273 lines
7 KiB
C
273 lines
7 KiB
C
/*
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* Copyright (C) 2015 Facebook. 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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#include "ctree.h"
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#include "disk-io.h"
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#include "free-space-cache.h"
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#include "free-space-tree.h"
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static struct btrfs_free_space_info *
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search_free_space_info(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info,
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struct btrfs_block_group_cache *block_group,
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struct btrfs_path *path, int cow)
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{
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struct btrfs_root *root = fs_info->free_space_root;
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struct btrfs_key key;
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int ret;
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key.objectid = block_group->key.objectid;
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key.type = BTRFS_FREE_SPACE_INFO_KEY;
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key.offset = block_group->key.offset;
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ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
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if (ret < 0)
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return ERR_PTR(ret);
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if (ret != 0)
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return ERR_PTR(-ENOENT);
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return btrfs_item_ptr(path->nodes[0], path->slots[0],
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struct btrfs_free_space_info);
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}
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static int free_space_test_bit(struct btrfs_block_group_cache *block_group,
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struct btrfs_path *path, u64 offset,
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u64 sectorsize)
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{
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struct extent_buffer *leaf;
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struct btrfs_key key;
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u64 found_start, found_end;
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unsigned long ptr, i;
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leaf = path->nodes[0];
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btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
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ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
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found_start = key.objectid;
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found_end = key.objectid + key.offset;
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ASSERT(offset >= found_start && offset < found_end);
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ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
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i = (offset - found_start) / sectorsize;
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return !!extent_buffer_test_bit(leaf, ptr, i);
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}
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static int load_free_space_bitmaps(struct btrfs_fs_info *fs_info,
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struct btrfs_block_group_cache *block_group,
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struct btrfs_path *path,
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u32 expected_extent_count,
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int *errors)
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{
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struct btrfs_root *root = fs_info->free_space_root;
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struct btrfs_key key;
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int prev_bit = 0, bit;
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u64 extent_start = 0;
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u64 start, end, offset;
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u32 extent_count = 0;
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int ret;
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start = block_group->key.objectid;
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end = block_group->key.objectid + block_group->key.offset;
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while (1) {
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ret = btrfs_next_item(root, path);
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if (ret < 0)
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goto out;
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if (ret)
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break;
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btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
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if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
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break;
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if (key.type != BTRFS_FREE_SPACE_BITMAP_KEY) {
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fprintf(stderr, "unexpected key of type %u\n", key.type);
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(*errors)++;
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break;
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}
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if (key.objectid >= end) {
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fprintf(stderr,
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"free space bitmap starts at %llu, beyond end of block group %llu-%llu\n",
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key.objectid, start, end);
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(*errors)++;
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break;
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}
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if (key.objectid + key.offset > end) {
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fprintf(stderr,
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"free space bitmap ends at %llu, beyond end of block group %llu-%llu\n",
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key.objectid, start, end);
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(*errors)++;
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break;
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}
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offset = key.objectid;
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while (offset < key.objectid + key.offset) {
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bit = free_space_test_bit(block_group, path, offset,
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root->sectorsize);
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if (prev_bit == 0 && bit == 1) {
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extent_start = offset;
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} else if (prev_bit == 1 && bit == 0) {
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add_new_free_space(block_group, fs_info, extent_start, offset);
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extent_count++;
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}
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prev_bit = bit;
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offset += root->sectorsize;
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}
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}
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if (prev_bit == 1) {
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add_new_free_space(block_group, fs_info, extent_start, end);
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extent_count++;
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}
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if (extent_count != expected_extent_count) {
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fprintf(stderr, "free space info recorded %u extents, counted %u\n",
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expected_extent_count, extent_count);
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(*errors)++;
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}
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ret = 0;
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out:
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return ret;
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}
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static int load_free_space_extents(struct btrfs_fs_info *fs_info,
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struct btrfs_block_group_cache *block_group,
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struct btrfs_path *path,
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u32 expected_extent_count,
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int *errors)
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{
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struct btrfs_root *root = fs_info->free_space_root;
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struct btrfs_key key, prev_key;
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int have_prev = 0;
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u64 start, end;
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u32 extent_count = 0;
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int ret;
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start = block_group->key.objectid;
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end = block_group->key.objectid + block_group->key.offset;
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while (1) {
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ret = btrfs_next_item(root, path);
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if (ret < 0)
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goto out;
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if (ret)
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break;
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btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
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if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
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break;
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if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
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fprintf(stderr, "unexpected key of type %u\n", key.type);
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(*errors)++;
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break;
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}
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if (key.objectid >= end) {
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fprintf(stderr,
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"free space extent starts at %llu, beyond end of block group %llu-%llu\n",
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key.objectid, start, end);
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(*errors)++;
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break;
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}
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if (key.objectid + key.offset > end) {
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fprintf(stderr,
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"free space extent ends at %llu, beyond end of block group %llu-%llu\n",
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key.objectid, start, end);
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(*errors)++;
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break;
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}
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if (have_prev) {
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u64 cur_start = key.objectid;
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u64 cur_end = cur_start + key.offset;
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u64 prev_start = prev_key.objectid;
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u64 prev_end = prev_start + prev_key.offset;
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if (cur_start < prev_end) {
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fprintf(stderr,
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"free space extent %llu-%llu overlaps with previous %llu-%llu\n",
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cur_start, cur_end,
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prev_start, prev_end);
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(*errors)++;
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} else if (cur_start == prev_end) {
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fprintf(stderr,
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"free space extent %llu-%llu is unmerged with previous %llu-%llu\n",
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cur_start, cur_end,
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prev_start, prev_end);
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(*errors)++;
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}
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}
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add_new_free_space(block_group, fs_info, key.objectid, key.objectid + key.offset);
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extent_count++;
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prev_key = key;
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have_prev = 1;
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}
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if (extent_count != expected_extent_count) {
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fprintf(stderr, "free space info recorded %u extents, counted %u\n",
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expected_extent_count, extent_count);
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(*errors)++;
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}
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ret = 0;
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out:
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return ret;
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}
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int load_free_space_tree(struct btrfs_fs_info *fs_info,
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struct btrfs_block_group_cache *block_group)
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{
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struct btrfs_free_space_info *info;
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struct btrfs_path *path;
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u32 extent_count, flags;
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int errors = 0;
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int ret;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->reada = 1;
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info = search_free_space_info(NULL, fs_info, block_group, path, 0);
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if (IS_ERR(info)) {
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ret = PTR_ERR(info);
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goto out;
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}
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extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
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flags = btrfs_free_space_flags(path->nodes[0], info);
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if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
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ret = load_free_space_bitmaps(fs_info, block_group, path,
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extent_count, &errors);
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} else {
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ret = load_free_space_extents(fs_info, block_group, path,
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extent_count, &errors);
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}
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if (ret)
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goto out;
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ret = 0;
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out:
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btrfs_free_path(path);
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return ret ? ret : errors;
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}
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