free-space-tree.c - pub/scm/linux/kernel/git/mason/btrfs-progs - Git at Google

 /*
  * Copyright (C) 2015 Facebook.  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 "ctree.h"
 #include "disk-io.h"
 #include "free-space-cache.h"
 #include "free-space-tree.h"

 static struct btrfs_free_space_info *
 search_free_space_info(struct btrfs_trans_handle *trans,
 		       struct btrfs_fs_info *fs_info,
 		       struct btrfs_block_group_cache *block_group,
 		       struct btrfs_path *path, int cow)
 {
 	struct btrfs_root *root = fs_info->free_space_root;
 	struct btrfs_key key;
 	int ret;

 	key.objectid = block_group->key.objectid;
 	key.type = BTRFS_FREE_SPACE_INFO_KEY;
 	key.offset = block_group->key.offset;

 	ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
 	if (ret < 0)
 		return ERR_PTR(ret);
 	if (ret != 0)
 		return ERR_PTR(-ENOENT);

 	return btrfs_item_ptr(path->nodes[0], path->slots[0],
 			      struct btrfs_free_space_info);
 }

 static int free_space_test_bit(struct btrfs_block_group_cache *block_group,
 			       struct btrfs_path *path, u64 offset,
 			       u64 sectorsize)
 {
 	struct extent_buffer *leaf;
 	struct btrfs_key key;
 	u64 found_start, found_end;
 	unsigned long ptr, i;

 	leaf = path->nodes[0];
 	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 	ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);

 	found_start = key.objectid;
 	found_end = key.objectid + key.offset;
 	ASSERT(offset >= found_start && offset < found_end);

 	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
 	i = (offset - found_start) / sectorsize;
 	return !!extent_buffer_test_bit(leaf, ptr, i);
 }

 static int load_free_space_bitmaps(struct btrfs_fs_info *fs_info,
 				   struct btrfs_block_group_cache *block_group,
 				   struct btrfs_path *path,
 				   u32 expected_extent_count,
 				   int *errors)
 {
 	struct btrfs_root *root = fs_info->free_space_root;
 	struct btrfs_key key;
 	int prev_bit = 0, bit;
 	u64 extent_start = 0;
 	u64 start, end, offset;
 	u32 extent_count = 0;
 	int ret;

 	start = block_group->key.objectid;
 	end = block_group->key.objectid + block_group->key.offset;

 	while (1) {
 		ret = btrfs_next_item(root, path);
 		if (ret < 0)
 			goto out;
 		if (ret)
 			break;

 		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);

 		if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
 			break;

 		if (key.type != BTRFS_FREE_SPACE_BITMAP_KEY) {
 			fprintf(stderr, "unexpected key of type %u\n", key.type);
 			(*errors)++;
 			break;
 		}
 		if (key.objectid >= end) {
 			fprintf(stderr,
 	"free space bitmap starts at %llu, beyond end of block group %llu-%llu\n",
 				key.objectid, start, end);
 			(*errors)++;
 			break;
 		}
 		if (key.objectid + key.offset > end) {
 			fprintf(stderr,
 	"free space bitmap ends at %llu, beyond end of block group %llu-%llu\n",
 				key.objectid, start, end);
 			(*errors)++;
 			break;
 		}

 		offset = key.objectid;
 		while (offset < key.objectid + key.offset) {
 			bit = free_space_test_bit(block_group, path, offset,
 						  root->sectorsize);
 			if (prev_bit == 0 && bit == 1) {
 				extent_start = offset;
 			} else if (prev_bit == 1 && bit == 0) {
 				add_new_free_space(block_group, fs_info, extent_start, offset);
 				extent_count++;
 			}
 			prev_bit = bit;
 			offset += root->sectorsize;
 		}
 	}

 	if (prev_bit == 1) {
 		add_new_free_space(block_group, fs_info, extent_start, end);
 		extent_count++;
 	}

 	if (extent_count != expected_extent_count) {
 		fprintf(stderr, "free space info recorded %u extents, counted %u\n",
 			expected_extent_count, extent_count);
 		(*errors)++;
 	}

 	ret = 0;
 out:
 	return ret;
 }

 static int load_free_space_extents(struct btrfs_fs_info *fs_info,
 				   struct btrfs_block_group_cache *block_group,
 				   struct btrfs_path *path,
 				   u32 expected_extent_count,
 				   int *errors)
 {
 	struct btrfs_root *root = fs_info->free_space_root;
 	struct btrfs_key key, prev_key;
 	int have_prev = 0;
 	u64 start, end;
 	u32 extent_count = 0;
 	int ret;

 	start = block_group->key.objectid;
 	end = block_group->key.objectid + block_group->key.offset;

 	while (1) {
 		ret = btrfs_next_item(root, path);
 		if (ret < 0)
 			goto out;
 		if (ret)
 			break;

 		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);

 		if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
 			break;

 		if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
 			fprintf(stderr, "unexpected key of type %u\n", key.type);
 			(*errors)++;
 			break;
 		}
 		if (key.objectid >= end) {
 			fprintf(stderr,
 	"free space extent starts at %llu, beyond end of block group %llu-%llu\n",
 				key.objectid, start, end);
 			(*errors)++;
 			break;
 		}
 		if (key.objectid + key.offset > end) {
 			fprintf(stderr,
 	"free space extent ends at %llu, beyond end of block group %llu-%llu\n",
 				key.objectid, start, end);
 			(*errors)++;
 			break;
 		}

 		if (have_prev) {
 			u64 cur_start = key.objectid;
 			u64 cur_end = cur_start + key.offset;
 			u64 prev_start = prev_key.objectid;
 			u64 prev_end = prev_start + prev_key.offset;

 			if (cur_start < prev_end) {
 				fprintf(stderr,
 	"free space extent %llu-%llu overlaps with previous %llu-%llu\n",
 					cur_start, cur_end,
 					prev_start, prev_end);
 				(*errors)++;
 			} else if (cur_start == prev_end) {
 				fprintf(stderr,
 	"free space extent %llu-%llu is unmerged with previous %llu-%llu\n",
 					cur_start, cur_end,
 					prev_start, prev_end);
 				(*errors)++;
 			}
 		}

 		add_new_free_space(block_group, fs_info, key.objectid, key.objectid + key.offset);
 		extent_count++;

 		prev_key = key;
 		have_prev = 1;
 	}

 	if (extent_count != expected_extent_count) {
 		fprintf(stderr, "free space info recorded %u extents, counted %u\n",
 			expected_extent_count, extent_count);
 		(*errors)++;
 	}

 	ret = 0;
 out:
 	return ret;
 }

 int load_free_space_tree(struct btrfs_fs_info *fs_info,
 			 struct btrfs_block_group_cache *block_group)
 {
 	struct btrfs_free_space_info *info;
 	struct btrfs_path *path;
 	u32 extent_count, flags;
 	int errors = 0;
 	int ret;

 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 	path->reada = 1;

 	info = search_free_space_info(NULL, fs_info, block_group, path, 0);
 	if (IS_ERR(info)) {
 		ret = PTR_ERR(info);
 		goto out;
 	}
 	extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
 	flags = btrfs_free_space_flags(path->nodes[0], info);

 	if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
 		ret = load_free_space_bitmaps(fs_info, block_group, path,
 					      extent_count, &errors);
 	} else {
 		ret = load_free_space_extents(fs_info, block_group, path,
 					      extent_count, &errors);
 	}
 	if (ret)
 		goto out;

 	ret = 0;
 out:
 	btrfs_free_path(path);
 	return ret ? ret : errors;
 }
	/*
	* Copyright (C) 2015 Facebook. 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 "ctree.h"
	#include "disk-io.h"
	#include "free-space-cache.h"
	#include "free-space-tree.h"

	static struct btrfs_free_space_info *
	search_free_space_info(struct btrfs_trans_handle *trans,
	struct btrfs_fs_info *fs_info,
	struct btrfs_block_group_cache *block_group,
	struct btrfs_path *path, int cow)
	{
	struct btrfs_root *root = fs_info->free_space_root;
	struct btrfs_key key;
	int ret;

	key.objectid = block_group->key.objectid;
	key.type = BTRFS_FREE_SPACE_INFO_KEY;
	key.offset = block_group->key.offset;

	ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
	if (ret < 0)
	return ERR_PTR(ret);
	if (ret != 0)
	return ERR_PTR(-ENOENT);

	return btrfs_item_ptr(path->nodes[0], path->slots[0],
	struct btrfs_free_space_info);
	}

	static int free_space_test_bit(struct btrfs_block_group_cache *block_group,
	struct btrfs_path *path, u64 offset,
	u64 sectorsize)
	{
	struct extent_buffer *leaf;
	struct btrfs_key key;
	u64 found_start, found_end;
	unsigned long ptr, i;

	leaf = path->nodes[0];
	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
	ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);

	found_start = key.objectid;
	found_end = key.objectid + key.offset;
	ASSERT(offset >= found_start && offset < found_end);

	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
	i = (offset - found_start) / sectorsize;
	return !!extent_buffer_test_bit(leaf, ptr, i);
	}

	static int load_free_space_bitmaps(struct btrfs_fs_info *fs_info,
	struct btrfs_block_group_cache *block_group,
	struct btrfs_path *path,
	u32 expected_extent_count,
	int *errors)
	{
	struct btrfs_root *root = fs_info->free_space_root;
	struct btrfs_key key;
	int prev_bit = 0, bit;
	u64 extent_start = 0;
	u64 start, end, offset;
	u32 extent_count = 0;
	int ret;

	start = block_group->key.objectid;
	end = block_group->key.objectid + block_group->key.offset;

	while (1) {
	ret = btrfs_next_item(root, path);
	if (ret < 0)
	goto out;
	if (ret)
	break;

	btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);

	if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
	break;

	if (key.type != BTRFS_FREE_SPACE_BITMAP_KEY) {
	fprintf(stderr, "unexpected key of type %u\n", key.type);
	(*errors)++;
	break;
	}
	if (key.objectid >= end) {
	fprintf(stderr,
	"free space bitmap starts at %llu, beyond end of block group %llu-%llu\n",
	key.objectid, start, end);
	(*errors)++;
	break;
	}
	if (key.objectid + key.offset > end) {
	fprintf(stderr,
	"free space bitmap ends at %llu, beyond end of block group %llu-%llu\n",
	key.objectid, start, end);
	(*errors)++;
	break;
	}

	offset = key.objectid;
	while (offset < key.objectid + key.offset) {
	bit = free_space_test_bit(block_group, path, offset,
	root->sectorsize);
	if (prev_bit == 0 && bit == 1) {
	extent_start = offset;
	} else if (prev_bit == 1 && bit == 0) {
	add_new_free_space(block_group, fs_info, extent_start, offset);
	extent_count++;
	}
	prev_bit = bit;
	offset += root->sectorsize;
	}
	}

	if (prev_bit == 1) {
	add_new_free_space(block_group, fs_info, extent_start, end);
	extent_count++;
	}

	if (extent_count != expected_extent_count) {
	fprintf(stderr, "free space info recorded %u extents, counted %u\n",
	expected_extent_count, extent_count);
	(*errors)++;
	}

	ret = 0;
	out:
	return ret;
	}

	static int load_free_space_extents(struct btrfs_fs_info *fs_info,
	struct btrfs_block_group_cache *block_group,
	struct btrfs_path *path,
	u32 expected_extent_count,
	int *errors)
	{
	struct btrfs_root *root = fs_info->free_space_root;
	struct btrfs_key key, prev_key;
	int have_prev = 0;
	u64 start, end;
	u32 extent_count = 0;
	int ret;

	start = block_group->key.objectid;
	end = block_group->key.objectid + block_group->key.offset;

	while (1) {
	ret = btrfs_next_item(root, path);
	if (ret < 0)
	goto out;
	if (ret)
	break;

	btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);

	if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
	break;

	if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
	fprintf(stderr, "unexpected key of type %u\n", key.type);
	(*errors)++;
	break;
	}
	if (key.objectid >= end) {
	fprintf(stderr,
	"free space extent starts at %llu, beyond end of block group %llu-%llu\n",
	key.objectid, start, end);
	(*errors)++;
	break;
	}
	if (key.objectid + key.offset > end) {
	fprintf(stderr,
	"free space extent ends at %llu, beyond end of block group %llu-%llu\n",
	key.objectid, start, end);
	(*errors)++;
	break;
	}

	if (have_prev) {
	u64 cur_start = key.objectid;
	u64 cur_end = cur_start + key.offset;
	u64 prev_start = prev_key.objectid;
	u64 prev_end = prev_start + prev_key.offset;

	if (cur_start < prev_end) {
	fprintf(stderr,
	"free space extent %llu-%llu overlaps with previous %llu-%llu\n",
	cur_start, cur_end,
	prev_start, prev_end);
	(*errors)++;
	} else if (cur_start == prev_end) {
	fprintf(stderr,
	"free space extent %llu-%llu is unmerged with previous %llu-%llu\n",
	cur_start, cur_end,
	prev_start, prev_end);
	(*errors)++;
	}
	}

	add_new_free_space(block_group, fs_info, key.objectid, key.objectid + key.offset);
	extent_count++;

	prev_key = key;
	have_prev = 1;
	}

	if (extent_count != expected_extent_count) {
	fprintf(stderr, "free space info recorded %u extents, counted %u\n",
	expected_extent_count, extent_count);
	(*errors)++;
	}

	ret = 0;
	out:
	return ret;
	}

	int load_free_space_tree(struct btrfs_fs_info *fs_info,
	struct btrfs_block_group_cache *block_group)
	{
	struct btrfs_free_space_info *info;
	struct btrfs_path *path;
	u32 extent_count, flags;
	int errors = 0;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
	return -ENOMEM;
	path->reada = 1;

	info = search_free_space_info(NULL, fs_info, block_group, path, 0);
	if (IS_ERR(info)) {
	ret = PTR_ERR(info);
	goto out;
	}
	extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
	flags = btrfs_free_space_flags(path->nodes[0], info);

	if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
	ret = load_free_space_bitmaps(fs_info, block_group, path,
	extent_count, &errors);
	} else {
	ret = load_free_space_extents(fs_info, block_group, path,
	extent_count, &errors);
	}
	if (ret)
	goto out;

	ret = 0;
	out:
	btrfs_free_path(path);
	return ret ? ret : errors;
	}