/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#ifndef __BTRFS_CTREE__
#define __BTRFS_CTREE__

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

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

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
#define STATIC noinline
#else
#define STATIC static noinline
#endif

#define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */

#define BTRFS_MAX_MIRRORS 3

#define BTRFS_MAX_LEVEL 8

#define BTRFS_COMPAT_EXTENT_TREE_V0

/* 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

/* holds quota configuration and tracking */
#define BTRFS_QUOTA_TREE_OBJECTID 8ULL

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

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

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

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

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

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

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

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

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

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

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

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


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

#define BTRFS_BTREE_INODE_OBJECTID 1

#define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2

#define BTRFS_DEV_REPLACE_DEVID 0ULL

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

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

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

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

/* csum types */
#define BTRFS_CSUM_TYPE_CRC32   0

static const int btrfs_csum_sizes[] = { 4 };

/* four bytes for CRC32 */
#define BTRFS_EMPTY_DIR_SIZE 0

/* spefic to btrfs_map_block(), therefore not in include/linux/blk_types.h */
#define REQ_GET_READ_MIRRORS    (1 << 30)

#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

/* ioprio of readahead is set to idle */
#define BTRFS_IOPRIO_READA (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0))

#define BTRFS_DIRTY_METADATA_THRESH     SZ_32M

#define BTRFS_MAX_EXTENT_SIZE SZ_128M

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

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

struct btrfs_mapping_tree {
        struct extent_map_tree map_tree;
};

struct btrfs_dev_item {
        /* the internal btrfs device id */
        __le64 devid;

        /* size of the device */
        __le64 total_bytes;

        /* bytes used */
        __le64 bytes_used;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        __le64 stripe_len;
        __le64 type;

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

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

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

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

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

#define BTRFS_FREE_SPACE_EXTENT 1
#define BTRFS_FREE_SPACE_BITMAP 2

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

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

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

#define BTRFS_HEADER_FLAG_WRITTEN       (1ULL << 0)
#define BTRFS_HEADER_FLAG_RELOC         (1ULL << 1)

/*
 * File system states
 */
#define BTRFS_FS_STATE_ERROR            0
#define BTRFS_FS_STATE_REMOUNTING       1
#define BTRFS_FS_STATE_TRANS_ABORTED    2
#define BTRFS_FS_STATE_DEV_REPLACING    3

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

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

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

#define BTRFS_OLD_BACKREF_REV           0
#define BTRFS_MIXED_BACKREF_REV         1

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

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

#define BTRFS_NODEPTRS_PER_BLOCK(r) (((r)->nodesize - \
                                      sizeof(struct btrfs_header)) / \
                                     sizeof(struct btrfs_key_ptr))
#define __BTRFS_LEAF_DATA_SIZE(bs) ((bs) - sizeof(struct btrfs_header))
#define BTRFS_LEAF_DATA_SIZE(r) (__BTRFS_LEAF_DATA_SIZE(r->nodesize))
#define BTRFS_FILE_EXTENT_INLINE_DATA_START             \
                (offsetof(struct btrfs_file_extent_item, disk_bytenr))
#define BTRFS_MAX_INLINE_DATA_SIZE(r) (BTRFS_LEAF_DATA_SIZE(r) - \
                                        sizeof(struct btrfs_item) - \
                                        BTRFS_FILE_EXTENT_INLINE_DATA_START)
#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

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

        __le64 chunk_root;
        __le64 chunk_root_gen;

        __le64 extent_root;
        __le64 extent_root_gen;

        __le64 fs_root;
        __le64 fs_root_gen;

        __le64 dev_root;
        __le64 dev_root_gen;

        __le64 csum_root;
        __le64 csum_root_gen;

        __le64 total_bytes;
        __le64 bytes_used;
        __le64 num_devices;
        /* future */
        __le64 unused_64[4];

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

/*
 * 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 __unused_leafsize;
        __le32 stripesize;
        __le32 sys_chunk_array_size;
        __le64 chunk_root_generation;
        __le64 compat_flags;
        __le64 compat_ro_flags;
        __le64 incompat_flags;
        __le16 csum_type;
        u8 root_level;
        u8 chunk_root_level;
        u8 log_root_level;
        struct btrfs_dev_item dev_item;

        char label[BTRFS_LABEL_SIZE];

        __le64 cache_generation;
        __le64 uuid_tree_generation;

        /* future expansion */
        __le64 reserved[30];
        u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
        struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
} __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_COMPAT_RO_FREE_SPACE_TREE (1ULL << 0)

#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF    (1ULL << 0)
#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL   (1ULL << 1)
#define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS     (1ULL << 2)
#define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO     (1ULL << 3)
/*
 * some patches floated around with a second compression method
 * lets save that incompat here for when they do get in
 * Note we don't actually support it, we're just reserving the
 * number
 */
#define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZOv2   (1ULL << 4)

/*
 * older kernels tried to do bigger metadata blocks, but the
 * code was pretty buggy.  Lets not let them try anymore.
 */
#define BTRFS_FEATURE_INCOMPAT_BIG_METADATA     (1ULL << 5)

#define BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF    (1ULL << 6)
#define BTRFS_FEATURE_INCOMPAT_RAID56           (1ULL << 7)
#define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA  (1ULL << 8)
#define BTRFS_FEATURE_INCOMPAT_NO_HOLES         (1ULL << 9)

#define BTRFS_FEATURE_COMPAT_SUPP               0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_SET           0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_CLEAR         0ULL

#define BTRFS_FEATURE_COMPAT_RO_SUPP                    \
        (BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE)

#define BTRFS_FEATURE_COMPAT_RO_SAFE_SET        0ULL
#define BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR      0ULL

#define BTRFS_FEATURE_INCOMPAT_SUPP                     \
        (BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |         \
         BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |        \
         BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |          \
         BTRFS_FEATURE_INCOMPAT_BIG_METADATA |          \
         BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |          \
         BTRFS_FEATURE_INCOMPAT_RAID56 |                \
         BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |         \
         BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |       \
         BTRFS_FEATURE_INCOMPAT_NO_HOLES)

#define BTRFS_FEATURE_INCOMPAT_SAFE_SET                 \
        (BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
#define BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR               0ULL

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

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

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

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

/*
 * btrfs_paths remember the path taken from the root down to the leaf.
 * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
 * to any other levels that are present.
 *
 * The slots array records the index of the item or block pointer
 * used while walking the tree.
 */
enum { READA_NONE = 0, READA_BACK, READA_FORWARD };
struct btrfs_path {
        struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
        int slots[BTRFS_MAX_LEVEL];
        /* if there is real range locking, this locks field will change */
        u8 locks[BTRFS_MAX_LEVEL];
        u8 reada;
        /* keep some upper locks as we walk down */
        u8 lowest_level;

        /*
         * set by btrfs_split_item, tells search_slot to keep all locks
         * and to force calls to keep space in the nodes
         */
        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;
        unsigned int need_commit_sem:1;
        unsigned int skip_release_on_error:1;
};

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

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

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

#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r) >> 4) - \
                                        sizeof(struct btrfs_item))

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

/* following flags only apply to tree blocks */

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

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

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

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

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

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

/* old style backrefs item */
struct btrfs_extent_ref_v0 {
        __le64 root;
        __le64 generation;
        __le64 objectid;
        __le32 count;
} __attribute__ ((__packed__));


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

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

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

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

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

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

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

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

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

#define BTRFS_ROOT_SUBVOL_RDONLY        (1ULL << 0)

/*
 * Internal in-memory flag that a subvolume has been marked for deletion but
 * still visible as a directory
 */
#define BTRFS_ROOT_SUBVOL_DEAD          (1ULL << 48)

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

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

        /*
         * This generation number is used to test if the new fields are valid
         * and up to date while reading the root item. Every time the root item
         * is written out, the "generation" field is copied into this field. If
         * anyone ever mounted the fs with an older kernel, we will have
         * mismatching generation values here and thus must invalidate the
         * new fields. See btrfs_update_root and btrfs_find_last_root for
         * details.
         * the offset of generation_v2 is also used as the start for the memset
         * when invalidating the fields.
         */
        __le64 generation_v2;
        u8 uuid[BTRFS_UUID_SIZE];
        u8 parent_uuid[BTRFS_UUID_SIZE];
        u8 received_uuid[BTRFS_UUID_SIZE];
        __le64 ctransid; /* updated when an inode changes */
        __le64 otransid; /* trans when created */
        __le64 stransid; /* trans when sent. non-zero for received subvol */
        __le64 rtransid; /* trans when received. non-zero for received subvol */
        struct btrfs_timespec ctime;
        struct btrfs_timespec otime;
        struct btrfs_timespec stime;
        struct btrfs_timespec rtime;
        __le64 reserved[8]; /* for future */
} __attribute__ ((__packed__));

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

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

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

        /* devid filter */
        __le64 devid;

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

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

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

        /* BTRFS_BALANCE_ARGS_* */
        __le64 flags;

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

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

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

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

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

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

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

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

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

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

        /*
         * disk space consumed by the extent, checksum blocks are included
         * in these numbers
         *
         * At this offset in the structure, the inline extent data start.
         */
        __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__));

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

#define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS     0
#define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID      1
#define BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED      0
#define BTRFS_DEV_REPLACE_ITEM_STATE_STARTED            1
#define BTRFS_DEV_REPLACE_ITEM_STATE_SUSPENDED          2
#define BTRFS_DEV_REPLACE_ITEM_STATE_FINISHED           3
#define BTRFS_DEV_REPLACE_ITEM_STATE_CANCELED           4

struct btrfs_dev_replace {
        u64 replace_state;      /* see #define above */
        u64 time_started;       /* seconds since 1-Jan-1970 */
        u64 time_stopped;       /* seconds since 1-Jan-1970 */
        atomic64_t num_write_errors;
        atomic64_t num_uncorrectable_read_errors;

        u64 cursor_left;
        u64 committed_cursor_left;
        u64 cursor_left_last_write_of_item;
        u64 cursor_right;

        u64 cont_reading_from_srcdev_mode;      /* see #define above */

        int is_valid;
        int item_needs_writeback;
        struct btrfs_device *srcdev;
        struct btrfs_device *tgtdev;

        pid_t lock_owner;
        atomic_t nesting_level;
        struct mutex lock_finishing_cancel_unmount;
        rwlock_t lock;

        atomic_t read_locks;
        atomic_t blocking_readers;
        wait_queue_head_t read_lock_wq;

        struct btrfs_scrub_progress scrub_progress;
};

struct btrfs_dev_replace_item {
        /*
         * grow this item struct at the end for future enhancements and keep
         * the existing values unchanged
         */
        __le64 src_devid;
        __le64 cursor_left;
        __le64 cursor_right;
        __le64 cont_reading_from_srcdev_mode;

        __le64 replace_state;
        __le64 time_started;
        __le64 time_stopped;
        __le64 num_write_errors;
        __le64 num_uncorrectable_read_errors;
} __attribute__ ((__packed__));

/* different types of block groups (and chunks) */
#define BTRFS_BLOCK_GROUP_DATA          (1ULL << 0)
#define BTRFS_BLOCK_GROUP_SYSTEM        (1ULL << 1)
#define BTRFS_BLOCK_GROUP_METADATA      (1ULL << 2)
#define BTRFS_BLOCK_GROUP_RAID0         (1ULL << 3)
#define BTRFS_BLOCK_GROUP_RAID1         (1ULL << 4)
#define BTRFS_BLOCK_GROUP_DUP           (1ULL << 5)
#define BTRFS_BLOCK_GROUP_RAID10        (1ULL << 6)
#define BTRFS_BLOCK_GROUP_RAID5         (1ULL << 7)
#define BTRFS_BLOCK_GROUP_RAID6         (1ULL << 8)
#define BTRFS_BLOCK_GROUP_RESERVED      (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
                                         BTRFS_SPACE_INFO_GLOBAL_RSV)

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

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

#define BTRFS_BLOCK_GROUP_PROFILE_MASK  (BTRFS_BLOCK_GROUP_RAID0 |   \
                                         BTRFS_BLOCK_GROUP_RAID1 |   \
                                         BTRFS_BLOCK_GROUP_RAID5 |   \
                                         BTRFS_BLOCK_GROUP_RAID6 |   \
                                         BTRFS_BLOCK_GROUP_DUP |     \
                                         BTRFS_BLOCK_GROUP_RAID10)
#define BTRFS_BLOCK_GROUP_RAID56_MASK   (BTRFS_BLOCK_GROUP_RAID5 |   \
                                         BTRFS_BLOCK_GROUP_RAID6)

/*
 * We need a bit for restriper to be able to tell when chunks of type
 * SINGLE are available.  This "extended" profile format is used in
 * fs_info->avail_*_alloc_bits (in-memory) and balance item fields
 * (on-disk).  The corresponding on-disk bit in chunk.type is reserved
 * to avoid remappings between two formats in future.
 */
#define BTRFS_AVAIL_ALLOC_BIT_SINGLE    (1ULL << 48)

/*
 * A fake block group type that is used to communicate global block reserve
 * size to userspace via the SPACE_INFO ioctl.
 */
#define BTRFS_SPACE_INFO_GLOBAL_RSV     (1ULL << 49)

#define BTRFS_EXTENDED_PROFILE_MASK     (BTRFS_BLOCK_GROUP_PROFILE_MASK | \
                                         BTRFS_AVAIL_ALLOC_BIT_SINGLE)

static inline u64 chunk_to_extended(u64 flags)
{
        if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0)
                flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;

        return flags;
}
static inline u64 extended_to_chunk(u64 flags)
{
        return flags & ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
}

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

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

#define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0)

#define BTRFS_QGROUP_LEVEL_SHIFT                48
static inline u64 btrfs_qgroup_level(u64 qgroupid)
{
        return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
}

/*
 * is subvolume quota turned on?
 */
#define BTRFS_QGROUP_STATUS_FLAG_ON             (1ULL << 0)
/*
 * RESCAN is set during the initialization phase
 */
#define BTRFS_QGROUP_STATUS_FLAG_RESCAN         (1ULL << 1)
/*
 * Some qgroup entries are known to be out of date,
 * either because the configuration has changed in a way that
 * makes a rescan necessary, or because the fs has been mounted
 * with a non-qgroup-aware version.
 * Turning qouta off and on again makes it inconsistent, too.
 */
#define BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT   (1ULL << 2)

#define BTRFS_QGROUP_STATUS_VERSION        1

struct btrfs_qgroup_status_item {
        __le64 version;
        /*
         * the generation is updated during every commit. As older
         * versions of btrfs are not aware of qgroups, it will be
         * possible to detect inconsistencies by checking the
         * generation on mount time
         */
        __le64 generation;

        /* flag definitions see above */
        __le64 flags;

        /*
         * only used during scanning to record the progress
         * of the scan. It contains a logical address
         */
        __le64 rescan;
} __attribute__ ((__packed__));

struct btrfs_qgroup_info_item {
        __le64 generation;
        __le64 rfer;
        __le64 rfer_cmpr;
        __le64 excl;
        __le64 excl_cmpr;
} __attribute__ ((__packed__));

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

struct btrfs_qgroup_limit_item {
        /*
         * only updated when any of the other values change
         */
        __le64 flags;
        __le64 max_rfer;
        __le64 max_excl;
        __le64 rsv_rfer;
        __le64 rsv_excl;
} __attribute__ ((__packed__));

/* For raid type sysfs entries */
struct raid_kobject {
        int raid_type;
        struct kobject kobj;
};

struct btrfs_space_info {
        spinlock_t lock;

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

        u64 max_extent_size;    /* This will hold the maximum extent size of
                                   the space info if we had an ENOSPC in the
                                   allocator. */

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

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

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

        u64 disk_used;          /* total bytes used on disk */
        u64 disk_total;         /* total bytes on disk, takes mirrors into
                                   account */

        u64 flags;

        /*
         * bytes_pinned is kept in line with what is actually pinned, as in
         * we've called update_block_group and dropped the bytes_used counter
         * and increased the bytes_pinned counter.  However this means that
         * bytes_pinned does not reflect the bytes that will be pinned once the
         * delayed refs are flushed, so this counter is inc'ed every time we
         * call btrfs_free_extent so it is a realtime count of what will be
         * freed once the transaction is committed.  It will be zero'ed every
         * time the transaction commits.
         */
        struct percpu_counter total_bytes_pinned;

        struct list_head list;
        /* Protected by the spinlock 'lock'. */
        struct list_head ro_bgs;

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

        struct kobject kobj;
        struct kobject *block_group_kobjs[BTRFS_NR_RAID_TYPES];
};

#define BTRFS_BLOCK_RSV_GLOBAL          1
#define BTRFS_BLOCK_RSV_DELALLOC        2
#define BTRFS_BLOCK_RSV_TRANS           3
#define BTRFS_BLOCK_RSV_CHUNK           4
#define BTRFS_BLOCK_RSV_DELOPS          5
#define BTRFS_BLOCK_RSV_EMPTY           6
#define BTRFS_BLOCK_RSV_TEMP            7

struct btrfs_block_rsv {
        u64 size;
        u64 reserved;
        struct btrfs_space_info *space_info;
        spinlock_t lock;
        unsigned short full;
        unsigned short type;
        unsigned short failfast;
};

/*
 * 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;

        /* We did a full search and couldn't create a cluster */
        bool fragmented;

        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_FAST        = 2,
        BTRFS_CACHE_FINISHED    = 3,
        BTRFS_CACHE_ERROR       = 4,
};

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

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

/* Once caching_thread() finds this much free space, it will wake up waiters. */
#define CACHING_CTL_WAKE_UP (1024 * 1024 * 2)

struct btrfs_io_ctl {
        void *cur, *orig;
        struct page *page;
        struct page **pages;
        struct btrfs_root *root;
        struct inode *inode;
        unsigned long size;
        int index;
        int num_pages;
        int entries;
        int bitmaps;
        unsigned check_crcs:1;
};

struct btrfs_block_group_cache {
        struct btrfs_key key;
        struct btrfs_block_group_item item;
        struct btrfs_fs_info *fs_info;
        struct inode *inode;
        spinlock_t lock;
        u64 pinned;
        u64 reserved;
        u64 delalloc_bytes;
        u64 bytes_super;
        u64 flags;
        u64 cache_generation;
        u32 sectorsize;

        /*
         * If the free space extent count exceeds this number, convert the block
         * group to bitmaps.
         */
        u32 bitmap_high_thresh;

        /*
         * If the free space extent count drops below this number, convert the
         * block group back to extents.
         */
        u32 bitmap_low_thresh;

        /*
         * It is just used for the delayed data space allocation because
         * only the data space allocation and the relative metadata update
         * can be done cross the transaction.
         */
        struct rw_semaphore data_rwsem;

        /* for raid56, this is a full stripe, without parity */
        unsigned long full_stripe_len;

        unsigned int ro;
        unsigned int iref:1;
        unsigned int has_caching_ctl:1;
        unsigned int removed:1;

        int disk_cache_state;

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

        struct btrfs_space_info *space_info;

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

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

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

        /* usage count */
        atomic_t count;

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

        /* For delayed block group creation or deletion of empty block groups */
        struct list_head bg_list;

        /* For read-only block groups */
        struct list_head ro_list;

        atomic_t trimming;

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

        struct btrfs_io_ctl io_ctl;

        /* Lock for free space tree operations. */
        struct mutex free_space_lock;

        /*
         * Does the block group need to be added to the free space tree?
         * Protected by free_space_lock.
         */
        int needs_free_space;
};

/* delayed seq elem */
struct seq_list {
        struct list_head list;
        u64 seq;
};

#define SEQ_LIST_INIT(name)     { .list = LIST_HEAD_INIT((name).list), .seq = 0 }

enum btrfs_orphan_cleanup_state {
        ORPHAN_CLEANUP_STARTED  = 1,
        ORPHAN_CLEANUP_DONE     = 2,
};

/* used by the raid56 code to lock stripes for read/modify/write */
struct btrfs_stripe_hash {
        struct list_head hash_list;
        wait_queue_head_t wait;
        spinlock_t lock;
};

/* used by the raid56 code to lock stripes for read/modify/write */
struct btrfs_stripe_hash_table {
        struct list_head stripe_cache;
        spinlock_t cache_lock;
        int cache_size;
        struct btrfs_stripe_hash table[];
};

#define BTRFS_STRIPE_HASH_TABLE_BITS 11

void btrfs_init_async_reclaim_work(struct work_struct *work);

/* fs_info */
struct reloc_control;
struct btrfs_device;
struct btrfs_fs_devices;
struct btrfs_balance_control;
struct btrfs_delayed_root;
struct btrfs_fs_info {
        u8 fsid[BTRFS_FSID_SIZE];
        u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
        struct btrfs_root *extent_root;
        struct btrfs_root *tree_root;
        struct btrfs_root *chunk_root;
        struct btrfs_root *dev_root;
        struct btrfs_root *fs_root;
        struct btrfs_root *csum_root;
        struct btrfs_root *quota_root;
        struct btrfs_root *uuid_root;
        struct btrfs_root *free_space_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;
        u64 first_logical_byte;
        struct rb_root block_group_cache_tree;

        /* keep track of unallocated space */
        spinlock_t free_chunk_lock;
        u64 free_chunk_space;

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

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

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

        struct btrfs_block_rsv empty_block_rsv;

        u64 generation;
        u64 last_trans_committed;
        u64 avg_delayed_ref_runtime;

        /*
         * this is updated to the current trans every time a full commit
         * is required instead of the faster short fsync log commits
         */
        u64 last_trans_log_full_commit;
        unsigned long mount_opt;
        /*
         * Track requests for actions that need to be done during transaction
         * commit (like for some mount options).
         */
        unsigned long pending_changes;
        unsigned long compress_type:4;
        int commit_interval;
        /*
         * It is a suggestive number, the read side is safe even it gets a
         * wrong number because we will write out the data into a regular
         * extent. The write side(mount/remount) is under ->s_umount lock,
         * so it is also safe.
         */
        u64 max_inline;
        /*
         * Protected by ->chunk_mutex and sb->s_umount.
         *
         * The reason that we use two lock to protect it is because only
         * remount and mount operations can change it and these two operations
         * are under sb->s_umount, but the read side (chunk allocation) can not
         * acquire sb->s_umount or the deadlock would happen. So we use two
         * locks to protect it. On the write side, we must acquire two locks,
         * and on the read side, we just need acquire one of them.
         */
        u64 alloc_start;
        struct btrfs_transaction *running_transaction;
        wait_queue_head_t transaction_throttle;
        wait_queue_head_t transaction_wait;
        wait_queue_head_t transaction_blocked_wait;
        wait_queue_head_t async_submit_wait;

        /*
         * Used to protect the incompat_flags, compat_flags, compat_ro_flags
         * when they are updated.
         *
         * Because we do not clear the flags for ever, so we needn't use
         * the lock on the read side.
         *
         * We also needn't use the lock when we mount the fs, because
         * there is no other task which will update the flag.
         */
        spinlock_t super_lock;
        struct btrfs_super_block *super_copy;
        struct btrfs_super_block *super_for_commit;
        struct block_device *__bdev;
        struct super_block *sb;
        struct inode *btree_inode;
        struct backing_dev_info bdi;
        struct mutex tree_log_mutex;
        struct mutex transaction_kthread_mutex;
        struct mutex cleaner_mutex;
        struct mutex chunk_mutex;
        struct mutex volume_mutex;

        /*
         * this is taken to make sure we don't set block groups ro after
         * the free space cache has been allocated on them
         */
        struct mutex ro_block_group_mutex;

        /* this is used during read/modify/write to make sure
         * no two ios are trying to mod the same stripe at the same
         * time
         */
        struct btrfs_stripe_hash_table *stripe_hash_table;

        /*
         * 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 commit_root_sem;

        struct rw_semaphore cleanup_work_sem;

        struct rw_semaphore subvol_sem;
        struct srcu_struct subvol_srcu;

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

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

        spinlock_t delayed_iput_lock;
        struct list_head delayed_iputs;
        struct mutex cleaner_delayed_iput_mutex;

        /* this protects tree_mod_seq_list */
        spinlock_t tree_mod_seq_lock;
        atomic64_t tree_mod_seq;
        struct list_head tree_mod_seq_list;

        /* this protects tree_mod_log */
        rwlock_t tree_mod_log_lock;
        struct rb_root tree_mod_log;

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

        /*
         * this is used to protect the following list -- ordered_roots.
         */
        spinlock_t ordered_root_lock;

        /*
         * all fs/file tree roots in which there are data=ordered extents
         * pending writeback are added into this list.
         *
         * these can span multiple transactions and basically include
         * every dirty data page that isn't from nodatacow
         */
        struct list_head ordered_roots;

        struct mutex delalloc_root_mutex;
        spinlock_t delalloc_root_lock;
        /* all fs/file tree roots that have delalloc inodes. */
        struct list_head delalloc_roots;

        /*
         * 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_workqueue *workers;
        struct btrfs_workqueue *delalloc_workers;
        struct btrfs_workqueue *flush_workers;
        struct btrfs_workqueue *endio_workers;
        struct btrfs_workqueue *endio_meta_workers;
        struct btrfs_workqueue *endio_raid56_workers;
        struct btrfs_workqueue *endio_repair_workers;
        struct btrfs_workqueue *rmw_workers;
        struct btrfs_workqueue *endio_meta_write_workers;
        struct btrfs_workqueue *endio_write_workers;
        struct btrfs_workqueue *endio_freespace_worker;
        struct btrfs_workqueue *submit_workers;
        struct btrfs_workqueue *caching_workers;
        struct btrfs_workqueue *readahead_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_workqueue *fixup_workers;
        struct btrfs_workqueue *delayed_workers;

        /* the extent workers do delayed refs on the extent allocation tree */
        struct btrfs_workqueue *extent_workers;
        struct task_struct *transaction_kthread;
        struct task_struct *cleaner_kthread;
        int thread_pool_size;

        struct kobject *space_info_kobj;
        int do_barriers;
        int closing;
        int log_root_recovering;
        int open;

        u64 total_pinned;

        /* used to keep from writing metadata until there is a nice batch */
        struct percpu_counter dirty_metadata_bytes;
        struct percpu_counter delalloc_bytes;
        s32 dirty_metadata_batch;
        s32 delalloc_batch;

        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 btrfs_space_info *data_sinfo;

        struct reloc_control *reloc_ctl;

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

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

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

        /* Used to protect avail_{data, metadata, system}_alloc_bits */
        seqlock_t profiles_lock;
        /*
         * these three are in extended format (availability of single
         * chunks is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other
         * types are denoted by corresponding BTRFS_BLOCK_GROUP_* bits)
         */
        u64 avail_data_alloc_bits;
        u64 avail_metadata_alloc_bits;
        u64 avail_system_alloc_bits;

        /* restriper state */
        spinlock_t balance_lock;
        struct mutex balance_mutex;
        atomic_t balance_running;
        atomic_t balance_pause_req;
        atomic_t balance_cancel_req;
        struct btrfs_balance_control *balance_ctl;
        wait_queue_head_t balance_wait_q;

        unsigned data_chunk_allocations;
        unsigned metadata_ratio;

        void *bdev_holder;

        /* private scrub information */
        struct mutex scrub_lock;
        atomic_t scrubs_running;
        atomic_t scrub_pause_req;
        atomic_t scrubs_paused;
        atomic_t scrub_cancel_req;
        wait_queue_head_t scrub_pause_wait;
        int scrub_workers_refcnt;
        struct btrfs_workqueue *scrub_workers;
        struct btrfs_workqueue *scrub_wr_completion_workers;
        struct btrfs_workqueue *scrub_nocow_workers;
        struct btrfs_workqueue *scrub_parity_workers;

#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
        u32 check_integrity_print_mask;
#endif
        /*
         * quota information
         */
        unsigned int quota_enabled:1;

        /*
         * quota_enabled only changes state after a commit. This holds the
         * next state.
         */
        unsigned int pending_quota_state:1;

        /* is qgroup tracking in a consistent state? */
        u64 qgroup_flags;

        /* holds configuration and tracking. Protected by qgroup_lock */
        struct rb_root qgroup_tree;
        struct rb_root qgroup_op_tree;
        spinlock_t qgroup_lock;
        spinlock_t qgroup_op_lock;
        atomic_t qgroup_op_seq;

        /*
         * used to avoid frequently calling ulist_alloc()/ulist_free()
         * when doing qgroup accounting, it must be protected by qgroup_lock.
         */
        struct ulist *qgroup_ulist;

        /* protect user change for quota operations */
        struct mutex qgroup_ioctl_lock;

        /* list of dirty qgroups to be written at next commit */
        struct list_head dirty_qgroups;

        /* used by qgroup for an efficient tree traversal */
        u64 qgroup_seq;

        /* qgroup rescan items */
        struct mutex qgroup_rescan_lock; /* protects the progress item */
        struct btrfs_key qgroup_rescan_progress;
        struct btrfs_workqueue *qgroup_rescan_workers;
        struct completion qgroup_rescan_completion;
        struct btrfs_work qgroup_rescan_work;

        /* filesystem state */
        unsigned long fs_state;

        struct btrfs_delayed_root *delayed_root;

        /* readahead tree */
        spinlock_t reada_lock;
        struct radix_tree_root reada_tree;

        /* readahead works cnt */
        atomic_t reada_works_cnt;

        /* Extent buffer radix tree */
        spinlock_t buffer_lock;
        struct radix_tree_root buffer_radix;

        /* next backup root to be overwritten */
        int backup_root_index;

        int num_tolerated_disk_barrier_failures;

        /* device replace state */
        struct btrfs_dev_replace dev_replace;

        atomic_t mutually_exclusive_operation_running;

        struct percpu_counter bio_counter;
        wait_queue_head_t replace_wait;

        struct semaphore uuid_tree_rescan_sem;
        unsigned int update_uuid_tree_gen:1;

        /* Used to reclaim the metadata space in the background. */
        struct work_struct async_reclaim_work;

        spinlock_t unused_bgs_lock;
        struct list_head unused_bgs;
        struct mutex unused_bg_unpin_mutex;
        struct mutex delete_unused_bgs_mutex;

        /* For btrfs to record security options */
        struct security_mnt_opts security_opts;

        /*
         * Chunks that can't be freed yet (under a trim/discard operation)
         * and will be latter freed. Protected by fs_info->chunk_mutex.
         */
        struct list_head pinned_chunks;

        int creating_free_space_tree;
};

struct btrfs_subvolume_writers {
        struct percpu_counter   counter;
        wait_queue_head_t       wait;
};

/*
 * The state of btrfs root
 */
/*
 * btrfs_record_root_in_trans is a multi-step process,
 * and it can race with the balancing code.   But the
 * race is very small, and only the first time the root
 * is added to each transaction.  So IN_TRANS_SETUP
 * is used to tell us when more checks are required
 */
#define BTRFS_ROOT_IN_TRANS_SETUP       0
#define BTRFS_ROOT_REF_COWS             1
#define BTRFS_ROOT_TRACK_DIRTY          2
#define BTRFS_ROOT_IN_RADIX             3
#define BTRFS_ROOT_DUMMY_ROOT           4
#define BTRFS_ROOT_ORPHAN_ITEM_INSERTED 5
#define BTRFS_ROOT_DEFRAG_RUNNING       6
#define BTRFS_ROOT_FORCE_COW            7
#define BTRFS_ROOT_MULTI_LOG_TASKS      8
#define BTRFS_ROOT_DIRTY                9

/*
 * in ram representation of the tree.  extent_root is used for all allocations
 * and for the extent tree extent_root root.
 */
struct btrfs_root {
        struct extent_buffer *node;

        struct extent_buffer *commit_root;
        struct btrfs_root *log_root;
        struct btrfs_root *reloc_root;

        unsigned long state;
        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 mutex objectid_mutex;

        spinlock_t accounting_lock;
        struct btrfs_block_rsv *block_rsv;

        /* free ino cache stuff */
        struct btrfs_free_space_ctl *free_ino_ctl;
        enum btrfs_caching_type ino_cache_state;
        spinlock_t ino_cache_lock;
        wait_queue_head_t ino_cache_wait;
        struct btrfs_free_space_ctl *free_ino_pinned;
        u64 ino_cache_progress;
        struct inode *ino_cache_inode;

        struct mutex log_mutex;
        wait_queue_head_t log_writer_wait;
        wait_queue_head_t log_commit_wait[2];
        struct list_head log_ctxs[2];
        atomic_t log_writers;
        atomic_t log_commit[2];
        atomic_t log_batch;
        int log_transid;
        /* No matter the commit succeeds or not*/
        int log_transid_committed;
        /* Just be updated when the commit succeeds. */
        int last_log_commit;
        pid_t log_start_pid;

        u64 objectid;
        u64 last_trans;

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

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

        u32 stripesize;

        u32 type;

        u64 highest_objectid;

        /* only used with CONFIG_BTRFS_FS_RUN_SANITY_TESTS is enabled */
        u64 alloc_bytenr;

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

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

        struct list_head root_list;

        spinlock_t log_extents_lock[2];
        struct list_head logged_list[2];

        spinlock_t orphan_lock;
        atomic_t orphan_inodes;
        struct btrfs_block_rsv *orphan_block_rsv;
        int orphan_cleanup_state;

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

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

        spinlock_t root_item_lock;
        atomic_t refs;

        struct mutex delalloc_mutex;
        spinlock_t delalloc_lock;
        /*
         * 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;
        struct list_head delalloc_root;
        u64 nr_delalloc_inodes;

        struct mutex ordered_extent_mutex;
        /*
         * 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;
        struct list_head ordered_root;
        u64 nr_ordered_extents;

        /*
         * Number of currently running SEND ioctls to prevent
         * manipulation with the read-only status via SUBVOL_SETFLAGS
         */
        int send_in_progress;
        struct btrfs_subvolume_writers *subv_writers;
        atomic_t will_be_snapshoted;

        /* For qgroup metadata space reserve */
        atomic_t qgroup_meta_rsv;
};

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

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

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

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

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

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


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

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

#define BTRFS_TREE_BLOCK_REF_KEY        176

#define BTRFS_EXTENT_DATA_REF_KEY       178

#define BTRFS_EXTENT_REF_V0_KEY         180

#define BTRFS_SHARED_BLOCK_REF_KEY      182

#define BTRFS_SHARED_DATA_REF_KEY       184

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

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

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

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

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

/*
 * Records the overall state of the qgroups.
 * There's only one instance of this key present,
 * (0, BTRFS_QGROUP_STATUS_KEY, 0)
 */
#define BTRFS_QGROUP_STATUS_KEY         240
/*
 * Records the currently used space of the qgroup.
 * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid).
 */
#define BTRFS_QGROUP_INFO_KEY           242
/*
 * Contains the user configured limits for the qgroup.
 * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid).
 */
#define BTRFS_QGROUP_LIMIT_KEY          244
/*
 * Records the child-parent relationship of qgroups. For
 * each relation, 2 keys are present:
 * (childid, BTRFS_QGROUP_RELATION_KEY, parentid)
 * (parentid, BTRFS_QGROUP_RELATION_KEY, childid)
 */
#define BTRFS_QGROUP_RELATION_KEY       246

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

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

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

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

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

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

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

/*
 * Flags for mount options.
 *
 * Note: don't forget to add new options to btrfs_show_options()
 */
#define BTRFS_MOUNT_NODATASUM           (1 << 0)
#define BTRFS_MOUNT_NODATACOW           (1 << 1)
#define BTRFS_MOUNT_NOBARRIER           (1 << 2)
#define BTRFS_MOUNT_SSD                 (1 << 3)
#define BTRFS_MOUNT_DEGRADED            (1 << 4)
#define BTRFS_MOUNT_COMPRESS            (1 << 5)
#define BTRFS_MOUNT_NOTREELOG           (1 << 6)
#define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)
#define BTRFS_MOUNT_SSD_SPREAD          (1 << 8)
#define BTRFS_MOUNT_NOSSD               (1 << 9)
#define BTRFS_MOUNT_DISCARD             (1 << 10)
#define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
#define BTRFS_MOUNT_SPACE_CACHE         (1 << 12)
#define BTRFS_MOUNT_CLEAR_CACHE         (1 << 13)
#define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
#define BTRFS_MOUNT_ENOSPC_DEBUG         (1 << 15)
#define BTRFS_MOUNT_AUTO_DEFRAG         (1 << 16)
#define BTRFS_MOUNT_INODE_MAP_CACHE     (1 << 17)
#define BTRFS_MOUNT_USEBACKUPROOT       (1 << 18)
#define BTRFS_MOUNT_SKIP_BALANCE        (1 << 19)
#define BTRFS_MOUNT_CHECK_INTEGRITY     (1 << 20)
#define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
#define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR        (1 << 22)
#define BTRFS_MOUNT_RESCAN_UUID_TREE    (1 << 23)
#define BTRFS_MOUNT_FRAGMENT_DATA       (1 << 24)
#define BTRFS_MOUNT_FRAGMENT_METADATA   (1 << 25)
#define BTRFS_MOUNT_FREE_SPACE_TREE     (1 << 26)
#define BTRFS_MOUNT_NOLOGREPLAY         (1 << 27)

#define BTRFS_DEFAULT_COMMIT_INTERVAL   (30)
#define BTRFS_DEFAULT_MAX_INLINE        (2048)

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

#define btrfs_set_and_info(root, opt, fmt, args...)                     \
{                                                                       \
        if (!btrfs_test_opt(root, opt))                                 \
                btrfs_info(root->fs_info, fmt, ##args);                 \
        btrfs_set_opt(root->fs_info->mount_opt, opt);                   \
}

#define btrfs_clear_and_info(root, opt, fmt, args...)                   \
{                                                                       \
        if (btrfs_test_opt(root, opt))                                  \
                btrfs_info(root->fs_info, fmt, ##args);                 \
        btrfs_clear_opt(root->fs_info->mount_opt, opt);                 \
}

#ifdef CONFIG_BTRFS_DEBUG
static inline int
btrfs_should_fragment_free_space(struct btrfs_root *root,
                                 struct btrfs_block_group_cache *block_group)
{
        return (btrfs_test_opt(root, FRAGMENT_METADATA) &&
                block_group->flags & BTRFS_BLOCK_GROUP_METADATA) ||
               (btrfs_test_opt(root, FRAGMENT_DATA) &&
                block_group->flags &  BTRFS_BLOCK_GROUP_DATA);
}
#endif

/*
 * Requests for changes that need to be done during transaction commit.
 *
 * Internal mount options that are used for special handling of the real
 * mount options (eg. cannot be set during remount and have to be set during
 * transaction commit)
 */

#define BTRFS_PENDING_SET_INODE_MAP_CACHE       (0)
#define BTRFS_PENDING_CLEAR_INODE_MAP_CACHE     (1)
#define BTRFS_PENDING_COMMIT                    (2)

#define btrfs_test_pending(info, opt)   \
        test_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)
#define btrfs_set_pending(info, opt)    \
        set_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)
#define btrfs_clear_pending(info, opt)  \
        clear_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)

/*
 * Helpers for setting pending mount option changes.
 *
 * Expects corresponding macros
 * BTRFS_PENDING_SET_ and CLEAR_ + short mount option name
 */
#define btrfs_set_pending_and_info(info, opt, fmt, args...)            \
do {                                                                   \
       if (!btrfs_raw_test_opt((info)->mount_opt, opt)) {              \
               btrfs_info((info), fmt, ##args);                        \
               btrfs_set_pending((info), SET_##opt);                   \
               btrfs_clear_pending((info), CLEAR_##opt);               \
       }                                                               \
} while(0)

#define btrfs_clear_pending_and_info(info, opt, fmt, args...)          \
do {                                                                   \
       if (btrfs_raw_test_opt((info)->mount_opt, opt)) {               \
               btrfs_info((info), fmt, ##args);                        \
               btrfs_set_pending((info), CLEAR_##opt);                 \
               btrfs_clear_pending((info), SET_##opt);                 \
       }                                                               \
} while(0)

/*
 * Inode flags
 */
#define BTRFS_INODE_NODATASUM           (1 << 0)
#define BTRFS_INODE_NODATACOW           (1 << 1)
#define BTRFS_INODE_READONLY            (1 << 2)
#define BTRFS_INODE_NOCOMPRESS          (1 << 3)
#define BTRFS_INODE_PREALLOC            (1 << 4)
#define BTRFS_INODE_SYNC                (1 << 5)
#define BTRFS_INODE_IMMUTABLE           (1 << 6)
#define BTRFS_INODE_APPEND              (1 << 7)
#define BTRFS_INODE_NODUMP              (1 << 8)
#define BTRFS_INODE_NOATIME             (1 << 9)
#define BTRFS_INODE_DIRSYNC             (1 << 10)
#define BTRFS_INODE_COMPRESS            (1 << 11)

#define BTRFS_INODE_ROOT_ITEM_INIT      (1 << 31)

struct btrfs_map_token {
        struct extent_buffer *eb;
        char *kaddr;
        unsigned long offset;
};

#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
                                ((bytes) >> (fs_info)->sb->s_blocksize_bits)

static inline void btrfs_init_map_token (struct btrfs_map_token *token)
{
        token->kaddr = NULL;
}

/* 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)))

#define DECLARE_BTRFS_SETGET_BITS(bits)                                 \
u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr,     \
                               unsigned long off,                       \
                              struct btrfs_map_token *token);           \
void btrfs_set_token_##bits(struct extent_buffer *eb, void *ptr,        \
                            unsigned long off, u##bits val,             \
                            struct btrfs_map_token *token);             \
static inline u##bits btrfs_get_##bits(struct extent_buffer *eb, void *ptr, \
                                       unsigned long off)               \
{                                                                       \
        return btrfs_get_token_##bits(eb, ptr, off, NULL);              \
}                                                                       \
static inline void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
                                    unsigned long off, u##bits val)     \
{                                                                       \
       btrfs_set_token_##bits(eb, ptr, off, val, NULL);                 \
}

DECLARE_BTRFS_SETGET_BITS(8)
DECLARE_BTRFS_SETGET_BITS(16)
DECLARE_BTRFS_SETGET_BITS(32)
DECLARE_BTRFS_SETGET_BITS(64)

#define BTRFS_SETGET_FUNCS(name, type, member, bits)                    \
static inline u##bits btrfs_##name(struct extent_buffer *eb, type *s)   \
{                                                                       \
        BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);   \
        return btrfs_get_##bits(eb, s, offsetof(type, member));         \
}                                                                       \
static inline void btrfs_set_##name(struct extent_buffer *eb, type *s,  \
                                    u##bits val)                        \
{                                                                       \
        BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);   \
        btrfs_set_##bits(eb, s, offsetof(type, member), val);           \
}                                                                       \
static inline u##bits btrfs_token_##name(struct extent_buffer *eb, type *s, \
                                         struct btrfs_map_token *token) \
{                                                                       \
        BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);   \
        return btrfs_get_token_##bits(eb, s, offsetof(type, member), token); \
}                                                                       \
static inline void btrfs_set_token_##name(struct extent_buffer *eb,     \
                                          type *s, u##bits val,         \
                                         struct btrfs_map_token *token) \
{                                                                       \
        BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);   \
        btrfs_set_token_##bits(eb, s, offsetof(type, member), val, token); \
}

#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)             \
static inline u##bits btrfs_##name(struct extent_buffer *eb)            \
{                                                                       \
        type *p = page_address(eb->pages[0]);                           \
        u##bits res = le##bits##_to_cpu(p->member);                     \
        return res;                                                     \
}                                                                       \
static inline void btrfs_set_##name(struct extent_buffer *eb,           \
                                    u##bits val)                        \
{                                                                       \
        type *p = page_address(eb->pages[0]);                           \
        p->member = cpu_to_le##bits(val);                               \
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

/* struct btrfs_inode_item */
BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
BTRFS_SETGET_FUNCS(inode_sequence, struct btrfs_inode_item, sequence, 64);
BTRFS_SETGET_FUNCS(inode_transid, struct btrfs_inode_item, transid, 64);
BTRFS_SETGET_FUNCS(inode_size, struct btrfs_inode_item, size, 64);
BTRFS_SETGET_FUNCS(inode_nbytes, struct btrfs_inode_item, nbytes, 64);
BTRFS_SETGET_FUNCS(inode_block_group, struct btrfs_inode_item, block_group, 64);
BTRFS_SETGET_FUNCS(inode_nlink, struct btrfs_inode_item, nlink, 32);
BTRFS_SETGET_FUNCS(inode_uid, struct btrfs_inode_item, uid, 32);
BTRFS_SETGET_FUNCS(inode_gid, struct btrfs_inode_item, gid, 32);
BTRFS_SETGET_FUNCS(inode_mode, struct btrfs_inode_item, mode, 32);
BTRFS_SETGET_FUNCS(inode_rdev, struct btrfs_inode_item, rdev, 64);
BTRFS_SETGET_FUNCS(inode_flags, struct btrfs_inode_item, flags, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_generation, struct btrfs_inode_item,
                         generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_sequence, struct btrfs_inode_item,
                         sequence, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_transid, struct btrfs_inode_item,
                         transid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_size, struct btrfs_inode_item, size, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_nbytes, struct btrfs_inode_item,
                         nbytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_block_group, struct btrfs_inode_item,
                         block_group, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_nlink, struct btrfs_inode_item, nlink, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_uid, struct btrfs_inode_item, uid, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_gid, struct btrfs_inode_item, gid, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_mode, struct btrfs_inode_item, mode, 32);
BTRFS_SETGET_STACK_FUNCS(stack_inode_rdev, struct btrfs_inode_item, rdev, 64);
BTRFS_SETGET_STACK_FUNCS(stack_inode_flags, struct btrfs_inode_item, flags, 64);
BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);

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

static inline unsigned long btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
{
        unsigned long ptr = offsetof(struct btrfs_dev_extent, chunk_tree_uuid);
        return (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);
BTRFS_SETGET_STACK_FUNCS(stack_key_blockptr, struct btrfs_key_ptr,
                         blockptr, 64);
BTRFS_SETGET_STACK_FUNCS(stack_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);
BTRFS_SETGET_STACK_FUNCS(stack_item_offset, struct btrfs_item, offset, 32);
BTRFS_SETGET_STACK_FUNCS(stack_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(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(nr));
}

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

static inline u32 btrfs_item_size_nr(struct extent_buffer *eb, int nr)
{
        return btrfs_item_size(eb, btrfs_item_nr(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(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(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);
BTRFS_SETGET_STACK_FUNCS(stack_dir_type, struct btrfs_dir_item, type, 8);
BTRFS_SETGET_STACK_FUNCS(stack_dir_data_len, struct btrfs_dir_item,
                         data_len, 16);
BTRFS_SETGET_STACK_FUNCS(stack_dir_name_len, struct btrfs_dir_item,
                         name_len, 16);
BTRFS_SETGET_STACK_FUNCS(stack_dir_transid, struct btrfs_dir_item,
                         transid, 64);

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

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

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

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

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

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

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

static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
                                         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);
BTRFS_SETGET_STACK_FUNCS(stack_header_generation, struct btrfs_header,
                         generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_header_owner, struct btrfs_header, owner, 64);
BTRFS_SETGET_STACK_FUNCS(stack_header_nritems, struct btrfs_header,
                         nritems, 32);
BTRFS_SETGET_STACK_FUNCS(stack_header_bytenr, struct btrfs_header, bytenr, 64);

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

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

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

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

        return flags >> BTRFS_BACKREF_REV_SHIFT;
}

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

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

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

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

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

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

static inline bool btrfs_root_readonly(struct btrfs_root *root)
{
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
}

static inline bool btrfs_root_dead(struct btrfs_root *root)
{
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
}

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

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

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

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

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

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

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

static inline void btrfs_balance_data(struct extent_buffer *eb,
                                      struct btrfs_balance_item *bi,
                                      struct btrfs_disk_balance_args *ba)
{
        read_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
}

static inline void btrfs_set_balance_data(struct extent_buffer *eb,
                                          struct btrfs_balance_item *bi,
                                          struct btrfs_disk_balance_args *ba)
{
        write_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
}

static inline void btrfs_balance_meta(struct extent_buffer *eb,
                                      struct btrfs_balance_item *bi,
                                      struct btrfs_disk_balance_args *ba)
{
        read_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
}

static inline void btrfs_set_balance_meta(struct extent_buffer *eb,
                                          struct btrfs_balance_item *bi,
                                          struct btrfs_disk_balance_args *ba)
{
        write_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
}

static inline void btrfs_balance_sys(struct extent_buffer *eb,
                                     struct btrfs_balance_item *bi,
                                     struct btrfs_disk_balance_args *ba)
{
        read_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
}

static inline void btrfs_set_balance_sys(struct extent_buffer *eb,
                                         struct btrfs_balance_item *bi,
                                         struct btrfs_disk_balance_args *ba)
{
        write_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
}

static inline void
btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,
                               struct btrfs_disk_balance_args *disk)
{
        memset(cpu, 0, sizeof(*cpu));

        cpu->profiles = le64_to_cpu(disk->profiles);
        cpu->usage = le64_to_cpu(disk->usage);
        cpu->devid = le64_to_cpu(disk->devid);
        cpu->pstart = le64_to_cpu(disk->pstart);
        cpu->pend = le64_to_cpu(disk->pend);
        cpu->vstart = le64_to_cpu(disk->vstart);
        cpu->vend = le64_to_cpu(disk->vend);
        cpu->target = le64_to_cpu(disk->target);
        cpu->flags = le64_to_cpu(disk->flags);
        cpu->limit = le64_to_cpu(disk->limit);
}

static inline void
btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,
                               struct btrfs_balance_args *cpu)
{
        memset(disk, 0, sizeof(*disk));

        disk->profiles = cpu_to_le64(cpu->profiles);
        disk->usage = cpu_to_le64(cpu->usage);
        disk->devid = cpu_to_le64(cpu->devid);
        disk->pstart = cpu_to_le64(cpu->pstart);
        disk->pend = cpu_to_le64(cpu->pend);
        disk->vstart = cpu_to_le64(cpu->vstart);
        disk->vend = cpu_to_le64(cpu->vend);
        disk->target = cpu_to_le64(cpu->target);
        disk->flags = cpu_to_le64(cpu->flags);
        disk->limit = cpu_to_le64(cpu->limit);
}

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

static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
{
        u16 t = btrfs_super_csum_type(s);
        /*
         * csum type is validated at mount time
         */
        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);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_disk_bytenr,
                         struct btrfs_file_extent_item, disk_bytenr, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_offset,
                         struct btrfs_file_extent_item, offset, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_generation,
                         struct btrfs_file_extent_item, generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_num_bytes,
                         struct btrfs_file_extent_item, num_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_disk_num_bytes,
                         struct btrfs_file_extent_item, disk_num_bytes, 64);
BTRFS_SETGET_STACK_FUNCS(stack_file_extent_compression,
                         struct btrfs_file_extent_item, compression, 8);

static inline unsigned long
btrfs_file_extent_inline_start(struct btrfs_file_extent_item *e)
{
        return (unsigned long)e + BTRFS_FILE_EXTENT_INLINE_DATA_START;
}

static inline u32 btrfs_file_extent_calc_inline_size(u32 datasize)
{
        return BTRFS_FILE_EXTENT_INLINE_DATA_START + 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 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)
{
        return btrfs_item_size(eb, e) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
}

/* 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,
                                               int slot,
                                               struct btrfs_file_extent_item *fi)
{
        struct btrfs_map_token token;

        btrfs_init_map_token(&token);
        /*
         * return the space used on disk if this item isn't
         * compressed or encoded
         */
        if (btrfs_token_file_extent_compression(eb, fi, &token) == 0 &&
            btrfs_token_file_extent_encryption(eb, fi, &token) == 0 &&
            btrfs_token_file_extent_other_encoding(eb, fi, &token) == 0) {
                return btrfs_file_extent_inline_item_len(eb,
                                                         btrfs_item_nr(slot));
        }

        /* otherwise use the ram bytes field */
        return btrfs_token_file_extent_ram_bytes(eb, fi, &token);
}


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

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

static inline void btrfs_set_dev_stats_value(struct extent_buffer *eb,
                                             struct btrfs_dev_stats_item *ptr,
                                             int index, u64 val)
{
        write_extent_buffer(eb, &val,
                            offsetof(struct btrfs_dev_stats_item, values) +
                             ((unsigned long)ptr) + (index * sizeof(u64)),
                            sizeof(val));
}

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

/* btrfs_qgroup_info_item */
BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,
                   generation, 64);
BTRFS_SETGET_FUNCS(qgroup_info_rfer, struct btrfs_qgroup_info_item, rfer, 64);
BTRFS_SETGET_FUNCS(qgroup_info_rfer_cmpr, struct btrfs_qgroup_info_item,
                   rfer_cmpr, 64);
BTRFS_SETGET_FUNCS(qgroup_info_excl, struct btrfs_qgroup_info_item, excl, 64);
BTRFS_SETGET_FUNCS(qgroup_info_excl_cmpr, struct btrfs_qgroup_info_item,
                   excl_cmpr, 64);

BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_generation,
                         struct btrfs_qgroup_info_item, generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_rfer, struct btrfs_qgroup_info_item,
                         rfer, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_rfer_cmpr,
                         struct btrfs_qgroup_info_item, rfer_cmpr, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_excl, struct btrfs_qgroup_info_item,
                         excl, 64);
BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_excl_cmpr,
                         struct btrfs_qgroup_info_item, excl_cmpr, 64);

/* btrfs_qgroup_limit_item */
BTRFS_SETGET_FUNCS(qgroup_limit_flags, struct btrfs_qgroup_limit_item,
                   flags, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_max_rfer, struct btrfs_qgroup_limit_item,
                   max_rfer, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_max_excl, struct btrfs_qgroup_limit_item,
                   max_excl, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_rsv_rfer, struct btrfs_qgroup_limit_item,
                   rsv_rfer, 64);
BTRFS_SETGET_FUNCS(qgroup_limit_rsv_excl, struct btrfs_qgroup_limit_item,
                   rsv_excl, 64);

/* btrfs_dev_replace_item */
BTRFS_SETGET_FUNCS(dev_replace_src_devid,
                   struct btrfs_dev_replace_item, src_devid, 64);
BTRFS_SETGET_FUNCS(dev_replace_cont_reading_from_srcdev_mode,
                   struct btrfs_dev_replace_item, cont_reading_from_srcdev_mode,
                   64);
BTRFS_SETGET_FUNCS(dev_replace_replace_state, struct btrfs_dev_replace_item,
                   replace_state, 64);
BTRFS_SETGET_FUNCS(dev_replace_time_started, struct btrfs_dev_replace_item,
                   time_started, 64);
BTRFS_SETGET_FUNCS(dev_replace_time_stopped, struct btrfs_dev_replace_item,
                   time_stopped, 64);
BTRFS_SETGET_FUNCS(dev_replace_num_write_errors, struct btrfs_dev_replace_item,
                   num_write_errors, 64);
BTRFS_SETGET_FUNCS(dev_replace_num_uncorrectable_read_errors,
                   struct btrfs_dev_replace_item, num_uncorrectable_read_errors,
                   64);
BTRFS_SETGET_FUNCS(dev_replace_cursor_left, struct btrfs_dev_replace_item,
                   cursor_left, 64);
BTRFS_SETGET_FUNCS(dev_replace_cursor_right, struct btrfs_dev_replace_item,
                   cursor_right, 64);

BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_src_devid,
                         struct btrfs_dev_replace_item, src_devid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cont_reading_from_srcdev_mode,
                         struct btrfs_dev_replace_item,
                         cont_reading_from_srcdev_mode, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_replace_state,
                         struct btrfs_dev_replace_item, replace_state, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_time_started,
                         struct btrfs_dev_replace_item, time_started, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_time_stopped,
                         struct btrfs_dev_replace_item, time_stopped, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_num_write_errors,
                         struct btrfs_dev_replace_item, num_write_errors, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_num_uncorrectable_read_errors,
                         struct btrfs_dev_replace_item,
                         num_uncorrectable_read_errors, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cursor_left,
                         struct btrfs_dev_replace_item, cursor_left, 64);
BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cursor_right,
                         struct btrfs_dev_replace_item, cursor_right, 64);

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

/* 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 bool btrfs_mixed_space_info(struct btrfs_space_info *space_info)
{
        return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) &&
                (space_info->flags & BTRFS_BLOCK_GROUP_DATA));
}

static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
{
        return mapping_gfp_constraint(mapping, ~__GFP_FS);
}

/* extent-tree.c */

u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes);

static inline u64 btrfs_calc_trans_metadata_size(struct btrfs_root *root,
                                                 unsigned num_items)
{
        return root->nodesize * BTRFS_MAX_LEVEL * 2 * num_items;
}

/*
 * Doing a truncate won't result in new nodes or leaves, just what we need for
 * COW.
 */
static inline u64 btrfs_calc_trunc_metadata_size(struct btrfs_root *root,
                                                 unsigned num_items)
{
        return root->nodesize * BTRFS_MAX_LEVEL * num_items;
}

int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
                                       struct btrfs_root *root);
int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
                                       struct btrfs_root *root);
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_async_run_delayed_refs(struct btrfs_root *root,
                                 unsigned long count, int wait);
int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len);
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root, u64 bytenr,
                             u64 offset, int metadata, u64 *refs, u64 *flags);
int btrfs_pin_extent(struct btrfs_root *root,
                     u64 bytenr, u64 num, int reserved);
int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
                                    u64 bytenr, u64 num_bytes);
int btrfs_exclude_logged_extents(struct btrfs_root *root,
                                 struct extent_buffer *eb);
int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root,
                          u64 objectid, u64 offset, u64 bytenr);
struct btrfs_block_group_cache *btrfs_lookup_block_group(
                                                 struct btrfs_fs_info *info,
                                                 u64 bytenr);
void btrfs_get_block_group(struct btrfs_block_group_cache *cache);
void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
int get_block_group_index(struct btrfs_block_group_cache *cache);
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
                                        struct btrfs_root *root, u64 parent,
                                        u64 root_objectid,
                                        struct btrfs_disk_key *key, int level,
                                        u64 hint, u64 empty_size);
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root,
                           struct extent_buffer *buf,
                           u64 parent, int last_ref);
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
                                     struct btrfs_root *root,
                                     u64 root_objectid, u64 owner,
                                     u64 offset, u64 ram_bytes,
                                     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_root *root, u64 num_bytes,
                         u64 min_alloc_size, u64 empty_size, u64 hint_byte,
                         struct btrfs_key *ins, int is_data, int delalloc);
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 level, 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 delalloc);
int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
                                       u64 start, u64 len);
void 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_start_dirty_block_groups(struct btrfs_trans_handle *trans,
                                   struct btrfs_root *root);
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                                    struct btrfs_root *root);
int btrfs_setup_space_cache(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);
struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
                                struct btrfs_fs_info *fs_info,
                                const u64 chunk_offset);
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root, u64 group_start,
                             struct extent_map *em);
void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info);
void btrfs_get_block_group_trimming(struct btrfs_block_group_cache *cache);
void btrfs_put_block_group_trimming(struct btrfs_block_group_cache *cache);
void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
                                       struct btrfs_root *root);
u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data);
void btrfs_clear_space_info_full(struct btrfs_fs_info *info);

enum btrfs_reserve_flush_enum {
        /* If we are in the transaction, we can't flush anything.*/
        BTRFS_RESERVE_NO_FLUSH,
        /*
         * Flushing delalloc may cause deadlock somewhere, in this
         * case, use FLUSH LIMIT
         */
        BTRFS_RESERVE_FLUSH_LIMIT,
        BTRFS_RESERVE_FLUSH_ALL,
};

int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len);
int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes);
void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len);
void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
                                            u64 len);
void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root);
void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
                                  struct inode *inode);
void btrfs_orphan_release_metadata(struct inode *inode);
int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
                                     struct btrfs_block_rsv *rsv,
                                     int nitems,
                                     u64 *qgroup_reserved, bool use_global_rsv);
void btrfs_subvolume_release_metadata(struct btrfs_root *root,
                                      struct btrfs_block_rsv *rsv,
                                      u64 qgroup_reserved);
int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes);
void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes);
int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len);
void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len);
void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type);
struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
                                              unsigned short type);
void btrfs_free_block_rsv(struct btrfs_root *root,
                          struct btrfs_block_rsv *rsv);
void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv);
int btrfs_block_rsv_add(struct btrfs_root *root,
                        struct btrfs_block_rsv *block_rsv, u64 num_bytes,
                        enum btrfs_reserve_flush_enum flush);
int btrfs_block_rsv_check(struct btrfs_root *root,
                          struct btrfs_block_rsv *block_rsv, int min_factor);
int btrfs_block_rsv_refill(struct btrfs_root *root,
                           struct btrfs_block_rsv *block_rsv, u64 min_reserved,
                           enum btrfs_reserve_flush_enum flush);
int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
                            struct btrfs_block_rsv *dst_rsv,
                            u64 num_bytes);
int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
                             struct btrfs_block_rsv *dest, u64 num_bytes,
                             int min_factor);
void btrfs_block_rsv_release(struct btrfs_root *root,
                             struct btrfs_block_rsv *block_rsv,
                             u64 num_bytes);
int btrfs_inc_block_group_ro(struct btrfs_root *root,
                             struct btrfs_block_group_cache *cache);
void btrfs_dec_block_group_ro(struct btrfs_root *root,
                              struct btrfs_block_group_cache *cache);
void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
int btrfs_error_unpin_extent_range(struct btrfs_root *root,
                                   u64 start, u64 end);
int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
                         u64 num_bytes, u64 *actual_bytes);
int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root, u64 type);
int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range);

int btrfs_init_space_info(struct btrfs_fs_info *fs_info);
int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
                                         struct btrfs_fs_info *fs_info);
int __get_raid_index(u64 flags);
int btrfs_start_write_no_snapshoting(struct btrfs_root *root);
void btrfs_end_write_no_snapshoting(struct btrfs_root *root);
void btrfs_wait_for_snapshot_creation(struct btrfs_root *root);
void check_system_chunk(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root,
                        const u64 type);
u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
                       struct btrfs_fs_info *info, u64 start, u64 end);

/* 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_previous_extent_item(struct btrfs_root *root,
                        struct btrfs_path *path, u64 min_objectid);
void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
                             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,
                        u64 min_trans);
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
                         struct btrfs_path *path,
                         u64 min_trans);
enum btrfs_compare_tree_result {
        BTRFS_COMPARE_TREE_NEW,
        BTRFS_COMPARE_TREE_DELETED,
        BTRFS_COMPARE_TREE_CHANGED,
        BTRFS_COMPARE_TREE_SAME,
};
typedef int (*btrfs_changed_cb_t)(struct btrfs_root *left_root,
                                  struct btrfs_root *right_root,
                                  struct btrfs_path *left_path,
                                  struct btrfs_path *right_path,
                                  struct btrfs_key *key,
                                  enum btrfs_compare_tree_result result,
                                  void *ctx);
int btrfs_compare_trees(struct btrfs_root *left_root,
                        struct btrfs_root *right_root,
                        btrfs_changed_cb_t cb, void *ctx);
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);
void btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
                       u32 data_size);
void btrfs_truncate_item(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_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
                u64 inum, u64 ioff, u8 key_type, struct btrfs_key *found_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_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
                          struct btrfs_path *p, u64 time_seq);
int btrfs_search_slot_for_read(struct btrfs_root *root,
                               struct btrfs_key *key, struct btrfs_path *p,
                               int find_higher, int return_any);
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root, struct extent_buffer *parent,
                       int start_slot, u64 *last_ret,
                       struct btrfs_key *progress);
void btrfs_release_path(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_clear_path_blocking(struct btrfs_path *p,
                               struct extent_buffer *held, int held_rw);
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);
}

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

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

int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
                        u64 time_seq);
static inline int btrfs_next_old_item(struct btrfs_root *root,
                                      struct btrfs_path *p, u64 time_seq)
{
        ++p->slots[0];
        if (p->slots[0] >= btrfs_header_nritems(p->nodes[0]))
                return btrfs_next_old_leaf(root, p, time_seq);
        return 0;
}
static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
{
        return btrfs_next_old_item(root, p, 0);
}
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
int __must_check btrfs_drop_snapshot(struct btrfs_root *root,
                                     struct btrfs_block_rsv *block_rsv,
                                     int update_ref, int for_reloc);
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root,
                        struct extent_buffer *node,
                        struct extent_buffer *parent);
static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
{
        /*
         * Get synced with close_ctree()
         */
        smp_mb();
        return fs_info->closing;
}

/*
 * If we remount the fs to be R/O or umount the fs, the cleaner needn't do
 * anything except sleeping. This function is used to check the status of
 * the fs.
 */
static inline int btrfs_need_cleaner_sleep(struct btrfs_root *root)
{
        return (root->fs_info->sb->s_flags & MS_RDONLY ||
                btrfs_fs_closing(root->fs_info));
}

static inline void free_fs_info(struct btrfs_fs_info *fs_info)
{
        kfree(fs_info->balance_ctl);
        kfree(fs_info->delayed_root);
        kfree(fs_info->extent_root);
        kfree(fs_info->tree_root);
        kfree(fs_info->chunk_root);
        kfree(fs_info->dev_root);
        kfree(fs_info->csum_root);
        kfree(fs_info->quota_root);
        kfree(fs_info->uuid_root);
        kfree(fs_info->free_space_root);
        kfree(fs_info->super_copy);
        kfree(fs_info->super_for_commit);
        security_free_mnt_opts(&fs_info->security_opts);
        kfree(fs_info);
}

/* tree mod log functions from ctree.c */
u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
                           struct seq_list *elem);
void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
                            struct seq_list *elem);
int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq);

/* 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 __must_check btrfs_update_root(struct btrfs_trans_handle *trans,
                                   struct btrfs_root *root,
                                   struct btrfs_key *key,
                                   struct btrfs_root_item *item);
int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
                    struct btrfs_path *path, struct btrfs_root_item *root_item,
                    struct btrfs_key *root_key);
int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
void btrfs_set_root_node(struct btrfs_root_item *item,
                         struct extent_buffer *node);
void btrfs_check_and_init_root_item(struct btrfs_root_item *item);
void btrfs_update_root_times(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root);

/* uuid-tree.c */
int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans,
                        struct btrfs_root *uuid_root, u8 *uuid, u8 type,
                        u64 subid);
int btrfs_uuid_tree_rem(struct btrfs_trans_handle *trans,
                        struct btrfs_root *uuid_root, u8 *uuid, u8 type,
                        u64 subid);
int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info,
                            int (*check_func)(struct btrfs_fs_info *, u8 *, u8,
                                              u64));

/* dir-item.c */
int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
                          const char *name, int name_len);
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root, const char *name,
                          int name_len, struct inode *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);
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);
int verify_dir_item(struct btrfs_root *root,
                    struct extent_buffer *leaf,
                    struct btrfs_dir_item *dir_item);
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
                                                 struct btrfs_path *path,
                                                 const char *name,
                                                 int name_len);

/* 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-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);

struct btrfs_inode_extref *
btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root,
                          struct btrfs_path *path,
                          const char *name, int name_len,
                          u64 inode_objectid, u64 ref_objectid, int ins_len,
                          int cow);

int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
                                   u64 ref_objectid, const char *name,
                                   int name_len,
                                   struct btrfs_inode_extref **extref_ret);

/* file-item.c */
struct btrfs_dio_private;
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_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
                              struct bio *bio, u64 logical_offset);
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,