#ifndef __EXTENTIO__
  #define __EXTENTIO__
  
  #include <linux/rbtree.h>
  
  /* bits for the extent state */
  #define EXTENT_DIRTY 1
  #define EXTENT_WRITEBACK (1 << 1)
  #define EXTENT_UPTODATE (1 << 2)
  #define EXTENT_LOCKED (1 << 3)
  #define EXTENT_NEW (1 << 4)
  #define EXTENT_DELALLOC (1 << 5)
  #define EXTENT_DEFRAG (1 << 6)
  #define EXTENT_DEFRAG_DONE (1 << 7)
  #define EXTENT_BUFFER_FILLED (1 << 8)

  #define EXTENT_BOUNDARY (1 << 9)
  #define EXTENT_NODATASUM (1 << 10)

  #define EXTENT_DO_ACCOUNTING (1 << 11)

  #define EXTENT_FIRST_DELALLOC (1 << 12)

  #define EXTENT_NEED_WAIT (1 << 13)

  #define EXTENT_DAMAGED (1 << 14)

  #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)

  #define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC)

  /*
   * flags for bio submission. The high bits indicate the compression
   * type for this bio
   */

  #define EXTENT_BIO_COMPRESSED 1

  #define EXTENT_BIO_FLAG_SHIFT 16

  /* these are bit numbers for test/set bit */
  #define EXTENT_BUFFER_UPTODATE 0
  #define EXTENT_BUFFER_BLOCKING 1

  #define EXTENT_BUFFER_DIRTY 2

  #define EXTENT_BUFFER_CORRUPT 3

  #define EXTENT_BUFFER_READAHEAD 4	/* this got triggered by readahead */

  /* these are flags for extent_clear_unlock_delalloc */
  #define EXTENT_CLEAR_UNLOCK_PAGE 0x1
  #define EXTENT_CLEAR_UNLOCK	 0x2
  #define EXTENT_CLEAR_DELALLOC	 0x4
  #define EXTENT_CLEAR_DIRTY	 0x8
  #define EXTENT_SET_WRITEBACK	 0x10
  #define EXTENT_END_WRITEBACK	 0x20
  #define EXTENT_SET_PRIVATE2	 0x40

  #define EXTENT_CLEAR_ACCOUNTING  0x80

  /*
   * page->private values.  Every page that is controlled by the extent
   * map has page->private set to one.
   */
  #define EXTENT_PAGE_PRIVATE 1
  #define EXTENT_PAGE_PRIVATE_FIRST_PAGE 3

  struct extent_state;

  typedef	int (extent_submit_bio_hook_t)(struct inode *inode, int rw,

  				       struct bio *bio, int mirror_num,

  				       unsigned long bio_flags, u64 bio_offset);

  struct extent_io_ops {

  	int (*fill_delalloc)(struct inode *inode, struct page *locked_page,

  			     u64 start, u64 end, int *page_started,
  			     unsigned long *nr_written);

  	int (*writepage_start_hook)(struct page *page, u64 start, u64 end);

  	int (*writepage_io_hook)(struct page *page, u64 start, u64 end);

  	extent_submit_bio_hook_t *submit_bio_hook;

  	int (*merge_bio_hook)(struct page *page, unsigned long offset,

  			      size_t size, struct bio *bio,
  			      unsigned long bio_flags);

  	int (*readpage_io_hook)(struct page *page, u64 start, u64 end);

  	int (*readpage_io_failed_hook)(struct bio *bio, struct page *page,

  				       u64 start, u64 end, int failed_mirror,

  				       struct extent_state *state);

  	int (*writepage_io_failed_hook)(struct bio *bio, struct page *page,
  					u64 start, u64 end,
  				       struct extent_state *state);

  	int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end,
  				    struct extent_state *state);

  	int (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,

  				      struct extent_state *state, int uptodate);

  	void (*set_bit_hook)(struct inode *inode, struct extent_state *state,
  			     int *bits);
  	void (*clear_bit_hook)(struct inode *inode, struct extent_state *state,
  			       int *bits);
  	void (*merge_extent_hook)(struct inode *inode,
  				  struct extent_state *new,
  				  struct extent_state *other);
  	void (*split_extent_hook)(struct inode *inode,
  				  struct extent_state *orig, u64 split);

  	int (*write_cache_pages_lock_hook)(struct page *page, void *data,
  					   void (*flush_fn)(void *));

  };
  
  struct extent_io_tree {
  	struct rb_root state;

  	struct radix_tree_root buffer;

  	struct address_space *mapping;
  	u64 dirty_bytes;

  	spinlock_t lock;

  	spinlock_t buffer_lock;

  	struct extent_io_ops *ops;

  };
  
  struct extent_state {
  	u64 start;
  	u64 end; /* inclusive */

  	struct rb_node rb_node;

  
  	/* ADD NEW ELEMENTS AFTER THIS */

  	struct extent_io_tree *tree;

  	wait_queue_head_t wq;
  	atomic_t refs;
  	unsigned long state;
  
  	/* for use by the FS */
  	u64 private;

  	struct list_head leak_list;

  };
  
  struct extent_buffer {
  	u64 start;
  	unsigned long len;

  	unsigned long map_start;
  	unsigned long map_len;
  	struct page *first_page;

  	unsigned long bflags;

  	struct list_head leak_list;

  	struct rcu_head rcu_head;

  	atomic_t refs;

  	/* count of read lock holders on the extent buffer */
  	atomic_t write_locks;
  	atomic_t read_locks;
  	atomic_t blocking_writers;
  	atomic_t blocking_readers;
  	atomic_t spinning_readers;
  	atomic_t spinning_writers;
  
  	/* protects write locks */
  	rwlock_t lock;
  
  	/* readers use lock_wq while they wait for the write
  	 * lock holders to unlock
  	 */
  	wait_queue_head_t write_lock_wq;

  	/* writers use read_lock_wq while they wait for readers
  	 * to unlock

  	 */

  	wait_queue_head_t read_lock_wq;

  };

  static inline void extent_set_compress_type(unsigned long *bio_flags,
  					    int compress_type)
  {
  	*bio_flags |= compress_type << EXTENT_BIO_FLAG_SHIFT;
  }
  
  static inline int extent_compress_type(unsigned long bio_flags)
  {
  	return bio_flags >> EXTENT_BIO_FLAG_SHIFT;
  }

  struct extent_map_tree;
  
  typedef struct extent_map *(get_extent_t)(struct inode *inode,
  					  struct page *page,

  					  size_t pg_offset,

  					  u64 start, u64 len,
  					  int create);
  
  void extent_io_tree_init(struct extent_io_tree *tree,

  			 struct address_space *mapping);

  int try_release_extent_mapping(struct extent_map_tree *map,

  			       struct extent_io_tree *tree, struct page *page,
  			       gfp_t mask);

  int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page);

  int try_release_extent_state(struct extent_map_tree *map,
  			     struct extent_io_tree *tree, struct page *page,
  			     gfp_t mask);

  int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);

  int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,

  		     int bits, struct extent_state **cached, gfp_t mask);

  int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);

  int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
  			 struct extent_state **cached, gfp_t mask);

  int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
  		    gfp_t mask);

  int extent_read_full_page(struct extent_io_tree *tree, struct page *page,

  			  get_extent_t *get_extent, int mirror_num);

  int __init extent_io_init(void);
  void extent_io_exit(void);
  
  u64 count_range_bits(struct extent_io_tree *tree,
  		     u64 *start, u64 search_end,

  		     u64 max_bytes, unsigned long bits, int contig);

  void free_extent_state(struct extent_state *state);

  int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,

  		   int bits, int filled, struct extent_state *cached_state);

  int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
  		      int bits, gfp_t mask);

  int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,

  		     int bits, int wake, int delete, struct extent_state **cached,
  		     gfp_t mask);

  int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
  		    int bits, gfp_t mask);

  int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
  		   int bits, int exclusive_bits, u64 *failed_start,
  		   struct extent_state **cached_state, gfp_t mask);

  int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,

  			struct extent_state **cached_state, gfp_t mask);

  int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
  		   gfp_t mask);
  int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
  		     gfp_t mask);
  int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
  		       gfp_t mask);

  int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
  		       int bits, int clear_bits, gfp_t mask);

  int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,

  			struct extent_state **cached_state, gfp_t mask);

  int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
  			  u64 *start_ret, u64 *end_ret, int bits);

  struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
  						 u64 start, int bits);

  int extent_invalidatepage(struct extent_io_tree *tree,
  			  struct page *page, unsigned long offset);
  int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
  			  get_extent_t *get_extent,
  			  struct writeback_control *wbc);

  int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
  			      u64 start, u64 end, get_extent_t *get_extent,
  			      int mode);

  int extent_writepages(struct extent_io_tree *tree,
  		      struct address_space *mapping,
  		      get_extent_t *get_extent,
  		      struct writeback_control *wbc);
  int extent_readpages(struct extent_io_tree *tree,
  		     struct address_space *mapping,
  		     struct list_head *pages, unsigned nr_pages,
  		     get_extent_t get_extent);

  int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  		__u64 start, __u64 len, get_extent_t *get_extent);

  int set_state_private(struct extent_io_tree *tree, u64 start, u64 private);
  int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private);
  void set_page_extent_mapped(struct page *page);
  
  struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
  					  u64 start, unsigned long len,

  					  struct page *page0);

  struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,

  					 u64 start, unsigned long len);

  void free_extent_buffer(struct extent_buffer *eb);

  #define WAIT_NONE	0
  #define WAIT_COMPLETE	1
  #define WAIT_PAGE_LOCK	2

  int read_extent_buffer_pages(struct extent_io_tree *tree,

  			     struct extent_buffer *eb, u64 start, int wait,

  			     get_extent_t *get_extent, int mirror_num);

  unsigned long num_extent_pages(u64 start, u64 len);
  struct page *extent_buffer_page(struct extent_buffer *eb, unsigned long i);

  
  static inline void extent_buffer_get(struct extent_buffer *eb)
  {
  	atomic_inc(&eb->refs);
  }
  
  int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
  			  unsigned long start,
  			  unsigned long len);
  void read_extent_buffer(struct extent_buffer *eb, void *dst,
  			unsigned long start,
  			unsigned long len);
  void write_extent_buffer(struct extent_buffer *eb, const void *src,
  			 unsigned long start, unsigned long len);
  void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
  			unsigned long dst_offset, unsigned long src_offset,
  			unsigned long len);
  void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
  			   unsigned long src_offset, unsigned long len);
  void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
  			   unsigned long src_offset, unsigned long len);
  void memset_extent_buffer(struct extent_buffer *eb, char c,
  			  unsigned long start, unsigned long len);

  int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits);

  int clear_extent_buffer_dirty(struct extent_io_tree *tree,
  			      struct extent_buffer *eb);
  int set_extent_buffer_dirty(struct extent_io_tree *tree,
  			     struct extent_buffer *eb);
  int set_extent_buffer_uptodate(struct extent_io_tree *tree,
  			       struct extent_buffer *eb);

  int clear_extent_buffer_uptodate(struct extent_io_tree *tree,

  				struct extent_buffer *eb,
  				struct extent_state **cached_state);

  int extent_buffer_uptodate(struct extent_io_tree *tree,

  			   struct extent_buffer *eb,
  			   struct extent_state *cached_state);

  int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,

  		      unsigned long min_len, char **map,

  		      unsigned long *map_start,

  		      unsigned long *map_len);

  int extent_range_uptodate(struct extent_io_tree *tree,
  			  u64 start, u64 end);

  int extent_clear_unlock_delalloc(struct inode *inode,
  				struct extent_io_tree *tree,
  				u64 start, u64 end, struct page *locked_page,

  				unsigned long op);

  struct bio *
  btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
  		gfp_t gfp_flags);

  
  struct btrfs_mapping_tree;
  
  int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
  			u64 length, u64 logical, struct page *page,
  			int mirror_num);

  #endif