btrfs-progs/find-root.c

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/*
* Copyright (C) 2015 Fujitsu. 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 "kerncompat.h"
#include <stdio.h>
#include <stdlib.h>
#include "ctree.h"
#include "utils.h"
#include "find-root.h"
#include "volumes.h"
#include "disk-io.h"
#include "extent-cache.h"
/* Return value is the same as btrfs_find_root_search(). */
static int add_eb_to_result(struct extent_buffer *eb,
struct cache_tree *result,
u32 nodesize,
struct btrfs_find_root_filter *filter,
struct cache_extent **match)
{
u64 generation = btrfs_header_generation(eb);
u64 level = btrfs_header_level(eb);
u64 owner = btrfs_header_owner(eb);
u64 start = eb->start;
struct cache_extent *cache;
struct btrfs_find_root_gen_cache *gen_cache = NULL;
int ret = 0;
if (owner != filter->objectid || level < filter->level ||
generation < filter->generation)
return ret;
/*
* Get the generation cache or create one
*
* NOTE: search_cache_extent() may return cache that doesn't cover
* the range. So we need an extra check to make sure it's the right one.
*/
cache = search_cache_extent(result, generation);
if (!cache || cache->start != generation) {
gen_cache = malloc(sizeof(*gen_cache));
BUG_ON(!gen_cache);
cache = &gen_cache->cache;
cache->start = generation;
cache->size = 1;
cache->objectid = 0;
gen_cache->highest_level = 0;
cache_tree_init(&gen_cache->eb_tree);
ret = insert_cache_extent(result, cache);
if (ret < 0)
return ret;
}
gen_cache = container_of(cache, struct btrfs_find_root_gen_cache,
cache);
/* Higher level, clean tree and insert the new one */
if (level > gen_cache->highest_level) {
free_extent_cache_tree(&gen_cache->eb_tree);
gen_cache->highest_level = level;
/* Fall into the insert routine */
}
/* Same level, insert it into the eb_tree */
if (level == gen_cache->highest_level) {
ret = add_cache_extent(&gen_cache->eb_tree,
start, nodesize);
if (ret < 0 && ret != -EEXIST)
return ret;
ret = 0;
}
if (generation == filter->match_gen &&
level == filter->match_level &&
!filter->search_all) {
ret = 1;
if (match)
*match = search_cache_extent(&gen_cache->eb_tree,
start);
}
return ret;
}
/*
* Return 0 if iterating all the metadata extents.
* Return 1 if found root with given gen/level and set *match to it.
* Return <0 if error happens
*/
int btrfs_find_root_search(struct btrfs_fs_info *fs_info,
struct btrfs_find_root_filter *filter,
struct cache_tree *result,
struct cache_extent **match)
{
struct extent_buffer *eb;
u64 chunk_offset = 0;
u64 chunk_size = 0;
u64 offset = 0;
u32 nodesize = btrfs_super_nodesize(fs_info->super_copy);
int suppress_errors = 0;
int ret = 0;
suppress_errors = fs_info->suppress_check_block_errors;
fs_info->suppress_check_block_errors = 1;
while (1) {
if (filter->objectid != BTRFS_CHUNK_TREE_OBJECTID)
ret = btrfs_next_bg_metadata(&fs_info->mapping_tree,
&chunk_offset,
&chunk_size);
else
ret = btrfs_next_bg_system(&fs_info->mapping_tree,
&chunk_offset,
&chunk_size);
if (ret) {
if (ret == -ENOENT)
ret = 0;
break;
}
for (offset = chunk_offset;
offset < chunk_offset + chunk_size;
offset += nodesize) {
eb = read_tree_block_fs_info(fs_info, offset, nodesize,
0);
if (!eb || IS_ERR(eb))
continue;
ret = add_eb_to_result(eb, result, nodesize, filter,
match);
free_extent_buffer(eb);
if (ret)
goto out;
}
}
out:
fs_info->suppress_check_block_errors = suppress_errors;
return ret;
}