[pandora-kernel.git] / 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/version.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/fs.h>
#include <linux/completion.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <asm/kmap_types.h>
#include "extent_io.h"
#include "extent_map.h"
#include "async-thread.h"

struct btrfs_trans_handle;
struct btrfs_transaction;
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;
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

/* 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;
};

#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__));

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_FSID_SIZE 16
#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_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];

        /* future expansion */
        __le64 reserved[32];
        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   (2ULL << 0)

#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)

/*
 * 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)

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_LAST = 2,
};

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 {
        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 */
        u64 bytes_used;         /* total bytes used,
                                   this does'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_super;        /* total bytes reserved for the super blocks */
        u64 bytes_root;         /* the number of bytes needed to commit a
                                   transaction */
        u64 bytes_may_use;      /* number of bytes that may be used for
                                   delalloc/allocations */
        u64 bytes_delalloc;     /* number of bytes currently reserved for
                                   delayed allocation */
        u64 disk_used;          /* total bytes used on disk */

        int full;               /* indicates that we cannot allocate any more
                                   chunks for this space */
        int force_alloc;        /* set if we need to force a chunk alloc for
                                   this space */
        int force_delalloc;     /* make people start doing filemap_flush until
                                   we're under a threshold */

        struct list_head list;

        /* for controlling how we free up space for allocations */
        wait_queue_head_t allocate_wait;
        wait_queue_head_t flush_wait;
        int allocating_chunk;
        int flushing;

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

/*
 * 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;

        /* if this cluster simply points at a bitmap in the block group */
        bool points_to_bitmap;

        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,
};

struct btrfs_caching_control {
        struct list_head list;
        struct mutex mutex;
        wait_queue_head_t wait;
        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;
        spinlock_t lock;
        u64 pinned;
        u64 reserved;
        u64 bytes_super;
        u64 flags;
        u64 sectorsize;
        int extents_thresh;
        int free_extents;
        int total_bitmaps;
        int ro;
        int dirty;

        /* 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 */
        spinlock_t tree_lock;
        struct rb_root free_space_offset;
        u64 free_space;

        /* 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_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;

        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;
        u64 open_ioctl_trans;
        unsigned long mount_opt;
        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 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 trans_mutex;
        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;

        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;

        /*
         * 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 submit_workers;
        struct btrfs_workers enospc_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 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;

        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;
        spinlock_t new_trans_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;

        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;
};

/*
 * 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;

        /* the node lock is held while changing the node pointer */
        spinlock_t node_lock;

        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;

        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;
        int ref_cows;
        int track_dirty;
        int in_radix;
        int clean_orphans;

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

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

        struct list_head root_list;

        spinlock_t list_lock;
        struct list_head orphan_list;

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

        /*
         * right now this just gets used so that a root has its own devid
         * for stat.  It may be used for more later
         */
        struct super_block anon_super;
};

/*
 * 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

#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_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)

/* 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 = kmap_atomic(eb->first_page, KM_USER0);                \
        u##bits res = le##bits##_to_cpu(p->member);                     \
        kunmap_atomic(p, KM_USER0);                                     \
        return res;                                                     \
}                                                                       \
static inline void btrfs_set_##name(struct extent_buffer *eb,           \
                                    u##bits val)                        \
{                                                                       \
        type *p = kmap_atomic(eb->first_page, KM_USER0);                \
        p->member = cpu_to_le##bits(val);                               \
        kunmap_atomic(p, KM_USER0);                                     \
}

#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 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(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;
}

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);

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

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

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

static inline u32 btrfs_item_end_nr(struct extent_buffer *eb, int nr)
{
        return btrfs_item_end(eb, btrfs_item_nr(eb, nr));
}

static inline u32 btrfs_item_offset_nr(struct extent_buffer *eb, int nr)
{
        return btrfs_item_offset(eb, btrfs_item_nr(eb, nr));
}

static inline u32 btrfs_item_size_nr(struct extent_buffer *eb, int nr)
{
        return btrfs_item_size(eb, btrfs_item_nr(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);

/* 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);

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_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,
                                         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);
}


static inline u8 btrfs_key_type(struct btrfs_key *key)
{
        return key->type;
}

static inline void btrfs_set_key_type(struct btrfs_key *key, u8 val)
{
        key->type = val;
}

/* 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);

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 u8 *btrfs_header_fsid(struct extent_buffer *eb)
{
        unsigned long ptr = offsetof(struct btrfs_header, fsid);
        return (u8 *)ptr;
}

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

static inline u8 *btrfs_super_fsid(struct extent_buffer *eb)
{
        unsigned long ptr = offsetof(struct btrfs_super_block, fsid);
        return (u8 *)ptr;
}

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

static inline struct btrfs_node *btrfs_buffer_node(struct extent_buffer *eb)
{
        return NULL;
}

static inline struct btrfs_leaf *btrfs_buffer_leaf(struct extent_buffer *eb)
{
        return NULL;
}

static inline struct btrfs_header *btrfs_buffer_header(struct extent_buffer *eb)
{
        return NULL;
}

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);

/* 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_leafsize, struct btrfs_super_block,
                         leafsize, 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);

static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
{
        int t = btrfs_super_csum_type(s);
        BUG_ON(t >= ARRAY_SIZE(btrfs_csum_sizes));
        return btrfs_csum_sizes[t];
}

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);

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_FUNCS(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_FUNCS(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_FUNCS(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);

/* this returns the number of file bytes represented by the inline item.
 * If an item is compressed, this is the uncompressed size
 */
static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
                                               struct btrfs_file_extent_item *e)
{
        return btrfs_file_extent_ram_bytes(eb, e);
}

/*
 * 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,
                                                    struct btrfs_item *e)
{
        unsigned long offset;
        offset = offsetof(struct btrfs_file_extent_item, disk_bytenr);
        return btrfs_item_size(eb, e) - offset;
}

static inline struct btrfs_root *btrfs_sb(struct super_block *sb)
{
        return sb->s_fs_info;
}

static inline int btrfs_set_root_name(struct btrfs_root *root,
                                      const char *name, int len)
{
        /* if we already have a name just free it */
        kfree(root->name);

        root->name = kmalloc(len+1, GFP_KERNEL);
        if (!root->name)
                return -ENOMEM;

        memcpy(root->name, name, len);
        root->name[len] = '\0';

        return 0;
}

static inline u32 btrfs_level_size(struct btrfs_root *root, int level)
{
        if (level == 0)
                return root->leafsize;
        return root->nodesize;
}

/* 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_nr(leaf, slot)))

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

static inline struct dentry *fdentry(struct file *file)
{
        return file->f_path.dentry;
}

/* extent-tree.c */
void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root, unsigned long count);
int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len);
int btrfs_pin_extent(struct btrfs_root *root,
                     u64 bytenr, u64 num, int reserved);
int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct extent_buffer *leaf);
int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root,
                          u64 objectid, u64 offset, u64 bytenr);
int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy);
struct btrfs_block_group_cache *btrfs_lookup_block_group(
                                                 struct btrfs_fs_info *info,
                                                 u64 bytenr);
void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
u64 btrfs_find_block_group(struct btrfs_root *root,
                           u64 search_start, u64 search_hint, int owner);
struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                                        struct btrfs_root *root, u32 blocksize,
                                        u64 parent, u64 root_objectid,
                                        struct btrfs_disk_key *key, int level,
                                        u64 hint, u64 empty_size);
int btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root,
                          u64 bytenr, u32 blocksize,
                          u64 parent, u64 root_objectid, int level);
struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
                                            struct btrfs_root *root,
                                            u64 bytenr, u32 blocksize,
                                            int level);
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
                                     struct btrfs_root *root,
                                     u64 root_objectid, u64 owner,
                                     u64 offset, struct btrfs_key *ins);
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
                                   struct btrfs_root *root,
                                   u64 root_objectid, u64 owner, u64 offset,
                                   struct btrfs_key *ins);
int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
                                  struct btrfs_root *root,
                                  u64 num_bytes, u64 min_alloc_size,
                                  u64 empty_size, u64 hint_byte,
                                  u64 search_end, struct btrfs_key *ins,
                                  u64 data);
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                  struct extent_buffer *buf, int full_backref);
int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                  struct extent_buffer *buf, int full_backref);
int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root,
                                u64 bytenr, u64 num_bytes, u64 flags,
                                int is_data);
int btrfs_free_extent(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root,
                      u64 bytenr, u64 num_bytes, u64 parent,
                      u64 root_objectid, u64 owner, u64 offset);

int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len);
int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root);
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
                         u64 bytenr, u64 num_bytes, u64 parent,
                         u64 root_objectid, u64 owner, u64 offset);

int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                                    struct btrfs_root *root);
int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr);
int btrfs_free_block_groups(struct btrfs_fs_info *info);
int btrfs_read_block_groups(struct btrfs_root *root);
int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr);
int btrfs_make_block_group(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root, u64 bytes_used,
                           u64 type, u64 chunk_objectid, u64 chunk_offset,
                           u64 size);
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root, u64 group_start);
int btrfs_prepare_block_group_relocation(struct btrfs_root *root,
                                struct btrfs_block_group_cache *group);

u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags);
void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *ionde);
void btrfs_clear_space_info_full(struct btrfs_fs_info *info);

int btrfs_reserve_metadata_space(struct btrfs_root *root, int num_items);
int btrfs_unreserve_metadata_space(struct btrfs_root *root, int num_items);
int btrfs_unreserve_metadata_for_delalloc(struct btrfs_root *root,
                                          struct inode *inode, int num_items);
int btrfs_reserve_metadata_for_delalloc(struct btrfs_root *root,
                                        struct inode *inode, int num_items);
int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
                                u64 bytes);
void btrfs_free_reserved_data_space(struct btrfs_root *root,
                                    struct inode *inode, u64 bytes);
void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
                                 u64 bytes);
void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
                              u64 bytes);
/* ctree.c */
int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
                     int level, int *slot);
int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2);
int btrfs_previous_item(struct btrfs_root *root,
                        struct btrfs_path *path, u64 min_objectid,
                        int type);
int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root, struct btrfs_path *path,
                            struct btrfs_key *new_key);
struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
                        struct btrfs_key *key, int lowest_level,
                        int cache_only, u64 min_trans);
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
                         struct btrfs_key *max_key,
                         struct btrfs_path *path, int cache_only,
                         u64 min_trans);
int btrfs_cow_block(struct btrfs_trans_handle *trans,
                    struct btrfs_root *root, struct extent_buffer *buf,
                    struct extent_buffer *parent, int parent_slot,
                    struct extent_buffer **cow_ret);
int btrfs_copy_root(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root,
                      struct extent_buffer *buf,
                      struct extent_buffer **cow_ret, u64 new_root_objectid);
int btrfs_block_can_be_shared(struct btrfs_root *root,
                              struct extent_buffer *buf);
int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_path *path, u32 data_size);
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root,
                        struct btrfs_path *path,
                        u32 new_size, int from_end);
int btrfs_split_item(struct btrfs_trans_handle *trans,
                     struct btrfs_root *root,
                     struct btrfs_path *path,
                     struct btrfs_key *new_key,
                     unsigned long split_offset);
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
                         struct btrfs_path *path,
                         struct btrfs_key *new_key);
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, struct btrfs_path *p, int
                      ins_len, int cow);
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root, struct extent_buffer *parent,
                       int start_slot, int cache_only, u64 *last_ret,
                       struct btrfs_key *progress);
void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
struct btrfs_path *btrfs_alloc_path(void);
void btrfs_free_path(struct btrfs_path *p);
void btrfs_set_path_blocking(struct btrfs_path *p);
void btrfs_unlock_up_safe(struct btrfs_path *p, int level);

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_some_items(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            struct btrfs_path *path,
                            struct btrfs_key *cpu_key, u32 *data_size,
                            int nr);
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_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref);
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root,
                        struct extent_buffer *node,
                        struct extent_buffer *parent);
/* root-item.c */
int btrfs_find_root_ref(struct btrfs_root *tree_root,
                        struct btrfs_path *path,
                        u64 root_id, u64 ref_id);
int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
                       struct btrfs_root *tree_root,
                       u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
                       const char *name, int name_len);
int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
                       struct btrfs_root *tree_root,
                       u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
                       const char *name, int name_len);
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct btrfs_key *key);
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, struct btrfs_root_item
                      *item);
int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, struct btrfs_root_item
                      *item);
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
                         btrfs_root_item *item, struct btrfs_key *key);
int btrfs_search_root(struct btrfs_root *root, u64 search_start,
                      u64 *found_objectid);
int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
int btrfs_set_root_node(struct btrfs_root_item *item,
                        struct extent_buffer *node);
/* dir-item.c */
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root, const char *name,
                          int name_len, u64 dir,
                          struct btrfs_key *location, u8 type, u64 index);
struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
                                             struct btrfs_root *root,
                                             struct btrfs_path *path, u64 dir,
                                             const char *name, int name_len,
                                             int mod);
struct btrfs_dir_item *
btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            struct btrfs_path *path, u64 dir,
                            u64 objectid, const char *name, int name_len,
                            int mod);
struct btrfs_dir_item *
btrfs_search_dir_index_item(struct btrfs_root *root,
                            struct btrfs_path *path, u64 dirid,
                            const char *name, int name_len);
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
                              struct btrfs_path *path,
                              const char *name, int name_len);
int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root,
                              struct btrfs_path *path,
                              struct btrfs_dir_item *di);
int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            struct btrfs_path *path, u64 objectid,
                            const char *name, u16 name_len,
                            const void *data, u16 data_len);
struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
                                          struct btrfs_root *root,
                                          struct btrfs_path *path, u64 dir,
                                          const char *name, u16 name_len,
                                          int mod);

/* orphan.c */
int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root, u64 offset);
int btrfs_del_orphan_item(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root, u64 offset);
int btrfs_find_orphan_item(struct btrfs_root *root, u64 offset);

/* inode-map.c */
int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
                             struct btrfs_root *fs_root,
                             u64 dirid, u64 *objectid);
int btrfs_find_highest_inode(struct btrfs_root *fs_root, u64 *objectid);

/* inode-item.c */
int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root,
                           const char *name, int name_len,
                           u64 inode_objectid, u64 ref_objectid, u64 index);
int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root,
                           const char *name, int name_len,
                           u64 inode_objectid, u64 ref_objectid, u64 *index);
int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             struct btrfs_path *path, u64 objectid);
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_path *path,
                       struct btrfs_key *location, int mod);

/* file-item.c */
int btrfs_del_csums(struct btrfs_trans_handle *trans,
                    struct btrfs_root *root, u64 bytenr, u64 len);
int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
                          struct bio *bio, u32 *dst);
int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             u64 objectid, u64 pos,
                             u64 disk_offset, u64 disk_num_bytes,
                             u64 num_bytes, u64 offset, u64 ram_bytes,
                             u8 compression, u8 encryption, u16 other_encoding);
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             struct btrfs_path *path, u64 objectid,
                             u64 bytenr, int mod);
int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root,
                           struct btrfs_ordered_sum *sums);
int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
                       struct bio *bio, u64 file_start, int contig);
int btrfs_csum_file_bytes(struct btrfs_root *root, struct inode *inode,
                          u64 start, unsigned long len);
struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
                                          struct btrfs_root *root,
                                          struct btrfs_path *path,
                                          u64 bytenr, int cow);
int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct btrfs_path *path,
                        u64 isize);
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start,
                             u64 end, struct list_head *list);
/* inode.c */

/* RHEL and EL kernels have a patch that renames PG_checked to FsMisc */
#if defined(ClearPageFsMisc) && !defined(ClearPageChecked)
#define ClearPageChecked ClearPageFsMisc
#define SetPageChecked SetPageFsMisc
#define PageChecked PageFsMisc
#endif

struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
int btrfs_set_inode_index(struct inode *dir, u64 *index);
int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root,
                       struct inode *dir, struct inode *inode,
                       const char *name, int name_len);
int btrfs_add_link(struct btrfs_trans_handle *trans,
                   struct inode *parent_inode, struct inode *inode,
                   const char *name, int name_len, int add_backref, u64 index);
int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root,
                        struct inode *dir, u64 objectid,
                        const char *name, int name_len);
int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root,
                               struct inode *inode, u64 new_size,
                               u32 min_type);

int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput);
int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
                              struct extent_state **cached_state);
int btrfs_writepages(struct address_space *mapping,
                     struct writeback_control *wbc);
int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
                             struct btrfs_root *new_root,
                             u64 new_dirid, u64 alloc_hint);
int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
                         size_t size, struct bio *bio, unsigned long bio_flags);

unsigned long btrfs_force_ra(struct address_space *mapping,
                              struct file_ra_state *ra, struct file *file,
                              pgoff_t offset, pgoff_t last_index);
int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
int btrfs_readpage(struct file *file, struct page *page);
void btrfs_delete_inode(struct inode *inode);
void btrfs_put_inode(struct inode *inode);
int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc);
void btrfs_dirty_inode(struct inode *inode);
struct inode *btrfs_alloc_inode(struct super_block *sb);
void btrfs_destroy_inode(struct inode *inode);
void btrfs_drop_inode(struct inode *inode);
int btrfs_init_cachep(void);
void btrfs_destroy_cachep(void);
long btrfs_ioctl_trans_end(struct file *file);
struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
                         struct btrfs_root *root, int *was_new);
int btrfs_commit_write(struct file *file, struct page *page,
                       unsigned from, unsigned to);
struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
                                    size_t page_offset, u64 start, u64 end,
                                    int create);
int btrfs_update_inode(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root,
                              struct inode *inode);
int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode);
int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode);
void btrfs_orphan_cleanup(struct btrfs_root *root);
int btrfs_cont_expand(struct inode *inode, loff_t size);
int btrfs_invalidate_inodes(struct btrfs_root *root);
void btrfs_add_delayed_iput(struct inode *inode);
void btrfs_run_delayed_iputs(struct btrfs_root *root);
extern const struct dentry_operations btrfs_dentry_operations;

/* ioctl.c */
long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
void btrfs_update_iflags(struct inode *inode);
void btrfs_inherit_iflags(struct inode *inode, struct inode *dir);

/* file.c */
int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync);
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                            int skip_pinned);
int btrfs_check_file(struct btrfs_root *root, struct inode *inode);
extern const struct file_operations btrfs_file_operations;
int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
                       u64 start, u64 end, u64 *hint_byte, int drop_cache);
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
                              struct inode *inode, u64 start, u64 end);
int btrfs_release_file(struct inode *inode, struct file *file);

/* tree-defrag.c */
int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, int cache_only);

/* sysfs.c */
int btrfs_init_sysfs(void);
void btrfs_exit_sysfs(void);
int btrfs_sysfs_add_super(struct btrfs_fs_info *fs);
int btrfs_sysfs_add_root(struct btrfs_root *root);
void btrfs_sysfs_del_root(struct btrfs_root *root);
void btrfs_sysfs_del_super(struct btrfs_fs_info *root);

/* xattr.c */
ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);

/* super.c */
int btrfs_parse_options(struct btrfs_root *root, char *options);
int btrfs_sync_fs(struct super_block *sb, int wait);

/* acl.c */
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
int btrfs_check_acl(struct inode *inode, int mask);
#else
#define btrfs_check_acl NULL
#endif
int btrfs_init_acl(struct btrfs_trans_handle *trans,
                   struct inode *inode, struct inode *dir);
int btrfs_acl_chmod(struct inode *inode);

/* relocation.c */
int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start);
int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root);
int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root);
int btrfs_recover_relocation(struct btrfs_root *root);
int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len);
#endif