alistair23-linux/fs/btrfs/extent_map.h

#ifndef __EXTENTMAP__
#define __EXTENTMAP__

#include <linux/rbtree.h>

#define EXTENT_MAP_HOLE (u64)-3
#define EXTENT_MAP_INLINE (u64)-2
#define EXTENT_MAP_DELALLOC (u64)-1

/* 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_CSUM (1 << 9)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)

/*
 * 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_map_ops {
	int (*fill_delalloc)(struct inode *inode, u64 start, u64 end);
	int (*writepage_io_hook)(struct page *page, u64 start, u64 end);
	int (*readpage_io_hook)(struct page *page, u64 start, u64 end);
	int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end);
	void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end);
};

struct extent_map_tree {
	struct rb_root map;
	struct rb_root state;
	struct address_space *mapping;
	rwlock_t lock;
	struct extent_map_ops *ops;
	spinlock_t lru_lock;
	struct list_head buffer_lru;
	int lru_size;
};

/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
struct extent_map {
	u64 start;
	u64 end; /* inclusive */
	int in_tree;
	struct rb_node rb_node;
	/* block_start and block_end are in bytes */
	u64 block_start;
	u64 block_end; /* inclusive */
	struct block_device *bdev;
	atomic_t refs;
};

/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
struct extent_state {
	u64 start;
	u64 end; /* inclusive */
	int in_tree;
	struct rb_node rb_node;
	wait_queue_head_t wq;
	atomic_t refs;
	unsigned long state;

	/* for use by the FS */
	u64 private;

	struct list_head list;
};

struct extent_buffer {
	u64 start;
	unsigned long len;
	char *map_token;
	char *kaddr;
	unsigned long map_start;
	unsigned long map_len;
	struct page *first_page;
	struct list_head lru;
	atomic_t refs;
	int flags;
};

typedef struct extent_map *(get_extent_t)(struct inode *inode,
					  struct page *page,
					  size_t page_offset,
					  u64 start, u64 end,
					  int create);

void extent_map_tree_init(struct extent_map_tree *tree,
			  struct address_space *mapping, gfp_t mask);
void extent_map_tree_empty_lru(struct extent_map_tree *tree);
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
					 u64 start, u64 end);
int add_extent_mapping(struct extent_map_tree *tree,
		       struct extent_map *em);
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page);
int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
struct extent_map *alloc_extent_map(gfp_t mask);
void free_extent_map(struct extent_map *em);
int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
			  get_extent_t *get_extent);
void __init extent_map_init(void);
void __exit extent_map_exit(void);

int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end,
		   int bits, int filled);
int clear_extent_bits(struct extent_map_tree *tree, u64 start, u64 end,
		      int bits, gfp_t mask);
int set_extent_bits(struct extent_map_tree *tree, u64 start, u64 end,
		    int bits, gfp_t mask);
int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
			gfp_t mask);
int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
		   gfp_t mask);
int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
		     gfp_t mask);
int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
		       gfp_t mask);
int set_extent_delalloc(struct extent_map_tree *tree, u64 start, u64 end,
		     gfp_t mask);
int find_first_extent_bit(struct extent_map_tree *tree, u64 start,
			  u64 *start_ret, u64 *end_ret, int bits);
int extent_invalidatepage(struct extent_map_tree *tree,
			  struct page *page, unsigned long offset);
int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
			  get_extent_t *get_extent,
			  struct writeback_control *wbc);
int extent_writepages(struct extent_map_tree *tree,
		      struct address_space *mapping,
		      get_extent_t *get_extent,
		      struct writeback_control *wbc);
int extent_readpages(struct extent_map_tree *tree,
		     struct address_space *mapping,
		     struct list_head *pages, unsigned nr_pages,
		     get_extent_t get_extent);
int extent_prepare_write(struct extent_map_tree *tree,
			 struct inode *inode, struct page *page,
			 unsigned from, unsigned to, get_extent_t *get_extent);
int extent_commit_write(struct extent_map_tree *tree,
			struct inode *inode, struct page *page,
			unsigned from, unsigned to);
sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
		get_extent_t *get_extent);
int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end);
int set_state_private(struct extent_map_tree *tree, u64 start, u64 private);
int get_state_private(struct extent_map_tree *tree, u64 start, u64 *private);
void set_page_extent_mapped(struct page *page);

struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree,
					  u64 start, unsigned long len,
					  struct page *page0,
					  gfp_t mask);
struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree,
					 u64 start, unsigned long len,
					  gfp_t mask);
void free_extent_buffer(struct extent_buffer *eb);
int read_extent_buffer_pages(struct extent_map_tree *tree,
			     struct extent_buffer *eb, u64 start, int wait);

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_on_extent_buffer_writeback(struct extent_map_tree *tree,
				    struct extent_buffer *eb);
int clear_extent_buffer_dirty(struct extent_map_tree *tree,
			      struct extent_buffer *eb);
int set_extent_buffer_dirty(struct extent_map_tree *tree,
			     struct extent_buffer *eb);
int set_extent_buffer_uptodate(struct extent_map_tree *tree,
			       struct extent_buffer *eb);
int extent_buffer_uptodate(struct extent_map_tree *tree,
			   struct extent_buffer *eb);
int map_extent_buffer(struct extent_buffer *eb, unsigned long offset,
		      unsigned long min_len, char **token, char **map,
		      unsigned long *map_start,
		      unsigned long *map_len, int km);
int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,
		      unsigned long min_len, char **token, char **map,
		      unsigned long *map_start,
		      unsigned long *map_len, int km);
void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km);
#endif