fs/btrfs/extent_io.h - kernel/msm-5.4 - Gitiles

 /* SPDX-License-Identifier: GPL-2.0 */

 #ifndef BTRFS_EXTENT_IO_H
 #define BTRFS_EXTENT_IO_H

 #include <linux/rbtree.h>
 #include <linux/refcount.h>
 #include "ulist.h"

 /* bits for the extent state */
 #define EXTENT_DIRTY		(1U << 0)
 #define EXTENT_UPTODATE		(1U << 1)
 #define EXTENT_LOCKED		(1U << 2)
 #define EXTENT_NEW		(1U << 3)
 #define EXTENT_DELALLOC		(1U << 4)
 #define EXTENT_DEFRAG		(1U << 5)
 #define EXTENT_BOUNDARY		(1U << 6)
 #define EXTENT_NODATASUM	(1U << 7)
 #define EXTENT_CLEAR_META_RESV	(1U << 8)
 #define EXTENT_NEED_WAIT	(1U << 9)
 #define EXTENT_DAMAGED		(1U << 10)
 #define EXTENT_NORESERVE	(1U << 11)
 #define EXTENT_QGROUP_RESERVED	(1U << 12)
 #define EXTENT_CLEAR_DATA_RESV	(1U << 13)
 #define EXTENT_DELALLOC_NEW	(1U << 14)
 #define EXTENT_DO_ACCOUNTING    (EXTENT_CLEAR_META_RESV | \
 				 EXTENT_CLEAR_DATA_RESV)
 #define EXTENT_CTLBITS		(EXTENT_DO_ACCOUNTING)

 /*
  * Redefined bits above which are used only in the device allocation tree,
  * shouldn't be using EXTENT_LOCKED / EXTENT_BOUNDARY / EXTENT_CLEAR_META_RESV
  * / EXTENT_CLEAR_DATA_RESV because they have special meaning to the bit
  * manipulation functions
  */
 #define CHUNK_ALLOCATED EXTENT_DIRTY
 #define CHUNK_TRIMMED   EXTENT_DEFRAG

 /*
  * 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

 enum {
 	EXTENT_BUFFER_UPTODATE,
 	EXTENT_BUFFER_DIRTY,
 	EXTENT_BUFFER_CORRUPT,
 	/* this got triggered by readahead */
 	EXTENT_BUFFER_READAHEAD,
 	EXTENT_BUFFER_TREE_REF,
 	EXTENT_BUFFER_STALE,
 	EXTENT_BUFFER_WRITEBACK,
 	/* read IO error */
 	EXTENT_BUFFER_READ_ERR,
 	EXTENT_BUFFER_UNMAPPED,
 	EXTENT_BUFFER_IN_TREE,
 	/* write IO error */
 	EXTENT_BUFFER_WRITE_ERR,
 };

 /* these are flags for __process_pages_contig */
 #define PAGE_UNLOCK		(1 << 0)
 #define PAGE_CLEAR_DIRTY	(1 << 1)
 #define PAGE_SET_WRITEBACK	(1 << 2)
 #define PAGE_END_WRITEBACK	(1 << 3)
 #define PAGE_SET_PRIVATE2	(1 << 4)
 #define PAGE_SET_ERROR		(1 << 5)
 #define PAGE_LOCK		(1 << 6)

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

 /*
  * The extent buffer bitmap operations are done with byte granularity instead of
  * word granularity for two reasons:
  * 1. The bitmaps must be little-endian on disk.
  * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
  *    single word in a bitmap may straddle two pages in the extent buffer.
  */
 #define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
 #define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
 #define BITMAP_FIRST_BYTE_MASK(start) \
 	((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
 #define BITMAP_LAST_BYTE_MASK(nbits) \
 	(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))

 struct extent_state;
 struct btrfs_root;
 struct btrfs_inode;
 struct btrfs_io_bio;
 struct io_failure_record;


 typedef blk_status_t (extent_submit_bio_start_t)(void *private_data,
 		struct bio *bio, u64 bio_offset);

 struct extent_io_ops {
 	/*
 	 * The following callbacks must be always defined, the function
 	 * pointer will be called unconditionally.
 	 */
 	blk_status_t (*submit_bio_hook)(struct inode *inode, struct bio *bio,
 					int mirror_num, unsigned long bio_flags);
 	int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset,
 				    struct page *page, u64 start, u64 end,
 				    int mirror);
 };

 enum {
 	IO_TREE_FS_INFO_FREED_EXTENTS0,
 	IO_TREE_FS_INFO_FREED_EXTENTS1,
 	IO_TREE_INODE_IO,
 	IO_TREE_INODE_IO_FAILURE,
 	IO_TREE_RELOC_BLOCKS,
 	IO_TREE_TRANS_DIRTY_PAGES,
 	IO_TREE_ROOT_DIRTY_LOG_PAGES,
 	IO_TREE_SELFTEST,
 };

 struct extent_io_tree {
 	struct rb_root state;
 	struct btrfs_fs_info *fs_info;
 	void *private_data;
 	u64 dirty_bytes;
 	bool track_uptodate;

 	/* Who owns this io tree, should be one of IO_TREE_* */
 	u8 owner;

 	spinlock_t lock;
 	const struct extent_io_ops *ops;
 };

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

 	/* ADD NEW ELEMENTS AFTER THIS */
 	wait_queue_head_t wq;
 	refcount_t refs;
 	unsigned state;

 	struct io_failure_record *failrec;

 #ifdef CONFIG_BTRFS_DEBUG
 	struct list_head leak_list;
 #endif
 };

 #define INLINE_EXTENT_BUFFER_PAGES 16
 #define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE)
 struct extent_buffer {
 	u64 start;
 	unsigned long len;
 	unsigned long bflags;
 	struct btrfs_fs_info *fs_info;
 	spinlock_t refs_lock;
 	atomic_t refs;
 	atomic_t io_pages;
 	int read_mirror;
 	struct rcu_head rcu_head;
 	pid_t lock_owner;

 	atomic_t blocking_writers;
 	atomic_t blocking_readers;
 	bool lock_nested;
 	/* >= 0 if eb belongs to a log tree, -1 otherwise */
 	short log_index;

 	/* 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;
 	struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
 #ifdef CONFIG_BTRFS_DEBUG
 	atomic_t spinning_writers;
 	atomic_t spinning_readers;
 	atomic_t read_locks;
 	atomic_t write_locks;
 	struct list_head leak_list;
 #endif
 };

 /*
  * Structure to record how many bytes and which ranges are set/cleared
  */
 struct extent_changeset {
 	/* How many bytes are set/cleared in this operation */
 	unsigned int bytes_changed;

 	/* Changed ranges */
 	struct ulist range_changed;
 };

 static inline void extent_changeset_init(struct extent_changeset *changeset)
 {
 	changeset->bytes_changed = 0;
 	ulist_init(&changeset->range_changed);
 }

 static inline struct extent_changeset *extent_changeset_alloc(void)
 {
 	struct extent_changeset *ret;

 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
 	if (!ret)
 		return NULL;

 	extent_changeset_init(ret);
 	return ret;
 }

 static inline void extent_changeset_release(struct extent_changeset *changeset)
 {
 	if (!changeset)
 		return;
 	changeset->bytes_changed = 0;
 	ulist_release(&changeset->range_changed);
 }

 static inline void extent_changeset_free(struct extent_changeset *changeset)
 {
 	if (!changeset)
 		return;
 	extent_changeset_release(changeset);
 	kfree(changeset);
 }

 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 btrfs_inode *inode,
 					  struct page *page,
 					  size_t pg_offset,
 					  u64 start, u64 len,
 					  int create);

 void extent_io_tree_init(struct btrfs_fs_info *fs_info,
 			 struct extent_io_tree *tree, unsigned int owner,
 			 void *private_data);
 void extent_io_tree_release(struct extent_io_tree *tree);
 int try_release_extent_mapping(struct page *page, gfp_t mask);
 int try_release_extent_buffer(struct page *page);
 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 		     struct extent_state **cached);

 static inline int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
 {
 	return lock_extent_bits(tree, start, end, NULL);
 }

 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
 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 __cold extent_io_exit(void);

 u64 count_range_bits(struct extent_io_tree *tree,
 		     u64 *start, u64 search_end,
 		     u64 max_bytes, unsigned bits, int contig);

 void free_extent_state(struct extent_state *state);
 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
 		   unsigned bits, int filled,
 		   struct extent_state *cached_state);
 int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 		unsigned bits, struct extent_changeset *changeset);
 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 		     unsigned bits, int wake, int delete,
 		     struct extent_state **cached);
 int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 		     unsigned bits, int wake, int delete,
 		     struct extent_state **cached, gfp_t mask,
 		     struct extent_changeset *changeset);

 static inline int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
 {
 	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL);
 }

 static inline int unlock_extent_cached(struct extent_io_tree *tree, u64 start,
 		u64 end, struct extent_state **cached)
 {
 	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
 				GFP_NOFS, NULL);
 }

 static inline int unlock_extent_cached_atomic(struct extent_io_tree *tree,
 		u64 start, u64 end, struct extent_state **cached)
 {
 	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
 				GFP_ATOMIC, NULL);
 }

 static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start,
 		u64 end, unsigned bits)
 {
 	int wake = 0;

 	if (bits & EXTENT_LOCKED)
 		wake = 1;

 	return clear_extent_bit(tree, start, end, bits, wake, 0, NULL);
 }

 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 			   unsigned bits, struct extent_changeset *changeset);
 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 		   unsigned bits, u64 *failed_start,
 		   struct extent_state **cached_state, gfp_t mask);
 int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
 			   unsigned bits);

 static inline int set_extent_bits(struct extent_io_tree *tree, u64 start,
 		u64 end, unsigned bits)
 {
 	return set_extent_bit(tree, start, end, bits, NULL, NULL, GFP_NOFS);
 }

 static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
 		u64 end, struct extent_state **cached_state)
 {
 	return __clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
 				cached_state, GFP_NOFS, NULL);
 }

 static inline int set_extent_dirty(struct extent_io_tree *tree, u64 start,
 		u64 end, gfp_t mask)
 {
 	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
 			      NULL, mask);
 }

 static inline int clear_extent_dirty(struct extent_io_tree *tree, u64 start,
 				     u64 end, struct extent_state **cached)
 {
 	return clear_extent_bit(tree, start, end,
 				EXTENT_DIRTY | EXTENT_DELALLOC |
 				EXTENT_DO_ACCOUNTING, 0, 0, cached);
 }

 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 		       unsigned bits, unsigned clear_bits,
 		       struct extent_state **cached_state);

 static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start,
 				      u64 end, unsigned int extra_bits,
 				      struct extent_state **cached_state)
 {
 	return set_extent_bit(tree, start, end,
 			      EXTENT_DELALLOC | EXTENT_UPTODATE | extra_bits,
 			      NULL, cached_state, GFP_NOFS);
 }

 static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start,
 		u64 end, struct extent_state **cached_state)
 {
 	return set_extent_bit(tree, start, end,
 			      EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
 			      NULL, cached_state, GFP_NOFS);
 }

 static inline int set_extent_new(struct extent_io_tree *tree, u64 start,
 		u64 end)
 {
 	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, NULL,
 			GFP_NOFS);
 }

 static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start,
 		u64 end, struct extent_state **cached_state, gfp_t mask)
 {
 	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
 			      cached_state, mask);
 }

 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
 			  u64 *start_ret, u64 *end_ret, unsigned bits,
 			  struct extent_state **cached_state);
 void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
 				 u64 *start_ret, u64 *end_ret, unsigned bits);
 int extent_invalidatepage(struct extent_io_tree *tree,
 			  struct page *page, unsigned long offset);
 int extent_write_full_page(struct page *page, struct writeback_control *wbc);
 int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
 			      int mode);
 int extent_writepages(struct address_space *mapping,
 		      struct writeback_control *wbc);
 int btree_write_cache_pages(struct address_space *mapping,
 			    struct writeback_control *wbc);
 int extent_readpages(struct address_space *mapping, struct list_head *pages,
 		     unsigned nr_pages);
 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		__u64 start, __u64 len);
 void set_page_extent_mapped(struct page *page);

 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 					  u64 start);
 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 						  u64 start, unsigned long len);
 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 						u64 start);
 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
 					 u64 start);
 void free_extent_buffer(struct extent_buffer *eb);
 void free_extent_buffer_stale(struct extent_buffer *eb);
 #define WAIT_NONE	0
 #define WAIT_COMPLETE	1
 #define WAIT_PAGE_LOCK	2
 int read_extent_buffer_pages(struct extent_buffer *eb, int wait,
 			     int mirror_num);
 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);

 static inline int num_extent_pages(const struct extent_buffer *eb)
 {
 	return (round_up(eb->start + eb->len, PAGE_SIZE) >> PAGE_SHIFT) -
 	       (eb->start >> PAGE_SHIFT);
 }

 static inline void extent_buffer_get(struct extent_buffer *eb)
 {
 	atomic_inc(&eb->refs);
 }

 static inline int extent_buffer_uptodate(struct extent_buffer *eb)
 {
 	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
 }

 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
 			 unsigned long start, unsigned long len);
 void read_extent_buffer(const struct extent_buffer *eb, void *dst,
 			unsigned long start,
 			unsigned long len);
 int read_extent_buffer_to_user(const struct extent_buffer *eb,
 			       void __user *dst, unsigned long start,
 			       unsigned long len);
 void write_extent_buffer_fsid(struct extent_buffer *eb, const void *src);
 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
 		const void *src);
 void write_extent_buffer(struct extent_buffer *eb, const void *src,
 			 unsigned long start, unsigned long len);
 void copy_extent_buffer_full(struct extent_buffer *dst,
 			     struct extent_buffer *src);
 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 memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
 			   unsigned long len);
 int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
 			   unsigned long pos);
 void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
 			      unsigned long pos, unsigned long len);
 void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
 				unsigned long pos, unsigned long len);
 void clear_extent_buffer_dirty(struct extent_buffer *eb);
 bool set_extent_buffer_dirty(struct extent_buffer *eb);
 void set_extent_buffer_uptodate(struct extent_buffer *eb);
 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_under_io(struct extent_buffer *eb);
 int map_private_extent_buffer(const struct extent_buffer *eb,
 			      unsigned long offset, unsigned long min_len,
 			      char **map, unsigned long *map_start,
 			      unsigned long *map_len);
 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
 void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
 				 u64 delalloc_end, struct page *locked_page,
 				 unsigned bits_to_clear,
 				 unsigned long page_ops);
 struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte);
 struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs);
 struct bio *btrfs_bio_clone(struct bio *bio);
 struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size);

 struct btrfs_fs_info;
 struct btrfs_inode;

 int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
 		      u64 length, u64 logical, struct page *page,
 		      unsigned int pg_offset, int mirror_num);
 int clean_io_failure(struct btrfs_fs_info *fs_info,
 		     struct extent_io_tree *failure_tree,
 		     struct extent_io_tree *io_tree, u64 start,
 		     struct page *page, u64 ino, unsigned int pg_offset);
 void end_extent_writepage(struct page *page, int err, u64 start, u64 end);
 int btrfs_repair_eb_io_failure(struct extent_buffer *eb, int mirror_num);

 /*
  * When IO fails, either with EIO or csum verification fails, we
  * try other mirrors that might have a good copy of the data.  This
  * io_failure_record is used to record state as we go through all the
  * mirrors.  If another mirror has good data, the page is set up to date
  * and things continue.  If a good mirror can't be found, the original
  * bio end_io callback is called to indicate things have failed.
  */
 struct io_failure_record {
 	struct page *page;
 	u64 start;
 	u64 len;
 	u64 logical;
 	unsigned long bio_flags;
 	int this_mirror;
 	int failed_mirror;
 	int in_validation;
 };


 void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start,
 		u64 end);
 int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
 				struct io_failure_record **failrec_ret);
 bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
 			    struct io_failure_record *failrec, int fail_mirror);
 struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
 				    struct io_failure_record *failrec,
 				    struct page *page, int pg_offset, int icsum,
 				    bio_end_io_t *endio_func, void *data);
 int free_io_failure(struct extent_io_tree *failure_tree,
 		    struct extent_io_tree *io_tree,
 		    struct io_failure_record *rec);
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 bool find_lock_delalloc_range(struct inode *inode, struct extent_io_tree *tree,
 			     struct page *locked_page, u64 *start,
 			     u64 *end);
 #endif
 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
 					       u64 start);

 #endif
	/* SPDX-License-Identifier: GPL-2.0 */

	#ifndef BTRFS_EXTENT_IO_H
	#define BTRFS_EXTENT_IO_H

	#include <linux/rbtree.h>
	#include <linux/refcount.h>
	#include "ulist.h"

	/* bits for the extent state */
	#define EXTENT_DIRTY (1U << 0)
	#define EXTENT_UPTODATE (1U << 1)
	#define EXTENT_LOCKED (1U << 2)
	#define EXTENT_NEW (1U << 3)
	#define EXTENT_DELALLOC (1U << 4)
	#define EXTENT_DEFRAG (1U << 5)
	#define EXTENT_BOUNDARY (1U << 6)
	#define EXTENT_NODATASUM (1U << 7)
	#define EXTENT_CLEAR_META_RESV (1U << 8)
	#define EXTENT_NEED_WAIT (1U << 9)
	#define EXTENT_DAMAGED (1U << 10)
	#define EXTENT_NORESERVE (1U << 11)
	#define EXTENT_QGROUP_RESERVED (1U << 12)
	#define EXTENT_CLEAR_DATA_RESV (1U << 13)
	#define EXTENT_DELALLOC_NEW (1U << 14)
	#define EXTENT_DO_ACCOUNTING (EXTENT_CLEAR_META_RESV \| \
	EXTENT_CLEAR_DATA_RESV)
	#define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING)

	/*
	* Redefined bits above which are used only in the device allocation tree,
	* shouldn't be using EXTENT_LOCKED / EXTENT_BOUNDARY / EXTENT_CLEAR_META_RESV
	* / EXTENT_CLEAR_DATA_RESV because they have special meaning to the bit
	* manipulation functions
	*/
	#define CHUNK_ALLOCATED EXTENT_DIRTY
	#define CHUNK_TRIMMED EXTENT_DEFRAG

	/*
	* 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

	enum {
	EXTENT_BUFFER_UPTODATE,
	EXTENT_BUFFER_DIRTY,
	EXTENT_BUFFER_CORRUPT,
	/* this got triggered by readahead */
	EXTENT_BUFFER_READAHEAD,
	EXTENT_BUFFER_TREE_REF,
	EXTENT_BUFFER_STALE,
	EXTENT_BUFFER_WRITEBACK,
	/* read IO error */
	EXTENT_BUFFER_READ_ERR,
	EXTENT_BUFFER_UNMAPPED,
	EXTENT_BUFFER_IN_TREE,
	/* write IO error */
	EXTENT_BUFFER_WRITE_ERR,
	};

	/* these are flags for __process_pages_contig */
	#define PAGE_UNLOCK (1 << 0)
	#define PAGE_CLEAR_DIRTY (1 << 1)
	#define PAGE_SET_WRITEBACK (1 << 2)
	#define PAGE_END_WRITEBACK (1 << 3)
	#define PAGE_SET_PRIVATE2 (1 << 4)
	#define PAGE_SET_ERROR (1 << 5)
	#define PAGE_LOCK (1 << 6)

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

	/*
	* The extent buffer bitmap operations are done with byte granularity instead of
	* word granularity for two reasons:
	* 1. The bitmaps must be little-endian on disk.
	* 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
	* single word in a bitmap may straddle two pages in the extent buffer.
	*/
	#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
	#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
	#define BITMAP_FIRST_BYTE_MASK(start) \
	((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
	#define BITMAP_LAST_BYTE_MASK(nbits) \
	(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))

	struct extent_state;
	struct btrfs_root;
	struct btrfs_inode;
	struct btrfs_io_bio;
	struct io_failure_record;


	typedef blk_status_t (extent_submit_bio_start_t)(void *private_data,
	struct bio *bio, u64 bio_offset);

	struct extent_io_ops {
	/*
	* The following callbacks must be always defined, the function
	* pointer will be called unconditionally.
	*/
	blk_status_t (submit_bio_hook)(struct inode inode, struct bio *bio,
	int mirror_num, unsigned long bio_flags);
	int (readpage_end_io_hook)(struct btrfs_io_bio io_bio, u64 phy_offset,
	struct page *page, u64 start, u64 end,
	int mirror);
	};

	enum {
	IO_TREE_FS_INFO_FREED_EXTENTS0,
	IO_TREE_FS_INFO_FREED_EXTENTS1,
	IO_TREE_INODE_IO,
	IO_TREE_INODE_IO_FAILURE,
	IO_TREE_RELOC_BLOCKS,
	IO_TREE_TRANS_DIRTY_PAGES,
	IO_TREE_ROOT_DIRTY_LOG_PAGES,
	IO_TREE_SELFTEST,
	};

	struct extent_io_tree {
	struct rb_root state;
	struct btrfs_fs_info *fs_info;
	void *private_data;
	u64 dirty_bytes;
	bool track_uptodate;

	/* Who owns this io tree, should be one of IO_TREE_* */
	u8 owner;

	spinlock_t lock;
	const struct extent_io_ops *ops;
	};

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

	/* ADD NEW ELEMENTS AFTER THIS */
	wait_queue_head_t wq;
	refcount_t refs;
	unsigned state;

	struct io_failure_record *failrec;

	#ifdef CONFIG_BTRFS_DEBUG
	struct list_head leak_list;
	#endif
	};

	#define INLINE_EXTENT_BUFFER_PAGES 16
	#define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE)
	struct extent_buffer {
	u64 start;
	unsigned long len;
	unsigned long bflags;
	struct btrfs_fs_info *fs_info;
	spinlock_t refs_lock;
	atomic_t refs;
	atomic_t io_pages;
	int read_mirror;
	struct rcu_head rcu_head;
	pid_t lock_owner;

	atomic_t blocking_writers;
	atomic_t blocking_readers;
	bool lock_nested;
	/* >= 0 if eb belongs to a log tree, -1 otherwise */
	short log_index;

	/* 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;
	struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
	#ifdef CONFIG_BTRFS_DEBUG
	atomic_t spinning_writers;
	atomic_t spinning_readers;
	atomic_t read_locks;
	atomic_t write_locks;
	struct list_head leak_list;
	#endif
	};

	/*
	* Structure to record how many bytes and which ranges are set/cleared
	*/
	struct extent_changeset {
	/* How many bytes are set/cleared in this operation */
	unsigned int bytes_changed;

	/* Changed ranges */
	struct ulist range_changed;
	};

	static inline void extent_changeset_init(struct extent_changeset *changeset)
	{
	changeset->bytes_changed = 0;
	ulist_init(&changeset->range_changed);
	}

	static inline struct extent_changeset *extent_changeset_alloc(void)
	{
	struct extent_changeset *ret;

	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
	if (!ret)
	return NULL;

	extent_changeset_init(ret);
	return ret;
	}

	static inline void extent_changeset_release(struct extent_changeset *changeset)
	{
	if (!changeset)
	return;
	changeset->bytes_changed = 0;
	ulist_release(&changeset->range_changed);
	}

	static inline void extent_changeset_free(struct extent_changeset *changeset)
	{
	if (!changeset)
	return;
	extent_changeset_release(changeset);
	kfree(changeset);
	}

	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 btrfs_inode inode,
	struct page *page,
	size_t pg_offset,
	u64 start, u64 len,
	int create);

	void extent_io_tree_init(struct btrfs_fs_info *fs_info,
	struct extent_io_tree *tree, unsigned int owner,
	void *private_data);
	void extent_io_tree_release(struct extent_io_tree *tree);
	int try_release_extent_mapping(struct page *page, gfp_t mask);
	int try_release_extent_buffer(struct page *page);
	int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
	struct extent_state **cached);

	static inline int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
	{
	return lock_extent_bits(tree, start, end, NULL);
	}

	int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
	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 __cold extent_io_exit(void);

	u64 count_range_bits(struct extent_io_tree *tree,
	u64 *start, u64 search_end,
	u64 max_bytes, unsigned bits, int contig);

	void free_extent_state(struct extent_state *state);
	int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, int filled,
	struct extent_state *cached_state);
	int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, struct extent_changeset *changeset);
	int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, int wake, int delete,
	struct extent_state **cached);
	int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, int wake, int delete,
	struct extent_state **cached, gfp_t mask,
	struct extent_changeset *changeset);

	static inline int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
	{
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL);
	}

	static inline int unlock_extent_cached(struct extent_io_tree *tree, u64 start,
	u64 end, struct extent_state **cached)
	{
	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
	GFP_NOFS, NULL);
	}

	static inline int unlock_extent_cached_atomic(struct extent_io_tree *tree,
	u64 start, u64 end, struct extent_state **cached)
	{
	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
	GFP_ATOMIC, NULL);
	}

	static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start,
	u64 end, unsigned bits)
	{
	int wake = 0;

	if (bits & EXTENT_LOCKED)
	wake = 1;

	return clear_extent_bit(tree, start, end, bits, wake, 0, NULL);
	}

	int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, struct extent_changeset *changeset);
	int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, u64 *failed_start,
	struct extent_state **cached_state, gfp_t mask);
	int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits);

	static inline int set_extent_bits(struct extent_io_tree *tree, u64 start,
	u64 end, unsigned bits)
	{
	return set_extent_bit(tree, start, end, bits, NULL, NULL, GFP_NOFS);
	}

	static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
	u64 end, struct extent_state **cached_state)
	{
	return __clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
	cached_state, GFP_NOFS, NULL);
	}

	static inline int set_extent_dirty(struct extent_io_tree *tree, u64 start,
	u64 end, gfp_t mask)
	{
	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
	NULL, mask);
	}

	static inline int clear_extent_dirty(struct extent_io_tree *tree, u64 start,
	u64 end, struct extent_state **cached)
	{
	return clear_extent_bit(tree, start, end,
	EXTENT_DIRTY \| EXTENT_DELALLOC \|
	EXTENT_DO_ACCOUNTING, 0, 0, cached);
	}

	int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
	unsigned bits, unsigned clear_bits,
	struct extent_state **cached_state);

	static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start,
	u64 end, unsigned int extra_bits,
	struct extent_state **cached_state)
	{
	return set_extent_bit(tree, start, end,
	EXTENT_DELALLOC \| EXTENT_UPTODATE \| extra_bits,
	NULL, cached_state, GFP_NOFS);
	}

	static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start,
	u64 end, struct extent_state **cached_state)
	{
	return set_extent_bit(tree, start, end,
	EXTENT_DELALLOC \| EXTENT_UPTODATE \| EXTENT_DEFRAG,
	NULL, cached_state, GFP_NOFS);
	}

	static inline int set_extent_new(struct extent_io_tree *tree, u64 start,
	u64 end)
	{
	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, NULL,
	GFP_NOFS);
	}

	static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start,
	u64 end, struct extent_state **cached_state, gfp_t mask)
	{
	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
	cached_state, mask);
	}

	int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
	u64 start_ret, u64 end_ret, unsigned bits,
	struct extent_state **cached_state);
	void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
	u64 start_ret, u64 end_ret, unsigned bits);
	int extent_invalidatepage(struct extent_io_tree *tree,
	struct page *page, unsigned long offset);
	int extent_write_full_page(struct page page, struct writeback_control wbc);
	int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
	int mode);
	int extent_writepages(struct address_space *mapping,
	struct writeback_control *wbc);
	int btree_write_cache_pages(struct address_space *mapping,
	struct writeback_control *wbc);
	int extent_readpages(struct address_space mapping, struct list_head pages,
	unsigned nr_pages);
	int extent_fiemap(struct inode inode, struct fiemap_extent_info fieinfo,
	__u64 start, __u64 len);
	void set_page_extent_mapped(struct page *page);

	struct extent_buffer alloc_extent_buffer(struct btrfs_fs_info fs_info,
	u64 start);
	struct extent_buffer __alloc_dummy_extent_buffer(struct btrfs_fs_info fs_info,
	u64 start, unsigned long len);
	struct extent_buffer alloc_dummy_extent_buffer(struct btrfs_fs_info fs_info,
	u64 start);
	struct extent_buffer btrfs_clone_extent_buffer(struct extent_buffer src);
	struct extent_buffer find_extent_buffer(struct btrfs_fs_info fs_info,
	u64 start);
	void free_extent_buffer(struct extent_buffer *eb);
	void free_extent_buffer_stale(struct extent_buffer *eb);
	#define WAIT_NONE 0
	#define WAIT_COMPLETE 1
	#define WAIT_PAGE_LOCK 2
	int read_extent_buffer_pages(struct extent_buffer *eb, int wait,
	int mirror_num);
	void wait_on_extent_buffer_writeback(struct extent_buffer *eb);

	static inline int num_extent_pages(const struct extent_buffer *eb)
	{
	return (round_up(eb->start + eb->len, PAGE_SIZE) >> PAGE_SHIFT) -
	(eb->start >> PAGE_SHIFT);
	}

	static inline void extent_buffer_get(struct extent_buffer *eb)
	{
	atomic_inc(&eb->refs);
	}

	static inline int extent_buffer_uptodate(struct extent_buffer *eb)
	{
	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
	}

	int memcmp_extent_buffer(const struct extent_buffer eb, const void ptrv,
	unsigned long start, unsigned long len);
	void read_extent_buffer(const struct extent_buffer eb, void dst,
	unsigned long start,
	unsigned long len);
	int read_extent_buffer_to_user(const struct extent_buffer *eb,
	void __user *dst, unsigned long start,
	unsigned long len);
	void write_extent_buffer_fsid(struct extent_buffer eb, const void src);
	void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
	const void *src);
	void write_extent_buffer(struct extent_buffer eb, const void src,
	unsigned long start, unsigned long len);
	void copy_extent_buffer_full(struct extent_buffer *dst,
	struct extent_buffer *src);
	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 memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
	unsigned long len);
	int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
	unsigned long pos);
	void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
	unsigned long pos, unsigned long len);
	void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
	unsigned long pos, unsigned long len);
	void clear_extent_buffer_dirty(struct extent_buffer *eb);
	bool set_extent_buffer_dirty(struct extent_buffer *eb);
	void set_extent_buffer_uptodate(struct extent_buffer *eb);
	void clear_extent_buffer_uptodate(struct extent_buffer *eb);
	int extent_buffer_under_io(struct extent_buffer *eb);
	int map_private_extent_buffer(const struct extent_buffer *eb,
	unsigned long offset, unsigned long min_len,
	char *map, unsigned long map_start,
	unsigned long *map_len);
	void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
	void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
	void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
	u64 delalloc_end, struct page *locked_page,
	unsigned bits_to_clear,
	unsigned long page_ops);
	struct bio btrfs_bio_alloc(struct block_device bdev, u64 first_byte);
	struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs);
	struct bio btrfs_bio_clone(struct bio bio);
	struct bio btrfs_bio_clone_partial(struct bio orig, int offset, int size);

	struct btrfs_fs_info;
	struct btrfs_inode;

	int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
	u64 length, u64 logical, struct page *page,
	unsigned int pg_offset, int mirror_num);
	int clean_io_failure(struct btrfs_fs_info *fs_info,
	struct extent_io_tree *failure_tree,
	struct extent_io_tree *io_tree, u64 start,
	struct page *page, u64 ino, unsigned int pg_offset);
	void end_extent_writepage(struct page *page, int err, u64 start, u64 end);
	int btrfs_repair_eb_io_failure(struct extent_buffer *eb, int mirror_num);

	/*
	* When IO fails, either with EIO or csum verification fails, we
	* try other mirrors that might have a good copy of the data. This
	* io_failure_record is used to record state as we go through all the
	* mirrors. If another mirror has good data, the page is set up to date
	* and things continue. If a good mirror can't be found, the original
	* bio end_io callback is called to indicate things have failed.
	*/
	struct io_failure_record {
	struct page *page;
	u64 start;
	u64 len;
	u64 logical;
	unsigned long bio_flags;
	int this_mirror;
	int failed_mirror;
	int in_validation;
	};


	void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start,
	u64 end);
	int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
	struct io_failure_record **failrec_ret);
	bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
	struct io_failure_record *failrec, int fail_mirror);
	struct bio btrfs_create_repair_bio(struct inode inode, struct bio *failed_bio,
	struct io_failure_record *failrec,
	struct page *page, int pg_offset, int icsum,
	bio_end_io_t endio_func, void data);
	int free_io_failure(struct extent_io_tree *failure_tree,
	struct extent_io_tree *io_tree,
	struct io_failure_record *rec);
	#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
	bool find_lock_delalloc_range(struct inode inode, struct extent_io_tree tree,
	struct page locked_page, u64 start,
	u64 *end);
	#endif
	struct extent_buffer alloc_test_extent_buffer(struct btrfs_fs_info fs_info,
	u64 start);

	#endif