start of support for subvolumes

[btrfs-progs-unstable.git] / ctree.h

#ifndef __BTRFS__
#define __BTRFS__

#include "list.h"
#include "kerncompat.h"

struct btrfs_trans_handle;

#define BTRFS_MAGIC "_BtRfS_M"

#define BTRFS_ROOT_TREE_OBJECTID 1ULL
#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
#define BTRFS_INODE_MAP_OBJECTID 3ULL
#define BTRFS_FS_TREE_OBJECTID 4ULL
#define BTRFS_FIRST_FREE_OBJECTID 5ULL

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

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

/*
 * the key defines the order in the tree, and so it also defines (optimal)
 * block layout.  objectid corresonds to the inode number.  The flags
 * tells us things about the object, and is a kind of stream selector.
 * so for a given inode, keys with flags of 1 might refer to the inode
 * data, flags of 2 may point to file data in the btree and flags == 3
 * may point to extents.
 *
 * offset is the starting byte offset for this key in the stream.
 *
 * btrfs_disk_key is in disk byte order.  struct btrfs_key is always
 * in cpu native order.  Otherwise they are identical and their sizes
 * should be the same (ie both packed)
 */
struct btrfs_disk_key {
        __le64 objectid;
        __le64 offset;
        __le32 flags;
} __attribute__ ((__packed__));

struct btrfs_key {
        u64 objectid;
        u64 offset;
        u32 flags;
} __attribute__ ((__packed__));

/*
 * every tree block (leaf or node) starts with this header.
 */
struct btrfs_header {
        u8 csum[BTRFS_CSUM_SIZE];
        u8 fsid[16]; /* FS specific uuid */
        __le64 blocknr; /* which block this node is supposed to live in */
        __le64 generation;
        __le64 parentid; /* objectid of the tree root */
        __le32 ham;
        __le16 nritems;
        __le16 flags;
        u8 level;
} __attribute__ ((__packed__));

#define BTRFS_MAX_LEVEL 8
#define BTRFS_NODEPTRS_PER_BLOCK(r) (((r)->blocksize - \
                                sizeof(struct btrfs_header)) / \
                               (sizeof(struct btrfs_disk_key) + sizeof(u64)))
#define __BTRFS_LEAF_DATA_SIZE(bs) ((bs) - sizeof(struct btrfs_header))
#define BTRFS_LEAF_DATA_SIZE(r) (__BTRFS_LEAF_DATA_SIZE(r->blocksize))

struct btrfs_buffer;
/*
 * the super block basically lists the main trees of the FS
 * it currently lacks any block count etc etc
 */
struct btrfs_super_block {
        u8 csum[BTRFS_CSUM_SIZE];
        /* the first 3 fields must match struct btrfs_header */
        u8 fsid[16];    /* FS specific uuid */
        __le64 blocknr; /* this block number */
        __le64 magic;
        __le32 blocksize;
        __le64 generation;
        __le64 root;
        __le64 total_blocks;
        __le64 blocks_used;
        __le64 root_dir_objectid;
} __attribute__ ((__packed__));

/*
 * 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;
        __le16 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;
} __attribute__ ((__packed__));

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

/*
 * btrfs_paths remember the path taken from the root down to the leaf.
 * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
 * to any other levels that are present.
 *
 * The slots array records the index of the item or block pointer
 * used while walking the tree.
 */
struct btrfs_path {
        struct btrfs_buffer *nodes[BTRFS_MAX_LEVEL];
        int slots[BTRFS_MAX_LEVEL];
};

/*
 * items in the extent btree are used to record the objectid of the
 * owner of the block and the number of references
 */
struct btrfs_extent_item {
        __le32 refs;
        __le64 owner;
} __attribute__ ((__packed__));

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

/*
 * there is no padding here on purpose.  If you want to extent the inode,
 * make a new item type
 */
struct btrfs_inode_item {
        __le64 generation;
        __le64 size;
        __le64 nblocks;
        __le32 nlink;
        __le32 uid;
        __le32 gid;
        __le32 mode;
        __le32 rdev;
        __le16 flags;
        __le16 compat_flags;
        struct btrfs_inode_timespec atime;
        struct btrfs_inode_timespec ctime;
        struct btrfs_inode_timespec mtime;
        struct btrfs_inode_timespec otime;
} __attribute__ ((__packed__));

/* inline data is just a blob of bytes */
struct btrfs_inline_data_item {
        u8 data;
} __attribute__ ((__packed__));

struct btrfs_dir_item {
        struct btrfs_disk_key location;
        __le16 flags;
        __le16 name_len;
        u8 type;
} __attribute__ ((__packed__));

struct btrfs_root_item {
        struct btrfs_inode_item inode;
        __le64 root_dirid;
        __le64 blocknr;
        __le32 flags;
        __le64 block_limit;
        __le64 blocks_used;
        __le32 refs;
} __attribute__ ((__packed__));

struct btrfs_file_extent_item {
        __le64 generation;
        /*
         * disk space consumed by the extent, checksum blocks are included
         * in these numbers
         */
        __le64 disk_blocknr;
        __le64 disk_num_blocks;
        /*
         * the logical offset in file blocks (no csums)
         * this extent record is for.  This allows a file extent to point
         * into the middle of an existing extent on disk, sharing it
         * between two snapshots (useful if some bytes in the middle of the
         * extent have changed
         */
        __le64 offset;
        /*
         * the logical number of file blocks (no csums included)
         */
        __le64 num_blocks;
} __attribute__ ((__packed__));

struct btrfs_csum_item {
        u8 csum[BTRFS_CSUM_SIZE];
} __attribute__ ((__packed__));

struct btrfs_inode_map_item {
        struct btrfs_disk_key key;
} __attribute__ ((__packed__));


struct btrfs_fs_info {
        struct btrfs_root *fs_root;
        struct btrfs_root *extent_root;
        struct btrfs_root *tree_root;
        struct btrfs_root *inode_root;
        struct btrfs_key current_insert;
        struct btrfs_key last_insert;
        struct radix_tree_root cache_radix;
        struct radix_tree_root pinned_radix;
        struct list_head trans;
        struct list_head cache;
        u64 last_inode_alloc;
        u64 last_inode_alloc_dirid;
        u64 generation;
        int cache_size;
        int fp;
        struct btrfs_trans_handle *running_transaction;
        struct btrfs_super_block *disk_super;
};

/*
 * in ram representation of the tree.  extent_root is used for all allocations
 * and for the extent tree extent_root root.  current_insert is used
 * only for the extent tree.
 */
struct btrfs_root {
        struct btrfs_buffer *node;
        struct btrfs_buffer *commit_root;
        struct btrfs_root_item root_item;
        struct btrfs_key root_key;
        struct btrfs_fs_info *fs_info;
        u32 blocksize;
        int ref_cows;
        u32 type;
};

/* the lower bits in the key flags defines the item type */
#define BTRFS_KEY_TYPE_MAX      256
#define BTRFS_KEY_TYPE_MASK     (BTRFS_KEY_TYPE_MAX - 1)

#define BTRFS_KEY_OVERFLOW_MAX 128
#define BTRFS_KEY_OVERFLOW_SHIFT 8
#define BTRFS_KEY_OVERFLOW_MASK (0x7FULL << BTRFS_KEY_OVERFLOW_SHIFT)

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

/*
 * dir items are the name -> inode pointers in a directory.  There is one
 * for every name in a directory.
 */
#define BTRFS_DIR_ITEM_KEY      2
#define BTRFS_DIR_INDEX_KEY     3
/*
 * inline data is file data that fits in the btree.
 */
#define BTRFS_INLINE_DATA_KEY   4
/*
 * extent data is for data that can't fit in the btree.  It points to
 * a (hopefully) huge chunk of disk
 */
#define BTRFS_EXTENT_DATA_KEY   5
/*
 * csum items have the checksums for data in the extents
 */
#define BTRFS_CSUM_ITEM_KEY     6

/*
 * root items point to tree roots.  There are typically in the root
 * tree used by the super block to find all the other trees
 */
#define BTRFS_ROOT_ITEM_KEY     7
/*
 * extent items are in the extent map tree.  These record which blocks
 * are used, and how many references there are to each block
 */
#define BTRFS_EXTENT_ITEM_KEY   8

/*
 * the inode map records which inode numbers are in use and where
 * they actually live on disk
 */
#define BTRFS_INODE_MAP_ITEM_KEY 9
/*
 * string items are for debugging.  They just store a short string of
 * data in the FS
 */
#define BTRFS_STRING_ITEM_KEY   10

static inline u64 btrfs_inode_generation(struct btrfs_inode_item *i)
{
        return le64_to_cpu(i->generation);
}

static inline void btrfs_set_inode_generation(struct btrfs_inode_item *i,
                                              u64 val)
{
        i->generation = cpu_to_le64(val);
}

static inline u64 btrfs_inode_size(struct btrfs_inode_item *i)
{
        return le64_to_cpu(i->size);
}

static inline void btrfs_set_inode_size(struct btrfs_inode_item *i, u64 val)
{
        i->size = cpu_to_le64(val);
}

static inline u64 btrfs_inode_nblocks(struct btrfs_inode_item *i)
{
        return le64_to_cpu(i->nblocks);
}

static inline void btrfs_set_inode_nblocks(struct btrfs_inode_item *i, u64 val)
{
        i->nblocks = cpu_to_le64(val);
}

static inline u32 btrfs_inode_nlink(struct btrfs_inode_item *i)
{
        return le32_to_cpu(i->nlink);
}

static inline void btrfs_set_inode_nlink(struct btrfs_inode_item *i, u32 val)
{
        i->nlink = cpu_to_le32(val);
}

static inline u32 btrfs_inode_uid(struct btrfs_inode_item *i)
{
        return le32_to_cpu(i->uid);
}

static inline void btrfs_set_inode_uid(struct btrfs_inode_item *i, u32 val)
{
        i->uid = cpu_to_le32(val);
}

static inline u32 btrfs_inode_gid(struct btrfs_inode_item *i)
{
        return le32_to_cpu(i->gid);
}

static inline void btrfs_set_inode_gid(struct btrfs_inode_item *i, u32 val)
{
        i->gid = cpu_to_le32(val);
}

static inline u32 btrfs_inode_mode(struct btrfs_inode_item *i)
{
        return le32_to_cpu(i->mode);
}

static inline void btrfs_set_inode_mode(struct btrfs_inode_item *i, u32 val)
{
        i->mode = cpu_to_le32(val);
}

static inline u32 btrfs_inode_rdev(struct btrfs_inode_item *i)
{
        return le32_to_cpu(i->rdev);
}

static inline void btrfs_set_inode_rdev(struct btrfs_inode_item *i, u32 val)
{
        i->rdev = cpu_to_le32(val);
}

static inline u16 btrfs_inode_flags(struct btrfs_inode_item *i)
{
        return le16_to_cpu(i->flags);
}

static inline void btrfs_set_inode_flags(struct btrfs_inode_item *i, u16 val)
{
        i->flags = cpu_to_le16(val);
}

static inline u16 btrfs_inode_compat_flags(struct btrfs_inode_item *i)
{
        return le16_to_cpu(i->compat_flags);
}

static inline void btrfs_set_inode_compat_flags(struct btrfs_inode_item *i,
                                                u16 val)
{
        i->compat_flags = cpu_to_le16(val);
}

static inline u64 btrfs_timespec_sec(struct btrfs_inode_timespec *ts)
{
        return le64_to_cpu(ts->sec);
}

static inline void btrfs_set_timespec_sec(struct btrfs_inode_timespec *ts,
                                          u64 val)
{
        ts->sec = cpu_to_le64(val);
}

static inline u32 btrfs_timespec_nsec(struct btrfs_inode_timespec *ts)
{
        return le32_to_cpu(ts->nsec);
}

static inline void btrfs_set_timespec_nsec(struct btrfs_inode_timespec *ts,
                                          u32 val)
{
        ts->nsec = cpu_to_le32(val);
}

static inline u64 btrfs_extent_owner(struct btrfs_extent_item *ei)
{
        return le64_to_cpu(ei->owner);
}

static inline void btrfs_set_extent_owner(struct btrfs_extent_item *ei, u64 val)
{
        ei->owner = cpu_to_le64(val);
}

static inline u32 btrfs_extent_refs(struct btrfs_extent_item *ei)
{
        return le32_to_cpu(ei->refs);
}

static inline void btrfs_set_extent_refs(struct btrfs_extent_item *ei, u32 val)
{
        ei->refs = cpu_to_le32(val);
}

static inline u64 btrfs_node_blockptr(struct btrfs_node *n, int nr)
{
        return le64_to_cpu(n->ptrs[nr].blockptr);
}

static inline void btrfs_set_node_blockptr(struct btrfs_node *n, int nr,
                                           u64 val)
{
        n->ptrs[nr].blockptr = cpu_to_le64(val);
}

static inline u32 btrfs_item_offset(struct btrfs_item *item)
{
        return le32_to_cpu(item->offset);
}

static inline void btrfs_set_item_offset(struct btrfs_item *item, u32 val)
{
        item->offset = cpu_to_le32(val);
}

static inline u32 btrfs_item_end(struct btrfs_item *item)
{
        return le32_to_cpu(item->offset) + le16_to_cpu(item->size);
}

static inline u16 btrfs_item_size(struct btrfs_item *item)
{
        return le16_to_cpu(item->size);
}

static inline void btrfs_set_item_size(struct btrfs_item *item, u16 val)
{
        item->size = cpu_to_le16(val);
}

static inline u16 btrfs_dir_flags(struct btrfs_dir_item *d)
{
        return le16_to_cpu(d->flags);
}

static inline void btrfs_set_dir_flags(struct btrfs_dir_item *d, u16 val)
{
        d->flags = cpu_to_le16(val);
}

static inline u8 btrfs_dir_type(struct btrfs_dir_item *d)
{
        return d->type;
}

static inline void btrfs_set_dir_type(struct btrfs_dir_item *d, u8 val)
{
        d->type = val;
}

static inline u16 btrfs_dir_name_len(struct btrfs_dir_item *d)
{
        return le16_to_cpu(d->name_len);
}

static inline void btrfs_set_dir_name_len(struct btrfs_dir_item *d, u16 val)
{
        d->name_len = cpu_to_le16(val);
}

static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
                                         struct btrfs_disk_key *disk)
{
        cpu->offset = le64_to_cpu(disk->offset);
        cpu->flags = le32_to_cpu(disk->flags);
        cpu->objectid = le64_to_cpu(disk->objectid);
}

static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
                                         struct btrfs_key *cpu)
{
        disk->offset = cpu_to_le64(cpu->offset);
        disk->flags = cpu_to_le32(cpu->flags);
        disk->objectid = cpu_to_le64(cpu->objectid);
}

static inline u64 btrfs_disk_key_objectid(struct btrfs_disk_key *disk)
{
        return le64_to_cpu(disk->objectid);
}

static inline void btrfs_set_disk_key_objectid(struct btrfs_disk_key *disk,
                                               u64 val)
{
        disk->objectid = cpu_to_le64(val);
}

static inline u64 btrfs_disk_key_offset(struct btrfs_disk_key *disk)
{
        return le64_to_cpu(disk->offset);
}

static inline void btrfs_set_disk_key_offset(struct btrfs_disk_key *disk,
                                             u64 val)
{
        disk->offset = cpu_to_le64(val);
}

static inline u32 btrfs_disk_key_flags(struct btrfs_disk_key *disk)
{
        return le32_to_cpu(disk->flags);
}

static inline void btrfs_set_disk_key_flags(struct btrfs_disk_key *disk,
                                            u32 val)
{
        disk->flags = cpu_to_le32(val);
}

static inline u32 btrfs_key_overflow(struct btrfs_key *key)
{
        u32 over = key->flags & BTRFS_KEY_OVERFLOW_MASK;
        return over >> BTRFS_KEY_OVERFLOW_SHIFT;
}

static inline void btrfs_set_key_overflow(struct btrfs_key *key, u32 over)
{
        BUG_ON(over >= BTRFS_KEY_OVERFLOW_MAX);
        over = over << BTRFS_KEY_OVERFLOW_SHIFT;
        key->flags = (key->flags & ~((u64)BTRFS_KEY_OVERFLOW_MASK)) | over;
}

static inline u32 btrfs_key_type(struct btrfs_key *key)
{
        return key->flags & BTRFS_KEY_TYPE_MASK;
}

static inline u32 btrfs_disk_key_type(struct btrfs_disk_key *key)
{
        return le32_to_cpu(key->flags) & BTRFS_KEY_TYPE_MASK;
}

static inline void btrfs_set_key_type(struct btrfs_key *key, u32 type)
{
        BUG_ON(type >= BTRFS_KEY_TYPE_MAX);
        key->flags = (key->flags & ~((u64)BTRFS_KEY_TYPE_MASK)) | type;
}

static inline void btrfs_set_disk_key_type(struct btrfs_disk_key *key, u32 type)
{
        u32 flags = btrfs_disk_key_flags(key);
        BUG_ON(type >= BTRFS_KEY_TYPE_MAX);
        flags = (flags & ~((u64)BTRFS_KEY_TYPE_MASK)) | type;
        btrfs_set_disk_key_flags(key, flags);
}

static inline u32 btrfs_disk_key_overflow(struct btrfs_disk_key *key)
{
        u32 over = le32_to_cpu(key->flags) & BTRFS_KEY_OVERFLOW_MASK;
        return over >> BTRFS_KEY_OVERFLOW_SHIFT;
}

static inline void btrfs_set_disK_key_overflow(struct btrfs_disk_key *key,
                                               u32 over)
{
        u32 flags = btrfs_disk_key_flags(key);
        BUG_ON(over >= BTRFS_KEY_OVERFLOW_MAX);
        over = over << BTRFS_KEY_OVERFLOW_SHIFT;
        flags = (flags & ~((u64)BTRFS_KEY_OVERFLOW_MASK)) | over;
        btrfs_set_disk_key_flags(key, flags);
}

static inline u64 btrfs_header_blocknr(struct btrfs_header *h)
{
        return le64_to_cpu(h->blocknr);
}

static inline void btrfs_set_header_blocknr(struct btrfs_header *h, u64 blocknr)
{
        h->blocknr = cpu_to_le64(blocknr);
}

static inline u64 btrfs_header_generation(struct btrfs_header *h)
{
        return le64_to_cpu(h->generation);
}

static inline void btrfs_set_header_generation(struct btrfs_header *h,
                                               u64 val)
{
        h->generation = cpu_to_le64(val);
}

static inline u64 btrfs_header_parentid(struct btrfs_header *h)
{
        return le64_to_cpu(h->parentid);
}

static inline void btrfs_set_header_parentid(struct btrfs_header *h,
                                             u64 parentid)
{
        h->parentid = cpu_to_le64(parentid);
}

static inline u16 btrfs_header_nritems(struct btrfs_header *h)
{
        return le16_to_cpu(h->nritems);
}

static inline void btrfs_set_header_nritems(struct btrfs_header *h, u16 val)
{
        h->nritems = cpu_to_le16(val);
}

static inline u16 btrfs_header_flags(struct btrfs_header *h)
{
        return le16_to_cpu(h->flags);
}

static inline void btrfs_set_header_flags(struct btrfs_header *h, u16 val)
{
        h->flags = cpu_to_le16(val);
}

static inline int btrfs_header_level(struct btrfs_header *h)
{
        return h->level;
}

static inline void btrfs_set_header_level(struct btrfs_header *h, int level)
{
        BUG_ON(level > BTRFS_MAX_LEVEL);
        h->level = level;
}

static inline int btrfs_is_leaf(struct btrfs_node *n)
{
        return (btrfs_header_level(&n->header) == 0);
}

static inline u64 btrfs_root_blocknr(struct btrfs_root_item *item)
{
        return le64_to_cpu(item->blocknr);
}

static inline void btrfs_set_root_blocknr(struct btrfs_root_item *item, u64 val)
{
        item->blocknr = cpu_to_le64(val);
}

static inline u64 btrfs_root_dirid(struct btrfs_root_item *item)
{
        return le64_to_cpu(item->root_dirid);
}

static inline void btrfs_set_root_dirid(struct btrfs_root_item *item, u64 val)
{
        item->root_dirid = cpu_to_le64(val);
}

static inline u32 btrfs_root_refs(struct btrfs_root_item *item)
{
        return le32_to_cpu(item->refs);
}

static inline void btrfs_set_root_refs(struct btrfs_root_item *item, u32 val)
{
        item->refs = cpu_to_le32(val);
}

static inline u64 btrfs_super_blocknr(struct btrfs_super_block *s)
{
        return le64_to_cpu(s->blocknr);
}

static inline void btrfs_set_super_blocknr(struct btrfs_super_block *s, u64 val)
{
        s->blocknr = cpu_to_le64(val);
}

static inline u64 btrfs_super_root(struct btrfs_super_block *s)
{
        return le64_to_cpu(s->root);
}

static inline void btrfs_set_super_root(struct btrfs_super_block *s, u64 val)
{
        s->root = cpu_to_le64(val);
}

static inline u64 btrfs_super_total_blocks(struct btrfs_super_block *s)
{
        return le64_to_cpu(s->total_blocks);
}

static inline void btrfs_set_super_total_blocks(struct btrfs_super_block *s,
                                                u64 val)
{
        s->total_blocks = cpu_to_le64(val);
}

static inline u64 btrfs_super_blocks_used(struct btrfs_super_block *s)
{
        return le64_to_cpu(s->blocks_used);
}

static inline void btrfs_set_super_blocks_used(struct btrfs_super_block *s,
                                                u64 val)
{
        s->blocks_used = cpu_to_le64(val);
}

static inline u32 btrfs_super_blocksize(struct btrfs_super_block *s)
{
        return le32_to_cpu(s->blocksize);
}

static inline void btrfs_set_super_blocksize(struct btrfs_super_block *s,
                                                u32 val)
{
        s->blocksize = cpu_to_le32(val);
}

static inline u64 btrfs_super_root_dir(struct btrfs_super_block *s)
{
        return le64_to_cpu(s->root_dir_objectid);
}

static inline void btrfs_set_super_root_dir(struct btrfs_super_block *s, u64
                                            val)
{
        s->root_dir_objectid = cpu_to_le64(val);
}

static inline u8 *btrfs_leaf_data(struct btrfs_leaf *l)
{
        return (u8 *)l->items;
}

static inline u64 btrfs_file_extent_disk_blocknr(struct btrfs_file_extent_item
                                                 *e)
{
        return le64_to_cpu(e->disk_blocknr);
}

static inline void btrfs_set_file_extent_disk_blocknr(struct
                                                      btrfs_file_extent_item
                                                      *e, u64 val)
{
        e->disk_blocknr = cpu_to_le64(val);
}

static inline u64 btrfs_file_extent_generation(struct btrfs_file_extent_item *e)
{
        return le64_to_cpu(e->generation);
}

static inline void btrfs_set_file_extent_generation(struct
                                                    btrfs_file_extent_item *e,
                                                    u64 val)
{
        e->generation = cpu_to_le64(val);
}

static inline u64 btrfs_file_extent_disk_num_blocks(struct
                                                    btrfs_file_extent_item *e)
{
        return le64_to_cpu(e->disk_num_blocks);
}

static inline void btrfs_set_file_extent_disk_num_blocks(struct
                                                         btrfs_file_extent_item
                                                         *e, u64 val)
{
        e->disk_num_blocks = cpu_to_le64(val);
}

static inline u64 btrfs_file_extent_offset(struct btrfs_file_extent_item *e)
{
        return le64_to_cpu(e->offset);
}

static inline void btrfs_set_file_extent_offset(struct btrfs_file_extent_item
                                                *e, u64 val)
{
        e->offset = cpu_to_le64(val);
}

static inline u64 btrfs_file_extent_num_blocks(struct btrfs_file_extent_item
                                               *e)
{
        return le64_to_cpu(e->num_blocks);
}

static inline void btrfs_set_file_extent_num_blocks(struct
                                                    btrfs_file_extent_item *e,
                                                    u64 val)
{
        e->num_blocks = cpu_to_le64(val);
}

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

struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                                            struct btrfs_root *root);
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                  struct btrfs_buffer *buf);
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, u64 blocknr, u64 num_blocks, int pin);
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, struct btrfs_path *p, int
                      ins_len, int cow);
void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
void btrfs_init_path(struct btrfs_path *p);
int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct btrfs_path *path);
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, void *data, u32 data_size);
int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
                            *root, struct btrfs_path *path, struct btrfs_key
                            *cpu_key, u32 data_size);
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf);
int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
                        *root, struct btrfs_buffer *snap);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
                               btrfs_root *root);
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct btrfs_key *key);
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, struct btrfs_root_item
                      *item);
int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, struct btrfs_key *key, struct btrfs_root_item
                      *item);
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
                         btrfs_root_item *item, struct btrfs_key *key);
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
                          *root, char *name, int name_len, u64 dir,
                          struct btrfs_key *location, u8 type);
int btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
                          *root, struct btrfs_path *path, u64 dir, char *name,
                          int name_len, int mod);
int btrfs_match_dir_item_name(struct btrfs_root *root, struct btrfs_path *path,
                              char *name, int name_len);
int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
                             struct btrfs_root *fs_root,
                             u64 dirid, u64 *objectid);
int btrfs_insert_inode_map(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root,
                           u64 objectid, struct btrfs_key *location);
int btrfs_lookup_inode_map(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root, struct btrfs_path *path,
                           u64 objectid, int mod);
int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, u64 objectid, struct btrfs_inode_item
                       *inode_item);
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_path *path, u64 objectid, int mod);
#endif