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{
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fprintf(stderr, "usage: btrfs-select-super -s number dev\n");
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fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
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exit(1);
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}
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int main(int ac, char **av)
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{
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struct btrfs_root *root;
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int ret;
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int num;
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u64 bytenr = 0;
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while(1) {
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int c;
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c = getopt(ac, av, "s:");
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if (c < 0)
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break;
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switch(c) {
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case 's':
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num = atol(optarg);
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bytenr = btrfs_sb_offset(num);
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printf("using SB copy %d, bytenr %llu\n", num,
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(unsigned long long)bytenr);
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break;
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default:
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print_usage();
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}
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}
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ac = ac - optind;
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if (ac != 1)
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print_usage();
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if (bytenr == 0) {
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fprintf(stderr, "Please select the super copy with -s\n");
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print_usage();
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}
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radix_tree_init();
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if((ret = check_mounted(av[optind])) < 0) {
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fprintf(stderr, "Could not check mount status: %s\n", strerror(ret));
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return ret;
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} else if(ret) {
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fprintf(stderr, "%s is currently mounted. Aborting.\n", av[optind]);
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return -EBUSY;
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}
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root = open_ctree(av[optind], bytenr, 1);
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if (root == NULL)
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return 1;
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/* make the super writing code think we've read the first super */
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root->fs_info->super_bytenr = BTRFS_SUPER_INFO_OFFSET;
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ret = write_all_supers(root);
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/* we don't close the ctree or anything, because we don't want a real
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* transaction commit. We just want the super copy we pulled off the
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* disk to overwrite all the other copies
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*/
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return ret;
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}
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