linux/fs/btrfs/ctree.h

#ifndef __BTRFS__
#define __BTRFS__

#include <linux/fs.h>
#include <linux/buffer_head.h>
#include "bit-radix.h"

struct btrfs_trans_handle;
struct btrfs_transaction;
extern struct kmem_cache *btrfs_path_cachep;

#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 buffer_head;
/*
 * 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 buffer_head *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 {
	__le64 objectid;
	__le16 flags;
	__le16 name_len;
	u8 type;
} __attribute__ ((__packed__));

struct btrfs_root_item {
	__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 crypto_hash;
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 pending_del_radix;
	struct radix_tree_root pinned_radix;
	u64 last_inode_alloc;
	u64 generation;
	struct btrfs_transaction *running_transaction;
	struct btrfs_super_block *disk_super;
	struct buffer_head *sb_buffer;
	struct super_block *sb;
	struct inode *btree_inode;
	struct mutex trans_mutex;
	struct mutex fs_mutex;
	struct crypto_hash *hash_tfm;
	spinlock_t hash_lock;
};

/*
 * 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 buffer_head *node;
	struct buffer_head *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)

/*
 * 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 u64 btrfs_dir_objectid(struct btrfs_dir_item *d)
{
	return le64_to_cpu(d->objectid);
}

static inline void btrfs_set_dir_objectid(struct btrfs_dir_item *d, u64 val)
{
	d->objectid = cpu_to_le64(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_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 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 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);
}

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

static inline void btrfs_check_bounds(void *vptr, size_t len,
				     void *vcontainer, size_t container_len)
{
	char *ptr = vptr;
	char *container = vcontainer;
	WARN_ON(ptr < container);
	WARN_ON(ptr + len > container + container_len);
}

static inline void btrfs_memcpy(struct btrfs_root *root,
				void *dst_block,
				void *dst, const void *src, size_t nr)
{
	btrfs_check_bounds(dst, nr, dst_block, root->fs_info->sb->s_blocksize);
	memcpy(dst, src, nr);
}

static inline void btrfs_memmove(struct btrfs_root *root,
				void *dst_block,
				void *dst, void *src, size_t nr)
{
	btrfs_check_bounds(dst, nr, dst_block, root->fs_info->sb->s_blocksize);
	memmove(dst, src, nr);
}

static inline void btrfs_mark_buffer_dirty(struct buffer_head *bh)
{
	WARN_ON(!atomic_read(&bh->b_count));
	mark_buffer_dirty(bh);
}

/* 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))))

/* extent-item.c */
struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
					    struct btrfs_root *root);
int btrfs_alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
			*root, u64 num_blocks, u64 search_start, u64
			search_end, u64 owner, struct btrfs_key *ins);
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		  struct buffer_head *buf);
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, u64 blocknr, u64 num_blocks, int pin);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
			       btrfs_root *root);
/* ctree.c */
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);
struct btrfs_path *btrfs_alloc_path(void);
void btrfs_free_path(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 buffer_head *snap);
/* root-item.c */
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);
/* dir-item.c */
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
			  *root, const char *name, int name_len, u64 dir, u64
			  objectid, u8 type);
int btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
			  *root, struct btrfs_path *path, u64 dir,
			  const char *name, int name_len, int mod);
int btrfs_match_dir_item_name(struct btrfs_root *root, struct btrfs_path *path,
			      const char *name, int name_len);
/* inode-map.c */
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);
/* inode-item.c */
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);

/* file-item.c */
int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root,
			       u64 objectid, u64 offset,
			       u64 num_blocks, u64 hint_block,
			       u64 *result);
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root,
			     struct btrfs_path *path, u64 objectid,
			     u64 blocknr, int mod);
int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root,
			  u64 objectid, u64 offset,
			  char *data, size_t len);
int btrfs_csum_verify_file_block(struct btrfs_root *root,
				 u64 objectid, u64 offset,
				 char *data, size_t len);
#endif