btrfs-progs/btrfs-find-root.c

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/*
* Copyright (C) 2011 Red Hat. 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 <zlib.h>
#include <getopt.h>
#include "kerncompat.h"
#include "ctree.h"
#include "disk-io.h"
#include "print-tree.h"
#include "transaction.h"
#include "list.h"
#include "volumes.h"
#include "utils.h"
#include "crc32c.h"
#include "extent-cache.h"
#include "find-root.h"
static void usage(void)
{
fprintf(stderr, "Usage: find-roots [-a] [-o search_objectid] "
"[ -g search_generation ] [ -l search_level ] <device>\n");
}
/*
* Get reliable generation and level for given root.
*
* We have two sources of gen/level: superblock and tree root.
* superblock include the following level:
* Root, chunk, log
* and the following generations:
* Root, chunk, uuid
* Other gen/leven can only be read from its btrfs_tree_root if possible.
*
* Currently we only believe things from superblock.
*/
static void get_root_gen_and_level(u64 objectid, struct btrfs_fs_info *fs_info,
u64 *ret_gen, u8 *ret_level)
{
struct btrfs_super_block *super = fs_info->super_copy;
u64 gen = (u64)-1;
u8 level = (u8)-1;
switch (objectid) {
case BTRFS_ROOT_TREE_OBJECTID:
level = btrfs_super_root_level(super);
gen = btrfs_super_generation(super);
break;
case BTRFS_CHUNK_TREE_OBJECTID:
level = btrfs_super_chunk_root_level(super);
gen = btrfs_super_chunk_root_generation(super);
printf("Search for chunk root is not supported yet\n");
break;
case BTRFS_TREE_LOG_OBJECTID:
level = btrfs_super_log_root_level(super);
gen = btrfs_super_log_root_transid(super);
break;
case BTRFS_UUID_TREE_OBJECTID:
gen = btrfs_super_uuid_tree_generation(super);
break;
}
if (gen != (u64)-1) {
printf("Superblock thinks the generation is %llu\n", gen);
if (ret_gen)
*ret_gen = gen;
} else {
printf("Superblock doesn't contain generation info for root %llu\n",
objectid);
}
if (level != (u8)-1) {
printf("Superblock thinks the level is %u\n", level);
if (ret_level)
*ret_level = level;
} else {
printf("Superblock doesn't contain the level info for root %llu\n",
objectid);
}
}
static void print_one_result(struct cache_extent *tree_block,
u8 level, u64 generation,
struct btrfs_find_root_filter *filter)
{
int unsure = 0;
if (filter->match_gen == (u64)-1 || filter->match_level == (u8)-1)
unsure = 1;
printf("Well block %llu(gen: %llu level: %u) seems good, ",
tree_block->start, generation, level);
if (unsure)
printf("but we are unsure about the correct generation/level\n");
else if (level == filter->match_level &&
generation == filter->match_gen)
printf("and it matches superblock\n");
else
printf("but generation/level doesn't match, want gen: %llu level: %u\n",
filter->match_gen, filter->match_level);
}
static void print_find_root_result(struct cache_tree *result,
struct btrfs_find_root_filter *filter)
{
struct btrfs_find_root_gen_cache *gen_cache;
struct cache_extent *cache;
struct cache_extent *tree_block;
u64 generation = 0;
u8 level = 0;
for (cache = last_cache_extent(result);
cache; cache = prev_cache_extent(cache)) {
gen_cache = container_of(cache,
struct btrfs_find_root_gen_cache, cache);
level = gen_cache->highest_level;
generation = cache->start;
/* For exact found one, skip it as it's output before */
if (level == filter->match_level &&
generation == filter->match_gen &&
!filter->search_all)
continue;
for (tree_block = last_cache_extent(&gen_cache->eb_tree);
tree_block; tree_block = prev_cache_extent(tree_block))
print_one_result(tree_block, level, generation, filter);
}
}
int main(int argc, char **argv)
{
struct btrfs_root *root;
struct btrfs_find_root_filter filter = {0};
struct cache_tree result;
struct cache_extent *found;
int ret;
/* Default to search root tree */
filter.objectid = BTRFS_ROOT_TREE_OBJECTID;
filter.match_gen = (u64)-1;
filter.match_level = (u8)-1;
while (1) {
static const struct option long_options[] = {
{ "help", no_argument, NULL, GETOPT_VAL_HELP},
{ NULL, 0, NULL, 0 }
};
int c = getopt_long(argc, argv, "al:o:g:", long_options, NULL);
if (c < 0)
break;
switch (c) {
case 'a':
filter.search_all = 1;
break;
case 'o':
filter.objectid = arg_strtou64(optarg);
break;
case 'g':
filter.generation = arg_strtou64(optarg);
break;
case 'l':
filter.level = arg_strtou64(optarg);
break;
case GETOPT_VAL_HELP:
default:
usage();
exit(c != GETOPT_VAL_HELP);
}
}
set_argv0(argv);
argc = argc - optind;
if (check_argc_min(argc, 1)) {
usage();
exit(1);
}
root = open_ctree(argv[optind], 0, OPEN_CTREE_CHUNK_ROOT_ONLY);
if (!root) {
fprintf(stderr, "Open ctree failed\n");
exit(1);
}
cache_tree_init(&result);
get_root_gen_and_level(filter.objectid, root->fs_info,
&filter.match_gen, &filter.match_level);
ret = btrfs_find_root_search(root, &filter, &result, &found);
if (ret < 0) {
fprintf(stderr, "Fail to search the tree root: %s\n",
strerror(-ret));
goto out;
}
if (ret > 0) {
printf("Found tree root at %llu gen %llu level %u\n",
found->start, filter.match_gen, filter.match_level);
ret = 0;
}
print_find_root_result(&result, &filter);
out:
btrfs_find_root_free(&result);
close_ctree(root);
return ret;
}