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Filename : extent-cache.h
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/*
 * Copyright (C) 2007 Oracle.  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.
 */

#ifndef __BTRFS_EXTENT_CACHE_H__
#define __BTRFS_EXTENT_CACHE_H__

#if BTRFS_FLAT_INCLUDES
#include "kerncompat.h"
#include "rbtree.h"
#else
#include <btrfs/kerncompat.h>
#include <btrfs/rbtree.h>
#endif /* BTRFS_FLAT_INCLUDES */

struct cache_tree {
	struct rb_root root;
};

struct cache_extent {
	struct rb_node rb_node;
	u64 objectid;
	u64 start;
	u64 size;
};

void cache_tree_init(struct cache_tree *tree);

struct cache_extent *first_cache_extent(struct cache_tree *tree);
struct cache_extent *last_cache_extent(struct cache_tree *tree);
struct cache_extent *prev_cache_extent(struct cache_extent *pe);
struct cache_extent *next_cache_extent(struct cache_extent *pe);

/*
 * Find a cache_extent which covers start.
 *
 * If not found, return next cache_extent if possible.
 */
struct cache_extent *search_cache_extent(struct cache_tree *tree, u64 start);

/*
 * Find a cahce_extent which restrictly covers start.
 *
 * If not found, return NULL.
 */
struct cache_extent *lookup_cache_extent(struct cache_tree *tree,
					 u64 start, u64 size);

/*
 * Add an non-overlap extent into cache tree
 *
 * If [start, start+size) overlap with existing one, it will return -EEXIST.
 */
int add_cache_extent(struct cache_tree *tree, u64 start, u64 size);

/*
 * Same with add_cache_extent, but with cache_extent strcut.
 */
int insert_cache_extent(struct cache_tree *tree, struct cache_extent *pe);
void remove_cache_extent(struct cache_tree *tree, struct cache_extent *pe);

static inline int cache_tree_empty(struct cache_tree *tree)
{
	return RB_EMPTY_ROOT(&tree->root);
}

typedef void (*free_cache_extent)(struct cache_extent *pe);

void cache_tree_free_extents(struct cache_tree *tree,
			     free_cache_extent free_func);

#define FREE_EXTENT_CACHE_BASED_TREE(name, free_func)		\
static void free_##name##_tree(struct cache_tree *tree)		\
{								\
	cache_tree_free_extents(tree, free_func);		\
}

void free_extent_cache_tree(struct cache_tree *tree);

/*
 * Search a cache_extent with same objectid, and covers start.
 *
 * If not found, return next if possible.
 */
struct cache_extent *search_cache_extent2(struct cache_tree *tree,
					  u64 objectid, u64 start);
/*
 * Search a cache_extent with same objectid, and covers the range
 * [start, start + size)
 *
 * If not found, return next cache_extent if possible.
 */
struct cache_extent *lookup_cache_extent2(struct cache_tree *tree,
					  u64 objectid, u64 start, u64 size);
int add_cache_extent2(struct cache_tree *tree,
		      u64 objectid, u64 start, u64 size);
int insert_cache_extent2(struct cache_tree *tree, struct cache_extent *pe);

/*
 * Insert a cache_extent range [start, start + size).
 *
 * This function may merge with existing cache_extent.
 * NOTE: caller must ensure the inserted range won't cover with any existing
 * range.
 */
int add_merge_cache_extent(struct cache_tree *tree, u64 start, u64 size);
#endif