btrfs-progs/libbtrfs/ctree.h

/*
 * 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_CTREE_H__
#define __BTRFS_CTREE_H__

#include <stdbool.h>

#if BTRFS_FLAT_INCLUDES
#include "kernel-lib/list.h"
#include "kernel-lib/rbtree.h"
#include "kerncompat.h"
#include "ioctl.h"
#else
#include <btrfs/list.h>
#include <btrfs/rbtree.h>
#include <btrfs/kerncompat.h>
#include <btrfs/ioctl.h>
#endif /* BTRFS_FLAT_INCLUDES */

struct btrfs_root;
struct btrfs_trans_handle;
struct btrfs_free_space_ctl;
#define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */

/*
 * Fake signature for an unfinalized filesystem, which only has barebone tree
 * structures (normally 6 near empty trees, on SINGLE meta/sys temporary chunks)
 *
 * ascii !BHRfS_M, no null
 */
#define BTRFS_MAGIC_TEMPORARY 0x4D5F536652484221ULL

#define BTRFS_MAX_MIRRORS 3

#define BTRFS_MAX_LEVEL 8

/* holds pointers to all of the tree roots */
#define BTRFS_ROOT_TREE_OBJECTID 1ULL

/* stores information about which extents are in use, and reference counts */
#define BTRFS_EXTENT_TREE_OBJECTID 2ULL

/*
 * chunk tree stores translations from logical -> physical block numbering
 * the super block points to the chunk tree
 */
#define BTRFS_CHUNK_TREE_OBJECTID 3ULL

/*
 * stores information about which areas of a given device are in use.
 * one per device.  The tree of tree roots points to the device tree
 */
#define BTRFS_DEV_TREE_OBJECTID 4ULL

/* one per subvolume, storing files and directories */
#define BTRFS_FS_TREE_OBJECTID 5ULL

/* directory objectid inside the root tree */
#define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL
/* holds checksums of all the data extents */
#define BTRFS_CSUM_TREE_OBJECTID 7ULL
#define BTRFS_QUOTA_TREE_OBJECTID 8ULL

/* for storing items that use the BTRFS_UUID_KEY* */
#define BTRFS_UUID_TREE_OBJECTID 9ULL

/* tracks free space in block groups. */
#define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL

/* hold the block group items. */
#define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL

/* device stats in the device tree */
#define BTRFS_DEV_STATS_OBJECTID 0ULL

/* for storing balance parameters in the root tree */
#define BTRFS_BALANCE_OBJECTID -4ULL

/* orphan objectid for tracking unlinked/truncated files */
#define BTRFS_ORPHAN_OBJECTID -5ULL

/* does write ahead logging to speed up fsyncs */
#define BTRFS_TREE_LOG_OBJECTID -6ULL
#define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL

/* space balancing */
#define BTRFS_TREE_RELOC_OBJECTID -8ULL
#define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL

/*
 * extent checksums all have this objectid
 * this allows them to share the logging tree
 * for fsyncs
 */
#define BTRFS_EXTENT_CSUM_OBJECTID -10ULL

/* For storing free space cache */
#define BTRFS_FREE_SPACE_OBJECTID -11ULL

/*
 * The inode number assigned to the special inode for storing
 * free ino cache
 */
#define BTRFS_FREE_INO_OBJECTID -12ULL

/* dummy objectid represents multiple objectids */
#define BTRFS_MULTIPLE_OBJECTIDS -255ULL

/*
 * All files have objectids in this range.
 */
#define BTRFS_FIRST_FREE_OBJECTID 256ULL
#define BTRFS_LAST_FREE_OBJECTID -256ULL
#define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL



/*
 * the device items go into the chunk tree.  The key is in the form
 * [ 1 BTRFS_DEV_ITEM_KEY device_id ]
 */
#define BTRFS_DEV_ITEMS_OBJECTID 1ULL

#define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2ULL

/*
 * the max metadata block size.  This limit is somewhat artificial,
 * but the memmove costs go through the roof for larger blocks.
 */
#define BTRFS_MAX_METADATA_BLOCKSIZE 65536

/*
 * we can actually store much bigger names, but lets not confuse the rest
 * of linux
 */
#define BTRFS_NAME_LEN 255

/*
 * Theoretical limit is larger, but we keep this down to a sane
 * value. That should limit greatly the possibility of collisions on
 * inode ref items.
 */
#define	BTRFS_LINK_MAX	65535U

/* 32 bytes in various csum fields */
#define BTRFS_CSUM_SIZE 32

/* csum types */
enum btrfs_csum_type {
	BTRFS_CSUM_TYPE_CRC32		= 0,
	BTRFS_CSUM_TYPE_XXHASH		= 1,
	BTRFS_CSUM_TYPE_SHA256		= 2,
	BTRFS_CSUM_TYPE_BLAKE2		= 3,
};

#define BTRFS_EMPTY_DIR_SIZE 0

#define BTRFS_FT_UNKNOWN	0
#define BTRFS_FT_REG_FILE	1
#define BTRFS_FT_DIR		2
#define BTRFS_FT_CHRDEV		3
#define BTRFS_FT_BLKDEV		4
#define BTRFS_FT_FIFO		5
#define BTRFS_FT_SOCK		6
#define BTRFS_FT_SYMLINK	7
#define BTRFS_FT_XATTR		8
#define BTRFS_FT_MAX		9

#define BTRFS_ROOT_SUBVOL_RDONLY	(1ULL << 0)

/*
 * the key defines the order in the tree, and so it also defines (optimal)
 * block layout.  objectid corresponds to the inode number.  The flags
 * tells us things about the object, and is a kind of stream selector.
 * so for a given inode, keys with flags of 1 might refer to the inode
 * data, flags of 2 may point to file data in the btree and flags == 3
 * may point to extents.
 *
 * offset is the starting byte offset for this key in the stream.
 *
 * btrfs_disk_key is in disk byte order.  struct btrfs_key is always
 * in cpu native order.  Otherwise they are identical and their sizes
 * should be the same (ie both packed)
 */
struct btrfs_disk_key {
	__le64 objectid;
	u8 type;
	__le64 offset;
} __attribute__ ((__packed__));

struct btrfs_key {
	u64 objectid;
	u8 type;
	u64 offset;
} __attribute__ ((__packed__));

struct cache_tree {
	struct rb_root root;
};

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

struct extent_io_tree {
	struct cache_tree state;
	struct cache_tree cache;
	struct list_head lru;
	u64 cache_size;
	u64 max_cache_size;
};

struct extent_state {
	struct cache_extent cache_node;
	u64 start;
	u64 end;
	int refs;
	unsigned long state;
	u64 xprivate;
};

struct extent_buffer {
	struct cache_extent cache_node;
	u64 start;
	struct list_head lru;
	struct list_head recow;
	u32 len;
	int refs;
	u32 flags;
	struct btrfs_fs_info *fs_info;
	char data[] __attribute__((aligned(8)));
};

struct btrfs_mapping_tree {
	struct cache_tree cache_tree;
};

#define BTRFS_UUID_SIZE 16
struct btrfs_dev_item {
	/* the internal btrfs device id */
	__le64 devid;

	/* size of the device */
	__le64 total_bytes;

	/* bytes used */
	__le64 bytes_used;

	/* optimal io alignment for this device */
	__le32 io_align;

	/* optimal io width for this device */
	__le32 io_width;

	/* minimal io size for this device */
	__le32 sector_size;

	/* type and info about this device */
	__le64 type;

	/* expected generation for this device */
	__le64 generation;

	/*
	 * starting byte of this partition on the device,
	 * to allow for stripe alignment in the future
	 */
	__le64 start_offset;

	/* grouping information for allocation decisions */
	__le32 dev_group;

	/* seek speed 0-100 where 100 is fastest */
	u8 seek_speed;

	/* bandwidth 0-100 where 100 is fastest */
	u8 bandwidth;

	/* btrfs generated uuid for this device */
	u8 uuid[BTRFS_UUID_SIZE];

	/* uuid of FS who owns this device */
	u8 fsid[BTRFS_UUID_SIZE];
} __attribute__ ((__packed__));

struct btrfs_stripe {
	__le64 devid;
	__le64 offset;
	u8 dev_uuid[BTRFS_UUID_SIZE];
} __attribute__ ((__packed__));

struct btrfs_chunk {
	/* size of this chunk in bytes */
	__le64 length;

	/* objectid of the root referencing this chunk */
	__le64 owner;

	__le64 stripe_len;
	__le64 type;

	/* optimal io alignment for this chunk */
	__le32 io_align;

	/* optimal io width for this chunk */
	__le32 io_width;

	/* minimal io size for this chunk */
	__le32 sector_size;

	/* 2^16 stripes is quite a lot, a second limit is the size of a single
	 * item in the btree
	 */
	__le16 num_stripes;

	/* sub stripes only matter for raid10 */
	__le16 sub_stripes;
	struct btrfs_stripe stripe;
	/* additional stripes go here */
} __attribute__ ((__packed__));

#define BTRFS_FREE_SPACE_EXTENT	1
#define BTRFS_FREE_SPACE_BITMAP	2

struct btrfs_free_space_entry {
	__le64 offset;
	__le64 bytes;
	u8 type;
} __attribute__ ((__packed__));

struct btrfs_free_space_header {
	struct btrfs_disk_key location;
	__le64 generation;
	__le64 num_entries;
	__le64 num_bitmaps;
} __attribute__ ((__packed__));

static inline unsigned long btrfs_chunk_item_size(int num_stripes)
{
	BUG_ON(num_stripes == 0);
	return sizeof(struct btrfs_chunk) +
		sizeof(struct btrfs_stripe) * (num_stripes - 1);
}

#define BTRFS_HEADER_FLAG_WRITTEN		(1ULL << 0)
#define BTRFS_HEADER_FLAG_RELOC			(1ULL << 1)
#define BTRFS_SUPER_FLAG_SEEDING		(1ULL << 32)
#define BTRFS_SUPER_FLAG_METADUMP		(1ULL << 33)
#define BTRFS_SUPER_FLAG_METADUMP_V2		(1ULL << 34)
#define BTRFS_SUPER_FLAG_CHANGING_FSID		(1ULL << 35)
#define BTRFS_SUPER_FLAG_CHANGING_FSID_V2	(1ULL << 36)
#define BTRFS_SUPER_FLAG_CHANGING_CSUM		(1ULL << 37)

#define BTRFS_BACKREF_REV_MAX		256
#define BTRFS_BACKREF_REV_SHIFT		56
#define BTRFS_BACKREF_REV_MASK		(((u64)BTRFS_BACKREF_REV_MAX - 1) << \
					 BTRFS_BACKREF_REV_SHIFT)

#define BTRFS_OLD_BACKREF_REV		0
#define BTRFS_MIXED_BACKREF_REV		1

/*
 * every tree block (leaf or node) starts with this header.
 */
struct btrfs_header {
	/* these first four must match the super block */
	u8 csum[BTRFS_CSUM_SIZE];
	u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
	__le64 bytenr; /* which block this node is supposed to live in */
	__le64 flags;

	/* allowed to be different from the super from here on down */
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
	__le64 generation;
	__le64 owner;
	__le32 nritems;
	u8 level;
} __attribute__ ((__packed__));

static inline u32 __BTRFS_LEAF_DATA_SIZE(u32 nodesize)
{
	return nodesize - sizeof(struct btrfs_header);
}

#define BTRFS_LEAF_DATA_SIZE(fs_info) (fs_info->leaf_data_size)

/*
 * this is a very generous portion of the super block, giving us
 * room to translate 14 chunks with 3 stripes each.
 */
#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
#define BTRFS_LABEL_SIZE 256

/*
 * just in case we somehow lose the roots and are not able to mount,
 * we store an array of the roots from previous transactions
 * in the super.
 */
#define BTRFS_NUM_BACKUP_ROOTS 4
struct btrfs_root_backup {
	__le64 tree_root;
	__le64 tree_root_gen;

	__le64 chunk_root;
	__le64 chunk_root_gen;

	__le64 extent_root;
	__le64 extent_root_gen;

	__le64 fs_root;
	__le64 fs_root_gen;

	__le64 dev_root;
	__le64 dev_root_gen;

	__le64 csum_root;
	__le64 csum_root_gen;

	__le64 total_bytes;
	__le64 bytes_used;
	__le64 num_devices;
	/* future */
	__le64 unsed_64[4];

	u8 tree_root_level;
	u8 chunk_root_level;
	u8 extent_root_level;
	u8 fs_root_level;
	u8 dev_root_level;
	u8 csum_root_level;
	/* future and to align */
	u8 unused_8[10];
} __attribute__ ((__packed__));

#define BTRFS_SUPER_INFO_OFFSET			(65536)
#define BTRFS_SUPER_INFO_SIZE			(4096)

/*
 * the super block basically lists the main trees of the FS
 * it currently lacks any block count etc etc
 */
struct btrfs_super_block {
	u8 csum[BTRFS_CSUM_SIZE];
	/* the first 3 fields must match struct btrfs_header */
	u8 fsid[BTRFS_FSID_SIZE];    /* FS specific uuid */
	__le64 bytenr; /* this block number */
	__le64 flags;

	/* allowed to be different from the btrfs_header from here own down */
	__le64 magic;
	__le64 generation;
	__le64 root;
	__le64 chunk_root;
	__le64 log_root;

	/* this will help find the new super based on the log root */
	__le64 log_root_transid;
	__le64 total_bytes;
	__le64 bytes_used;
	__le64 root_dir_objectid;
	__le64 num_devices;
	__le32 sectorsize;
	__le32 nodesize;
	/* Unused and must be equal to nodesize */
	__le32 __unused_leafsize;
	__le32 stripesize;
	__le32 sys_chunk_array_size;
	__le64 chunk_root_generation;
	__le64 compat_flags;
	__le64 compat_ro_flags;
	__le64 incompat_flags;
	__le16 csum_type;
	u8 root_level;
	u8 chunk_root_level;
	u8 log_root_level;
	struct btrfs_dev_item dev_item;

	char label[BTRFS_LABEL_SIZE];

	__le64 cache_generation;
	__le64 uuid_tree_generation;

	u8 metadata_uuid[BTRFS_FSID_SIZE];

	__le64 nr_global_roots;

	__le64 block_group_root;
	__le64 block_group_root_generation;
	u8 block_group_root_level;

	/* future expansion */
	u8 reserved8[7];
	__le64 reserved[24];
	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
	struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
	/* Padded to 4096 bytes */
	u8 padding[565];
} __attribute__ ((__packed__));
BUILD_ASSERT(sizeof(struct btrfs_super_block) == BTRFS_SUPER_INFO_SIZE);

/*
 * Compat flags that we support.  If any incompat flags are set other than the
 * ones specified below then we will fail to mount
 */
#define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE	(1ULL << 0)
/*
 * Older kernels on big-endian systems produced broken free space tree bitmaps,
 * and btrfs-progs also used to corrupt the free space tree. If this bit is
 * clear, then the free space tree cannot be trusted. btrfs-progs can also
 * intentionally clear this bit to ask the kernel to rebuild the free space
 * tree.
 */
#define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID	(1ULL << 1)

#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF	(1ULL << 0)
#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL	(1ULL << 1)
#define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS	(1ULL << 2)
#define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO	(1ULL << 3)
#define BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD	(1ULL << 4)

/*
 * older kernels tried to do bigger metadata blocks, but the
 * code was pretty buggy.  Lets not let them try anymore.
 */
#define BTRFS_FEATURE_INCOMPAT_BIG_METADATA     (1ULL << 5)
#define BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF	(1ULL << 6)
#define BTRFS_FEATURE_INCOMPAT_RAID56		(1ULL << 7)
#define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA	(1ULL << 8)
#define BTRFS_FEATURE_INCOMPAT_NO_HOLES		(1ULL << 9)
#define BTRFS_FEATURE_INCOMPAT_METADATA_UUID    (1ULL << 10)
#define BTRFS_FEATURE_INCOMPAT_RAID1C34		(1ULL << 11)
#define BTRFS_FEATURE_INCOMPAT_ZONED		(1ULL << 12)
#define BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2	(1ULL << 13)

#define BTRFS_FEATURE_COMPAT_SUPP		0ULL

/*
 * The FREE_SPACE_TREE and FREE_SPACE_TREE_VALID compat_ro bits must not be
 * added here until read-write support for the free space tree is implemented in
 * btrfs-progs.
 */
#define BTRFS_FEATURE_COMPAT_RO_SUPP			\
	(BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE |	\
	 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID)

#if EXPERIMENTAL
#define BTRFS_FEATURE_INCOMPAT_SUPP			\
	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD |		\
	 BTRFS_FEATURE_INCOMPAT_BIG_METADATA |		\
	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
	 BTRFS_FEATURE_INCOMPAT_NO_HOLES |		\
	 BTRFS_FEATURE_INCOMPAT_RAID1C34 |		\
	 BTRFS_FEATURE_INCOMPAT_METADATA_UUID |		\
	 BTRFS_FEATURE_INCOMPAT_ZONED |			\
	 BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
#else
#define BTRFS_FEATURE_INCOMPAT_SUPP			\
	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD |		\
	 BTRFS_FEATURE_INCOMPAT_BIG_METADATA |		\
	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
	 BTRFS_FEATURE_INCOMPAT_NO_HOLES |		\
	 BTRFS_FEATURE_INCOMPAT_RAID1C34 |		\
	 BTRFS_FEATURE_INCOMPAT_METADATA_UUID |		\
	 BTRFS_FEATURE_INCOMPAT_ZONED)
#endif

/*
 * A leaf is full of items. offset and size tell us where to find
 * the item in the leaf (relative to the start of the data area)
 */
struct btrfs_item {
	struct btrfs_disk_key key;
	__le32 offset;
	__le32 size;
} __attribute__ ((__packed__));

/*
 * leaves have an item area and a data area:
 * [item0, item1....itemN] [free space] [dataN...data1, data0]
 *
 * The data is separate from the items to get the keys closer together
 * during searches.
 */
struct btrfs_leaf {
	struct btrfs_header header;
	struct btrfs_item items[];
} __attribute__ ((__packed__));

/*
 * all non-leaf blocks are nodes, they hold only keys and pointers to
 * other blocks
 */
struct btrfs_key_ptr {
	struct btrfs_disk_key key;
	__le64 blockptr;
	__le64 generation;
} __attribute__ ((__packed__));

struct btrfs_node {
	struct btrfs_header header;
	struct btrfs_key_ptr ptrs[];
} __attribute__ ((__packed__));

/*
 * btrfs_paths remember the path taken from the root down to the leaf.
 * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
 * to any other levels that are present.
 *
 * The slots array records the index of the item or block pointer
 * used while walking the tree.
 */
enum { READA_NONE = 0, READA_BACK, READA_FORWARD };
struct btrfs_path {
	struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
	int slots[BTRFS_MAX_LEVEL];
#if 0
	/* The kernel locking scheme is not done in userspace. */
	int locks[BTRFS_MAX_LEVEL];
#endif
	signed char reada;
	/* keep some upper locks as we walk down */
	u8 lowest_level;

	/*
	 * set by btrfs_split_item, tells search_slot to keep all locks
	 * and to force calls to keep space in the nodes
	 */
	u8 search_for_split;
	u8 skip_check_block;
};

/*
 * items in the extent btree are used to record the objectid of the
 * owner of the block and the number of references
 */

struct btrfs_extent_item {
	__le64 refs;
	__le64 generation;
	__le64 flags;
} __attribute__ ((__packed__));

struct btrfs_extent_item_v0 {
	__le32 refs;
} __attribute__ ((__packed__));

#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) \
			((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
					sizeof(struct btrfs_item))
#define BTRFS_MAX_EXTENT_SIZE		128UL * 1024 * 1024

#define BTRFS_EXTENT_FLAG_DATA		(1ULL << 0)
#define BTRFS_EXTENT_FLAG_TREE_BLOCK	(1ULL << 1)

/* following flags only apply to tree blocks */

/* use full backrefs for extent pointers in the block*/
#define BTRFS_BLOCK_FLAG_FULL_BACKREF	(1ULL << 8)

struct btrfs_tree_block_info {
	struct btrfs_disk_key key;
	u8 level;
} __attribute__ ((__packed__));

struct btrfs_extent_data_ref {
	__le64 root;
	__le64 objectid;
	__le64 offset;
	__le32 count;
} __attribute__ ((__packed__));

struct btrfs_shared_data_ref {
	__le32 count;
} __attribute__ ((__packed__));

struct btrfs_extent_inline_ref {
	u8 type;
	__le64 offset;
} __attribute__ ((__packed__));

struct btrfs_extent_ref_v0 {
	__le64 root;
	__le64 generation;
	__le64 objectid;
	__le32 count;
} __attribute__ ((__packed__));

/* dev extents record free space on individual devices.  The owner
 * field points back to the chunk allocation mapping tree that allocated
 * the extent.  The chunk tree uuid field is a way to double check the owner
 */
struct btrfs_dev_extent {
	__le64 chunk_tree;
	__le64 chunk_objectid;
	__le64 chunk_offset;
	__le64 length;
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
} __attribute__ ((__packed__));

struct btrfs_inode_ref {
	__le64 index;
	__le16 name_len;
	/* name goes here */
} __attribute__ ((__packed__));

struct btrfs_inode_extref {
	__le64 parent_objectid;
	__le64 index;
	__le16 name_len;
	__u8   name[0]; /* name goes here */
} __attribute__ ((__packed__));

struct btrfs_timespec {
	__le64 sec;
	__le32 nsec;
} __attribute__ ((__packed__));

typedef enum {
	BTRFS_COMPRESS_NONE  = 0,
	BTRFS_COMPRESS_ZLIB  = 1,
	BTRFS_COMPRESS_LZO   = 2,
	BTRFS_COMPRESS_ZSTD  = 3,
	BTRFS_COMPRESS_TYPES = 3,
	BTRFS_COMPRESS_LAST  = 4,
} btrfs_compression_type;

/* we don't understand any encryption methods right now */
typedef enum {
	BTRFS_ENCRYPTION_NONE = 0,
	BTRFS_ENCRYPTION_LAST = 1,
} btrfs_encryption_type;

enum btrfs_tree_block_status {
	BTRFS_TREE_BLOCK_CLEAN,
	BTRFS_TREE_BLOCK_INVALID_NRITEMS,
	BTRFS_TREE_BLOCK_INVALID_PARENT_KEY,
	BTRFS_TREE_BLOCK_BAD_KEY_ORDER,
	BTRFS_TREE_BLOCK_INVALID_LEVEL,
	BTRFS_TREE_BLOCK_INVALID_FREE_SPACE,
	BTRFS_TREE_BLOCK_INVALID_OFFSETS,
	BTRFS_TREE_BLOCK_INVALID_BLOCKPTR,
};

struct btrfs_inode_item {
	/* nfs style generation number */
	__le64 generation;
	/* transid that last touched this inode */
	__le64 transid;
	__le64 size;
	__le64 nbytes;
	__le64 block_group;
	__le32 nlink;
	__le32 uid;
	__le32 gid;
	__le32 mode;
	__le64 rdev;
	__le64 flags;

	/* modification sequence number for NFS */
	__le64 sequence;

	/*
	 * a little future expansion, for more than this we can
	 * just grow the inode item and version it
	 */
	__le64 reserved[4];
	struct btrfs_timespec atime;
	struct btrfs_timespec ctime;
	struct btrfs_timespec mtime;
	struct btrfs_timespec otime;
} __attribute__ ((__packed__));

struct btrfs_dir_log_item {
	__le64 end;
} __attribute__ ((__packed__));

struct btrfs_dir_item {
	struct btrfs_disk_key location;
	__le64 transid;
	__le16 data_len;
	__le16 name_len;
	u8 type;
} __attribute__ ((__packed__));

struct btrfs_root_item_v0 {
	struct btrfs_inode_item inode;
	__le64 generation;
	__le64 root_dirid;
	__le64 bytenr;
	__le64 byte_limit;
	__le64 bytes_used;
	__le64 last_snapshot;
	__le64 flags;
	__le32 refs;
	struct btrfs_disk_key drop_progress;
	u8 drop_level;
	u8 level;
} __attribute__ ((__packed__));

struct btrfs_root_item {
	struct btrfs_inode_item inode;
	__le64 generation;
	__le64 root_dirid;
	__le64 bytenr;
	__le64 byte_limit;
	__le64 bytes_used;
	__le64 last_snapshot;
	__le64 flags;
	__le32 refs;
	struct btrfs_disk_key drop_progress;
	u8 drop_level;
	u8 level;

	/*
	 * The following fields appear after subvol_uuids+subvol_times
	 * were introduced.
	 */

	/*
	 * This generation number is used to test if the new fields are valid
	 * and up to date while reading the root item. Every time the root item
	 * is written out, the "generation" field is copied into this field. If
	 * anyone ever mounted the fs with an older kernel, we will have
	 * mismatching generation values here and thus must invalidate the
	 * new fields. See btrfs_update_root and btrfs_find_last_root for
	 * details.
	 * the offset of generation_v2 is also used as the start for the memset
	 * when invalidating the fields.
	 */
	__le64 generation_v2;
	u8 uuid[BTRFS_UUID_SIZE];
	u8 parent_uuid[BTRFS_UUID_SIZE];
	u8 received_uuid[BTRFS_UUID_SIZE];
	__le64 ctransid; /* updated when an inode changes */
	__le64 otransid; /* trans when created */
	__le64 stransid; /* trans when sent. non-zero for received subvol */
	__le64 rtransid; /* trans when received. non-zero for received subvol */
	struct btrfs_timespec ctime;
	struct btrfs_timespec otime;
	struct btrfs_timespec stime;
	struct btrfs_timespec rtime;

	/*
	 * If we want to use a specific set of fst/checksum/extent roots for
	 * this root.
	 */
	__le64 global_tree_id;
        __le64 reserved[7]; /* for future */
} __attribute__ ((__packed__));

/*
 * this is used for both forward and backward root refs
 */
struct btrfs_root_ref {
	__le64 dirid;
	__le64 sequence;
	__le16 name_len;
} __attribute__ ((__packed__));

struct btrfs_disk_balance_args {
	/*
	 * profiles to operate on, single is denoted by
	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
	 */
	__le64 profiles;

	/*
	 * usage filter
	 * BTRFS_BALANCE_ARGS_USAGE with a single value means '0..N'
	 * BTRFS_BALANCE_ARGS_USAGE_RANGE - range syntax, min..max
	 */
	union {
		__le64 usage;
		struct {
			__le32 usage_min;
			__le32 usage_max;
		};
	};

	/* devid filter */
	__le64 devid;

	/* devid subset filter [pstart..pend) */
	__le64 pstart;
	__le64 pend;

	/* btrfs virtual address space subset filter [vstart..vend) */
	__le64 vstart;
	__le64 vend;

	/*
	 * profile to convert to, single is denoted by
	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
	 */
	__le64 target;

	/* BTRFS_BALANCE_ARGS_* */
	__le64 flags;

	/*
	 * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'
	 * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum
	 * and maximum
	 */
	union {
		__le64 limit;
		struct {
			__le32 limit_min;
			__le32 limit_max;
		};
	};

	/*
	 * Process chunks that cross stripes_min..stripes_max devices,
	 * BTRFS_BALANCE_ARGS_STRIPES_RANGE
	 */
	__le32 stripes_min;
	__le32 stripes_max;

	__le64 unused[6];
} __attribute__ ((__packed__));

/*
 * store balance parameters to disk so that balance can be properly
 * resumed after crash or unmount
 */
struct btrfs_balance_item {
	/* BTRFS_BALANCE_* */
	__le64 flags;

	struct btrfs_disk_balance_args data;
	struct btrfs_disk_balance_args meta;
	struct btrfs_disk_balance_args sys;

	__le64 unused[4];
} __attribute__ ((__packed__));

#define BTRFS_FILE_EXTENT_INLINE 0
#define BTRFS_FILE_EXTENT_REG 1
#define BTRFS_FILE_EXTENT_PREALLOC 2

struct btrfs_file_extent_item {
	/*
	 * transaction id that created this extent
	 */
	__le64 generation;
	/*
	 * max number of bytes to hold this extent in ram
	 * when we split a compressed extent we can't know how big
	 * each of the resulting pieces will be.  So, this is
	 * an upper limit on the size of the extent in ram instead of
	 * an exact limit.
	 */
	__le64 ram_bytes;

	/*
	 * 32 bits for the various ways we might encode the data,
	 * including compression and encryption.  If any of these
	 * are set to something a given disk format doesn't understand
	 * it is treated like an incompat flag for reading and writing,
	 * but not for stat.
	 */
	u8 compression;
	u8 encryption;
	__le16 other_encoding; /* spare for later use */

	/* are we inline data or a real extent? */
	u8 type;

	/*
	 * Disk space consumed by the data extent
	 * Data checksum is stored in csum tree, thus no bytenr/length takes
	 * csum into consideration.
	 *
	 * The inline extent data starts at this offset in the structure.
	 */
	__le64 disk_bytenr;
	__le64 disk_num_bytes;
	/*
	 * The logical offset in file blocks.
	 * this extent record is for.  This allows a file extent to point
	 * into the middle of an existing extent on disk, sharing it
	 * between two snapshots (useful if some bytes in the middle of the
	 * extent have changed
	 */
	__le64 offset;
	/*
	 * The logical number of file blocks. This always reflects the size
	 * uncompressed and without encoding.
	 */
	__le64 num_bytes;

} __attribute__ ((__packed__));

struct btrfs_dev_stats_item {
        /*
         * grow this item struct at the end for future enhancements and keep
         * the existing values unchanged
         */
        __le64 values[BTRFS_DEV_STAT_VALUES_MAX];
} __attribute__ ((__packed__));

struct btrfs_csum_item {
	u8 csum;
} __attribute__ ((__packed__));

/*
 * We don't want to overwrite 1M at the beginning of device, even though
 * there is our 1st superblock at 64k. Some possible reasons:
 *  - the first 64k blank is useful for some boot loader/manager
 *  - the first 1M could be scratched by buggy partitioner or somesuch
 */
#define BTRFS_BLOCK_RESERVED_1M_FOR_SUPER	((u64)1 * 1024 * 1024)

#define BTRFS_BLOCK_GROUP_DATA		(1ULL << 0)
#define BTRFS_BLOCK_GROUP_SYSTEM	(1ULL << 1)
#define BTRFS_BLOCK_GROUP_METADATA	(1ULL << 2)
#define BTRFS_BLOCK_GROUP_RAID0		(1ULL << 3)
#define BTRFS_BLOCK_GROUP_RAID1		(1ULL << 4)
#define BTRFS_BLOCK_GROUP_DUP		(1ULL << 5)
#define BTRFS_BLOCK_GROUP_RAID10	(1ULL << 6)
#define BTRFS_BLOCK_GROUP_RAID5    	(1ULL << 7)
#define BTRFS_BLOCK_GROUP_RAID6    	(1ULL << 8)
#define BTRFS_BLOCK_GROUP_RAID1C3    	(1ULL << 9)
#define BTRFS_BLOCK_GROUP_RAID1C4    	(1ULL << 10)
#define BTRFS_BLOCK_GROUP_RESERVED	(BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
					 BTRFS_SPACE_INFO_GLOBAL_RSV)

enum btrfs_raid_types {
	BTRFS_RAID_RAID10,
	BTRFS_RAID_RAID1,
	BTRFS_RAID_DUP,
	BTRFS_RAID_RAID0,
	BTRFS_RAID_SINGLE,
	BTRFS_RAID_RAID5,
	BTRFS_RAID_RAID6,
	BTRFS_RAID_RAID1C3,
	BTRFS_RAID_RAID1C4,
	BTRFS_NR_RAID_TYPES
};

#define BTRFS_BLOCK_GROUP_TYPE_MASK	(BTRFS_BLOCK_GROUP_DATA |    \
					 BTRFS_BLOCK_GROUP_SYSTEM |  \
					 BTRFS_BLOCK_GROUP_METADATA)

#define BTRFS_BLOCK_GROUP_PROFILE_MASK	(BTRFS_BLOCK_GROUP_RAID0 |   \
					 BTRFS_BLOCK_GROUP_RAID1 |   \
					 BTRFS_BLOCK_GROUP_RAID5 |   \
					 BTRFS_BLOCK_GROUP_RAID6 |   \
					 BTRFS_BLOCK_GROUP_RAID1C3 | \
					 BTRFS_BLOCK_GROUP_RAID1C4 | \
					 BTRFS_BLOCK_GROUP_DUP |     \
					 BTRFS_BLOCK_GROUP_RAID10)

#define BTRFS_BLOCK_GROUP_RAID56_MASK	(BTRFS_BLOCK_GROUP_RAID5 |	\
                                         BTRFS_BLOCK_GROUP_RAID6)

#define BTRFS_BLOCK_GROUP_RAID1_MASK    (BTRFS_BLOCK_GROUP_RAID1 |	\
                                         BTRFS_BLOCK_GROUP_RAID1C3 |	\
                                         BTRFS_BLOCK_GROUP_RAID1C4)

/* used in struct btrfs_balance_args fields */
#define BTRFS_AVAIL_ALLOC_BIT_SINGLE	(1ULL << 48)

#define BTRFS_EXTENDED_PROFILE_MASK	(BTRFS_BLOCK_GROUP_PROFILE_MASK | \
					 BTRFS_AVAIL_ALLOC_BIT_SINGLE)

/*
 * GLOBAL_RSV does not exist as a on-disk block group type and is used
 * internally for exporting info about global block reserve from space infos
 */
#define BTRFS_SPACE_INFO_GLOBAL_RSV    (1ULL << 49)

#define BTRFS_QGROUP_LEVEL_SHIFT		48

static inline __u16 btrfs_qgroup_level(u64 qgroupid)
{
	return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
}

static inline u64 btrfs_qgroup_subvid(u64 qgroupid)
{
	return qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1);
}

static inline u64 btrfs_qgroup_subvolid(u64 qgroupid)
{
	return qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1);
}

#define BTRFS_QGROUP_STATUS_FLAG_ON		(1ULL << 0)
#define BTRFS_QGROUP_STATUS_FLAG_RESCAN		(1ULL << 1)
#define BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT	(1ULL << 2)

struct btrfs_qgroup_status_item {
	__le64 version;
	__le64 generation;
	__le64 flags;
	__le64 rescan;		/* progress during scanning */
} __attribute__ ((__packed__));

#define BTRFS_QGROUP_STATUS_VERSION		1
struct btrfs_block_group_item {
	__le64 used;
	__le64 chunk_objectid;
	__le64 flags;
} __attribute__ ((__packed__));

struct btrfs_free_space_info {
	__le32 extent_count;
	__le32 flags;
} __attribute__ ((__packed__));

#define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0)

struct btrfs_qgroup_info_item {
	__le64 generation;
	__le64 referenced;
	__le64 referenced_compressed;
	__le64 exclusive;
	__le64 exclusive_compressed;
} __attribute__ ((__packed__));

/* flags definition for qgroup limits */
#define BTRFS_QGROUP_LIMIT_MAX_RFER	(1ULL << 0)
#define BTRFS_QGROUP_LIMIT_MAX_EXCL	(1ULL << 1)
#define BTRFS_QGROUP_LIMIT_RSV_RFER	(1ULL << 2)
#define BTRFS_QGROUP_LIMIT_RSV_EXCL	(1ULL << 3)
#define BTRFS_QGROUP_LIMIT_RFER_CMPR	(1ULL << 4)
#define BTRFS_QGROUP_LIMIT_EXCL_CMPR	(1ULL << 5)

struct btrfs_qgroup_limit_item {
	__le64 flags;
	__le64 max_referenced;
	__le64 max_exclusive;
	__le64 rsv_referenced;
	__le64 rsv_exclusive;
} __attribute__ ((__packed__));

struct btrfs_space_info {
	u64 flags;
	u64 total_bytes;
	/*
	 * Space already used.
	 * Only accounting space in current extent tree, thus delayed ref
	 * won't be accounted here.
	 */
	u64 bytes_used;

	/*
	 * Space being pinned down.
	 * So extent allocator will not try to allocate space from them.
	 *
	 * For cases like extents being freed in current transaction, or
	 * manually pinned bytes for re-initializing certain trees.
	 */
	u64 bytes_pinned;

	/*
	 * Space being reserved.
	 * Space has already being reserved but not yet reach extent tree.
	 *
	 * New tree blocks allocated in current transaction goes here.
	 */
	u64 bytes_reserved;
	int full;
	struct list_head list;
};

struct btrfs_block_group {
	struct btrfs_space_info *space_info;
	struct btrfs_free_space_ctl *free_space_ctl;
	u64 start;
	u64 length;
	u64 used;
	u64 bytes_super;
	u64 pinned;
	u64 flags;
	int cached;
	int ro;
	/*
	 * If the free space extent count exceeds this number, convert the block
	 * group to bitmaps.
	 */
	u32 bitmap_high_thresh;
	/*
	 * If the free space extent count drops below this number, convert the
	 * block group back to extents.
	 */
	u32 bitmap_low_thresh;

	/* Block group cache stuff */
	struct rb_node cache_node;

	/* For dirty block groups */
	struct list_head dirty_list;

	/*
	 * Allocation offset for the block group to implement sequential
	 * allocation. This is used only with ZONED mode enabled.
	 */
	u64 alloc_offset;
	u64 write_offset;

	u64 global_root_id;
};

struct btrfs_device;
struct btrfs_fs_devices;
struct btrfs_fs_info {
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
	u8 *new_chunk_tree_uuid;
	struct btrfs_root *fs_root;
	struct btrfs_root *tree_root;
	struct btrfs_root *chunk_root;
	struct btrfs_root *dev_root;
	struct btrfs_root *quota_root;
	struct btrfs_root *uuid_root;
	struct btrfs_root *block_group_root;

	struct rb_root global_roots_tree;
	struct rb_root fs_root_tree;

	/* the log root tree is a directory of all the other log roots */
	struct btrfs_root *log_root_tree;

	struct extent_io_tree extent_cache;
	struct extent_io_tree free_space_cache;
	struct extent_io_tree pinned_extents;
	struct extent_io_tree extent_ins;
	struct extent_io_tree *excluded_extents;

	struct rb_root block_group_cache_tree;
	/* logical->physical extent mapping */
	struct btrfs_mapping_tree mapping_tree;

	u64 generation;
	u64 last_trans_committed;

	u64 avail_data_alloc_bits;
	u64 avail_metadata_alloc_bits;
	u64 avail_system_alloc_bits;
	u64 data_alloc_profile;
	u64 metadata_alloc_profile;
	u64 system_alloc_profile;

	struct btrfs_trans_handle *running_transaction;
	struct btrfs_super_block *super_copy;

	u64 super_bytenr;
	u64 total_pinned;
	u64 nr_global_roots;

	struct list_head dirty_cowonly_roots;
	struct list_head recow_ebs;

	struct btrfs_fs_devices *fs_devices;
	struct list_head space_info;

	unsigned int system_allocs:1;
	unsigned int readonly:1;
	unsigned int on_restoring:1;
	unsigned int is_chunk_recover:1;
	unsigned int quota_enabled:1;
	unsigned int suppress_check_block_errors:1;
	unsigned int ignore_fsid_mismatch:1;
	/* Don't verify checksums at all */
	unsigned int skip_csum_check:1;
	unsigned int ignore_chunk_tree_error:1;
	unsigned int avoid_meta_chunk_alloc:1;
	unsigned int avoid_sys_chunk_alloc:1;
	unsigned int finalize_on_close:1;
	unsigned int hide_names:1;
	unsigned int allow_transid_mismatch:1;

	int transaction_aborted;
	int force_csum_type;

	int (*free_extent_hook)(u64 bytenr, u64 num_bytes, u64 parent,
				u64 root_objectid, u64 owner, u64 offset,
				int refs_to_drop);
	struct cache_tree *fsck_extent_cache;
	struct cache_tree *corrupt_blocks;

	/* Cached block sizes */
	u32 nodesize;
	u32 sectorsize;
	u32 stripesize;
	u32 leaf_data_size;
	u16 csum_type;
	u16 csum_size;

	/*
	 * Zone size > 0 when in ZONED mode, otherwise it's used for a check
	 * if the mode is enabled
	 */
	union {
		u64 zone_size;
		u64 zoned;
	};
};

static inline bool btrfs_is_zoned(const struct btrfs_fs_info *fs_info)
{
	return fs_info->zoned != 0;
}

/*
 * in ram representation of the tree.  extent_root is used for all allocations
 * and for the extent tree extent_root root.
 */
struct btrfs_root {
	struct extent_buffer *node;
	struct extent_buffer *commit_root;
	struct btrfs_root_item root_item;
	struct btrfs_key root_key;
	struct btrfs_fs_info *fs_info;
	u64 objectid;
	u64 last_trans;

	int ref_cows;
	int track_dirty;


	u32 type;
	u64 last_inode_alloc;

	struct list_head unaligned_extent_recs;

	/* the dirty list is only used by non-reference counted roots */
	struct list_head dirty_list;
	struct rb_node rb_node;
};

static inline u32 BTRFS_MAX_ITEM_SIZE(const struct btrfs_fs_info *info)
{
	return BTRFS_LEAF_DATA_SIZE(info) - sizeof(struct btrfs_item);
}

static inline u32 BTRFS_NODEPTRS_PER_BLOCK(const struct btrfs_fs_info *info)
{
	return BTRFS_LEAF_DATA_SIZE(info) / sizeof(struct btrfs_key_ptr);
}

static inline u32 BTRFS_NODEPTRS_PER_EXTENT_BUFFER(const struct extent_buffer *eb)
{
	BUG_ON(!eb->fs_info);
	BUG_ON(eb->fs_info->nodesize != eb->len);
	return BTRFS_LEAF_DATA_SIZE(eb->fs_info) / sizeof(struct btrfs_key_ptr);
}

#define BTRFS_FILE_EXTENT_INLINE_DATA_START		\
	(offsetof(struct btrfs_file_extent_item, disk_bytenr))
static inline u32 BTRFS_MAX_INLINE_DATA_SIZE(const struct btrfs_fs_info *info)
{
	return BTRFS_MAX_ITEM_SIZE(info) -
		BTRFS_FILE_EXTENT_INLINE_DATA_START;
}

static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
{
	return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
}

/*
 * inode items have the data typically returned from stat and store other
 * info about object characteristics.  There is one for every file and dir in
 * the FS
 */
#define BTRFS_INODE_ITEM_KEY		1
#define BTRFS_INODE_REF_KEY		12
#define BTRFS_INODE_EXTREF_KEY		13
#define BTRFS_XATTR_ITEM_KEY		24

#define BTRFS_VERITY_DESC_ITEM_KEY	36
#define BTRFS_VERITY_MERKLE_ITEM_KEY	37

#define BTRFS_ORPHAN_ITEM_KEY		48

#define BTRFS_DIR_LOG_ITEM_KEY  60
#define BTRFS_DIR_LOG_INDEX_KEY 72
/*
 * dir items are the name -> inode pointers in a directory.  There is one
 * for every name in a directory.
 */
#define BTRFS_DIR_ITEM_KEY	84
#define BTRFS_DIR_INDEX_KEY	96

/*
 * extent data is for file data
 */
#define BTRFS_EXTENT_DATA_KEY	108

/*
 * csum items have the checksums for data in the extents
 */
#define BTRFS_CSUM_ITEM_KEY	120
/*
 * extent csums are stored in a separate tree and hold csums for
 * an entire extent on disk.
 */
#define BTRFS_EXTENT_CSUM_KEY	128

/*
 * root items point to tree roots.  There are typically in the root
 * tree used by the super block to find all the other trees
 */
#define BTRFS_ROOT_ITEM_KEY	132

/*
 * root backrefs tie subvols and snapshots to the directory entries that
 * reference them
 */
#define BTRFS_ROOT_BACKREF_KEY	144

/*
 * root refs make a fast index for listing all of the snapshots and
 * subvolumes referenced by a given root.  They point directly to the
 * directory item in the root that references the subvol
 */
#define BTRFS_ROOT_REF_KEY	156

/*
 * extent items are in the extent map tree.  These record which blocks
 * are used, and how many references there are to each block
 */
#define BTRFS_EXTENT_ITEM_KEY	168

/*
 * The same as the BTRFS_EXTENT_ITEM_KEY, except it's metadata we already know
 * the length, so we save the level in key->offset instead of the length.
 */
#define BTRFS_METADATA_ITEM_KEY	169

#define BTRFS_TREE_BLOCK_REF_KEY	176

#define BTRFS_EXTENT_DATA_REF_KEY	178

/* old style extent backrefs */
#define BTRFS_EXTENT_REF_V0_KEY		180

#define BTRFS_SHARED_BLOCK_REF_KEY	182

#define BTRFS_SHARED_DATA_REF_KEY	184


/*
 * block groups give us hints into the extent allocation trees.  Which
 * blocks are free etc etc
 */
#define BTRFS_BLOCK_GROUP_ITEM_KEY 192

/*
 * Every block group is represented in the free space tree by a free space info
 * item, which stores some accounting information. It is keyed on
 * (block_group_start, FREE_SPACE_INFO, block_group_length).
 */
#define BTRFS_FREE_SPACE_INFO_KEY 198

/*
 * A free space extent tracks an extent of space that is free in a block group.
 * It is keyed on (start, FREE_SPACE_EXTENT, length).
 */
#define BTRFS_FREE_SPACE_EXTENT_KEY 199

/*
 * When a block group becomes very fragmented, we convert it to use bitmaps
 * instead of extents. A free space bitmap is keyed on
 * (start, FREE_SPACE_BITMAP, length); the corresponding item is a bitmap with
 * (length / sectorsize) bits.
 */
#define BTRFS_FREE_SPACE_BITMAP_KEY 200

#define BTRFS_DEV_EXTENT_KEY	204
#define BTRFS_DEV_ITEM_KEY	216
#define BTRFS_CHUNK_ITEM_KEY	228

#define BTRFS_BALANCE_ITEM_KEY	248

/*
 * quota groups
 */
#define BTRFS_QGROUP_STATUS_KEY		240
#define BTRFS_QGROUP_INFO_KEY		242
#define BTRFS_QGROUP_LIMIT_KEY		244
#define BTRFS_QGROUP_RELATION_KEY	246

/*
 * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY.
 */
#define BTRFS_BALANCE_ITEM_KEY	248

/*
 * The key type for tree items that are stored persistently, but do not need to
 * exist for extended period of time. The items can exist in any tree.
 *
 * [subtype, BTRFS_TEMPORARY_ITEM_KEY, data]
 *
 * Existing items:
 *
 * - balance status item
 *   (BTRFS_BALANCE_OBJECTID, BTRFS_TEMPORARY_ITEM_KEY, 0)
 */
#define BTRFS_TEMPORARY_ITEM_KEY	248

/*
 * Obsolete name, see BTRFS_PERSISTENT_ITEM_KEY
 */
#define BTRFS_DEV_STATS_KEY		249

/*
 * The key type for tree items that are stored persistently and usually exist
 * for a long period, eg. filesystem lifetime. The item kinds can be status
 * information, stats or preference values. The item can exist in any tree.
 *
 * [subtype, BTRFS_PERSISTENT_ITEM_KEY, data]
 *
 * Existing items:
 *
 * - device statistics, store IO stats in the device tree, one key for all
 *   stats
 *   (BTRFS_DEV_STATS_OBJECTID, BTRFS_DEV_STATS_KEY, 0)
 */
#define BTRFS_PERSISTENT_ITEM_KEY	249

/*
 * Persistently stores the device replace state in the device tree.
 * The key is built like this: (0, BTRFS_DEV_REPLACE_KEY, 0).
 */
#define BTRFS_DEV_REPLACE_KEY	250

/*
 * Stores items that allow to quickly map UUIDs to something else.
 * These items are part of the filesystem UUID tree.
 * The key is built like this:
 * (UUID_upper_64_bits, BTRFS_UUID_KEY*, UUID_lower_64_bits).
 */
#if BTRFS_UUID_SIZE != 16
#error "UUID items require BTRFS_UUID_SIZE == 16!"
#endif
#define BTRFS_UUID_KEY_SUBVOL	251	/* for UUIDs assigned to subvols */
#define BTRFS_UUID_KEY_RECEIVED_SUBVOL	252	/* for UUIDs assigned to
						 * received subvols */

/*
 * string items are for debugging.  They just store a short string of
 * data in the FS
 */
#define BTRFS_STRING_ITEM_KEY	253
/*
 * Inode flags
 */
#define BTRFS_INODE_NODATASUM		(1 << 0)
#define BTRFS_INODE_NODATACOW		(1 << 1)
#define BTRFS_INODE_READONLY		(1 << 2)
#define BTRFS_INODE_NOCOMPRESS		(1 << 3)
#define BTRFS_INODE_PREALLOC		(1 << 4)
#define BTRFS_INODE_SYNC		(1 << 5)
#define BTRFS_INODE_IMMUTABLE		(1 << 6)
#define BTRFS_INODE_APPEND		(1 << 7)
#define BTRFS_INODE_NODUMP		(1 << 8)
#define BTRFS_INODE_NOATIME		(1 << 9)
#define BTRFS_INODE_DIRSYNC		(1 << 10)
#define BTRFS_INODE_COMPRESS		(1 << 11)

void read_extent_buffer(const 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);

#define read_eb_member(eb, ptr, type, member, result) (			\
	read_extent_buffer(eb, (char *)(result),			\
			   ((unsigned long)(ptr)) +			\
			    offsetof(type, member),			\
			   sizeof(((type *)0)->member)))

#define write_eb_member(eb, ptr, type, member, result) (		\
	write_extent_buffer(eb, (char *)(result),			\
			   ((unsigned long)(ptr)) +			\
			    offsetof(type, member),			\
			   sizeof(((type *)0)->member)))

#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)		\
static inline u##bits btrfs_##name(const struct extent_buffer *eb)	\
{									\
	const struct btrfs_header *h = (struct btrfs_header *)eb->data;	\
	return le##bits##_to_cpu(h->member);				\
}									\
static inline void btrfs_set_##name(struct extent_buffer *eb,		\
				    u##bits val)			\
{									\
	struct btrfs_header *h = (struct btrfs_header *)eb->data;	\
	h->member = cpu_to_le##bits(val);				\
}

#define BTRFS_SETGET_FUNCS(name, type, member, bits)			\
static inline u##bits btrfs_##name(const struct extent_buffer *eb,	\
				   const type *s)			\
{									\
	unsigned long offset = (unsigned long)s;			\
	const type *p = (type *) (eb->data + offset);			\
	return get_unaligned_le##bits(&p->member);			\
}									\
static inline void btrfs_set_##name(struct extent_buffer *eb,		\
				    type *s, u##bits val)		\
{									\
	unsigned long offset = (unsigned long)s;			\
	type *p = (type *) (eb->data + offset);				\
	put_unaligned_le##bits(val, &p->member);			\
}

#define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)		\
static inline u##bits btrfs_##name(const type *s)			\
{									\
	return le##bits##_to_cpu(s->member);				\
}									\
static inline void btrfs_set_##name(type *s, u##bits val)		\
{									\
	s->member = cpu_to_le##bits(val);				\
}

BTRFS_SETGET_FUNCS(device_type, struct btrfs_dev_item, type, 64);
BTRFS_SETGET_FUNCS(device_total_bytes, struct btrfs_dev_item, total_bytes, 64);
BTRFS_SETGET_FUNCS(device_bytes_used, struct btrfs_dev_item, bytes_used, 64);
BTRFS_SETGET_FUNCS(device_io_align, struct btrfs_dev_item, io_align, 32);
BTRFS_SETGET_FUNCS(device_io_width, struct btrfs_dev_item, io_width, 32);
BTRFS_SETGET_FUNCS(device_start_offset, struct btrfs_dev_item,
		   start_offset, 64);
BTRFS_SETGET_FUNCS(device_sector_size, struct btrfs_dev_item, sector_size, 32);
BTRFS_SETGET_FUNCS(device_id, struct btrfs_dev_item, devid, 64);
BTRFS_SETGET_FUNCS(device_group, struct btrfs_dev_item, dev_group, 32);
BTRFS_SETGET_FUNCS(device_seek_speed, struct btrfs_dev_item, seek_speed, 8);
BTRFS_SETGET_FUNCS(device_bandwidth, struct btrfs_dev_item, bandwidth, 8);
BTRFS_SETGET_FUNCS(device_generation, struct btrfs_dev_item, generation, 64);

BTRFS_SETGET_STACK_FUNCS(stack_device_type, struct btrfs_dev_item, type, 64);
BTRFS_SETGET_STACK_FUNCS(stack_device_total_bytes, struct btrfs_dev_item,
			 total_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_device_bytes_used, struct btrfs_dev_item,
			 bytes_used, 64);
BTRFS_SETGET_STACK_FUNCS(stack_device_io_align, struct btrfs_dev_item,
			 io_align, 32);
BTRFS_SETGET_STACK_FUNCS(stack_device_io_width, struct btrfs_dev_item,
			 io_width, 32);
BTRFS_SETGET_STACK_FUNCS(stack_device_sector_size, struct btrfs_dev_item,
			 sector_size, 32);
BTRFS_SETGET_STACK_FUNCS(stack_device_id, struct btrfs_dev_item, devid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_device_group, struct btrfs_dev_item,
			 dev_group, 32);
BTRFS_SETGET_STACK_FUNCS(stack_device_seek_speed, struct btrfs_dev_item,
			 seek_speed, 8);
BTRFS_SETGET_STACK_FUNCS(stack_device_bandwidth, struct btrfs_dev_item,
			 bandwidth, 8);
BTRFS_SETGET_STACK_FUNCS(stack_device_generation, struct btrfs_dev_item,
			 generation, 64);

static inline char *btrfs_device_uuid(struct btrfs_dev_item *d)
{
	return (char *)d + offsetof(struct btrfs_dev_item, uuid);
}

static inline char *btrfs_device_fsid(struct btrfs_dev_item *d)
{
	return (char *)d + offsetof(struct btrfs_dev_item, fsid);
}

BTRFS_SETGET_FUNCS(chunk_length, struct btrfs_chunk, length, 64);
BTRFS_SETGET_FUNCS(chunk_owner, struct btrfs_chunk, owner, 64);
BTRFS_SETGET_FUNCS(chunk_stripe_len, struct btrfs_chunk, stripe_len, 64);
BTRFS_SETGET_FUNCS(chunk_io_align, struct btrfs_chunk, io_align, 32);
BTRFS_SETGET_FUNCS(chunk_io_width, struct btrfs_chunk, io_width, 32);
BTRFS_SETGET_FUNCS(chunk_sector_size, struct btrfs_chunk, sector_size, 32);
BTRFS_SETGET_FUNCS(chunk_type, struct btrfs_chunk, type, 64);
BTRFS_SETGET_FUNCS(chunk_num_stripes, struct btrfs_chunk, num_stripes, 16);
BTRFS_SETGET_FUNCS(chunk_sub_stripes, struct btrfs_chunk, sub_stripes, 16);
BTRFS_SETGET_FUNCS(stripe_devid, struct btrfs_stripe, devid, 64);
BTRFS_SETGET_FUNCS(stripe_offset, struct btrfs_stripe, offset, 64);

static inline char *btrfs_stripe_dev_uuid(struct btrfs_stripe *s)
{
	return (char *)s + offsetof(struct btrfs_stripe, dev_uuid);
}

BTRFS_SETGET_STACK_FUNCS(stack_chunk_length, struct btrfs_chunk, length, 64);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_owner, struct btrfs_chunk, owner, 64);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_stripe_len, struct btrfs_chunk,
			 stripe_len, 64);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_io_align, struct btrfs_chunk,
			 io_align, 32);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_io_width, struct btrfs_chunk,
			 io_width, 32);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_sector_size, struct btrfs_chunk,
			 sector_size, 32);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_type, struct btrfs_chunk, type, 64);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_num_stripes, struct btrfs_chunk,
			 num_stripes, 16);
BTRFS_SETGET_STACK_FUNCS(stack_chunk_sub_stripes, struct btrfs_chunk,
			 sub_stripes, 16);
BTRFS_SETGET_STACK_FUNCS(stack_stripe_devid, struct btrfs_stripe, devid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_stripe_offset, struct btrfs_stripe, offset, 64);

static inline struct btrfs_stripe *btrfs_stripe_nr(struct btrfs_chunk *c,
						   int nr)
{
	unsigned long offset = (unsigned long)c;
	offset += offsetof(struct btrfs_chunk, stripe);
	offset += nr * sizeof(struct btrfs_stripe);
	return (struct btrfs_stripe *)offset;
}

static inline char *btrfs_stripe_dev_uuid_nr(struct btrfs_chunk *c, int nr)
{
	return btrfs_stripe_dev_uuid(btrfs_stripe_nr(c, nr));
}

static inline u64 btrfs_stripe_offset_nr(struct extent_buffer *eb,
					 struct btrfs_chunk *c, int nr)
{
	return btrfs_stripe_offset(eb, btrfs_stripe_nr(c, nr));
}

static inline void btrfs_set_stripe_offset_nr(struct extent_buffer *eb,
					     struct btrfs_chunk *c, int nr,
					     u64 val)
{
	btrfs_set_stripe_offset(eb, btrfs_stripe_nr(c, nr), val);
}

static inline u64 btrfs_stripe_devid_nr(struct extent_buffer *eb,
					 struct btrfs_chunk *c, int nr)
{
	return btrfs_stripe_devid(eb, btrfs_stripe_nr(c, nr));
}

static inline void btrfs_set_stripe_devid_nr(struct extent_buffer *eb,
					     struct btrfs_chunk *c, int nr,
					     u64 val)
{
	btrfs_set_stripe_devid(eb, btrfs_stripe_nr(c, nr), val);
}

/* struct btrfs_block_group_item */
BTRFS_SETGET_STACK_FUNCS(stack_block_group_used, struct btrfs_block_group_item,
			 used, 64);
BTRFS_SETGET_FUNCS(block_group_used, struct btrfs_block_group_item,
			 used, 64);
BTRFS_SETGET_STACK_FUNCS(stack_block_group_chunk_objectid,
			struct btrfs_block_group_item, chunk_objectid, 64);

BTRFS_SETGET_FUNCS(block_group_chunk_objectid,
		   struct btrfs_block_group_item, chunk_objectid, 64);
BTRFS_SETGET_FUNCS(block_group_flags,
		   struct btrfs_block_group_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(stack_block_group_flags,
			struct btrfs_block_group_item, flags, 64);

/* extent tree v2 uses chunk_objectid for the global tree id. */
BTRFS_SETGET_STACK_FUNCS(stack_block_group_global_tree_id,
			 struct btrfs_block_group_item, chunk_objectid, 64);
BTRFS_SETGET_FUNCS(block_group_global_tree_id, struct btrfs_block_group_item,
		   chunk_objectid, 64);

/* struct btrfs_free_space_info */
BTRFS_SETGET_FUNCS(free_space_extent_count, struct btrfs_free_space_info,
		   extent_count, 32);
BTRFS_SETGET_FUNCS(free_space_flags, struct btrfs_free_space_info, flags, 32);

/* struct btrfs_inode_ref */
BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
BTRFS_SETGET_STACK_FUNCS(stack_inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
BTRFS_SETGET_FUNCS(inode_ref_index, struct btrfs_inode_ref, index, 64);

/* struct btrfs_inode_extref */
BTRFS_SETGET_FUNCS(inode_extref_parent, struct btrfs_inode_extref,
		   parent_objectid, 64);
BTRFS_SETGET_FUNCS(inode_extref_name_len, struct btrfs_inode_extref,
		   name_len, 16);
BTRFS_SETGET_FUNCS(inode_extref_index, struct btrfs_inode_extref, index, 64);

/* struct btrfs_inode_item */
BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
BTRFS_SETGET_FUNCS(inode_sequence, struct btrfs_inode_item, sequence, 64);
BTRFS_SETGET_FUNCS(inode_transid, struct btrfs_inode_item, transid, 64);
BTRFS_SETGET_FUNCS(inode_size, struct btrfs_inode_item, size, 64);
BTRFS_SETGET_FUNCS(inode_nbytes, struct btrfs_inode_item, nbytes, 64);
BTRFS_SETGET_FUNCS(inode_block_group, struct btrfs_inode_item, block_group, 64);
BTRFS_SETGET_FUNCS(inode_nlink, struct btrfs_inode_item, nlink, 32);
BTRFS_SETGET_FUNCS(inode_uid, struct btrfs_inode_item, uid, 32);
BTRFS_SETGET_FUNCS(inode_gid, struct btrfs_inode_item, gid, 32);
BTRFS_SETGET_FUNCS(inode_mode, struct btrfs_inode_item, mode, 32);
BTRFS_SETGET_FUNCS(inode_rdev, struct btrfs_inode_item, rdev, 64);
BTRFS_SETGET_FUNCS(inode_flags, struct btrfs_inode_item, flags, 64);

BTRFS_SETGET_STACK_FUNCS(stack_inode_generation,
			 struct btrfs_inode_item, generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_sequence,
			 struct btrfs_inode_item, sequence, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_transid,
			 struct btrfs_inode_item, transid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_size,
			 struct btrfs_inode_item, size, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_nbytes,
			 struct btrfs_inode_item, nbytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_block_group,
			 struct btrfs_inode_item, block_group, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_nlink,
			 struct btrfs_inode_item, nlink, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_uid,
			 struct btrfs_inode_item, uid, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_gid,
			 struct btrfs_inode_item, gid, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_mode,
			 struct btrfs_inode_item, mode, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_rdev,
			 struct btrfs_inode_item, rdev, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_flags,
			 struct btrfs_inode_item, flags, 64);

static inline struct btrfs_timespec *
btrfs_inode_atime(struct btrfs_inode_item *inode_item)
{
	unsigned long ptr = (unsigned long)inode_item;
	ptr += offsetof(struct btrfs_inode_item, atime);
	return (struct btrfs_timespec *)ptr;
}

static inline struct btrfs_timespec *
btrfs_inode_mtime(struct btrfs_inode_item *inode_item)
{
	unsigned long ptr = (unsigned long)inode_item;
	ptr += offsetof(struct btrfs_inode_item, mtime);
	return (struct btrfs_timespec *)ptr;
}

static inline struct btrfs_timespec *
btrfs_inode_ctime(struct btrfs_inode_item *inode_item)
{
	unsigned long ptr = (unsigned long)inode_item;
	ptr += offsetof(struct btrfs_inode_item, ctime);
	return (struct btrfs_timespec *)ptr;
}

static inline struct btrfs_timespec *
btrfs_inode_otime(struct btrfs_inode_item *inode_item)
{
	unsigned long ptr = (unsigned long)inode_item;
	ptr += offsetof(struct btrfs_inode_item, otime);
	return (struct btrfs_timespec *)ptr;
}

BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec,
			 sec, 64);
BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec,
			 nsec, 32);

/* struct btrfs_dev_extent */
BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
		   chunk_tree, 64);
BTRFS_SETGET_FUNCS(dev_extent_chunk_objectid, struct btrfs_dev_extent,
		   chunk_objectid, 64);
BTRFS_SETGET_FUNCS(dev_extent_chunk_offset, struct btrfs_dev_extent,
		   chunk_offset, 64);
BTRFS_SETGET_FUNCS(dev_extent_length, struct btrfs_dev_extent, length, 64);

BTRFS_SETGET_STACK_FUNCS(stack_dev_extent_length, struct btrfs_dev_extent,
			 length, 64);

static inline u8 *btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
{
	unsigned long ptr = offsetof(struct btrfs_dev_extent, chunk_tree_uuid);
	return (u8 *)((unsigned long)dev + ptr);
}


/* struct btrfs_extent_item */
BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 64);
BTRFS_SETGET_STACK_FUNCS(stack_extent_refs, struct btrfs_extent_item, refs, 64);
BTRFS_SETGET_FUNCS(extent_generation, struct btrfs_extent_item,
		   generation, 64);
BTRFS_SETGET_FUNCS(extent_flags, struct btrfs_extent_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(stack_extent_flags, struct btrfs_extent_item, flags, 64);

BTRFS_SETGET_FUNCS(extent_refs_v0, struct btrfs_extent_item_v0, refs, 32);

BTRFS_SETGET_FUNCS(tree_block_level, struct btrfs_tree_block_info, level, 8);

static inline void btrfs_tree_block_key(struct extent_buffer *eb,
					struct btrfs_tree_block_info *item,
					struct btrfs_disk_key *key)
{
	read_eb_member(eb, item, struct btrfs_tree_block_info, key, key);
}

static inline void btrfs_set_tree_block_key(struct extent_buffer *eb,
					    struct btrfs_tree_block_info *item,
					    struct btrfs_disk_key *key)
{
	write_eb_member(eb, item, struct btrfs_tree_block_info, key, key);
}

BTRFS_SETGET_FUNCS(extent_data_ref_root, struct btrfs_extent_data_ref,
		   root, 64);
BTRFS_SETGET_FUNCS(extent_data_ref_objectid, struct btrfs_extent_data_ref,
		   objectid, 64);
BTRFS_SETGET_FUNCS(extent_data_ref_offset, struct btrfs_extent_data_ref,
		   offset, 64);
BTRFS_SETGET_FUNCS(extent_data_ref_count, struct btrfs_extent_data_ref,
		   count, 32);

BTRFS_SETGET_FUNCS(shared_data_ref_count, struct btrfs_shared_data_ref,
		   count, 32);

BTRFS_SETGET_FUNCS(extent_inline_ref_type, struct btrfs_extent_inline_ref,
		   type, 8);
BTRFS_SETGET_FUNCS(extent_inline_ref_offset, struct btrfs_extent_inline_ref,
		   offset, 64);
BTRFS_SETGET_STACK_FUNCS(stack_extent_inline_ref_type,
			 struct btrfs_extent_inline_ref, type, 8);
BTRFS_SETGET_STACK_FUNCS(stack_extent_inline_ref_offset,
			 struct btrfs_extent_inline_ref, offset, 64);

static inline u32 btrfs_extent_inline_ref_size(int type)
{
	if (type == BTRFS_TREE_BLOCK_REF_KEY ||
	    type == BTRFS_SHARED_BLOCK_REF_KEY)
		return sizeof(struct btrfs_extent_inline_ref);
	if (type == BTRFS_SHARED_DATA_REF_KEY)
		return sizeof(struct btrfs_shared_data_ref) +
		       sizeof(struct btrfs_extent_inline_ref);
	if (type == BTRFS_EXTENT_DATA_REF_KEY)
		return sizeof(struct btrfs_extent_data_ref) +
		       offsetof(struct btrfs_extent_inline_ref, offset);
	BUG();
	return 0;
}

BTRFS_SETGET_FUNCS(ref_root_v0, struct btrfs_extent_ref_v0, root, 64);
BTRFS_SETGET_FUNCS(ref_generation_v0, struct btrfs_extent_ref_v0,
		   generation, 64);
BTRFS_SETGET_FUNCS(ref_objectid_v0, struct btrfs_extent_ref_v0, objectid, 64);
BTRFS_SETGET_FUNCS(ref_count_v0, struct btrfs_extent_ref_v0, count, 32);

/* struct btrfs_node */
BTRFS_SETGET_FUNCS(key_blockptr, struct btrfs_key_ptr, blockptr, 64);
BTRFS_SETGET_FUNCS(key_generation, struct btrfs_key_ptr, generation, 64);

static inline unsigned long btrfs_node_key_ptr_offset(const struct extent_buffer *eb, int nr)
{
	return offsetof(struct btrfs_node, ptrs) +
		sizeof(struct btrfs_key_ptr) * nr;
}

static inline struct btrfs_key_ptr *btrfs_node_key_ptr(const struct extent_buffer *eb, int nr)
{
	return (struct btrfs_key_ptr *)btrfs_node_key_ptr_offset(eb, nr);
}

static inline u64 btrfs_node_blockptr(struct extent_buffer *eb, int nr)
{
	return btrfs_key_blockptr(eb, btrfs_node_key_ptr(eb, nr));
}

static inline void btrfs_set_node_blockptr(struct extent_buffer *eb,
					   int nr, u64 val)
{
	btrfs_set_key_blockptr(eb, btrfs_node_key_ptr(eb, nr), val);
}

static inline u64 btrfs_node_ptr_generation(struct extent_buffer *eb, int nr)
{
	return btrfs_key_generation(eb, btrfs_node_key_ptr(eb, nr));
}

static inline void btrfs_set_node_ptr_generation(struct extent_buffer *eb,
						 int nr, u64 val)
{
	btrfs_set_key_generation(eb, btrfs_node_key_ptr(eb, nr), val);
}

static inline void btrfs_node_key(struct extent_buffer *eb,
				  struct btrfs_disk_key *disk_key, int nr)
{
	read_eb_member(eb, btrfs_node_key_ptr(eb, nr), struct btrfs_key_ptr,
		       key, disk_key);
}

static inline void btrfs_set_node_key(struct extent_buffer *eb,
				      struct btrfs_disk_key *disk_key, int nr)
{
	write_eb_member(eb, btrfs_node_key_ptr(eb, nr), struct btrfs_key_ptr,
			key, disk_key);
}

/* struct btrfs_item */
BTRFS_SETGET_FUNCS(raw_item_offset, struct btrfs_item, offset, 32);
BTRFS_SETGET_FUNCS(raw_item_size, struct btrfs_item, size, 32);

static inline unsigned long btrfs_item_nr_offset(const struct extent_buffer *eb, int nr)
{
	return offsetof(struct btrfs_leaf, items) +
		sizeof(struct btrfs_item) * nr;
}

static inline struct btrfs_item *btrfs_item_nr(const struct extent_buffer *eb, int nr)
{
	return (struct btrfs_item *)btrfs_item_nr_offset(eb, nr);
}

#define BTRFS_ITEM_SETGET_FUNCS(member)						\
static inline u32 btrfs_item_##member(const struct extent_buffer *eb, int slot)	\
{										\
	return btrfs_raw_item_##member(eb, btrfs_item_nr(eb, slot));		\
}										\
static inline void btrfs_set_item_##member(struct extent_buffer *eb,		\
					   int slot, u32 val)			\
{										\
	btrfs_set_raw_item_##member(eb, btrfs_item_nr(eb, slot), val);		\
}

BTRFS_ITEM_SETGET_FUNCS(size)
BTRFS_ITEM_SETGET_FUNCS(offset)

static inline u32 btrfs_item_end(struct extent_buffer *eb, int nr)
{
	return btrfs_item_offset(eb, nr) + btrfs_item_size(eb, nr);
}

static inline void btrfs_item_key(struct extent_buffer *eb,
			   struct btrfs_disk_key *disk_key, int nr)
{
	struct btrfs_item *item = btrfs_item_nr(eb, nr);
	read_eb_member(eb, item, struct btrfs_item, key, disk_key);
}

static inline void btrfs_set_item_key(struct extent_buffer *eb,
			       struct btrfs_disk_key *disk_key, int nr)
{
	struct btrfs_item *item = btrfs_item_nr(eb, nr);
	write_eb_member(eb, item, struct btrfs_item, key, disk_key);
}

BTRFS_SETGET_FUNCS(dir_log_end, struct btrfs_dir_log_item, end, 64);

/*
 * struct btrfs_root_ref
 */
BTRFS_SETGET_FUNCS(root_ref_dirid, struct btrfs_root_ref, dirid, 64);
BTRFS_SETGET_FUNCS(root_ref_sequence, struct btrfs_root_ref, sequence, 64);
BTRFS_SETGET_FUNCS(root_ref_name_len, struct btrfs_root_ref, name_len, 16);

BTRFS_SETGET_STACK_FUNCS(stack_root_ref_dirid, struct btrfs_root_ref, dirid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_root_ref_sequence, struct btrfs_root_ref, sequence, 64);
BTRFS_SETGET_STACK_FUNCS(stack_root_ref_name_len, struct btrfs_root_ref, name_len, 16);

/* struct btrfs_dir_item */
BTRFS_SETGET_FUNCS(dir_data_len, struct btrfs_dir_item, data_len, 16);
BTRFS_SETGET_FUNCS(dir_type, struct btrfs_dir_item, type, 8);
BTRFS_SETGET_FUNCS(dir_name_len, struct btrfs_dir_item, name_len, 16);
BTRFS_SETGET_FUNCS(dir_transid, struct btrfs_dir_item, transid, 64);

BTRFS_SETGET_STACK_FUNCS(stack_dir_data_len, struct btrfs_dir_item, data_len, 16);
BTRFS_SETGET_STACK_FUNCS(stack_dir_type, struct btrfs_dir_item, type, 8);
BTRFS_SETGET_STACK_FUNCS(stack_dir_name_len, struct btrfs_dir_item, name_len, 16);
BTRFS_SETGET_STACK_FUNCS(stack_dir_transid, struct btrfs_dir_item, transid, 64);

static inline void btrfs_dir_item_key(struct extent_buffer *eb,
				      struct btrfs_dir_item *item,
				      struct btrfs_disk_key *key)
{
	read_eb_member(eb, item, struct btrfs_dir_item, location, key);
}

static inline void btrfs_set_dir_item_key(struct extent_buffer *eb,
					  struct btrfs_dir_item *item,
					  struct btrfs_disk_key *key)
{
	write_eb_member(eb, item, struct btrfs_dir_item, location, key);
}

/* struct btrfs_free_space_header */
BTRFS_SETGET_FUNCS(free_space_entries, struct btrfs_free_space_header,
		   num_entries, 64);
BTRFS_SETGET_FUNCS(free_space_bitmaps, struct btrfs_free_space_header,
		   num_bitmaps, 64);
BTRFS_SETGET_FUNCS(free_space_generation, struct btrfs_free_space_header,
		   generation, 64);

static inline void btrfs_free_space_key(struct extent_buffer *eb,
					struct btrfs_free_space_header *h,
					struct btrfs_disk_key *key)
{
	read_eb_member(eb, h, struct btrfs_free_space_header, location, key);
}

static inline void btrfs_set_free_space_key(struct extent_buffer *eb,
					    struct btrfs_free_space_header *h,
					    struct btrfs_disk_key *key)
{
	write_eb_member(eb, h, struct btrfs_free_space_header, location, key);
}

/* struct btrfs_disk_key */
BTRFS_SETGET_STACK_FUNCS(disk_key_objectid, struct btrfs_disk_key,
			 objectid, 64);
BTRFS_SETGET_STACK_FUNCS(disk_key_offset, struct btrfs_disk_key, offset, 64);
BTRFS_SETGET_STACK_FUNCS(disk_key_type, struct btrfs_disk_key, type, 8);

static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
					 struct btrfs_disk_key *disk)
{
	cpu->offset = le64_to_cpu(disk->offset);
	cpu->type = disk->type;
	cpu->objectid = le64_to_cpu(disk->objectid);
}

static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
					 const struct btrfs_key *cpu)
{
	disk->offset = cpu_to_le64(cpu->offset);
	disk->type = cpu->type;
	disk->objectid = cpu_to_le64(cpu->objectid);
}

static inline void btrfs_node_key_to_cpu(struct extent_buffer *eb,
				  struct btrfs_key *key, int nr)
{
	struct btrfs_disk_key disk_key;
	btrfs_node_key(eb, &disk_key, nr);
	btrfs_disk_key_to_cpu(key, &disk_key);
}

static inline void btrfs_item_key_to_cpu(struct extent_buffer *eb,
				  struct btrfs_key *key, int nr)
{
	struct btrfs_disk_key disk_key;
	btrfs_item_key(eb, &disk_key, nr);
	btrfs_disk_key_to_cpu(key, &disk_key);
}

static inline void btrfs_dir_item_key_to_cpu(struct extent_buffer *eb,
				      struct btrfs_dir_item *item,
				      struct btrfs_key *key)
{
	struct btrfs_disk_key disk_key;
	btrfs_dir_item_key(eb, item, &disk_key);
	btrfs_disk_key_to_cpu(key, &disk_key);
}

/* struct btrfs_header */
BTRFS_SETGET_HEADER_FUNCS(header_bytenr, struct btrfs_header, bytenr, 64);
BTRFS_SETGET_HEADER_FUNCS(header_generation, struct btrfs_header,
			  generation, 64);
BTRFS_SETGET_HEADER_FUNCS(header_owner, struct btrfs_header, owner, 64);
BTRFS_SETGET_HEADER_FUNCS(header_nritems, struct btrfs_header, nritems, 32);
BTRFS_SETGET_HEADER_FUNCS(header_flags, struct btrfs_header, flags, 64);
BTRFS_SETGET_HEADER_FUNCS(header_level, struct btrfs_header, level, 8);
BTRFS_SETGET_STACK_FUNCS(stack_header_bytenr, struct btrfs_header, bytenr, 64);
BTRFS_SETGET_STACK_FUNCS(stack_header_nritems, struct btrfs_header, nritems,
			 32);
BTRFS_SETGET_STACK_FUNCS(stack_header_owner, struct btrfs_header, owner, 64);
BTRFS_SETGET_STACK_FUNCS(stack_header_generation, struct btrfs_header,
			 generation, 64);

static inline int btrfs_header_flag(struct extent_buffer *eb, u64 flag)
{
	return (btrfs_header_flags(eb) & flag) == flag;
}

static inline int btrfs_set_header_flag(struct extent_buffer *eb, u64 flag)
{
	u64 flags = btrfs_header_flags(eb);
	btrfs_set_header_flags(eb, flags | flag);
	return (flags & flag) == flag;
}

static inline int btrfs_clear_header_flag(struct extent_buffer *eb, u64 flag)
{
	u64 flags = btrfs_header_flags(eb);
	btrfs_set_header_flags(eb, flags & ~flag);
	return (flags & flag) == flag;
}

static inline int btrfs_header_backref_rev(struct extent_buffer *eb)
{
	u64 flags = btrfs_header_flags(eb);
	return flags >> BTRFS_BACKREF_REV_SHIFT;
}

static inline void btrfs_set_header_backref_rev(struct extent_buffer *eb,
						int rev)
{
	u64 flags = btrfs_header_flags(eb);
	flags &= ~BTRFS_BACKREF_REV_MASK;
	flags |= (u64)rev << BTRFS_BACKREF_REV_SHIFT;
	btrfs_set_header_flags(eb, flags);
}

static inline unsigned long btrfs_header_fsid(void)
{
	return offsetof(struct btrfs_header, fsid);
}

static inline unsigned long btrfs_header_chunk_tree_uuid(struct extent_buffer *eb)
{
	return offsetof(struct btrfs_header, chunk_tree_uuid);
}

static inline u8 *btrfs_header_csum(struct extent_buffer *eb)
{
	unsigned long ptr = offsetof(struct btrfs_header, csum);
	return (u8 *)ptr;
}

static inline int btrfs_is_leaf(struct extent_buffer *eb)
{
	return (btrfs_header_level(eb) == 0);
}

/* struct btrfs_root_item */
BTRFS_SETGET_FUNCS(disk_root_generation, struct btrfs_root_item,
		   generation, 64);
BTRFS_SETGET_FUNCS(disk_root_refs, struct btrfs_root_item, refs, 32);
BTRFS_SETGET_FUNCS(disk_root_bytenr, struct btrfs_root_item, bytenr, 64);
BTRFS_SETGET_FUNCS(disk_root_level, struct btrfs_root_item, level, 8);

BTRFS_SETGET_STACK_FUNCS(root_generation, struct btrfs_root_item,
			 generation, 64);
BTRFS_SETGET_STACK_FUNCS(root_bytenr, struct btrfs_root_item, bytenr, 64);
BTRFS_SETGET_STACK_FUNCS(root_level, struct btrfs_root_item, level, 8);
BTRFS_SETGET_STACK_FUNCS(root_dirid, struct btrfs_root_item, root_dirid, 64);
BTRFS_SETGET_STACK_FUNCS(root_refs, struct btrfs_root_item, refs, 32);
BTRFS_SETGET_STACK_FUNCS(root_flags, struct btrfs_root_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(root_used, struct btrfs_root_item, bytes_used, 64);
BTRFS_SETGET_STACK_FUNCS(root_limit, struct btrfs_root_item, byte_limit, 64);
BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item,
			 last_snapshot, 64);
BTRFS_SETGET_STACK_FUNCS(root_generation_v2, struct btrfs_root_item,
			 generation_v2, 64);
BTRFS_SETGET_STACK_FUNCS(root_ctransid, struct btrfs_root_item,
			 ctransid, 64);
BTRFS_SETGET_STACK_FUNCS(root_otransid, struct btrfs_root_item,
			 otransid, 64);
BTRFS_SETGET_STACK_FUNCS(root_stransid, struct btrfs_root_item,
			 stransid, 64);
BTRFS_SETGET_STACK_FUNCS(root_rtransid, struct btrfs_root_item,
			 rtransid, 64);

static inline struct btrfs_timespec* btrfs_root_ctime(
		struct btrfs_root_item *root_item)
{
	unsigned long ptr = (unsigned long)root_item;
	ptr += offsetof(struct btrfs_root_item, ctime);
	return (struct btrfs_timespec *)ptr;
}

static inline struct btrfs_timespec* btrfs_root_otime(
		struct btrfs_root_item *root_item)
{
	unsigned long ptr = (unsigned long)root_item;
	ptr += offsetof(struct btrfs_root_item, otime);
	return (struct btrfs_timespec *)ptr;
}

static inline struct btrfs_timespec* btrfs_root_stime(
		struct btrfs_root_item *root_item)
{
	unsigned long ptr = (unsigned long)root_item;
	ptr += offsetof(struct btrfs_root_item, stime);
	return (struct btrfs_timespec *)ptr;
}

static inline struct btrfs_timespec* btrfs_root_rtime(
		struct btrfs_root_item *root_item)
{
	unsigned long ptr = (unsigned long)root_item;
	ptr += offsetof(struct btrfs_root_item, rtime);
	return (struct btrfs_timespec *)ptr;
}

/* struct btrfs_root_backup */
BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
		   tree_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_tree_root_gen, struct btrfs_root_backup,
		   tree_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_tree_root_level, struct btrfs_root_backup,
		   tree_root_level, 8);

BTRFS_SETGET_STACK_FUNCS(backup_chunk_root, struct btrfs_root_backup,
		   chunk_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_gen, struct btrfs_root_backup,
		   chunk_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_level, struct btrfs_root_backup,
		   chunk_root_level, 8);

BTRFS_SETGET_STACK_FUNCS(backup_extent_root, struct btrfs_root_backup,
		   extent_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_extent_root_gen, struct btrfs_root_backup,
		   extent_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_extent_root_level, struct btrfs_root_backup,
		   extent_root_level, 8);

BTRFS_SETGET_STACK_FUNCS(backup_fs_root, struct btrfs_root_backup,
		   fs_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_fs_root_gen, struct btrfs_root_backup,
		   fs_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_fs_root_level, struct btrfs_root_backup,
		   fs_root_level, 8);

BTRFS_SETGET_STACK_FUNCS(backup_dev_root, struct btrfs_root_backup,
		   dev_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_dev_root_gen, struct btrfs_root_backup,
		   dev_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_dev_root_level, struct btrfs_root_backup,
		   dev_root_level, 8);

BTRFS_SETGET_STACK_FUNCS(backup_csum_root, struct btrfs_root_backup,
		   csum_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_csum_root_gen, struct btrfs_root_backup,
		   csum_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_csum_root_level, struct btrfs_root_backup,
		   csum_root_level, 8);
BTRFS_SETGET_STACK_FUNCS(backup_total_bytes, struct btrfs_root_backup,
		   total_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(backup_bytes_used, struct btrfs_root_backup,
		   bytes_used, 64);
BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
		   num_devices, 64);

/*
 * Extent tree v2 doesn't have a global csum or extent root, so we use the
 * extent root slot for the block group root.
 */
BTRFS_SETGET_STACK_FUNCS(backup_block_group_root, struct btrfs_root_backup,
		   extent_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_block_group_root_gen, struct btrfs_root_backup,
		   extent_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_block_group_root_level, struct btrfs_root_backup,
		   extent_root_level, 8);

/* struct btrfs_super_block */

BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);
BTRFS_SETGET_STACK_FUNCS(super_flags, struct btrfs_super_block, flags, 64);
BTRFS_SETGET_STACK_FUNCS(super_generation, struct btrfs_super_block,
			 generation, 64);
BTRFS_SETGET_STACK_FUNCS(super_root, struct btrfs_super_block, root, 64);
BTRFS_SETGET_STACK_FUNCS(super_sys_array_size,
			 struct btrfs_super_block, sys_chunk_array_size, 32);
BTRFS_SETGET_STACK_FUNCS(super_chunk_root_generation,
			 struct btrfs_super_block, chunk_root_generation, 64);
BTRFS_SETGET_STACK_FUNCS(super_root_level, struct btrfs_super_block,
			 root_level, 8);
BTRFS_SETGET_STACK_FUNCS(super_chunk_root, struct btrfs_super_block,
			 chunk_root, 64);
BTRFS_SETGET_STACK_FUNCS(super_chunk_root_level, struct btrfs_super_block,
			 chunk_root_level, 8);
BTRFS_SETGET_STACK_FUNCS(super_log_root, struct btrfs_super_block,
			 log_root, 64);
BTRFS_SETGET_STACK_FUNCS(super_log_root_transid, struct btrfs_super_block,
			 log_root_transid, 64);
BTRFS_SETGET_STACK_FUNCS(super_log_root_level, struct btrfs_super_block,
			 log_root_level, 8);
BTRFS_SETGET_STACK_FUNCS(super_total_bytes, struct btrfs_super_block,
			 total_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(super_bytes_used, struct btrfs_super_block,
			 bytes_used, 64);
BTRFS_SETGET_STACK_FUNCS(super_sectorsize, struct btrfs_super_block,
			 sectorsize, 32);
BTRFS_SETGET_STACK_FUNCS(super_nodesize, struct btrfs_super_block,
			 nodesize, 32);
BTRFS_SETGET_STACK_FUNCS(super_stripesize, struct btrfs_super_block,
			 stripesize, 32);
BTRFS_SETGET_STACK_FUNCS(super_root_dir, struct btrfs_super_block,
			 root_dir_objectid, 64);
BTRFS_SETGET_STACK_FUNCS(super_num_devices, struct btrfs_super_block,
			 num_devices, 64);
BTRFS_SETGET_STACK_FUNCS(super_compat_flags, struct btrfs_super_block,
			 compat_flags, 64);
BTRFS_SETGET_STACK_FUNCS(super_compat_ro_flags, struct btrfs_super_block,
			 compat_ro_flags, 64);
BTRFS_SETGET_STACK_FUNCS(super_incompat_flags, struct btrfs_super_block,
			 incompat_flags, 64);
BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block,
			 csum_type, 16);
BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block,
			 cache_generation, 64);
BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block,
			 uuid_tree_generation, 64);
BTRFS_SETGET_STACK_FUNCS(super_magic, struct btrfs_super_block, magic, 64);
BTRFS_SETGET_STACK_FUNCS(super_block_group_root, struct btrfs_super_block,
			 block_group_root, 64);
BTRFS_SETGET_STACK_FUNCS(super_block_group_root_generation,
			 struct btrfs_super_block,
			 block_group_root_generation, 64);
BTRFS_SETGET_STACK_FUNCS(super_block_group_root_level,
			 struct btrfs_super_block, block_group_root_level, 8);
BTRFS_SETGET_STACK_FUNCS(super_nr_global_roots, struct btrfs_super_block,
			 nr_global_roots, 64);

static inline unsigned long btrfs_leaf_data(struct extent_buffer *l)
{
	return offsetof(struct btrfs_leaf, items);
}

/* struct btrfs_file_extent_item */
BTRFS_SETGET_FUNCS(file_extent_type, struct btrfs_file_extent_item, type, 8);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_type, struct btrfs_file_extent_item, type, 8);

static inline unsigned long btrfs_file_extent_inline_start(struct
						   btrfs_file_extent_item *e)
{
	unsigned long offset = (unsigned long)e;
	offset += offsetof(struct btrfs_file_extent_item, disk_bytenr);
	return offset;
}

static inline u32 btrfs_file_extent_calc_inline_size(u32 datasize)
{
	return offsetof(struct btrfs_file_extent_item, disk_bytenr) + datasize;
}

BTRFS_SETGET_FUNCS(file_extent_disk_bytenr, struct btrfs_file_extent_item,
		   disk_bytenr, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_disk_bytenr, struct btrfs_file_extent_item,
		   disk_bytenr, 64);
BTRFS_SETGET_FUNCS(file_extent_generation, struct btrfs_file_extent_item,
		   generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_generation, struct btrfs_file_extent_item,
		   generation, 64);
BTRFS_SETGET_FUNCS(file_extent_disk_num_bytes, struct btrfs_file_extent_item,
		   disk_num_bytes, 64);
BTRFS_SETGET_FUNCS(file_extent_offset, struct btrfs_file_extent_item,
		  offset, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_offset, struct btrfs_file_extent_item,
		  offset, 64);
BTRFS_SETGET_FUNCS(file_extent_num_bytes, struct btrfs_file_extent_item,
		   num_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_num_bytes, struct btrfs_file_extent_item,
		   num_bytes, 64);
BTRFS_SETGET_FUNCS(file_extent_ram_bytes, struct btrfs_file_extent_item,
		   ram_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_ram_bytes, struct btrfs_file_extent_item,
		   ram_bytes, 64);
BTRFS_SETGET_FUNCS(file_extent_compression, struct btrfs_file_extent_item,
		   compression, 8);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_compression, struct btrfs_file_extent_item,
		   compression, 8);
BTRFS_SETGET_FUNCS(file_extent_encryption, struct btrfs_file_extent_item,
		   encryption, 8);
BTRFS_SETGET_FUNCS(file_extent_other_encoding, struct btrfs_file_extent_item,
		   other_encoding, 16);

/* btrfs_qgroup_status_item */
BTRFS_SETGET_FUNCS(qgroup_status_version, struct btrfs_qgroup_status_item,
		   version, 64);
BTRFS_SETGET_FUNCS(qgroup_status_generation, struct btrfs_qgroup_status_item,
		   generation, 64);
BTRFS_SETGET_FUNCS(qgroup_status_flags, struct btrfs_qgroup_status_item,
		   flags, 64);
BTRFS_SETGET_FUNCS(qgroup_status_rescan, struct btrfs_qgroup_status_item,
		   rescan, 64);

BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_version,
			 struct btrfs_qgroup_status_item, version, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_generation,
			 struct btrfs_qgroup_status_item, generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_flags,
			 struct btrfs_qgroup_status_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_rescan,
			 struct btrfs_qgroup_status_item, rescan, 64);

/* btrfs_qgroup_info_item */
BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,
		   generation, 64);
BTRFS_SETGET_FUNCS(qgroup_info_referenced, struct btrfs_qgroup_info_item,
		   referenced, 64);
BTRFS_SETGET_FUNCS(qgroup_info_referenced_compressed,
		   struct btrfs_qgroup_info_item, referenced_compressed, 64);
BTRFS_SETGET_FUNCS(qgroup_info_exclusive, struct btrfs_qgroup_info_item,
		   exclusive, 64);
BTRFS_SETGET_FUNCS(qgroup_info_exclusive_compressed,
		   struct btrfs_qgroup_info_item, exclusive_compressed, 64);

BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_generation,
			 struct btrfs_qgroup_info_item, generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_referenced,
			 struct btrfs_qgroup_info_item, referenced, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_referenced_compressed,
		   struct btrfs_qgroup_info_item, referenced_compressed, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_exclusive,
			 struct btrfs_qgroup_info_item, exclusive, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_exclusive_compressed,
		   struct btrfs_qgroup_info_item, exclusive_compressed, 64);

/* btrfs_qgroup_limit_item */
BTRFS_SETGET_FUNCS(qgroup_limit_flags, struct btrfs_qgroup_limit_item,
		   flags, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_max_referenced, struct btrfs_qgroup_limit_item,
		   max_referenced, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_max_exclusive, struct btrfs_qgroup_limit_item,
		   max_exclusive, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_rsv_referenced, struct btrfs_qgroup_limit_item,
		   rsv_referenced, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_rsv_exclusive, struct btrfs_qgroup_limit_item,
		   rsv_exclusive, 64);

BTRFS_SETGET_STACK_FUNCS(stack_qgroup_limit_flags,
			 struct btrfs_qgroup_limit_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_limit_max_referenced,
			 struct btrfs_qgroup_limit_item, max_referenced, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_limit_max_exclusive,
			 struct btrfs_qgroup_limit_item, max_exclusive, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_limit_rsv_referenced,
			 struct btrfs_qgroup_limit_item, rsv_referenced, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_limit_rsv_exclusive,
			 struct btrfs_qgroup_limit_item, rsv_exclusive, 64);

/* btrfs_balance_item */
BTRFS_SETGET_FUNCS(balance_item_flags, struct btrfs_balance_item, flags, 64);

static inline struct btrfs_disk_balance_args* btrfs_balance_item_data(
		struct extent_buffer *eb, struct btrfs_balance_item *bi)
{
	unsigned long offset = (unsigned long)bi;
	struct btrfs_balance_item *p;
	p = (struct btrfs_balance_item *)(eb->data + offset);
	return &p->data;
}

static inline struct btrfs_disk_balance_args* btrfs_balance_item_meta(
		struct extent_buffer *eb, struct btrfs_balance_item *bi)
{
	unsigned long offset = (unsigned long)bi;
	struct btrfs_balance_item *p;
	p = (struct btrfs_balance_item *)(eb->data + offset);
	return &p->meta;
}

static inline struct btrfs_disk_balance_args* btrfs_balance_item_sys(
		struct extent_buffer *eb, struct btrfs_balance_item *bi)
{
	unsigned long offset = (unsigned long)bi;
	struct btrfs_balance_item *p;
	p = (struct btrfs_balance_item *)(eb->data + offset);
	return &p->sys;
}

static inline u64 btrfs_dev_stats_value(const struct extent_buffer *eb,
					const struct btrfs_dev_stats_item *ptr,
					int index)
{
	u64 val;

	read_extent_buffer(eb, &val,
			   offsetof(struct btrfs_dev_stats_item, values) +
			    ((unsigned long)ptr) + (index * sizeof(u64)),
			   sizeof(val));
	return val;
}

/*
 * this returns the number of bytes used by the item on disk, minus the
 * size of any extent headers.  If a file is compressed on disk, this is
 * the compressed size
 */
static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
						    int nr)
{
	return btrfs_item_size(eb, nr) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
}

/* struct btrfs_ioctl_search_header */
static inline u64 btrfs_search_header_transid(struct btrfs_ioctl_search_header *sh)
{
	return get_unaligned_64(&sh->transid);
}

static inline u64 btrfs_search_header_objectid(struct btrfs_ioctl_search_header *sh)
{
	return get_unaligned_64(&sh->objectid);
}

static inline u64 btrfs_search_header_offset(struct btrfs_ioctl_search_header *sh)
{
	return get_unaligned_64(&sh->offset);
}

static inline u32 btrfs_search_header_type(struct btrfs_ioctl_search_header *sh)
{
	return get_unaligned_32(&sh->type);
}

static inline u32 btrfs_search_header_len(struct btrfs_ioctl_search_header *sh)
{
	return get_unaligned_32(&sh->len);
}

#define btrfs_fs_incompat(fs_info, opt) \
	__btrfs_fs_incompat((fs_info), BTRFS_FEATURE_INCOMPAT_##opt)

static inline bool __btrfs_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag)
{
	struct btrfs_super_block *disk_super;
	disk_super = fs_info->super_copy;
	return !!(btrfs_super_incompat_flags(disk_super) & flag);
}

#define btrfs_fs_compat_ro(fs_info, opt) \
	__btrfs_fs_compat_ro((fs_info), BTRFS_FEATURE_COMPAT_RO_##opt)

static inline int __btrfs_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag)
{
	struct btrfs_super_block *disk_super;
	disk_super = fs_info->super_copy;
	return !!(btrfs_super_compat_ro_flags(disk_super) & flag);
}

/* helper function to cast into the data area of the leaf. */
#define btrfs_item_ptr(leaf, slot, type) \
	((type *)(btrfs_leaf_data(leaf) + \
	btrfs_item_offset(leaf, slot)))

#define btrfs_item_ptr_offset(leaf, slot) \
	((unsigned long)(btrfs_leaf_data(leaf) + \
	btrfs_item_offset(leaf, slot)))

int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		   struct btrfs_path *path, int slot, int nr);

static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
				 struct btrfs_root *root,
				 struct btrfs_path *path)
{
	return btrfs_del_items(trans, root, path, path->slots[0], 1);
}

int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_key *key, void *data, u32 data_size);
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root,
			     struct btrfs_path *path,
			     struct btrfs_key *cpu_key, u32 *data_size, int nr);

static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
					  struct btrfs_root *root,
					  struct btrfs_path *path,
					  struct btrfs_key *key,
					  u32 data_size)
{
	return btrfs_insert_empty_items(trans, root, path, key, &data_size, 1);
}

int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info,
				  struct btrfs_path *path);

/*
 * Walk up the tree as far as necessary to find the next leaf.
 *
 * returns 0 if it found something or 1 if there are no greater leaves.
 * returns < 0 on io errors.
 */
static inline int btrfs_next_leaf(struct btrfs_root *root,
				  struct btrfs_path *path)
{
	path->lowest_level = 0;
	return btrfs_next_sibling_tree_block(root->fs_info, path);
}

#endif