/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#ifndef BTRFS_CTREE_H
#define BTRFS_CTREE_H

#include <linux/mm.h>
#include <linux/sched/signal.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 <trace/events/btrfs.h>
#include <asm/unaligned.h>
#include <linux/pagemap.h>
#include <linux/btrfs.h>
#include <linux/btrfs_tree.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/sizes.h>
#include <linux/dynamic_debug.h>
#include <linux/refcount.h>
#include <linux/crc32c.h>
#include <linux/iomap.h>
#include "extent-io-tree.h"
#include "extent_io.h"
#include "extent_map.h"
#include "async-thread.h"
#include "block-rsv.h"
#include "locking.h"

struct btrfs_trans_handle;
struct btrfs_transaction;
struct btrfs_pending_snapshot;
struct btrfs_delayed_ref_root;
struct btrfs_space_info;
struct btrfs_block_group;
extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_bit_radix_cachep;
extern struct kmem_cache *btrfs_path_cachep;
extern struct kmem_cache *btrfs_free_space_cachep;
extern struct kmem_cache *btrfs_free_space_bitmap_cachep;
struct btrfs_ordered_sum;
struct btrfs_ref;
struct btrfs_bio;
struct btrfs_ioctl_encoded_io_args;

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

/*
 * Maximum number of mirrors that can be available for all profiles counting
 * the target device of dev-replace as one. During an active device replace
 * procedure, the target device of the copy operation is a mirror for the
 * filesystem data as well that can be used to read data in order to repair
 * read errors on other disks.
 *
 * Current value is derived from RAID1C4 with 4 copies.
 */
#define BTRFS_MAX_MIRRORS (4 + 1)

#define BTRFS_MAX_LEVEL 8

#define BTRFS_OLDEST_GENERATION 0ULL

/*
 * 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

#define BTRFS_EMPTY_DIR_SIZE 0

/* 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

/*
 * Use large batch size to reduce overhead of metadata updates.  On the reader
 * side, we only read it when we are close to ENOSPC and the read overhead is
 * mostly related to the number of CPUs, so it is OK to use arbitrary large
 * value here.
 */
#define BTRFS_TOTAL_BYTES_PINNED_BATCH  SZ_128M

#define BTRFS_MAX_EXTENT_SIZE SZ_128M

/*
 * Deltas are an effective way to populate global statistics.  Give macro names
 * to make it clear what we're doing.  An example is discard_extents in
 * btrfs_free_space_ctl.
 */
#define BTRFS_STAT_NR_ENTRIES   2
#define BTRFS_STAT_CURR         0
#define BTRFS_STAT_PREV         1

/*
 * Count how many BTRFS_MAX_EXTENT_SIZE cover the @size
 */
static inline u32 count_max_extents(u64 size)
{
        return div_u64(size + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE);
}

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);
}

/*
 * Runtime (in-memory) states of filesystem
 */
enum {
        /* Global indicator of serious filesystem errors */
        BTRFS_FS_STATE_ERROR,
        /*
         * Filesystem is being remounted, allow to skip some operations, like
         * defrag
         */
        BTRFS_FS_STATE_REMOUNTING,
        /* Filesystem in RO mode */
        BTRFS_FS_STATE_RO,
        /* Track if a transaction abort has been reported on this filesystem */
        BTRFS_FS_STATE_TRANS_ABORTED,
        /*
         * Bio operations should be blocked on this filesystem because a source
         * or target device is being destroyed as part of a device replace
         */
        BTRFS_FS_STATE_DEV_REPLACING,
        /* The btrfs_fs_info created for self-tests */
        BTRFS_FS_STATE_DUMMY_FS_INFO,

        BTRFS_FS_STATE_NO_CSUMS,

        /* Indicates there was an error cleaning up a log tree. */
        BTRFS_FS_STATE_LOG_CLEANUP_ERROR,

        BTRFS_FS_STATE_COUNT
};

#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__));

/*
 * 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

/*
 * 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__));

#define BTRFS_SUPER_INFO_OFFSET                 SZ_64K
#define BTRFS_SUPER_INFO_SIZE                   4096

/*
 * the super block basically lists the main trees of the FS
 * it currently lacks any block count etc etc
 */
struct btrfs_super_block {
        /* the first 4 fields must match struct btrfs_header */
        u8 csum[BTRFS_CSUM_SIZE];
        /* FS specific UUID, visible to user */
        u8 fsid[BTRFS_FSID_SIZE];
        __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;

        /* the UUID written into btree blocks */
        u8 metadata_uuid[BTRFS_FSID_SIZE];

        /* Extent tree v2 */
        __le64 block_group_root;
        __le64 block_group_root_generation;
        u8 block_group_root_level;

        /* future expansion */
        u8 reserved8[7];
        __le64 reserved[25];
        u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
        struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];

        /* Padded to 4096 bytes */
        u8 padding[565];
} __attribute__ ((__packed__));
static_assert(sizeof(struct btrfs_super_block) == BTRFS_SUPER_INFO_SIZE);

/*
 * Compat flags that we support.  If any incompat flags are set other than the
 * ones specified below then we will fail to mount
 */
#define BTRFS_FEATURE_COMPAT_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 |      \
         BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID | \
         BTRFS_FEATURE_COMPAT_RO_VERITY)

#define BTRFS_FEATURE_COMPAT_RO_SAFE_SET        0ULL
#define BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR      0ULL

#ifdef CONFIG_BTRFS_DEBUG
/*
 * Extent tree v2 supported only with CONFIG_BTRFS_DEBUG
 */
#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_COMPRESS_ZSTD |         \
         BTRFS_FEATURE_INCOMPAT_RAID56 |                \
         BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |         \
         BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |       \
         BTRFS_FEATURE_INCOMPAT_NO_HOLES        |       \
         BTRFS_FEATURE_INCOMPAT_METADATA_UUID   |       \
         BTRFS_FEATURE_INCOMPAT_RAID1C34        |       \
         BTRFS_FEATURE_INCOMPAT_ZONED           |       \
         BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
#else
#define BTRFS_FEATURE_INCOMPAT_SUPP                     \
        (BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |         \
         BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |        \
         BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |          \
         BTRFS_FEATURE_INCOMPAT_BIG_METADATA |          \
         BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |          \
         BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD |         \
         BTRFS_FEATURE_INCOMPAT_RAID56 |                \
         BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |         \
         BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |       \
         BTRFS_FEATURE_INCOMPAT_NO_HOLES        |       \
         BTRFS_FEATURE_INCOMPAT_METADATA_UUID   |       \
         BTRFS_FEATURE_INCOMPAT_RAID1C34        |       \
         BTRFS_FEATURE_INCOMPAT_ZONED)
#endif

#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__));

/* Read ahead values for struct btrfs_path.reada */
enum {
        READA_NONE,
        READA_BACK,
        READA_FORWARD,
        /*
         * Similar to READA_FORWARD but unlike it:
         *
         * 1) It will trigger readahead even for leaves that are not close to
         *    each other on disk;
         * 2) It also triggers readahead for nodes;
         * 3) During a search, even when a node or leaf is already in memory, it
         *    will still trigger readahead for other nodes and leaves that follow
         *    it.
         *
         * This is meant to be used only when we know we are iterating over the
         * entire tree or a very large part of it.
         */
        READA_FORWARD_ALWAYS,
};

/*
 * btrfs_paths remember the path taken from the root down to the leaf.
 * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
 * to any other levels that are present.
 *
 * The slots array records the index of the item or block pointer
 * used while walking the tree.
 */
struct btrfs_path {
        struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
        int slots[BTRFS_MAX_LEVEL];
        /* if there is real range locking, this locks field will change */
        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 search_commit_root:1;
        unsigned int need_commit_sem:1;
        unsigned int skip_release_on_error:1;
        /*
         * Indicate that new item (btrfs_search_slot) is extending already
         * existing item and ins_len contains only the data size and not item
         * header (ie. sizeof(struct btrfs_item) is not included).
         */
        unsigned int search_for_extension:1;
};
#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
                                        sizeof(struct btrfs_item))
struct btrfs_dev_replace {
        u64 replace_state;      /* see #define above */
        time64_t time_started;  /* seconds since 1-Jan-1970 */
        time64_t 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;

        struct mutex lock_finishing_cancel_unmount;
        struct rw_semaphore rwsem;

        struct btrfs_scrub_progress scrub_progress;

        struct percpu_counter bio_counter;
        wait_queue_head_t replace_wait;
};

/*
 * 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. In ssd_spread mode they are also used for data allocations.
 */
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 *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,
        BTRFS_CACHE_STARTED,
        BTRFS_CACHE_FAST,
        BTRFS_CACHE_FINISHED,
        BTRFS_CACHE_ERROR,
};

/*
 * Tree to record all locked full stripes of a RAID5/6 block group
 */
struct btrfs_full_stripe_locks_tree {
        struct rb_root root;
        struct mutex lock;
};

/* Discard control. */
/*
 * Async discard uses multiple lists to differentiate the discard filter
 * parameters.  Index 0 is for completely free block groups where we need to
 * ensure the entire block group is trimmed without being lossy.  Indices
 * afterwards represent monotonically decreasing discard filter sizes to
 * prioritize what should be discarded next.
 */
#define BTRFS_NR_DISCARD_LISTS          3
#define BTRFS_DISCARD_INDEX_UNUSED      0
#define BTRFS_DISCARD_INDEX_START       1

struct btrfs_discard_ctl {
        struct workqueue_struct *discard_workers;
        struct delayed_work work;
        spinlock_t lock;
        struct btrfs_block_group *block_group;
        struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
        u64 prev_discard;
        u64 prev_discard_time;
        atomic_t discardable_extents;
        atomic64_t discardable_bytes;
        u64 max_discard_size;
        u64 delay_ms;
        u32 iops_limit;
        u32 kbps_limit;
        u64 discard_extent_bytes;
        u64 discard_bitmap_bytes;
        atomic64_t discard_bytes_saved;
};

void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info);

/* fs_info */
struct reloc_control;
struct btrfs_device;
struct btrfs_fs_devices;
struct btrfs_balance_control;
struct btrfs_delayed_root;

/*
 * Block group or device which contains an active swapfile. Used for preventing
 * unsafe operations while a swapfile is active.
 *
 * These are sorted on (ptr, inode) (note that a block group or device can
 * contain more than one swapfile). We compare the pointer values because we
 * don't actually care what the object is, we just need a quick check whether
 * the object exists in the rbtree.
 */
struct btrfs_swapfile_pin {
        struct rb_node node;
        void *ptr;
        struct inode *inode;
        /*
         * If true, ptr points to a struct btrfs_block_group. Otherwise, ptr
         * points to a struct btrfs_device.
         */
        bool is_block_group;
        /*
         * Only used when 'is_block_group' is true and it is the number of
         * extents used by a swapfile for this block group ('ptr' field).
         */
        int bg_extent_count;
};

bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr);

enum {
        BTRFS_FS_CLOSING_START,
        BTRFS_FS_CLOSING_DONE,
        BTRFS_FS_LOG_RECOVERING,
        BTRFS_FS_OPEN,
        BTRFS_FS_QUOTA_ENABLED,
        BTRFS_FS_UPDATE_UUID_TREE_GEN,
        BTRFS_FS_CREATING_FREE_SPACE_TREE,
        BTRFS_FS_BTREE_ERR,
        BTRFS_FS_LOG1_ERR,
        BTRFS_FS_LOG2_ERR,
        BTRFS_FS_QUOTA_OVERRIDE,
        /* Used to record internally whether fs has been frozen */
        BTRFS_FS_FROZEN,
        /*
         * Indicate that balance has been set up from the ioctl and is in the
         * main phase. The fs_info::balance_ctl is initialized.
         */
        BTRFS_FS_BALANCE_RUNNING,

        /*
         * Indicate that relocation of a chunk has started, it's set per chunk
         * and is toggled between chunks.
         */
        BTRFS_FS_RELOC_RUNNING,

        /* Indicate that the cleaner thread is awake and doing something. */
        BTRFS_FS_CLEANER_RUNNING,

        /*
         * The checksumming has an optimized version and is considered fast,
         * so we don't need to offload checksums to workqueues.
         */
        BTRFS_FS_CSUM_IMPL_FAST,

        /* Indicate that the discard workqueue can service discards. */
        BTRFS_FS_DISCARD_RUNNING,

        /* Indicate that we need to cleanup space cache v1 */
        BTRFS_FS_CLEANUP_SPACE_CACHE_V1,

        /* Indicate that we can't trust the free space tree for caching yet */
        BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,

        /* Indicate whether there are any tree modification log users */
        BTRFS_FS_TREE_MOD_LOG_USERS,

        /* Indicate that we want the transaction kthread to commit right now. */
        BTRFS_FS_COMMIT_TRANS,

        /* Indicate we have half completed snapshot deletions pending. */
        BTRFS_FS_UNFINISHED_DROPS,

#if BITS_PER_LONG == 32
        /* Indicate if we have error/warn message printed on 32bit systems */
        BTRFS_FS_32BIT_ERROR,
        BTRFS_FS_32BIT_WARN,
#endif
};

/*
 * Exclusive operations (device replace, resize, device add/remove, balance)
 */
enum btrfs_exclusive_operation {
        BTRFS_EXCLOP_NONE,
        BTRFS_EXCLOP_BALANCE_PAUSED,
        BTRFS_EXCLOP_BALANCE,
        BTRFS_EXCLOP_DEV_ADD,
        BTRFS_EXCLOP_DEV_REMOVE,
        BTRFS_EXCLOP_DEV_REPLACE,
        BTRFS_EXCLOP_RESIZE,
        BTRFS_EXCLOP_SWAP_ACTIVATE,
};

struct btrfs_fs_info {
        u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
        unsigned long flags;
        struct btrfs_root *tree_root;
        struct btrfs_root *chunk_root;
        struct btrfs_root *dev_root;
        struct btrfs_root *fs_root;
        struct btrfs_root *quota_root;
        struct btrfs_root *uuid_root;
        struct btrfs_root *data_reloc_root;
        struct btrfs_root *block_group_root;

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

        /* The tree that holds the global roots (csum, extent, etc) */
        rwlock_t global_root_lock;
        struct rb_root global_root_tree;

        spinlock_t fs_roots_radix_lock;
        struct radix_tree_root fs_roots_radix;

        /* block group cache stuff */
        rwlock_t block_group_cache_lock;
        struct rb_root_cached block_group_cache_tree;

        /* keep track of unallocated space */
        atomic64_t free_chunk_space;

        /* Track ranges which are used by log trees blocks/logged data extents */
        struct extent_io_tree excluded_extents;

        /* logical->physical extent mapping */
        struct extent_map_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 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;
        /* block reservation for delayed refs */
        struct btrfs_block_rsv delayed_refs_rsv;

        struct btrfs_block_rsv empty_block_rsv;

        u64 generation;
        u64 last_trans_committed;
        /*
         * Generation of the last transaction used for block group relocation
         * since the filesystem was last mounted (or 0 if none happened yet).
         * Must be written and read while holding btrfs_fs_info::commit_root_sem.
         */
        u64 last_reloc_trans;
        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;
        unsigned int compress_level;
        u32 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;

        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 super_block *sb;
        struct inode *btree_inode;
        struct mutex tree_log_mutex;
        struct mutex transaction_kthread_mutex;
        struct mutex cleaner_mutex;
        struct mutex chunk_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;

        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;
        atomic_t nr_delayed_iputs;
        wait_queue_head_t delayed_iputs_wait;

        atomic64_t tree_mod_seq;

        /* this protects tree_mod_log and tree_mod_seq_list */
        rwlock_t tree_mod_log_lock;
        struct rb_root tree_mod_log;
        struct list_head tree_mod_seq_list;

        atomic_t async_delalloc_pages;

        /*
         * 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 *hipri_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 workqueue_struct *rmw_workers;
        struct btrfs_workqueue *endio_meta_write_workers;
        struct btrfs_workqueue *endio_write_workers;
        struct btrfs_workqueue *endio_freespace_worker;
        struct btrfs_workqueue *caching_workers;

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

        struct task_struct *transaction_kthread;
        struct task_struct *cleaner_kthread;
        u32 thread_pool_size;

        struct kobject *space_info_kobj;
        struct kobject *qgroups_kobj;

        /* used to keep from writing metadata until there is a nice batch */
        struct percpu_counter dirty_metadata_bytes;
        struct percpu_counter delalloc_bytes;
        struct percpu_counter ordered_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 effectively read only after initial
         * setup.  It is populated at mount time and cleaned up after
         * all block groups are removed.  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_spread 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_pause_req;
        atomic_t balance_cancel_req;
        struct btrfs_balance_control *balance_ctl;
        wait_queue_head_t balance_wait_q;

        /* Cancellation requests for chunk relocation */
        atomic_t reloc_cancel_req;

        u32 data_chunk_allocations;
        u32 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;
        /*
         * The worker pointers are NULL iff the refcount is 0, ie. scrub is not
         * running.
         */
        refcount_t scrub_workers_refcnt;
        struct workqueue_struct *scrub_workers;
        struct workqueue_struct *scrub_wr_completion_workers;
        struct workqueue_struct *scrub_parity_workers;
        struct btrfs_subpage_info *subpage_info;

        struct btrfs_discard_ctl discard_ctl;

#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
        u32 check_integrity_print_mask;
#endif
        /* is qgroup tracking in a consistent state? */
        u64 qgroup_flags;

        /* holds configuration and tracking. Protected by qgroup_lock */
        struct rb_root qgroup_tree;
        spinlock_t qgroup_lock;

        /*
         * 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. If a transaction is needed,
         * it must be started before locking this lock.
         */
        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;
        bool qgroup_rescan_running;     /* protected by qgroup_rescan_lock */

        /* filesystem state */
        unsigned long fs_state;

        struct btrfs_delayed_root *delayed_root;

        /* Extent buffer radix tree */
        spinlock_t buffer_lock;
        /* Entries are eb->start / sectorsize */
        struct radix_tree_root buffer_radix;

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

        /* device replace state */
        struct btrfs_dev_replace dev_replace;

        struct semaphore uuid_tree_rescan_sem;

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

        /* Reclaim partially filled block groups in the background */
        struct work_struct reclaim_bgs_work;
        struct list_head reclaim_bgs;
        int bg_reclaim_threshold;

        spinlock_t unused_bgs_lock;
        struct list_head unused_bgs;
        struct mutex unused_bg_unpin_mutex;
        /* Protect block groups that are going to be deleted */
        struct mutex reclaim_bgs_lock;

        /* Cached block sizes */
        u32 nodesize;
        u32 sectorsize;
        /* ilog2 of sectorsize, use to avoid 64bit division */
        u32 sectorsize_bits;
        u32 csum_size;
        u32 csums_per_leaf;
        u32 stripesize;

        /* Block groups and devices containing active swapfiles. */
        spinlock_t swapfile_pins_lock;
        struct rb_root swapfile_pins;

        struct crypto_shash *csum_shash;

        /* Type of exclusive operation running, protected by super_lock */
        enum btrfs_exclusive_operation exclusive_operation;

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

        struct mutex zoned_meta_io_lock;
        spinlock_t treelog_bg_lock;
        u64 treelog_bg;

        /*
         * Start of the dedicated data relocation block group, protected by
         * relocation_bg_lock.
         */
        spinlock_t relocation_bg_lock;
        u64 data_reloc_bg;
        struct mutex zoned_data_reloc_io_lock;

        u64 nr_global_roots;

        spinlock_t zone_active_bgs_lock;
        struct list_head zone_active_bgs;

#ifdef CONFIG_BTRFS_FS_REF_VERIFY
        spinlock_t ref_verify_lock;
        struct rb_root block_tree;
#endif

#ifdef CONFIG_BTRFS_DEBUG
        struct kobject *debug_kobj;
        struct kobject *discard_debug_kobj;
        struct list_head allocated_roots;

        spinlock_t eb_leak_lock;
        struct list_head allocated_ebs;
#endif
};

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

/*
 * The state of btrfs root
 */
enum {
        /*
         * 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
         */
        BTRFS_ROOT_IN_TRANS_SETUP,

        /*
         * Set if tree blocks of this root can be shared by other roots.
         * Only subvolume trees and their reloc trees have this bit set.
         * Conflicts with TRACK_DIRTY bit.
         *
         * This affects two things:
         *
         * - How balance works
         *   For shareable roots, we need to use reloc tree and do path
         *   replacement for balance, and need various pre/post hooks for
         *   snapshot creation to handle them.
         *
         *   While for non-shareable trees, we just simply do a tree search
         *   with COW.
         *
         * - How dirty roots are tracked
         *   For shareable roots, btrfs_record_root_in_trans() is needed to
         *   track them, while non-subvolume roots have TRACK_DIRTY bit, they
         *   don't need to set this manually.
         */
        BTRFS_ROOT_SHAREABLE,
        BTRFS_ROOT_TRACK_DIRTY,
        BTRFS_ROOT_IN_RADIX,
        BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
        BTRFS_ROOT_DEFRAG_RUNNING,
        BTRFS_ROOT_FORCE_COW,
        BTRFS_ROOT_MULTI_LOG_TASKS,
        BTRFS_ROOT_DIRTY,
        BTRFS_ROOT_DELETING,

        /*
         * Reloc tree is orphan, only kept here for qgroup delayed subtree scan
         *
         * Set for the subvolume tree owning the reloc tree.
         */
        BTRFS_ROOT_DEAD_RELOC_TREE,
        /* Mark dead root stored on device whose cleanup needs to be resumed */
        BTRFS_ROOT_DEAD_TREE,
        /* The root has a log tree. Used for subvolume roots and the tree root. */
        BTRFS_ROOT_HAS_LOG_TREE,
        /* Qgroup flushing is in progress */
        BTRFS_ROOT_QGROUP_FLUSHING,
        /* We started the orphan cleanup for this root. */
        BTRFS_ROOT_ORPHAN_CLEANUP,
        /* This root has a drop operation that was started previously. */
        BTRFS_ROOT_UNFINISHED_DROP,
};

static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
{
        clear_and_wake_up_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
}

/*
 * Record swapped tree blocks of a subvolume tree for delayed subtree trace
 * code. For detail check comment in fs/btrfs/qgroup.c.
 */
struct btrfs_qgroup_swapped_blocks {
        spinlock_t lock;
        /* RM_EMPTY_ROOT() of above blocks[] */
        bool swapped;
        struct rb_root blocks[BTRFS_MAX_LEVEL];
};

/*
 * 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 rb_node rb_node;

        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;

        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];
        /* Used only for log trees of subvolumes, not for the log root tree */
        atomic_t log_writers;
        atomic_t log_commit[2];
        /* Used only for log trees of subvolumes, not for the log root tree */
        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 last_trans;

        u32 type;

        u64 free_objectid;

        struct btrfs_key defrag_progress;
        struct btrfs_key defrag_max;

        /* The dirty list is only used by non-shareable 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 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;
        refcount_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;

        /*
         * Not empty if this subvolume root has gone through tree block swap
         * (relocation)
         *
         * Will be used by reloc_control::dirty_subvol_roots.
         */
        struct list_head reloc_dirty_list;

        /*
         * Number of currently running SEND ioctls to prevent
         * manipulation with the read-only status via SUBVOL_SETFLAGS
         */
        int send_in_progress;
        /*
         * Number of currently running deduplication operations that have a
         * destination inode belonging to this root. Protected by the lock
         * root_item_lock.
         */
        int dedupe_in_progress;
        /* For exclusion of snapshot creation and nocow writes */
        struct btrfs_drew_lock snapshot_lock;

        atomic_t snapshot_force_cow;

        /* For qgroup metadata reserved space */
        spinlock_t qgroup_meta_rsv_lock;
        u64 qgroup_meta_rsv_pertrans;
        u64 qgroup_meta_rsv_prealloc;
        wait_queue_head_t qgroup_flush_wait;

        /* Number of active swapfiles */
        atomic_t nr_swapfiles;

        /* Record pairs of swapped blocks for qgroup */
        struct btrfs_qgroup_swapped_blocks swapped_blocks;

        /* Used only by log trees, when logging csum items */
        struct extent_io_tree log_csum_range;

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
        u64 alloc_bytenr;
#endif

#ifdef CONFIG_BTRFS_DEBUG
        struct list_head leak_list;
#endif
};

/*
 * Structure that conveys information about an extent that is going to replace
 * all the extents in a file range.
 */
struct btrfs_replace_extent_info {
        u64 disk_offset;
        u64 disk_len;
        u64 data_offset;
        u64 data_len;
        u64 file_offset;
        /* Pointer to a file extent item of type regular or prealloc. */
        char *extent_buf;
        /*
         * Set to true when attempting to replace a file range with a new extent
         * described by this structure, set to false when attempting to clone an
         * existing extent into a file range.
         */
        bool is_new_extent;
        /* Indicate if we should update the inode's mtime and ctime. */
        bool update_times;
        /* Meaningful only if is_new_extent is true. */
        int qgroup_reserved;
        /*
         * Meaningful only if is_new_extent is true.
         * Used to track how many extent items we have already inserted in a
         * subvolume tree that refer to the extent described by this structure,
         * so that we know when to create a new delayed ref or update an existing
         * one.
         */
        int insertions;
};

/* Arguments for btrfs_drop_extents() */
struct btrfs_drop_extents_args {
        /* Input parameters */

        /*
         * If NULL, btrfs_drop_extents() will allocate and free its own path.
         * If 'replace_extent' is true, this must not be NULL. Also the path
         * is always released except if 'replace_extent' is true and
         * btrfs_drop_extents() sets 'extent_inserted' to true, in which case
         * the path is kept locked.
         */
        struct btrfs_path *path;
        /* Start offset of the range to drop extents from */
        u64 start;
        /* End (exclusive, last byte + 1) of the range to drop extents from */
        u64 end;
        /* If true drop all the extent maps in the range */
        bool drop_cache;
        /*
         * If true it means we want to insert a new extent after dropping all
         * the extents in the range. If this is true, the 'extent_item_size'
         * parameter must be set as well and the 'extent_inserted' field will
         * be set to true by btrfs_drop_extents() if it could insert the new
         * extent.
         * Note: when this is set to true the path must not be NULL.
         */
        bool replace_extent;
        /*
         * Used if 'replace_extent' is true. Size of the file extent item to
         * insert after dropping all existing extents in the range
         */
        u32 extent_item_size;

        /* Output parameters */

        /*
         * Set to the minimum between the input parameter 'end' and the end
         * (exclusive, last byte + 1) of the last dropped extent. This is always
         * set even if btrfs_drop_extents() returns an error.
         */
        u64 drop_end;
        /*
         * The number of allocated bytes found in the range. This can be smaller
         * than the range's length when there are holes in the range.
         */
        u64 bytes_found;
        /*
         * Only set if 'replace_extent' is true. Set to true if we were able
         * to insert a replacement extent after dropping all extents in the
         * range, otherwise set to false by btrfs_drop_extents().
         * Also, if btrfs_drop_extents() has set this to true it means it
         * returned with the path locked, otherwise if it has set this to
         * false it has returned with the path released.
         */
        bool extent_inserted;
};

struct btrfs_file_private {
        void *filldir_buf;
};


static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)
{

        return info->nodesize - sizeof(struct btrfs_header);
}

#define BTRFS_LEAF_DATA_OFFSET          offsetof(struct btrfs_leaf, items)

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

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

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

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

/*
 * Flags for mount options.
 *
 * Note: don't forget to add new options to btrfs_show_options()
 */
enum {
        BTRFS_MOUNT_NODATASUM                   = (1UL << 0),
        BTRFS_MOUNT_NODATACOW                   = (1UL << 1),
        BTRFS_MOUNT_NOBARRIER                   = (1UL << 2),
        BTRFS_MOUNT_SSD                         = (1UL << 3),
        BTRFS_MOUNT_DEGRADED                    = (1UL << 4),
        BTRFS_MOUNT_COMPRESS                    = (1UL << 5),
        BTRFS_MOUNT_NOTREELOG                   = (1UL << 6),
        BTRFS_MOUNT_FLUSHONCOMMIT               = (1UL << 7),
        BTRFS_MOUNT_SSD_SPREAD                  = (1UL << 8),
        BTRFS_MOUNT_NOSSD                       = (1UL << 9),
        BTRFS_MOUNT_DISCARD_SYNC                = (1UL << 10),
        BTRFS_MOUNT_FORCE_COMPRESS              = (1UL << 11),
        BTRFS_MOUNT_SPACE_CACHE                 = (1UL << 12),
        BTRFS_MOUNT_CLEAR_CACHE                 = (1UL << 13),
        BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED      = (1UL << 14),
        BTRFS_MOUNT_ENOSPC_DEBUG                = (1UL << 15),
        BTRFS_MOUNT_AUTO_DEFRAG                 = (1UL << 16),
        BTRFS_MOUNT_USEBACKUPROOT               = (1UL << 17),
        BTRFS_MOUNT_SKIP_BALANCE                = (1UL << 18),
        BTRFS_MOUNT_CHECK_INTEGRITY             = (1UL << 19),
        BTRFS_MOUNT_CHECK_INTEGRITY_DATA        = (1UL << 20),
        BTRFS_MOUNT_PANIC_ON_FATAL_ERROR        = (1UL << 21),
        BTRFS_MOUNT_RESCAN_UUID_TREE            = (1UL << 22),
        BTRFS_MOUNT_FRAGMENT_DATA               = (1UL << 23),
        BTRFS_MOUNT_FRAGMENT_METADATA           = (1UL << 24),
        BTRFS_MOUNT_FREE_SPACE_TREE             = (1UL << 25),
        BTRFS_MOUNT_NOLOGREPLAY                 = (1UL << 26),
        BTRFS_MOUNT_REF_VERIFY                  = (1UL << 27),
        BTRFS_MOUNT_DISCARD_ASYNC               = (1UL << 28),
        BTRFS_MOUNT_IGNOREBADROOTS              = (1UL << 29),
        BTRFS_MOUNT_IGNOREDATACSUMS             = (1UL << 30),
};

#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(fs_info, opt)    ((fs_info)->mount_opt & \
                                         BTRFS_MOUNT_##opt)

#define btrfs_set_and_info(fs_info, opt, fmt, args...)                  \
do {                                                                    \
        if (!btrfs_test_opt(fs_info, opt))                              \
                btrfs_info(fs_info, fmt, ##args);                       \
        btrfs_set_opt(fs_info->mount_opt, opt);                         \
} while (0)

#define btrfs_clear_and_info(fs_info, opt, fmt, args...)                \
do {                                                                    \
        if (btrfs_test_opt(fs_info, opt))                               \
                btrfs_info(fs_info, fmt, ##args);                       \
        btrfs_clear_opt(fs_info->mount_opt, opt);                       \
} while (0)

/*
 * 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_COMMIT                    (0)

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

#define BTRFS_INODE_ROOT_ITEM_INIT      (1U << 31)

#define BTRFS_INODE_FLAG_MASK                                           \
        (BTRFS_INODE_NODATASUM |                                        \
         BTRFS_INODE_NODATACOW |                                        \
         BTRFS_INODE_READONLY |                                         \
         BTRFS_INODE_NOCOMPRESS |                                       \
         BTRFS_INODE_PREALLOC |                                         \
         BTRFS_INODE_SYNC |                                             \
         BTRFS_INODE_IMMUTABLE |                                        \
         BTRFS_INODE_APPEND |                                           \
         BTRFS_INODE_NODUMP |                                           \
         BTRFS_INODE_NOATIME |                                          \
         BTRFS_INODE_DIRSYNC |                                          \
         BTRFS_INODE_COMPRESS |                                         \
         BTRFS_INODE_ROOT_ITEM_INIT)

#define BTRFS_INODE_RO_VERITY           (1U << 0)

#define BTRFS_INODE_RO_FLAG_MASK        (BTRFS_INODE_RO_VERITY)

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

#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
                                ((bytes) >> (fs_info)->sectorsize_bits)

static inline void btrfs_init_map_token(struct btrfs_map_token *token,
                                        struct extent_buffer *eb)
{
        token->eb = eb;
        token->kaddr = page_address(eb->pages[0]);
        token->offset = 0;
}

/* some macros to generate set/get functions 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

static inline u8 get_unaligned_le8(const void *p)
{
       return *(u8 *)p;
}

static inline void put_unaligned_le8(u8 val, void *p)
{
       *(u8 *)p = val;
}

#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 btrfs_map_token *token,           \
                               const void *ptr, unsigned long off);     \
void btrfs_set_token_##bits(struct btrfs_map_token *token,              \
                            const void *ptr, unsigned long off,         \
                            u##bits val);                               \
u##bits btrfs_get_##bits(const struct extent_buffer *eb,                \
                         const void *ptr, unsigned long off);           \
void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr,        \
                      unsigned long off, u##bits val);

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

#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)             \
static inline u##bits btrfs_##name(const struct extent_buffer *eb)      \
{                                                                       \
        const type *p = page_address(eb->pages[0]) +                    \
                        offset_in_page(eb->start);                      \
        return get_unaligned_le##bits(&p->member);                      \
}                                                                       \
static inline void btrfs_set_##name(const struct extent_buffer *eb,     \
                                    u##bits val)                        \
{                                                                       \
        type *p = page_address(eb->pages[0]) + offset_in_page(eb->start); \
        put_unaligned_le##bits(val, &p->member);                        \
}

#define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)              \
static inline u##bits btrfs_##name(const type *s)                       \
{                                                                       \
        return get_unaligned_le##bits(&s->member);                      \
}                                                                       \
static inline void btrfs_set_##name(type *s, u##bits val)               \
{                                                                       \
        put_unaligned_le##bits(val, &s->member);                        \
}

static inline u64 btrfs_device_total_bytes(const struct extent_buffer *eb,
                                           struct btrfs_dev_item *s)
{
        static_assert(sizeof(u64) ==
                      sizeof(((struct btrfs_dev_item *)0))->total_bytes);
        return btrfs_get_64(eb, s, offsetof(struct btrfs_dev_item,
                                            total_bytes));
}
static inline void btrfs_set_device_total_bytes(const struct extent_buffer *eb,
                                                struct btrfs_dev_item *s,
                                                u64 val)
{
        static_assert(sizeof(u64) ==
                      sizeof(((struct btrfs_dev_item *)0))->total_bytes);
        WARN_ON(!IS_ALIGNED(val, eb->fs_info->sectorsize));
        btrfs_set_64(eb, s, offsetof(struct btrfs_dev_item, total_bytes), val);
}


BTRFS_SETGET_FUNCS(device_type, struct btrfs_dev_item, type, 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(const 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(const 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(stack_block_group_used, struct btrfs_block_group_item,
                         used, 64);
BTRFS_SETGET_FUNCS(block_group_used, struct btrfs_block_group_item,
                         used, 64);
BTRFS_SETGET_STACK_FUNCS(stack_block_group_chunk_objectid,
                        struct btrfs_block_group_item, chunk_objectid, 64);

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

/* 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);
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(tree_block_level, struct btrfs_tree_block_info, level, 8);

static inline void btrfs_tree_block_key(const 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(const 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);
        return 0;
}

/* 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(const 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(const 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(const 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(const 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(const struct extent_buffer *eb,
                    struct btrfs_disk_key *disk_key, int nr);

static inline void btrfs_set_node_key(const 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(raw_item_offset, struct btrfs_item, offset, 32);
BTRFS_SETGET_FUNCS(raw_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);
}

#define BTRFS_ITEM_SETGET_FUNCS(member)                                         \
static inline u32 btrfs_item_##member(const struct extent_buffer *eb,           \
                                      int slot)                                 \
{                                                                               \
        return btrfs_raw_item_##member(eb, btrfs_item_nr(slot));                \
}                                                                               \
static inline void btrfs_set_item_##member(const struct extent_buffer *eb,      \
                                           int slot, u32 val)                   \
{                                                                               \
        btrfs_set_raw_item_##member(eb, btrfs_item_nr(slot), val);              \
}                                                                               \
static inline u32 btrfs_token_item_##member(struct btrfs_map_token *token,      \
                                            int slot)                           \
{                                                                               \
        struct btrfs_item *item = btrfs_item_nr(slot);                          \
        return btrfs_token_raw_item_##member(token, item);                      \
}                                                                               \
static inline void btrfs_set_token_item_##member(struct btrfs_map_token *token, \
                                                 int slot, u32 val)             \
{                                                                               \
        struct btrfs_item *item = btrfs_item_nr(slot);                          \
        btrfs_set_token_raw_item_##member(token, item, val);                    \
}

BTRFS_ITEM_SETGET_FUNCS(offset)
BTRFS_ITEM_SETGET_FUNCS(size);

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

static inline void btrfs_item_key(const 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(const struct extent_buffer *eb,
                                      const 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,
                                          const 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(const struct extent_buffer *eb,
                                        const 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,
                                            const 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);

#ifdef __LITTLE_ENDIAN

/*
 * Optimized helpers for little-endian architectures where CPU and on-disk
 * structures have the same endianness and we can skip conversions.
 */

static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu_key,
                                         const struct btrfs_disk_key *disk_key)
{
        memcpy(cpu_key, disk_key, sizeof(struct btrfs_key));
}

static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk_key,
                                         const struct btrfs_key *cpu_key)
{
        memcpy(disk_key, cpu_key, sizeof(struct btrfs_key));
}

static inline void btrfs_node_key_to_cpu(const struct extent_buffer *eb,
                                         struct btrfs_key *cpu_key, int nr)
{
        struct btrfs_disk_key *disk_key = (struct btrfs_disk_key *)cpu_key;

        btrfs_node_key(eb, disk_key, nr);
}

static inline void btrfs_item_key_to_cpu(const struct extent_buffer *eb,
                                         struct btrfs_key *cpu_key, int nr)
{
        struct btrfs_disk_key *disk_key = (struct btrfs_disk_key *)cpu_key;

        btrfs_item_key(eb, disk_key, nr);
}

static inline void btrfs_dir_item_key_to_cpu(const struct extent_buffer *eb,
                                             const struct btrfs_dir_item *item,
                                             struct btrfs_key *cpu_key)
{
        struct btrfs_disk_key *disk_key = (struct btrfs_disk_key *)cpu_key;

        btrfs_dir_item_key(eb, item, disk_key);
}

#else

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

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

static inline void btrfs_node_key_to_cpu(const 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(const 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(const struct extent_buffer *eb,
                                             const 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);
}

#endif

/* 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(const struct extent_buffer *eb, u64 flag)
{
        return (btrfs_header_flags(eb) & flag) == flag;
}

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

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

static inline int btrfs_header_backref_rev(const 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 int btrfs_is_leaf(const 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_drop_level, struct btrfs_root_item, drop_level, 8);
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(const struct btrfs_root *root)
{
        /* Byte-swap the constant at compile time, root_item::flags is LE */
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
}

static inline bool btrfs_root_dead(const struct btrfs_root *root)
{
        /* Byte-swap the constant at compile time, root_item::flags is LE */
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
}

static inline u64 btrfs_root_id(const struct btrfs_root *root)
{
        return root->root_key.objectid;
}

/* 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);

/*
 * For extent tree v2 we overload the extent root with the block group root, as
 * we will have multiple extent roots.
 */
BTRFS_SETGET_STACK_FUNCS(backup_block_group_root, struct btrfs_root_backup,
                         extent_root, 64);
BTRFS_SETGET_STACK_FUNCS(backup_block_group_root_gen, struct btrfs_root_backup,
                         extent_root_gen, 64);
BTRFS_SETGET_STACK_FUNCS(backup_block_group_root_level,
                         struct btrfs_root_backup, extent_root_level, 8);

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

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

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

static inline void btrfs_balance_sys(const struct extent_buffer *eb,
                                     const 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,
                                 const 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,
                               const 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);
        cpu->stripes_min = le32_to_cpu(disk->stripes_min);
        cpu->stripes_max = le32_to_cpu(disk->stripes_max);
}

static inline void
btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,
                               const 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);
        disk->stripes_min = cpu_to_le32(cpu->stripes_min);
        disk->stripes_max = cpu_to_le32(cpu->stripes_max);
}

/* 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);
BTRFS_SETGET_STACK_FUNCS(super_block_group_root, struct btrfs_super_block,
                         block_group_root, 64);
BTRFS_SETGET_STACK_FUNCS(super_block_group_root_generation,
                         struct btrfs_super_block,
                         block_group_root_generation, 64);
BTRFS_SETGET_STACK_FUNCS(super_block_group_root_level, struct btrfs_super_block,
                         block_group_root_level, 8);

int btrfs_super_csum_size(const struct btrfs_super_block *s);
const char *btrfs_super_csum_name(u16 csum_type);
const char *btrfs_super_csum_driver(u16 csum_type);
size_t __attribute_const__ btrfs_get_num_csums(void);


/*
 * The leaf data grows from end-to-front in the node.
 * this returns the address of the start of the last item,
 * which is the stop of the leaf data stack
 */
static inline unsigned int leaf_data_end(const struct extent_buffer *leaf)
{
        u32 nr = btrfs_header_nritems(leaf);

        if (nr == 0)
                return BTRFS_LEAF_DATA_SIZE(leaf->fs_info);
        return btrfs_item_offset(leaf, nr - 1);
}

/* struct btrfs_file_extent_item */
BTRFS_SETGET_STACK_FUNCS(stack_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_ram_bytes,
                         struct btrfs_file_extent_item, ram_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(const 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_type, struct btrfs_file_extent_item, type, 8);
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(
                                                const struct extent_buffer *eb,
                                                int nr)
{
        return btrfs_item_size(eb, nr) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
}

/* 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);

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

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

static inline u32 btrfs_crc32c(u32 crc, const void *address, unsigned length)
{
        return crc32c(crc, address, length);
}

static inline void btrfs_crc32c_final(u32 crc, u8 *result)
{
        put_unaligned_le32(~crc, result);
}

static inline u64 btrfs_name_hash(const char *name, int len)
{
       return crc32c((u32)~1, name, len);
}

/*
 * Figure the key offset of an extended inode ref
 */
static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
                                   int len)
{
       return (u64) crc32c(parent_objectid, name, len);
}

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

/* extent-tree.c */

enum btrfs_inline_ref_type {
        BTRFS_REF_TYPE_INVALID,
        BTRFS_REF_TYPE_BLOCK,
        BTRFS_REF_TYPE_DATA,
        BTRFS_REF_TYPE_ANY,
};

int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
                                     struct btrfs_extent_inline_ref *iref,
                                     enum btrfs_inline_ref_type is_data);
u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset);

/*
 * Take the number of bytes to be checksummmed and figure out how many leaves
 * it would require to store the csums for that many bytes.
 */
static inline u64 btrfs_csum_bytes_to_leaves(
                        const struct btrfs_fs_info *fs_info, u64 csum_bytes)
{
        const u64 num_csums = csum_bytes >> fs_info->sectorsize_bits;

        return DIV_ROUND_UP_ULL(num_csums, fs_info->csums_per_leaf);
}

/*
 * Use this if we would be adding new items, as we could split nodes as we cow
 * down the tree.
 */
static inline u64 btrfs_calc_insert_metadata_size(struct btrfs_fs_info *fs_info,
                                                  unsigned num_items)
{
        return (u64)fs_info->nodesize * BTRFS_MAX_LEVEL * 2 * num_items;
}

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

int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
                              u64 start, u64 num_bytes);
void btrfs_free_excluded_extents(struct btrfs_block_group *cache);
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
                           unsigned long count);
void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
                                  struct btrfs_delayed_ref_root *delayed_refs,
                                  struct btrfs_delayed_ref_head *head);
int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len);
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
                             struct btrfs_fs_info *fs_info, u64 bytenr,
                             u64 offset, int metadata, u64 *refs, u64 *flags);
int btrfs_pin_extent(struct btrfs_trans_handle *trans, u64 bytenr, u64 num,
                     int reserved);
int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
                                    u64 bytenr, u64 num_bytes);
int btrfs_exclude_logged_extents(struct extent_buffer *eb);
int btrfs_cross_ref_exist(struct btrfs_root *root,
                          u64 objectid, u64 offset, u64 bytenr, bool strict,
                          struct btrfs_path *path);
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
                                             struct btrfs_root *root,
                                             u64 parent, u64 root_objectid,
                                             const struct btrfs_disk_key *key,
                                             int level, u64 hint,
                                             u64 empty_size,
                                             enum btrfs_lock_nesting nest);
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                           u64 root_id,
                           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 owner,
                                     u64 offset, u64 ram_bytes,
                                     struct btrfs_key *ins);
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
                                   u64 root_objectid, u64 owner, u64 offset,
                                   struct btrfs_key *ins);
int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, 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 extent_buffer *eb, u64 flags, int level);
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref);

int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
                               u64 start, u64 len, int delalloc);
int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans, u64 start,
                              u64 len);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans);
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
                         struct btrfs_ref *generic_ref);

void btrfs_clear_space_info_full(struct btrfs_fs_info *info);

/*
 * Different levels for to flush space when doing space reservations.
 *
 * The higher the level, the more methods we try to reclaim space.
 */
enum btrfs_reserve_flush_enum {
        /* If we are in the transaction, we can't flush anything.*/
        BTRFS_RESERVE_NO_FLUSH,

        /*
         * Flush space by:
         * - Running delayed inode items
         * - Allocating a new chunk
         */
        BTRFS_RESERVE_FLUSH_LIMIT,

        /*
         * Flush space by:
         * - Running delayed inode items
         * - Running delayed refs
         * - Running delalloc and waiting for ordered extents
         * - Allocating a new chunk
         */
        BTRFS_RESERVE_FLUSH_EVICT,

        /*
         * Flush space by above mentioned methods and by:
         * - Running delayed iputs
         * - Committing transaction
         *
         * Can be interrupted by a fatal signal.
         */
        BTRFS_RESERVE_FLUSH_DATA,
        BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE,
        BTRFS_RESERVE_FLUSH_ALL,

        /*
         * Pretty much the same as FLUSH_ALL, but can also steal space from
         * global rsv.
         *
         * Can be interrupted by a fatal signal.
         */
        BTRFS_RESERVE_FLUSH_ALL_STEAL,
};

enum btrfs_flush_state {
        FLUSH_DELAYED_ITEMS_NR  =       1,
        FLUSH_DELAYED_ITEMS     =       2,
        FLUSH_DELAYED_REFS_NR   =       3,
        FLUSH_DELAYED_REFS      =       4,
        FLUSH_DELALLOC          =       5,
        FLUSH_DELALLOC_WAIT     =       6,
        FLUSH_DELALLOC_FULL     =       7,
        ALLOC_CHUNK             =       8,
        ALLOC_CHUNK_FORCE       =       9,
        RUN_DELAYED_IPUTS       =       10,
        COMMIT_TRANS            =       11,
};

int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
                                     struct btrfs_block_rsv *rsv,
                                     int nitems, bool use_global_rsv);
void btrfs_subvolume_release_metadata(struct btrfs_root *root,
                                      struct btrfs_block_rsv *rsv);
void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes);

int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes,
                                    u64 disk_num_bytes, bool noflush);
u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
                                   u64 start, u64 end);
int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
                         u64 num_bytes, u64 *actual_bytes);
int btrfs_trim_fs(struct btrfs_fs_info *fs_info, 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 btrfs_start_write_no_snapshotting(struct btrfs_root *root);
void btrfs_end_write_no_snapshotting(struct btrfs_root *root);
void btrfs_wait_for_snapshot_creation(struct btrfs_root *root);

/* ctree.c */
int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
                     int *slot);
int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const 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,
                             const struct btrfs_key *new_key);
struct extent_buffer *btrfs_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);
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
                                           int slot);

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,
                    enum btrfs_lock_nesting nest);
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_path *path, u32 data_size);
void btrfs_truncate_item(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,
                     const 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,
                         const 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,
                      const struct btrfs_key *key, struct btrfs_path *p,
                      int ins_len, int cow);
int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
                          struct btrfs_path *p, u64 time_seq);
int btrfs_search_slot_for_read(struct btrfs_root *root,
                               const 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);

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);
}

/*
 * Describes a batch of items to insert in a btree. This is used by
 * btrfs_insert_empty_items().
 */
struct btrfs_item_batch {
        /*
         * Pointer to an array containing the keys of the items to insert (in
         * sorted order).
         */
        const struct btrfs_key *keys;
        /* Pointer to an array containing the data size for each item to insert. */
        const u32 *data_sizes;
        /*
         * The sum of data sizes for all items. The caller can compute this while
         * setting up the data_sizes array, so it ends up being more efficient
         * than having btrfs_insert_empty_items() or setup_item_for_insert()
         * doing it, as it would avoid an extra loop over a potentially large
         * array, and in the case of setup_item_for_insert(), we would be doing
         * it while holding a write lock on a leaf and often on upper level nodes
         * too, unnecessarily increasing the size of a critical section.