/fs/btrfs/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__
#define __BTRFS_CTREE__

#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/fs.h>
#include <linux/rwsem.h>
#include <linux/completion.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/kobject.h>
#include <trace/events/btrfs.h>
#include <asm/kmap_types.h>
#include "extent_io.h"
#include "extent_map.h"
#include "async-thread.h"
#include "ioctl.h"

struct btrfs_trans_handle;
struct btrfs_transaction;
struct btrfs_pending_snapshot;
extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_transaction_cachep;
extern struct kmem_cache *btrfs_bit_radix_cachep;
extern struct kmem_cache *btrfs_path_cachep;
extern struct kmem_cache *btrfs_free_space_cachep;
struct btrfs_ordered_sum;

#define BTRFS_MAGIC "_BHRfS_M"

#define BTRFS_MAX_LEVEL 8

#define BTRFS_COMPAT_EXTENT_TREE_V0

/*
 * files bigger than this get some pre-flushing when they are added
 * to the ordered operations list.  That way we limit the total
 * work done by the commit
 */
#define BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT (8 * 1024 * 1024)

/* 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

/* orhpan 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

/* for 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 sotring
 * 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_BTREE_INODE_OBJECTID 1

#define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2

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

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

/* csum types */
#define BTRFS_CSUM_TYPE_CRC32	0

static int btrfs_csum_sizes[] = { 4, 0 };

/* four bytes for CRC32 */
#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

/*
 * The key defines the order in the tree, and so it also defines (optimal)
 * block layout.
 *
 * objectid corresponds to the inode number.
 *
 * type tells us things about the object, and is a kind of stream selector.
 * so for a given inode, keys with type of 1 might refer to the inode data,
 * type of 2 may point to file data in the btree and type == 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 btrfs_mapping_tree {
	struct extent_map_tree map_tree;
};

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)

/*
 * File system states
 */

/* Errors detected */
#define BTRFS_SUPER_FLAG_ERROR		(1ULL << 2)

#define BTRFS_SUPER_FLAG_SEEDING	(1ULL << 32)
#define BTRFS_SUPER_FLAG_METADUMP	(1ULL << 33)

#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__));

#define BTRFS_NODEPTRS_PER_BLOCK(r) (((r)->nodesize - \
				      sizeof(struct btrfs_header)) / \
				     sizeof(struct btrfs_key_ptr))
#define __BTRFS_LEAF_DATA_SIZE(bs) ((bs) - sizeof(struct btrfs_header))
#define BTRFS_LEAF_DATA_SIZE(r) (__BTRFS_LEAF_DATA_SIZE(r->leafsize))
#define BTRFS_MAX_INLINE_DATA_SIZE(r) (BTRFS_LEAF_DATA_SIZE(r) - \
					sizeof(struct btrfs_item) - \
					sizeof(struct btrfs_file_extent_item))
#define BTRFS_MAX_XATTR_SIZE(r)	(BTRFS_LEAF_DATA_SIZE(r) - \
				 sizeof(struct btrfs_item) -\
				 sizeof(struct btrfs_dir_item))


/*
 * 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

/*
 * 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 4 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;
	__le32 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;

	/* future expansion */
	__le64 reserved[31];
	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
} __attribute__ ((__packed__));

/*
 * 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_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_COMPAT_SUPP		0ULL
#define BTRFS_FEATURE_COMPAT_RO_SUPP		0ULL
#define BTRFS_FEATURE_INCOMPAT_SUPP			\
	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO)

/*
 * 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.
 */
struct btrfs_path {
	struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
	int slots[BTRFS_MAX_LEVEL];
	/* if there is real range locking, this locks field will change */
	int locks[BTRFS_MAX_LEVEL];
	int reada;
	/* keep some upper locks as we walk down */
	int lowest_level;

	/*
	 * set by btrfs_split_item, tells search_slot to keep all locks
	 * and to force calls to keep space in the nodes
	 */
	unsigned int search_for_split:1;
	unsigned int keep_locks:1;
	unsigned int skip_locking:1;
	unsigned int leave_spinning:1;
	unsigned int search_commit_root:1;
};

/*
 * 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) >> 4) - \
					sizeof(struct btrfs_item))

#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)

/*
 * this flag is only used internally by scrub and may be changed at any time
 * it is only declared here to avoid collisions
 */
#define BTRFS_EXTENT_FLAG_SUPER		(1ULL << 48)

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__));

/* old style backrefs item */
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_timespec {
	__le64 sec;
	__le32 nsec;
} __attribute__ ((__packed__));

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

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__));

#define BTRFS_ROOT_SUBVOL_RDONLY	(1ULL << 0)

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;
} __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__));

#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 extent, checksum blocks are included
	 * in these numbers
	 */
	__le64 disk_bytenr;
	__le64 disk_num_bytes;
	/*
	 * the logical offset in file blocks (no csums)
	 * 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 (no csums included).  This
	 * always reflects the size uncompressed and without encoding.
	 */
	__le64 num_bytes;

} __attribute__ ((__packed__));

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

/* different types of block groups (and chunks) */
#define BTRFS_BLOCK_GROUP_DATA     (1 << 0)
#define BTRFS_BLOCK_GROUP_SYSTEM   (1 << 1)
#define BTRFS_BLOCK_GROUP_METADATA (1 << 2)
#define BTRFS_BLOCK_GROUP_RAID0    (1 << 3)
#define BTRFS_BLOCK_GROUP_RAID1    (1 << 4)
#define BTRFS_BLOCK_GROUP_DUP	   (1 << 5)
#define BTRFS_BLOCK_GROUP_RAID10   (1 << 6)
#define BTRFS_NR_RAID_TYPES	   5

struct btrfs_block_group_item {
	__le64 used;
	__le64 chunk_objectid;
	__le64 flags;
} __attribute__ ((__packed__));

struct btrfs_space_info {
	u64 flags;

	u64 total_bytes;	/* total bytes in the space,
				   this doesn't take mirrors into account */
	u64 bytes_used;		/* total bytes used,
				   this doesn't take mirrors into account */
	u64 bytes_pinned;	/* total bytes pinned, will be freed when the
				   transaction finishes */
	u64 bytes_reserved;	/* total bytes the allocator has reserved for
				   current allocations */
	u64 bytes_readonly;	/* total bytes that are read only */

	u64 bytes_may_use;	/* number of bytes that may be used for
				   delalloc/allocations */
	u64 disk_used;		/* total bytes used on disk */
	u64 disk_total;		/* total bytes on disk, takes mirrors into
				   account */

	/*
	 * we bump reservation progress every time we decrement
	 * bytes_reserved.  This way people waiting for reservations
	 * know something good has happened and they can check
	 * for progress.  The number here isn't to be trusted, it
	 * just shows reclaim activity
	 */
	unsigned long reservation_progress;

	unsigned int full:1;	/* indicates that we cannot allocate any more
				   chunks for this space */
	unsigned int chunk_alloc:1;	/* set if we are allocating a chunk */

	unsigned int flush:1;		/* set if we are trying to make space */

	unsigned int force_alloc;	/* set if we need to force a chunk
					   alloc for this space */

	struct list_head list;

	/* for block groups in our same type */
	struct list_head block_groups[BTRFS_NR_RAID_TYPES];
	spinlock_t lock;
	struct rw_semaphore groups_sem;
	wait_queue_head_t wait;
};

struct btrfs_block_rsv {
	u64 size;
	u64 reserved;
	u64 freed[2];
	struct btrfs_space_info *space_info;
	struct list_head list;
	spinlock_t lock;
	atomic_t usage;
	unsigned int priority:8;
	unsigned int durable:1;
	unsigned int refill_used:1;
	unsigned int full:1;
};

/*
 * free clusters are used to claim free space in relatively large chunks,
 * allowing us to do less seeky writes.  They are used for all metadata
 * allocations and data allocations in ssd mode.
 */
struct btrfs_free_cluster {
	spinlock_t lock;
	spinlock_t refill_lock;
	struct rb_root root;

	/* largest extent in this cluster */
	u64 max_size;

	/* first extent starting offset */
	u64 window_start;

	struct btrfs_block_group_cache *block_group;
	/*
	 * when a cluster is allocated from a block group, we put the
	 * cluster onto a list in the block group so that it can
	 * be freed before the block group is freed.
	 */
	struct list_head block_group_list;
};

enum btrfs_caching_type {
	BTRFS_CACHE_NO		= 0,
	BTRFS_CACHE_STARTED	= 1,
	BTRFS_CACHE_FINISHED	= 2,
};

enum btrfs_disk_cache_state {
	BTRFS_DC_WRITTEN	= 0,
	BTRFS_DC_ERROR		= 1,
	BTRFS_DC_CLEAR		= 2,
	BTRFS_DC_SETUP		= 3,
	BTRFS_DC_NEED_WRITE	= 4,
};

struct btrfs_caching_control {
	struct list_head list;
	struct mutex mutex;
	wait_queue_head_t wait;
	struct btrfs_work work;
	struct btrfs_block_group_cache *block_group;
	u64 progress;
	atomic_t count;
};

struct btrfs_block_group_cache {
	struct btrfs_key key;
	struct btrfs_block_group_item item;
	struct btrfs_fs_info *fs_info;
	struct inode *inode;
	spinlock_t lock;
	u64 pinned;
	u64 reserved;
	u64 reserved_pinned;
	u64 bytes_super;
	u64 flags;
	u64 sectorsize;
	unsigned int ro:1;
	unsigned int dirty:1;
	unsigned int iref:1;

	int disk_cache_state;

	/* cache tracking stuff */
	int cached;
	struct btrfs_caching_control *caching_ctl;
	u64 last_byte_to_unpin;

	struct btrfs_space_info *space_info;

	/* free space cache stuff */
	struct btrfs_free_space_ctl *free_space_ctl;

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

	/* for block groups in the same raid type */
	struct list_head list;

	/* usage count */
	atomic_t count;

	/* List of struct btrfs_free_clusters for this block group.
	 * Today it will only have one thing on it, but that may change
	 */
	struct list_head cluster_list;
};

struct reloc_control;
struct btrfs_device;
struct btrfs_fs_devices;
struct btrfs_delayed_root;
struct btrfs_fs_info {
	u8 fsid[BTRFS_FSID_SIZE];
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
	struct btrfs_root *extent_root;
	struct btrfs_root *tree_root;
	struct btrfs_root *chunk_root;
	struct btrfs_root *dev_root;
	struct btrfs_root *fs_root;
	struct btrfs_root *csum_root;

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

	spinlock_t fs_roots_radix_lock;
	struct radix_tree_root fs_roots_radix;

	/* block group cache stuff */
	spinlock_t block_group_cache_lock;
	struct rb_root block_group_cache_tree;

	struct extent_io_tree freed_extents[2];
	struct extent_io_tree *pinned_extents;

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

	/*
	 * block reservation for extent, checksum, root tree and
	 * delayed dir index item
	 */
	struct btrfs_block_rsv global_block_rsv;
	/* block reservation for delay allocation */
	struct btrfs_block_rsv delalloc_block_rsv;
	/* block reservation for metadata operations */
	struct btrfs_block_rsv trans_block_rsv;
	/* block reservation for chunk tree */
	struct btrfs_block_rsv chunk_block_rsv;

	struct btrfs_block_rsv empty_block_rsv;

	/* list of block reservations that cross multiple transactions */
	struct list_head durable_block_rsv_list;

	struct mutex durable_block_rsv_mutex;

	u64 generation;
	u64 last_trans_committed;

	/*
	 * this is updated to the current trans every time a full commit
	 * is required instead of the faster short fsync log commits
	 */
	u64 last_trans_log_full_commit;
	unsigned long mount_opt:20;
	unsigned long compress_type:4;
	u64 max_inline;
	u64 alloc_start;
	struct btrfs_transaction *running_transaction;
	wait_queue_head_t transaction_throttle;
	wait_queue_head_t transaction_wait;
	wait_queue_head_t transaction_blocked_wait;
	wait_queue_head_t async_submit_wait;

	struct btrfs_super_block super_copy;
	struct btrfs_super_block super_for_commit;
	struct block_device *__bdev;
	struct super_block *sb;
	struct inode *btree_inode;
	struct backing_dev_info bdi;
	struct mutex tree_log_mutex;
	struct mutex transaction_kthread_mutex;
	struct mutex cleaner_mutex;
	struct mutex chunk_mutex;
	struct mutex volume_mutex;
	/*
	 * this protects the ordered operations list only while we are
	 * processing all of the entries on it.  This way we make
	 * sure the commit code doesn't find the list temporarily empty
	 * because another function happens to be doing non-waiting preflush
	 * before jumping into the main commit.
	 */
	struct mutex ordered_operations_mutex;
	struct rw_semaphore extent_commit_sem;

	struct rw_semaphore cleanup_work_sem;

	struct rw_semaphore subvol_sem;
	struct srcu_struct subvol_srcu;

	spinlock_t trans_lock;
	/*
	 * the reloc mutex goes with the trans lock, it is taken
	 * during commit to protect us from the relocation code
	 */
	struct mutex reloc_mutex;

	struct list_head trans_list;
	struct list_head hashers;
	struct list_head dead_roots;
	struct list_head caching_block_groups;

	spinlock_t delayed_iput_lock;
	struct list_head delayed_iputs;

	atomic_t nr_async_submits;
	atomic_t async_submit_draining;
	atomic_t nr_async_bios;
	atomic_t async_delalloc_pages;
	atomic_t open_ioctl_trans;

	/*
	 * this is used by the balancing code to wait for all the pending
	 * ordered extents
	 */
	spinlock_t ordered_extent_lock;

	/*
	 * all of the data=ordered extents pending writeback
	 * these can span multiple transactions and basically include
	 * every dirty data page that isn't from nodatacow
	 */
	struct list_head ordered_extents;

	/*
	 * all of the inodes that have delalloc bytes.  It is possible for
	 * this list to be empty even when there is still dirty data=ordered
	 * extents waiting to finish IO.
	 */
	struct list_head delalloc_inodes;

	/*
	 * special rename and truncate targets that must be on disk before
	 * we're allowed to commit.  This is basically the ext3 style
	 * data=ordered list.
	 */
	struct list_head ordered_operations;

	/*
	 * there is a pool of worker threads for checksumming during writes
	 * and a pool for checksumming after reads.  This is because readers
	 * can run with FS locks held, and the writers may be waiting for
	 * those locks.  We don't want ordering in the pending list to cause
	 * deadlocks, and so the two are serviced separately.
	 *
	 * A third pool does submit_bio to avoid deadlocking with the other
	 * two
	 */
	struct btrfs_workers generic_worker;
	struct btrfs_workers workers;
	struct btrfs_workers delalloc_workers;
	struct btrfs_workers endio_workers;
	struct btrfs_workers endio_meta_workers;
	struct btrfs_workers endio_meta_write_workers;
	struct btrfs_workers endio_write_workers;
	struct btrfs_workers endio_freespace_worker;
	struct btrfs_workers submit_workers;
	struct btrfs_workers caching_workers;

	/*
	 * fixup workers take dirty pages that didn't properly go through
	 * the cow mechanism and make them safe to write.  It happens
	 * for the sys_munmap function call path
	 */
	struct btrfs_workers fixup_workers;
	struct btrfs_workers delayed_workers;
	struct task_struct *transaction_kthread;
	struct task_struct *cleaner_kthread;
	int thread_pool_size;

	struct kobject super_kobj;
	struct completion kobj_unregister;
	int do_barriers;
	int closing;
	int log_root_recovering;
	int enospc_unlink;
	int trans_no_join;

	u64 total_pinned;

	/* protected by the delalloc lock, used to keep from writing
	 * metadata until there is a nice batch
	 */
	u64 dirty_metadata_bytes;
	struct list_head dirty_cowonly_roots;

	struct btrfs_fs_devices *fs_devices;

	/*
	 * the space_info list is almost entirely read only.  It only changes
	 * when we add a new raid type to the FS, and that happens
	 * very rarely.  RCU is used to protect it.
	 */
	struct list_head space_info;

	struct reloc_control *reloc_ctl;

	spinlock_t delalloc_lock;
	u64 delalloc_bytes;

	/* data_alloc_cluster is only used in ssd mode */
	struct btrfs_free_cluster data_alloc_cluster;

	/* all metadata allocations go through this cluster */
	struct btrfs_free_cluster meta_alloc_cluster;

	/* auto defrag inodes go here */
	spinlock_t defrag_inodes_lock;
	struct rb_root defrag_inodes;
	atomic_t defrag_running;

	spinlock_t ref_cache_lock;
	u64 total_ref_cache_size;

	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;

	unsigned data_chunk_allocations;
	unsigned metadata_ratio;

	void *bdev_holder;

	/* private scrub information */
	struct mutex scrub_lock;
	atomic_t scrubs_running;
	atomic_t scrub_pause_req;
	atomic_t scrubs_paused;
	atomic_t scrub_cancel_req;
	wait_queue_head_t scrub_pause_wait;
	struct rw_semaphore scrub_super_lock;
	int scrub_workers_refcnt;
	struct btrfs_workers scrub_workers;

	/* filesystem state */
	u64 fs_state;

	struct btrfs_delayed_root *delayed_root;
};

/*
 * 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 *log_root;
	struct btrfs_root *reloc_root;

	struct btrfs_root_item root_item;
	struct btrfs_key root_key;
	struct btrfs_fs_info *fs_info;
	struct extent_io_tree dirty_log_pages;

	struct kobject root_kobj;
	struct completion kobj_unregister;
	struct mutex objectid_mutex;

	spinlock_t accounting_lock;
	struct btrfs_block_rsv *block_rsv;

	/* free ino cache stuff */
	struct mutex fs_commit_mutex;
	struct btrfs_free_space_ctl *free_ino_ctl;
	enum btrfs_caching_type cached;
	spinlock_t cache_lock;
	wait_queue_head_t cache_wait;
	struct btrfs_free_space_ctl *free_ino_pinned;
	u64 cache_progress;
	struct inode *cache_inode;

	struct mutex log_mutex;
	wait_queue_head_t log_writer_wait;
	wait_queue_head_t log_commit_wait[2];
	atomic_t log_writers;
	atomic_t log_commit[2];
	unsigned long log_transid;
	unsigned long last_log_commit;
	unsigned long log_batch;
	pid_t log_start_pid;
	bool log_multiple_pids;

	u64 objectid;
	u64 last_trans;

	/* data allocations are done in sectorsize units */
	u32 sectorsize;

	/* node allocations are done in nodesize units */
	u32 nodesize;

	/* leaf allocations are done in leafsize units */
	u32 leafsize;

	u32 stripesize;

	u32 type;

	u64 highest_objectid;

	/* btrfs_record_root_in_trans is a multi-step process,
	 * and it can race with the balancing code.   But the
	 * race is very small, and only the first time the root
	 * is added to each transaction.  So in_trans_setup
	 * is used to tell us when more checks are required
	 */
	unsigned long in_trans_setup;
	int ref_cows;
	int track_dirty;
	int in_radix;

	u64 defrag_trans_start;
	struct btrfs_key defrag_progress;
	struct btrfs_key defrag_max;
	int defrag_running;
	char *name;

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

	struct list_head root_list;

	spinlock_t orphan_lock;
	struct list_head orphan_list;
	struct btrfs_block_rsv *orphan_block_rsv;
	int orphan_item_inserted;
	int orphan_cleanup_state;

	spinlock_t inode_lock;
	/* red-black tree that keeps track of in-memory inodes */
	struct rb_root inode_tree;

	/*
	 * radix tree that keeps track of delayed nodes of every inode,
	 * protected by inode_lock
	 */
	struct radix_tree_root delayed_nodes_tree;
	/*
	 * right now this just gets used so that a root has its own devid
	 * for stat.  It may be used for more later
	 */
	dev_t anon_dev;
};

struct btrfs_ioctl_defrag_range_args {
	/* start of the defrag operation */
	__u64 start;

	/* number of bytes to defrag, use (u64)-1 to say all */
	__u64 len;

	/*
	 * flags for the operation, which can include turning
	 * on compression for this one defrag
	 */
	__u64 flags;

	/*
	 * any extent bigger than this will be considered
	 * already defragged.  Use 0 to take the kernel default
	 * Use 1 to say every single extent must be rewritten
	 */
	__u32 extent_thresh;

	/*
	 * which compression method to use if turning on compression
	 * for this defrag operation.  If unspecified, zlib will
	 * be used
	 */
	__u32 compress_type;

	/* spare for later */
	__u32 unused[4];
};


/*
 * 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_XATTR_ITEM_KEY		24
#define BTRFS_ORPHAN_ITEM_KEY		48
/* reserve 2-15 close to the inode for later flexibility */

/*
 * dir items are the name -> inode pointers in a directory.  There is one
 * for every name in a directory.
 */
#define BTRFS_DIR_LOG_ITEM_KEY  60
#define BTRFS_DIR_LOG_INDEX_KEY 72
#define BTRFS_DIR_ITEM_KEY	84
#define BTRFS_DIR_INDEX_KEY	96
/*
 * extent data is for file data
 */
#define BTRFS_EXTENT_DATA_KEY	108

/*
 * 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.  They 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

#define BTRFS_TREE_BLOCK_REF_KEY	176

#define BTRFS_EXTENT_DATA_REF_KEY	178

#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

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

/*
 * string items are for debugging.  They just store a short string of
 * data in the FS
 */
#define BTRFS_STRING_ITEM_KEY	253

/*
 * Flags for mount options.
 *
 * Note: don't forget to add new options to btrfs_show_options()
 */
#define BTRFS_MOUNT_NODATASUM		(1 << 0)
#define BTRFS_MOUNT_NODATACOW		(1 << 1)
#define BTRFS_MOUNT_NOBARRIER		(1 << 2)
#define BTRFS_MOUNT_SSD			(1 << 3)
#define BTRFS_MOUNT_DEGRADED		(1 << 4)
#define BTRFS_MOUNT_COMPRESS		(1 << 5)
#define BTRFS_MOUNT_NOTREELOG           (1 << 6)
#define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)
#define BTRFS_MOUNT_SSD_SPREAD		(1 << 8)
#define BTRFS_MOUNT_NOSSD		(1 << 9)
#define BTRFS_MOUNT_DISCARD		(1 << 10)
#define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
#define BTRFS_MOUNT_SPACE_CACHE		(1 << 12)
#define BTRFS_MOUNT_CLEAR_CACHE		(1 << 13)
#define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
#define BTRFS_MOUNT_ENOSPC_DEBUG	 (1 << 15)
#define BTRFS_MOUNT_AUTO_DEFRAG		(1 << 16)
#define BTRFS_MOUNT_INODE_MAP_CACHE	(1 << 17)

#define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
#define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
#define btrfs_test_opt(root, opt)	((root)->fs_info->mount_opt & \
					 BTRFS_MOUNT_##opt)
/*
 * 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)

#define BTRFS_INODE_ROOT_ITEM_INIT	(1 << 31)

/* some macros to generate set/get funcs for the struct fields.  This
 * assumes there is a lefoo_to_cpu for every type, so lets make a simple
 * one for u8:
 */
#define le8_to_cpu(v) (v)
#define cpu_to_le8(v) (v)
#define __le8 u8

#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)))

#ifndef BTRFS_SETGET_FUNCS
#define BTRFS_SETGET_FUNCS(name, type, member, bits)			\
u##bits btrfs_##name(struct extent_buffer *eb, type *s);		\
void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val);
#endif

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

#define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)		\
static inline u##bits btrfs_##name(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 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));
}

/* struct btrfs_block_group_item */
BTRFS_SETGET_STACK_FUNCS(block_group_used, struct btrfs_block_group_item,
			 used, 64);
BTRFS_SETGET_FUNCS(disk_block_group_used, struct btrfs_block_group_item,
			 used, 64);
BTRFS_SETGET_STACK_FUNCS(block_group_chunk_objectid,
			struct btrfs_block_group_item, chunk_objectid, 64);

BTRFS_SETGET_FUNCS(disk_block_group_chunk_objectid,
		   struct btrfs_block_group_item, chunk_objectid, 64);
BTRFS_SETGET_FUNCS(disk_block_group_flags,
		   struct btrfs_block_group_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(block_group_flags,
			struct btrfs_block_group_item, flags, 64);

/* struct btrfs_inode_ref */
BTRFS_SETGET_FUNCS(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_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);

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;
}

BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
BTRFS_SETGET_FUNCS(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);

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);
}

BTRFS_SETGET_FUNCS(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_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);

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 u64 btrfs_node_blockptr(struct extent_buffer *eb, int nr)
{
	unsigned long ptr;
	ptr = offsetof(struct btrfs_node, ptrs) +
		sizeof(struct btrfs_key_ptr) * nr;
	return btrfs_key_blockptr(eb, (struct btrfs_key_ptr *)ptr);
}

static inline void btrfs_set_node_blockptr(struct extent_buffer *eb,
					   int nr, u64 val)
{
	unsigned long ptr;
	ptr = offsetof(struct btrfs_node, ptrs) +
		sizeof(struct btrfs_key_ptr) * nr;
	btrfs_set_key_blockptr(eb, (struct btrfs_key_ptr *)ptr, val);
}

static inline u64 btrfs_node_ptr_generation(struct extent_buffer *eb, int nr)
{
	unsigned long ptr;
	ptr = offsetof(struct btrfs_node, ptrs) +
		sizeof(struct btrfs_key_ptr) * nr;
	return btrfs_key_generation(eb, (struct btrfs_key_ptr *)ptr);
}

static inline void btrfs_set_node_ptr_generation(struct extent_buffer *eb,
						 int nr, u64 val)
{
	unsigned long ptr;
	ptr = offsetof(struct btrfs_node, ptrs) +
		sizeof(struct btrfs_key_ptr) * nr;
	btrfs_set_key_generation(eb, (struct btrfs_key_ptr *)ptr, val);
}

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

void btrfs_node_key(struct extent_buffer *eb,
		    struct btrfs_disk_key *disk_key, int nr);

static inline void btrfs_set_node_key(struct extent_buffer *eb,
				      struct btrfs_disk_key *disk_key, int nr)
{
	unsigned long ptr;
	ptr = btrfs_node_key_ptr_offset(nr);
	write_eb_member(eb, (struct btrfs_key_ptr *)ptr,
		       struct btrfs_key_ptr, key, disk_key);
}

/* struct btrfs_item */
BTRFS_SETGET_FUNCS(item_offset, struct btrfs_item, offset, 32);
BTRFS_SETGET_FUNCS(item_size, struct btrfs_item, size, 32);

static inl