text: /*
   * Copyright (C) 2007 Oracle.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License v2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   */
  
  #ifndef __BTRFS_CTREE__
  #define __BTRFS_CTREE__
  
  #include <linux/mm.h>
  #include <linux/highmem.h>
  #include <linux/fs.h>
  #include <linux/rwsem.h>
  #include <linux/semaphore.h>
  #include <linux/completion.h>
  #include <linux/backing-dev.h>
  #include <linux/wait.h>
  #include <linux/slab.h>
  #include <linux/kobject.h>
  #include <trace/events/btrfs.h>
  #include <asm/kmap_types.h>
  #include <linux/pagemap.h>
  #include <linux/btrfs.h>
  #include <linux/workqueue.h>
  #include <linux/security.h>
  #include "extent_io.h"
  #include "extent_map.h"
  #include "async-thread.h"
  
  struct btrfs_trans_handle;
  struct btrfs_transaction;
  struct btrfs_pending_snapshot;
  extern struct kmem_cache *btrfs_trans_handle_cachep;
  extern struct kmem_cache *btrfs_transaction_cachep;
  extern struct kmem_cache *btrfs_bit_radix_cachep;
  extern struct kmem_cache *btrfs_path_cachep;
  extern struct kmem_cache *btrfs_free_space_cachep;
  struct btrfs_ordered_sum;
  
  #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
  #define STATIC noinline
  #else
  #define STATIC static noinline
  #endif
  
  #define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */
  
  #define BTRFS_MAX_MIRRORS 3
  
  #define BTRFS_MAX_LEVEL 8
  
  #define BTRFS_COMPAT_EXTENT_TREE_V0
  
  /* holds pointers to all of the tree roots */
  #define BTRFS_ROOT_TREE_OBJECTID 1ULL
  
  /* stores information about which extents are in use, and reference counts */
  #define BTRFS_EXTENT_TREE_OBJECTID 2ULL
  
  /*
   * chunk tree stores translations from logical -> physical block numbering
   * the super block points to the chunk tree
   */
  #define BTRFS_CHUNK_TREE_OBJECTID 3ULL
  
  /*
   * stores information about which areas of a given device are in use.
   * one per device.  The tree of tree roots points to the device tree
   */
  #define BTRFS_DEV_TREE_OBJECTID 4ULL
  
  /* one per subvolume, storing files and directories */
  #define BTRFS_FS_TREE_OBJECTID 5ULL
  
  /* directory objectid inside the root tree */
  #define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL
  
  /* holds checksums of all the data extents */
  #define BTRFS_CSUM_TREE_OBJECTID 7ULL
  
  /* holds quota configuration and tracking */
  #define BTRFS_QUOTA_TREE_OBJECTID 8ULL
  
  /* for storing items that use the BTRFS_UUID_KEY* types */
  #define BTRFS_UUID_TREE_OBJECTID 9ULL
  
  /* for storing balance parameters in the root tree */
  #define BTRFS_BALANCE_OBJECTID -4ULL
  
  /* orhpan objectid for tracking unlinked/truncated files */
  #define BTRFS_ORPHAN_OBJECTID -5ULL
  
  /* does write ahead logging to speed up fsyncs */
  #define BTRFS_TREE_LOG_OBJECTID -6ULL
  #define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL
  
  /* for space balancing */
  #define BTRFS_TREE_RELOC_OBJECTID -8ULL
  #define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL
  
  /*
   * extent checksums all have this objectid
   * this allows them to share the logging tree
   * for fsyncs
   */
  #define BTRFS_EXTENT_CSUM_OBJECTID -10ULL
  
  /* For storing free space cache */
  #define BTRFS_FREE_SPACE_OBJECTID -11ULL
  
  /*
   * The inode number assigned to the special inode for storing
   * free ino cache
   */
  #define BTRFS_FREE_INO_OBJECTID -12ULL
  
  /* dummy objectid represents multiple objectids */
  #define BTRFS_MULTIPLE_OBJECTIDS -255ULL
  
  /*
   * All files have objectids in this range.
   */
  #define BTRFS_FIRST_FREE_OBJECTID 256ULL
  #define BTRFS_LAST_FREE_OBJECTID -256ULL
  #define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL
  
  
  /*
   * the device items go into the chunk tree.  The key is in the form
   * [ 1 BTRFS_DEV_ITEM_KEY device_id ]
   */
  #define BTRFS_DEV_ITEMS_OBJECTID 1ULL
  
  #define BTRFS_BTREE_INODE_OBJECTID 1
  
  #define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2
  
  #define BTRFS_DEV_REPLACE_DEVID 0ULL
  
  /*
   * the max metadata block size.  This limit is somewhat artificial,
   * but the memmove costs go through the roof for larger blocks.
   */
  #define BTRFS_MAX_METADATA_BLOCKSIZE 65536
  
  /*
   * we can actually store much bigger names, but lets not confuse the rest
   * of linux
   */
  #define BTRFS_NAME_LEN 255
  
  /*
   * Theoretical limit is larger, but we keep this down to a sane
   * value. That should limit greatly the possibility of collisions on
   * inode ref items.
   */
  #define BTRFS_LINK_MAX 65535U
  
  /* 32 bytes in various csum fields */
  #define BTRFS_CSUM_SIZE 32
  
  /* csum types */
  #define BTRFS_CSUM_TYPE_CRC32	0
  
  static int btrfs_csum_sizes[] = { 4 };
  
  /* four bytes for CRC32 */
  #define BTRFS_EMPTY_DIR_SIZE 0
  
  /* spefic to btrfs_map_block(), therefore not in include/linux/blk_types.h */
  #define REQ_GET_READ_MIRRORS	(1 << 30)
  
  #define BTRFS_FT_UNKNOWN	0
  #define BTRFS_FT_REG_FILE	1
  #define BTRFS_FT_DIR		2
  #define BTRFS_FT_CHRDEV		3
  #define BTRFS_FT_BLKDEV		4
  #define BTRFS_FT_FIFO		5
  #define BTRFS_FT_SOCK		6
  #define BTRFS_FT_SYMLINK	7
  #define BTRFS_FT_XATTR		8
  #define BTRFS_FT_MAX		9
  
  /* ioprio of readahead is set to idle */
  #define BTRFS_IOPRIO_READA (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0))
  
  #define BTRFS_DIRTY_METADATA_THRESH	(32 * 1024 * 1024)
  
  #define BTRFS_MAX_EXTENT_SIZE (128 * 1024 * 1024)
  
  /*
   * The key defines the order in the tree, and so it also defines (optimal)
   * block layout.
   *
   * objectid corresponds to the inode number.
   *
   * type tells us things about the object, and is a kind of stream selector.
   * so for a given inode, keys with type of 1 might refer to the inode data,
   * type of 2 may point to file data in the btree and type == 3 may point to
   * extents.
   *
   * offset is the starting byte offset for this key in the stream.
   *
   * btrfs_disk_key is in disk byte order.  struct btrfs_key is always
   * in cpu native order.  Otherwise they are identical and their sizes
   * should be the same (ie both packed)
   */
  struct btrfs_disk_key {
  	__le64 objectid;
  	u8 type;
  	__le64 offset;
  } __attribute__ ((__packed__));
  
  struct btrfs_key {
  	u64 objectid;
  	u8 type;
  	u64 offset;
  } __attribute__ ((__packed__));
  
  struct btrfs_mapping_tree {
  	struct extent_map_tree map_tree;
  };
  
  struct btrfs_dev_item {
  	/* the internal btrfs device id */
  	__le64 devid;
  
  	/* size of the device */
  	__le64 total_bytes;
  
  	/* bytes used */
  	__le64 bytes_used;
  
  	/* optimal io alignment for this device */
  	__le32 io_align;
  
  	/* optimal io width for this device */
  	__le32 io_width;
  
  	/* minimal io size for this device */
  	__le32 sector_size;
  
  	/* type and info about this device */
  	__le64 type;
  
  	/* expected generation for this device */
  	__le64 generation;
  
  	/*
  	 * starting byte of this partition on the device,
  	 * to allow for stripe alignment in the future
  	 */
  	__le64 start_offset;
  
  	/* grouping information for allocation decisions */
  	__le32 dev_group;
  
  	/* seek speed 0-100 where 100 is fastest */
  	u8 seek_speed;
  
  	/* bandwidth 0-100 where 100 is fastest */
  	u8 bandwidth;
  
  	/* btrfs generated uuid for this device */
  	u8 uuid[BTRFS_UUID_SIZE];
  
  	/* uuid of FS who owns this device */
  	u8 fsid[BTRFS_UUID_SIZE];
  } __attribute__ ((__packed__));
  
  struct btrfs_stripe {
  	__le64 devid;
  	__le64 offset;
  	u8 dev_uuid[BTRFS_UUID_SIZE];
  } __attribute__ ((__packed__));
  
  struct btrfs_chunk {
  	/* size of this chunk in bytes */
  	__le64 length;
  
  	/* objectid of the root referencing this chunk */
  	__le64 owner;
  
  	__le64 stripe_len;
  	__le64 type;
  
  	/* optimal io alignment for this chunk */
  	__le32 io_align;
  
  	/* optimal io width for this chunk */
  	__le32 io_width;
  
  	/* minimal io size for this chunk */
  	__le32 sector_size;
  
  	/* 2^16 stripes is quite a lot, a second limit is the size of a single
  	 * item in the btree
  	 */
  	__le16 num_stripes;
  
  	/* sub stripes only matter for raid10 */
  	__le16 sub_stripes;
  	struct btrfs_stripe stripe;
  	/* additional stripes go here */
  } __attribute__ ((__packed__));
  
  #define BTRFS_FREE_SPACE_EXTENT	1
  #define BTRFS_FREE_SPACE_BITMAP	2
  
  struct btrfs_free_space_entry {
  	__le64 offset;
  	__le64 bytes;
  	u8 type;
  } __attribute__ ((__packed__));
  
  struct btrfs_free_space_header {
  	struct btrfs_disk_key location;
  	__le64 generation;
  	__le64 num_entries;
  	__le64 num_bitmaps;
  } __attribute__ ((__packed__));
  
  static inline unsigned long btrfs_chunk_item_size(int num_stripes)
  {
  	BUG_ON(num_stripes == 0);
  	return sizeof(struct btrfs_chunk) +
  		sizeof(struct btrfs_stripe) * (num_stripes - 1);
  }
  
  #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)
  #define BTRFS_HEADER_FLAG_RELOC		(1ULL << 1)
  
  /*
   * File system states
   */
  #define BTRFS_FS_STATE_ERROR		0
  #define BTRFS_FS_STATE_REMOUNTING	1
  #define BTRFS_FS_STATE_TRANS_ABORTED	2
  #define BTRFS_FS_STATE_DEV_REPLACING	3
  
  /* Super block flags */
  /* Errors detected */
  #define BTRFS_SUPER_FLAG_ERROR		(1ULL << 2)
  
  #define BTRFS_SUPER_FLAG_SEEDING	(1ULL << 32)
  #define BTRFS_SUPER_FLAG_METADUMP	(1ULL << 33)
  
  #define BTRFS_BACKREF_REV_MAX		256
  #define BTRFS_BACKREF_REV_SHIFT		56
  #define BTRFS_BACKREF_REV_MASK		(((u64)BTRFS_BACKREF_REV_MAX - 1) << \
  					 BTRFS_BACKREF_REV_SHIFT)
  
  #define BTRFS_OLD_BACKREF_REV		0
  #define BTRFS_MIXED_BACKREF_REV		1
  
  /*
   * every tree block (leaf or node) starts with this header.
   */
  struct btrfs_header {
  	/* these first four must match the super block */
  	u8 csum[BTRFS_CSUM_SIZE];
  	u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
  	__le64 bytenr; /* which block this node is supposed to live in */
  	__le64 flags;
  
  	/* allowed to be different from the super from here on down */
  	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
  	__le64 generation;
  	__le64 owner;
  	__le32 nritems;
  	u8 level;
  } __attribute__ ((__packed__));
  
  #define BTRFS_NODEPTRS_PER_BLOCK(r) (((r)->nodesize - \
  				      sizeof(struct btrfs_header)) / \
  				     sizeof(struct btrfs_key_ptr))
  #define __BTRFS_LEAF_DATA_SIZE(bs) ((bs) - sizeof(struct btrfs_header))
  #define BTRFS_LEAF_DATA_SIZE(r) (__BTRFS_LEAF_DATA_SIZE(r->nodesize))
  #define BTRFS_FILE_EXTENT_INLINE_DATA_START		\
  		(offsetof(struct btrfs_file_extent_item, disk_bytenr))
  #define BTRFS_MAX_INLINE_DATA_SIZE(r) (BTRFS_LEAF_DATA_SIZE(r) - \
  					sizeof(struct btrfs_item) - \
  					BTRFS_FILE_EXTENT_INLINE_DATA_START)
  #define BTRFS_MAX_XATTR_SIZE(r)	(BTRFS_LEAF_DATA_SIZE(r) - \
  				 sizeof(struct btrfs_item) -\
  				 sizeof(struct btrfs_dir_item))
  
  
  /*
   * this is a very generous portion of the super block, giving us
   * room to translate 14 chunks with 3 stripes each.
   */
  #define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
  #define BTRFS_LABEL_SIZE 256
  
  /*
   * just in case we somehow lose the roots and are not able to mount,
   * we store an array of the roots from previous transactions
   * in the super.
   */
  #define BTRFS_NUM_BACKUP_ROOTS 4
  struct btrfs_root_backup {
  	__le64 tree_root;
  	__le64 tree_root_gen;
  
  	__le64 chunk_root;
  	__le64 chunk_root_gen;
  
  	__le64 extent_root;
  	__le64 extent_root_gen;
  
  	__le64 fs_root;
  	__le64 fs_root_gen;
  
  	__le64 dev_root;
  	__le64 dev_root_gen;
  
  	__le64 csum_root;
  	__le64 csum_root_gen;
  
  	__le64 total_bytes;
  	__le64 bytes_used;
  	__le64 num_devices;
  	/* future */
  	__le64 unused_64[4];
  
  	u8 tree_root_level;
  	u8 chunk_root_level;
  	u8 extent_root_level;
  	u8 fs_root_level;
  	u8 dev_root_level;
  	u8 csum_root_level;
  	/* future and to align */
  	u8 unused_8[10];
  } __attribute__ ((__packed__));
  
  /*
   * the super block basically lists the main trees of the FS
   * it currently lacks any block count etc etc
   */
  struct btrfs_super_block {
  	u8 csum[BTRFS_CSUM_SIZE];
  	/* the first 4 fields must match struct btrfs_header */
  	u8 fsid[BTRFS_FSID_SIZE];    /* FS specific uuid */
  	__le64 bytenr; /* this block number */
  	__le64 flags;
  
  	/* allowed to be different from the btrfs_header from here own down */
  	__le64 magic;
  	__le64 generation;
  	__le64 root;
  	__le64 chunk_root;
  	__le64 log_root;
  
  	/* this will help find the new super based on the log root */
  	__le64 log_root_transid;
  	__le64 total_bytes;
  	__le64 bytes_used;
  	__le64 root_dir_objectid;
  	__le64 num_devices;
  	__le32 sectorsize;
  	__le32 nodesize;
  	__le32 __unused_leafsize;
  	__le32 stripesize;
  	__le32 sys_chunk_array_size;
  	__le64 chunk_root_generation;
  	__le64 compat_flags;
  	__le64 compat_ro_flags;
  	__le64 incompat_flags;
  	__le16 csum_type;
  	u8 root_level;
  	u8 chunk_root_level;
  	u8 log_root_level;
  	struct btrfs_dev_item dev_item;
  
  	char label[BTRFS_LABEL_SIZE];
  
  	__le64 cache_generation;
  	__le64 uuid_tree_generation;
  
  	/* future expansion */
  	__le64 reserved[30];
  	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
  	struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
  } __attribute__ ((__packed__));
  
  /*
   * Compat flags that we support.  If any incompat flags are set other than the
   * ones specified below then we will fail to mount
   */
  #define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF	(1ULL << 0)
  #define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL	(1ULL << 1)
  #define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS	(1ULL << 2)
  #define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO	(1ULL << 3)
  /*
   * some patches floated around with a second compression method
   * lets save that incompat here for when they do get in
   * Note we don't actually support it, we're just reserving the
   * number
   */
  #define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZOv2	(1ULL << 4)
  
  /*
   * older kernels tried to do bigger metadata blocks, but the
   * code was pretty buggy.  Lets not let them try anymore.
   */
  #define BTRFS_FEATURE_INCOMPAT_BIG_METADATA	(1ULL << 5)
  
  #define BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF	(1ULL << 6)
  #define BTRFS_FEATURE_INCOMPAT_RAID56		(1ULL << 7)
  #define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA	(1ULL << 8)
  #define BTRFS_FEATURE_INCOMPAT_NO_HOLES		(1ULL << 9)
  
  #define BTRFS_FEATURE_COMPAT_SUPP		0ULL
  #define BTRFS_FEATURE_COMPAT_SAFE_SET		0ULL
  #define BTRFS_FEATURE_COMPAT_SAFE_CLEAR		0ULL
  #define BTRFS_FEATURE_COMPAT_RO_SUPP		0ULL
  #define BTRFS_FEATURE_COMPAT_RO_SAFE_SET	0ULL
  #define BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR	0ULL
  
  #define BTRFS_FEATURE_INCOMPAT_SUPP			\
  	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
  	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
  	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
  	 BTRFS_FEATURE_INCOMPAT_BIG_METADATA |		\
  	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |		\
  	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
  	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
  	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
  	 BTRFS_FEATURE_INCOMPAT_NO_HOLES)
  
  #define BTRFS_FEATURE_INCOMPAT_SAFE_SET			\
  	(BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
  #define BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR		0ULL
  
  /*
   * A leaf is full of items. offset and size tell us where to find
   * the item in the leaf (relative to the start of the data area)
   */
  struct btrfs_item {
  	struct btrfs_disk_key key;
  	__le32 offset;
  	__le32 size;
  } __attribute__ ((__packed__));
  
  /*
   * leaves have an item area and a data area:
   * [item0, item1....itemN] [free space] [dataN...data1, data0]
   *
   * The data is separate from the items to get the keys closer together
   * during searches.
   */
  struct btrfs_leaf {
  	struct btrfs_header header;
  	struct btrfs_item items[];
  } __attribute__ ((__packed__));
  
  /*
   * all non-leaf blocks are nodes, they hold only keys and pointers to
   * other blocks
   */
  struct btrfs_key_ptr {
  	struct btrfs_disk_key key;
  	__le64 blockptr;
  	__le64 generation;
  } __attribute__ ((__packed__));
  
  struct btrfs_node {
  	struct btrfs_header header;
  	struct btrfs_key_ptr ptrs[];
  } __attribute__ ((__packed__));
  
  /*
   * btrfs_paths remember the path taken from the root down to the leaf.
   * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
   * to any other levels that are present.
   *
   * The slots array records the index of the item or block pointer
   * used while walking the tree.
   */
  struct btrfs_path {
  	struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
  	int slots[BTRFS_MAX_LEVEL];
  	/* if there is real range locking, this locks field will change */
  	int locks[BTRFS_MAX_LEVEL];
  	int reada;
  	/* keep some upper locks as we walk down */
  	int lowest_level;
  
  	/*
  	 * set by btrfs_split_item, tells search_slot to keep all locks
  	 * and to force calls to keep space in the nodes
  	 */
  	unsigned int search_for_split:1;
  	unsigned int keep_locks:1;
  	unsigned int skip_locking:1;
  	unsigned int leave_spinning:1;
  	unsigned int search_commit_root:1;
  	unsigned int need_commit_sem:1;
  	unsigned int skip_release_on_error:1;
  };
  
  /*
   * items in the extent btree are used to record the objectid of the
   * owner of the block and the number of references
   */
  
  struct btrfs_extent_item {
  	__le64 refs;
  	__le64 generation;
  	__le64 flags;
  } __attribute__ ((__packed__));
  
  struct btrfs_extent_item_v0 {
  	__le32 refs;
  } __attribute__ ((__packed__));
  
  #define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r) >> 4) - \
  					sizeof(struct btrfs_item))
  
  #define BTRFS_EXTENT_FLAG_DATA		(1ULL << 0)
  #define BTRFS_EXTENT_FLAG_TREE_BLOCK	(1ULL << 1)
  
  /* following flags only apply to tree blocks */
  
  /* use full backrefs for extent pointers in the block */
  #define BTRFS_BLOCK_FLAG_FULL_BACKREF	(1ULL << 8)
  
  /*
   * this flag is only used internally by scrub and may be changed at any time
   * it is only declared here to avoid collisions
   */
  #define BTRFS_EXTENT_FLAG_SUPER		(1ULL << 48)
  
  struct btrfs_tree_block_info {
  	struct btrfs_disk_key key;
  	u8 level;
  } __attribute__ ((__packed__));
  
  struct btrfs_extent_data_ref {
  	__le64 root;
  	__le64 objectid;
  	__le64 offset;
  	__le32 count;
  } __attribute__ ((__packed__));
  
  struct btrfs_shared_data_ref {
  	__le32 count;
  } __attribute__ ((__packed__));
  
  struct btrfs_extent_inline_ref {
  	u8 type;
  	__le64 offset;
  } __attribute__ ((__packed__));
  
  /* old style backrefs item */
  struct btrfs_extent_ref_v0 {
  	__le64 root;
  	__le64 generation;
  	__le64 objectid;
  	__le32 count;
  } __attribute__ ((__packed__));
  
  
  /* dev extents record free space on individual devices.  The owner
   * field points back to the chunk allocation mapping tree that allocated
   * the extent.  The chunk tree uuid field is a way to double check the owner
   */
  struct btrfs_dev_extent {
  	__le64 chunk_tree;
  	__le64 chunk_objectid;
  	__le64 chunk_offset;
  	__le64 length;
  	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
  } __attribute__ ((__packed__));
  
  struct btrfs_inode_ref {
  	__le64 index;
  	__le16 name_len;
  	/* name goes here */
  } __attribute__ ((__packed__));
  
  struct btrfs_inode_extref {
  	__le64 parent_objectid;
  	__le64 index;
  	__le16 name_len;
  	__u8   name[0];
  	/* name goes here */
  } __attribute__ ((__packed__));
  
  struct btrfs_timespec {
  	__le64 sec;
  	__le32 nsec;
  } __attribute__ ((__packed__));
  
  enum btrfs_compression_type {
  	BTRFS_COMPRESS_NONE  = 0,
  	BTRFS_COMPRESS_ZLIB  = 1,
  	BTRFS_COMPRESS_LZO   = 2,
  	BTRFS_COMPRESS_TYPES = 2,
  	BTRFS_COMPRESS_LAST  = 3,
  };
  
  struct btrfs_inode_item {
  	/* nfs style generation number */
  	__le64 generation;
  	/* transid that last touched this inode */
  	__le64 transid;
  	__le64 size;
  	__le64 nbytes;
  	__le64 block_group;
  	__le32 nlink;
  	__le32 uid;
  	__le32 gid;
  	__le32 mode;
  	__le64 rdev;
  	__le64 flags;
  
  	/* modification sequence number for NFS */
  	__le64 sequence;
  
  	/*
  	 * a little future expansion, for more than this we can
  	 * just grow the inode item and version it
  	 */
  	__le64 reserved[4];
  	struct btrfs_timespec atime;
  	struct btrfs_timespec ctime;
  	struct btrfs_timespec mtime;
  	struct btrfs_timespec otime;
  } __attribute__ ((__packed__));
  
  struct btrfs_dir_log_item {
  	__le64 end;
  } __attribute__ ((__packed__));
  
  struct btrfs_dir_item {
  	struct btrfs_disk_key location;
  	__le64 transid;
  	__le16 data_len;
  	__le16 name_len;
  	u8 type;
  } __attribute__ ((__packed__));
  
  #define BTRFS_ROOT_SUBVOL_RDONLY	(1ULL << 0)
  
  /*
   * Internal in-memory flag that a subvolume has been marked for deletion but
   * still visible as a directory
   */
  #define BTRFS_ROOT_SUBVOL_DEAD		(1ULL << 48)
  
  struct btrfs_root_item {
  	struct btrfs_inode_item inode;
  	__le64 generation;
  	__le64 root_dirid;
  	__le64 bytenr;
  	__le64 byte_limit;
  	__le64 bytes_used;
  	__le64 last_snapshot;
  	__le64 flags;
  	__le32 refs;
  	struct btrfs_disk_key drop_progress;
  	u8 drop_level;
  	u8 level;
  
  	/*
  	 * The following fields appear after subvol_uuids+subvol_times
  	 * were introduced.
  	 */
  
  	/*
  	 * This generation number is used to test if the new fields are valid
  	 * and up to date while reading the root item. Everytime the root item
  	 * is written out, the "generation" field is copied into this field. If
  	 * anyone ever mounted the fs with an older kernel, we will have
  	 * mismatching generation values here and thus must invalidate the
  	 * new fields. See btrfs_update_root and btrfs_find_last_root for
  	 * details.
  	 * the offset of generation_v2 is also used as the start for the memset
  	 * when invalidating the fields.
  	 */
  	__le64 generation_v2;
  	u8 uuid[BTRFS_UUID_SIZE];
  	u8 parent_uuid[BTRFS_UUID_SIZE];
  	u8 received_uuid[BTRFS_UUID_SIZE];
  	__le64 ctransid; /* updated when an inode changes */
  	__le64 otransid; /* trans when created */
  	__le64 stransid; /* trans when sent. non-zero for received subvol */
  	__le64 rtransid; /* trans when received. non-zero for received subvol */
  	struct btrfs_timespec ctime;
  	struct btrfs_timespec otime;
  	struct btrfs_timespec stime;
  	struct btrfs_timespec rtime;
  	__le64 reserved[8]; /* for future */
  } __attribute__ ((__packed__));
  
  /*
   * this is used for both forward and backward root refs
   */
  struct btrfs_root_ref {
  	__le64 dirid;
  	__le64 sequence;
  	__le16 name_len;
  } __attribute__ ((__packed__));
  
  struct btrfs_disk_balance_args {
  	/*
  	 * profiles to operate on, single is denoted by
  	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
  	 */
  	__le64 profiles;
  
  	/*
  	 * usage filter
  	 * BTRFS_BALANCE_ARGS_USAGE with a single value means '0..N'
  	 * BTRFS_BALANCE_ARGS_USAGE_RANGE - range syntax, min..max
  	 */
  	union {
  		__le64 usage;
  		struct {
  			__le32 usage_min;
  			__le32 usage_max;
  		};
  	};
  
  	/* devid filter */
  	__le64 devid;
  
  	/* devid subset filter [pstart..pend) */
  	__le64 pstart;
  	__le64 pend;
  
  	/* btrfs virtual address space subset filter [vstart..vend) */
  	__le64 vstart;
  	__le64 vend;
  
  	/*
  	 * profile to convert to, single is denoted by
  	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
  	 */
  	__le64 target;
  
  	/* BTRFS_BALANCE_ARGS_* */
  	__le64 flags;
  
  	/*
  	 * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'
  	 * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum
  	 * and maximum
  	 */
  	union {
  		__le64 limit;
  		struct {
  			__le32 limit_min;
  			__le32 limit_max;
  		};
  	};
  
  	/*
  	 * Process chunks that cross stripes_min..stripes_max devices,
  	 * BTRFS_BALANCE_ARGS_STRIPES_RANGE
  	 */
  	__le32 stripes_min;
  	__le32 stripes_max;
  
  	__le64 unused[6];
  } __attribute__ ((__packed__));
  
  /*
   * store balance parameters to disk so that balance can be properly
   * resumed after crash or unmount
   */
  struct btrfs_balance_item {
  	/* BTRFS_BALANCE_* */
  	__le64 flags;
  
  	struct btrfs_disk_balance_args data;
  	struct btrfs_disk_balance_args meta;
  	struct btrfs_disk_balance_args sys;
  
  	__le64 unused[4];
  } __attribute__ ((__packed__));
  
  #define BTRFS_FILE_EXTENT_INLINE 0
  #define BTRFS_FILE_EXTENT_REG 1
  #define BTRFS_FILE_EXTENT_PREALLOC 2
  
  struct btrfs_file_extent_item {
  	/*
  	 * transaction id that created this extent
  	 */
  	__le64 generation;
  	/*
  	 * max number of bytes to hold this extent in ram
  	 * when we split a compressed extent we can't know how big
  	 * each of the resulting pieces will be.  So, this is
  	 * an upper limit on the size of the extent in ram instead of
  	 * an exact limit.
  	 */
  	__le64 ram_bytes;
  
  	/*
  	 * 32 bits for the various ways we might encode the data,
  	 * including compression and encryption.  If any of these
  	 * are set to something a given disk format doesn't understand
  	 * it is treated like an incompat flag for reading and writing,
  	 * but not for stat.
  	 */
  	u8 compression;
  	u8 encryption;
  	__le16 other_encoding; /* spare for later use */
  
  	/* are we inline data or a real extent? */
  	u8 type;
  
  	/*
  	 * disk space consumed by the extent, checksum blocks are included
  	 * in these numbers
  	 *
  	 * At this offset in the structure, the inline extent data start.
  	 */
  	__le64 disk_bytenr;
  	__le64 disk_num_bytes;
  	/*
  	 * the logical offset in file blocks (no csums)
  	 * this extent record is for.  This allows a file extent to point
  	 * into the middle of an existing extent on disk, sharing it
  	 * between two snapshots (useful if some bytes in the middle of the
  	 * extent have changed
  	 */
  	__le64 offset;
  	/*
  	 * the logical number of file blocks (no csums included).  This
  	 * always reflects the size uncompressed and without encoding.
  	 */
  	__le64 num_bytes;
  
  } __attribute__ ((__packed__));
  
  struct btrfs_csum_item {
  	u8 csum;
  } __attribute__ ((__packed__));
  
  struct btrfs_dev_stats_item {
  	/*
  	 * grow this item struct at the end for future enhancements and keep
  	 * the existing values unchanged
  	 */
  	__le64 values[BTRFS_DEV_STAT_VALUES_MAX];
  } __attribute__ ((__packed__));
  
  #define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS	0
  #define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID	1
  #define BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED	0
  #define BTRFS_DEV_REPLACE_ITEM_STATE_STARTED		1
  #define BTRFS_DEV_REPLACE_ITEM_STATE_SUSPENDED		2
  #define BTRFS_DEV_REPLACE_ITEM_STATE_FINISHED		3
  #define BTRFS_DEV_REPLACE_ITEM_STATE_CANCELED		4
  
  struct btrfs_dev_replace {
  	u64 replace_state;	/* see #define above */
  	u64 time_started;	/* seconds since 1-Jan-1970 */
  	u64 time_stopped;	/* seconds since 1-Jan-1970 */
  	atomic64_t num_write_errors;
  	atomic64_t num_uncorrectable_read_errors;
  
  	u64 cursor_left;
  	u64 committed_cursor_left;
  	u64 cursor_left_last_write_of_item;
  	u64 cursor_right;
  
  	u64 cont_reading_from_srcdev_mode;	/* see #define above */
  
  	int is_valid;
  	int item_needs_writeback;
  	struct btrfs_device *srcdev;
  	struct btrfs_device *tgtdev;
  
  	pid_t lock_owner;
  	atomic_t nesting_level;
  	struct mutex lock_finishing_cancel_unmount;
  	struct mutex lock_management_lock;
  	struct mutex lock;
  
  	struct btrfs_scrub_progress scrub_progress;
  };
  
  struct btrfs_dev_replace_item {
  	/*
  	 * grow this item struct at the end for future enhancements and keep
  	 * the existing values unchanged
  	 */
  	__le64 src_devid;
  	__le64 cursor_left;
  	__le64 cursor_right;
  	__le64 cont_reading_from_srcdev_mode;
  
  	__le64 replace_state;
  	__le64 time_started;
  	__le64 time_stopped;
  	__le64 num_write_errors;
  	__le64 num_uncorrectable_read_errors;
  } __attribute__ ((__packed__));
  
  /* different types of block groups (and chunks) */
  #define BTRFS_BLOCK_GROUP_DATA		(1ULL << 0)
  #define BTRFS_BLOCK_GROUP_SYSTEM	(1ULL << 1)
  #define BTRFS_BLOCK_GROUP_METADATA	(1ULL << 2)
  #define BTRFS_BLOCK_GROUP_RAID0		(1ULL << 3)
  #define BTRFS_BLOCK_GROUP_RAID1		(1ULL << 4)
  #define BTRFS_BLOCK_GROUP_DUP		(1ULL << 5)
  #define BTRFS_BLOCK_GROUP_RAID10	(1ULL << 6)
  #define BTRFS_BLOCK_GROUP_RAID5         (1ULL << 7)
  #define BTRFS_BLOCK_GROUP_RAID6         (1ULL << 8)
  #define BTRFS_BLOCK_GROUP_RESERVED	(BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
  					 BTRFS_SPACE_INFO_GLOBAL_RSV)
  
  enum btrfs_raid_types {
  	BTRFS_RAID_RAID10,
  	BTRFS_RAID_RAID1,
  	BTRFS_RAID_DUP,
  	BTRFS_RAID_RAID0,
  	BTRFS_RAID_SINGLE,
  	BTRFS_RAID_RAID5,
  	BTRFS_RAID_RAID6,
  	BTRFS_NR_RAID_TYPES
  };
  
  #define BTRFS_BLOCK_GROUP_TYPE_MASK	(BTRFS_BLOCK_GROUP_DATA |    \
  					 BTRFS_BLOCK_GROUP_SYSTEM |  \
  					 BTRFS_BLOCK_GROUP_METADATA)
  
  #define BTRFS_BLOCK_GROUP_PROFILE_MASK	(BTRFS_BLOCK_GROUP_RAID0 |   \
  					 BTRFS_BLOCK_GROUP_RAID1 |   \
  					 BTRFS_BLOCK_GROUP_RAID5 |   \
  					 BTRFS_BLOCK_GROUP_RAID6 |   \
  					 BTRFS_BLOCK_GROUP_DUP |     \
  					 BTRFS_BLOCK_GROUP_RAID10)
  #define BTRFS_BLOCK_GROUP_RAID56_MASK	(BTRFS_BLOCK_GROUP_RAID5 |   \
  					 BTRFS_BLOCK_GROUP_RAID6)
  
  /*
   * We need a bit for restriper to be able to tell when chunks of type
   * SINGLE are available.  This "extended" profile format is used in
   * fs_info->avail_*_alloc_bits (in-memory) and balance item fields
   * (on-disk).  The corresponding on-disk bit in chunk.type is reserved
   * to avoid remappings between two formats in future.
   */
  #define BTRFS_AVAIL_ALLOC_BIT_SINGLE	(1ULL << 48)
  
  /*
   * A fake block group type that is used to communicate global block reserve
   * size to userspace via the SPACE_INFO ioctl.
   */
  #define BTRFS_SPACE_INFO_GLOBAL_RSV	(1ULL << 49)
  
  #define BTRFS_EXTENDED_PROFILE_MASK	(BTRFS_BLOCK_GROUP_PROFILE_MASK | \
  					 BTRFS_AVAIL_ALLOC_BIT_SINGLE)
  
  static inline u64 chunk_to_extended(u64 flags)
  {
  	if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0)
  		flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
  
  	return flags;
  }
  static inline u64 extended_to_chunk(u64 flags)
  {
  	return flags & ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
  }
  
  struct btrfs_block_group_item {
  	__le64 used;
  	__le64 chunk_objectid;
  	__le64 flags;
  } __attribute__ ((__packed__));
  
  #define BTRFS_QGROUP_LEVEL_SHIFT		48
  static inline u64 btrfs_qgroup_level(u64 qgroupid)
  {
  	return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
  }
  
  /*
   * is subvolume quota turned on?
   */
  #define BTRFS_QGROUP_STATUS_FLAG_ON		(1ULL << 0)
  /*
   * RESCAN is set during the initialization phase
   */
  #define BTRFS_QGROUP_STATUS_FLAG_RESCAN		(1ULL << 1)
  /*
   * Some qgroup entries are known to be out of date,
   * either because the configuration has changed in a way that
   * makes a rescan necessary, or because the fs has been mounted
   * with a non-qgroup-aware version.
   * Turning qouta off and on again makes it inconsistent, too.
   */
  #define BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT	(1ULL << 2)
  
  #define BTRFS_QGROUP_STATUS_VERSION        1
  
  struct btrfs_qgroup_status_item {
  	__le64 version;
  	/*
  	 * the generation is updated during every commit. As older
  	 * versions of btrfs are not aware of qgroups, it will be
  	 * possible to detect inconsistencies by checking the
  	 * generation on mount time
  	 */
  	__le64 generation;
  
  	/* flag definitions see above */
  	__le64 flags;
  
  	/*
  	 * only used during scanning to record the progress
  	 * of the scan. It contains a logical address
  	 */
  	__le64 rescan;
  } __attribute__ ((__packed__));
  
  struct btrfs_qgroup_info_item {
  	__le64 generation;
  	__le64 rfer;
  	__le64 rfer_cmpr;
  	__le64 excl;
  	__le64 excl_cmpr;
  } __attribute__ ((__packed__));
  
  /* flags definition for qgroup limits */
  #define BTRFS_QGROUP_LIMIT_MAX_RFER	(1ULL << 0)
  #define BTRFS_QGROUP_LIMIT_MAX_EXCL	(1ULL << 1)
  #define BTRFS_QGROUP_LIMIT_RSV_RFER	(1ULL << 2)
  #define BTRFS_QGROUP_LIMIT_RSV_EXCL	(1ULL << 3)
  #define BTRFS_QGROUP_LIMIT_RFER_CMPR	(1ULL << 4)
  #define BTRFS_QGROUP_LIMIT_EXCL_CMPR	(1ULL << 5)
  
  struct btrfs_qgroup_limit_item {
  	/*
  	 * only updated when any of the other values change
  	 */
  	__le64 flags;
  	__le64 max_rfer;
  	__le64 max_excl;
  	__le64 rsv_rfer;
  	__le64 rsv_excl;
  } __attribute__ ((__packed__));
  
  /* For raid type sysfs entries */
  struct raid_kobject {
  	int raid_type;
  	struct kobject kobj;
  };
  
  struct btrfs_space_info {
  	spinlock_t lock;
  
  	u64 total_bytes;	/* total bytes in the space,
  				   this doesn't take mirrors into account */
  	u64 bytes_used;		/* total bytes used,
  				   this doesn't take mirrors into account */
  	u64 bytes_pinned;	/* total bytes pinned, will be freed when the
  				   transaction finishes */
  	u64 bytes_reserved;	/* total bytes the allocator has reserved for
  				   current allocations */
  	u64 bytes_may_use;	/* number of bytes that may be used for
  				   delalloc/allocations */
  	u64 bytes_readonly;	/* total bytes that are read only */
  
  	u64 max_extent_size;	/* This will hold the maximum extent size of
  				   the space info if we had an ENOSPC in the
  				   allocator. */
  
  	unsigned int full:1;	/* indicates that we cannot allocate any more
  				   chunks for this space */
  	unsigned int chunk_alloc:1;	/* set if we are allocating a chunk */
  
  	unsigned int flush:1;		/* set if we are trying to make space */
  
  	unsigned int force_alloc;	/* set if we need to force a chunk
  					   alloc for this space */
  
  	u64 disk_used;		/* total bytes used on disk */
  	u64 disk_total;		/* total bytes on disk, takes mirrors into
  				   account */
  
  	u64 flags;
  
  	/*
  	 * bytes_pinned is kept in line with what is actually pinned, as in
  	 * we've called update_block_group and dropped the bytes_used counter
  	 * and increased the bytes_pinned counter.  However this means that
  	 * bytes_pinned does not reflect the bytes that will be pinned once the
  	 * delayed refs are flushed, so this counter is inc'ed everytime we call
  	 * btrfs_free_extent so it is a realtime count of what will be freed
  	 * once the transaction is committed.  It will be zero'ed everytime the
  	 * transaction commits.
  	 */
  	struct percpu_counter total_bytes_pinned;
  
  	struct list_head list;
  	/* Protected by the spinlock 'lock'. */
  	struct list_head ro_bgs;
  
  	struct rw_semaphore groups_sem;
  	/* for block groups in our same type */
  	struct list_head block_groups[BTRFS_NR_RAID_TYPES];
  	wait_queue_head_t wait;
  
  	struct kobject kobj;
  	struct kobject *block_group_kobjs[BTRFS_NR_RAID_TYPES];
  };
  
  #define	BTRFS_BLOCK_RSV_GLOBAL		1
  #define	BTRFS_BLOCK_RSV_DELALLOC	2
  #define	BTRFS_BLOCK_RSV_TRANS		3
  #define	BTRFS_BLOCK_RSV_CHUNK		4
  #define	BTRFS_BLOCK_RSV_DELOPS		5
  #define	BTRFS_BLOCK_RSV_EMPTY		6
  #define	BTRFS_BLOCK_RSV_TEMP		7
  
  struct btrfs_block_rsv {
  	u64 size;
  	u64 reserved;
  	struct btrfs_space_info *space_info;
  	spinlock_t lock;
  	unsigned short full;
  	unsigned short type;
  	unsigned short failfast;
  };
  
  /*
   * free clusters are used to claim free space in relatively large chunks,
   * allowing us to do less seeky writes.  They are used for all metadata
   * allocations and data allocations in ssd mode.
   */
  struct btrfs_free_cluster {
  	spinlock_t lock;
  	spinlock_t refill_lock;
  	struct rb_root root;
  
  	/* largest extent in this cluster */
  	u64 max_size;
  
  	/* first extent starting offset */
  	u64 window_start;
  
  	/* We did a full search and couldn't create a cluster */
  	bool fragmented;
  
  	struct btrfs_block_group_cache *block_group;
  	/*
  	 * when a cluster is allocated from a block group, we put the
  	 * cluster onto a list in the block group so that it can
  	 * be freed before the block group is freed.
  	 */
  	struct list_head block_group_list;
  };
  
  enum btrfs_caching_type {
  	BTRFS_CACHE_NO		= 0,
  	BTRFS_CACHE_STARTED	= 1,
  	BTRFS_CACHE_FAST	= 2,
  	BTRFS_CACHE_FINISHED	= 3,
  	BTRFS_CACHE_ERROR	= 4,
  };
  
  enum btrfs_disk_cache_state {
  	BTRFS_DC_WRITTEN	= 0,
  	BTRFS_DC_ERROR		= 1,
  	BTRFS_DC_CLEAR		= 2,
  	BTRFS_DC_SETUP		= 3,
  };
  
  struct btrfs_caching_control {
  	struct list_head list;
  	struct mutex mutex;
  	wait_queue_head_t wait;
  	struct btrfs_work work;
  	struct btrfs_block_group_cache *block_group;
  	u64 progress;
  	atomic_t count;
  };
  
  struct btrfs_io_ctl {
  	void *cur, *orig;
  	struct page *page;
  	struct page **pages;
  	struct btrfs_root *root;
  	struct inode *inode;
  	unsigned long size;
  	int index;
  	int num_pages;
  	int entries;
  	int bitmaps;
  	unsigned check_crcs:1;
  };
  
  struct btrfs_block_group_cache {
  	struct btrfs_key key;
  	struct btrfs_block_group_item item;
  	struct btrfs_fs_info *fs_info;
  	struct inode *inode;
  	spinlock_t lock;
  	u64 pinned;
  	u64 reserved;
  	u64 delalloc_bytes;
  	u64 bytes_super;
  	u64 flags;
  	u64 sectorsize;
  	u64 cache_generation;
  
  	/*
  	 * It is just used for the delayed data space allocation because
  	 * only the data space allocation and the relative metadata update
  	 * can be done cross the transaction.
  	 */
  	struct rw_semaphore data_rwsem;
  
  	/* for raid56, this is a full stripe, without parity */
  	unsigned long full_stripe_len;
  
  	unsigned int ro;
  	unsigned int iref:1;
  	unsigned int has_caching_ctl:1;
  	unsigned int removed:1;
  
  	int disk_cache_state;
  
  	/* cache tracking stuff */
  	int cached;
  	struct btrfs_caching_control *caching_ctl;
  	u64 last_byte_to_unpin;
  
  	struct btrfs_space_info *space_info;
  
  	/* free space cache stuff */
  	struct btrfs_free_space_ctl *free_space_ctl;
  
  	/* block group cache stuff */
  	struct rb_node cache_node;
  
  	/* for block groups in the same raid type */
  	struct list_head list;
  
  	/* usage count */
  	atomic_t count;
  
  	/* List of struct btrfs_free_clusters for this block group.
  	 * Today it will only have one thing on it, but that may change
  	 */
  	struct list_head cluster_list;
  
  	/* For delayed block group creation or deletion of empty block groups */
  	struct list_head bg_list;
  
  	/* For read-only block groups */
  	struct list_head ro_list;
  
  	atomic_t trimming;
  
  	/* For dirty block groups */
  	struct list_head dirty_list;
  	struct list_head io_list;
  
  	struct btrfs_io_ctl io_ctl;
  };
  
  /* delayed seq elem */
  struct seq_list {
  	struct list_head list;
  	u64 seq;
  };
  
  #define SEQ_LIST_INIT(name)	{ .list = LIST_HEAD_INIT((name).list), .seq = 0 }
  
  enum btrfs_orphan_cleanup_state {
  	ORPHAN_CLEANUP_STARTED	= 1,
  	ORPHAN_CLEANUP_DONE	= 2,
  };
  
  /* used by the raid56 code to lock stripes for read/modify/write */
  struct btrfs_stripe_hash {
  	struct list_head hash_list;
  	wait_queue_head_t wait;
  	spinlock_t lock;
  };
  
  /* used by the raid56 code to lock stripes for read/modify/write */
  struct btrfs_stripe_hash_table {
  	struct list_head stripe_cache;
  	spinlock_t cache_lock;
  	int cache_size;
  	struct btrfs_stripe_hash table[];
  };
  
  #define BTRFS_STRIPE_HASH_TABLE_BITS 11
  
  void btrfs_init_async_reclaim_work(struct work_struct *work);
  
  /* fs_info */
  struct reloc_control;
  struct btrfs_device;
  struct btrfs_fs_devices;
  struct btrfs_balance_control;
  struct btrfs_delayed_root;
  struct btrfs_fs_info {
  	u8 fsid[BTRFS_FSID_SIZE];
  	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
  	struct btrfs_root *extent_root;
  	struct btrfs_root *tree_root;
  	struct btrfs_root *chunk_root;
  	struct btrfs_root *dev_root;
  	struct btrfs_root *fs_root;
  	struct btrfs_root *csum_root;
  	struct btrfs_root *quota_root;
  	struct btrfs_root *uuid_root;
  
  	/* the log root tree is a directory of all the other log roots */
  	struct btrfs_root *log_root_tree;
  
  	spinlock_t fs_roots_radix_lock;
  	struct radix_tree_root fs_roots_radix;
  
  	/* block group cache stuff */
  	spinlock_t block_group_cache_lock;
  	u64 first_logical_byte;
  	struct rb_root block_group_cache_tree;
  
  	/* keep track of unallocated space */
  	spinlock_t free_chunk_lock;
  	u64 free_chunk_space;
  
  	struct extent_io_tree freed_extents[2];
  	struct extent_io_tree *pinned_extents;
  
  	/* logical->physical extent mapping */
  	struct btrfs_mapping_tree mapping_tree;
  
  	/*
  	 * block reservation for extent, checksum, root tree and
  	 * delayed dir index item
  	 */
  	struct btrfs_block_rsv global_block_rsv;
  	/* block reservation for delay allocation */
  	struct btrfs_block_rsv delalloc_block_rsv;
  	/* block reservation for metadata operations */
  	struct btrfs_block_rsv trans_block_rsv;
  	/* block reservation for chunk tree */
  	struct btrfs_block_rsv chunk_block_rsv;
  	/* block reservation for delayed operations */
  	struct btrfs_block_rsv delayed_block_rsv;
  
  	struct btrfs_block_rsv empty_block_rsv;
  
  	u64 generation;
  	u64 last_trans_committed;
  	u64 avg_delayed_ref_runtime;
  
  	/*
  	 * this is updated to the current trans every time a full commit
  	 * is required instead of the faster short fsync log commits
  	 */
  	u64 last_trans_log_full_commit;
  	unsigned long mount_opt;
  	/*
  	 * Track requests for actions that need to be done during transaction
  	 * commit (like for some mount options).
  	 */
  	unsigned long pending_changes;
  	unsigned long compress_type:4;
  	int commit_interval;
  	/*
  	 * It is a suggestive number, the read side is safe even it gets a
  	 * wrong number because we will write out the data into a regular
  	 * extent. The write side(mount/remount) is under ->s_umount lock,
  	 * so it is also safe.
  	 */
  	u64 max_inline;
  	/*
  	 * Protected by ->chunk_mutex and sb->s_umount.
  	 *
  	 * The reason that we use two lock to protect it is because only
  	 * remount and mount operations can change it and these two operations
  	 * are under sb->s_umount, but the read side (chunk allocation) can not
  	 * acquire sb->s_umount or the deadlock would happen. So we use two
  	 * locks to protect it. On the write side, we must acquire two locks,
  	 * and on the read side, we just need acquire one of them.
  	 */
  	u64 alloc_start;
  	struct btrfs_transaction *running_transaction;
  	wait_queue_head_t transaction_throttle;
  	wait_queue_head_t transaction_wait;
  	wait_queue_head_t transaction_blocked_wait;
  	wait_queue_head_t async_submit_wait;
  
  	/*
  	 * Used to protect the incompat_flags, compat_flags, compat_ro_flags
  	 * when they are updated.
  	 *
  	 * Because we do not clear the flags for ever, so we needn't use
  	 * the lock on the read side.
  	 *
  	 * We also needn't use the lock when we mount the fs, because
  	 * there is no other task which will update the flag.
  	 */
  	spinlock_t super_lock;
  	struct btrfs_super_block *super_copy;
  	struct btrfs_super_block *super_for_commit;
  	struct block_device *__bdev;
  	struct super_block *sb;
  	struct inode *btree_inode;
  	struct backing_dev_info bdi;
  	struct mutex tree_log_mutex;
  	struct mutex transaction_kthread_mutex;
  	struct mutex cleaner_mutex;
  	struct mutex chunk_mutex;
  	struct mutex volume_mutex;
  
  	/*
  	 * this is taken to make sure we don't set block groups ro after
  	 * the free space cache has been allocated on them
  	 */
  	struct mutex ro_block_group_mutex;
  
  	/* this is used during read/modify/write to make sure
  	 * no two ios are trying to mod the same stripe at the same
  	 * time
  	 */
  	struct btrfs_stripe_hash_table *stripe_hash_table;
  
  	/*
  	 * this protects the ordered operations list only while we are
  	 * processing all of the entries on it.  This way we make
  	 * sure the commit code doesn't find the list temporarily empty
  	 * because another function happens to be doing non-waiting preflush
  	 * before jumping into the main commit.
  	 */
  	struct mutex ordered_operations_mutex;
  
  	struct rw_semaphore commit_root_sem;
  
  	struct rw_semaphore cleanup_work_sem;
  
  	struct rw_semaphore subvol_sem;
  	struct srcu_struct subvol_srcu;
  
  	spinlock_t trans_lock;
  	/*
  	 * the reloc mutex goes with the trans lock, it is taken
  	 * during commit to protect us from the relocation code
  	 */
  	struct mutex reloc_mutex;
  
  	struct list_head trans_list;
  	struct list_head dead_roots;
  	struct list_head caching_block_groups;
  
  	spinlock_t delayed_iput_lock;
  	struct list_head delayed_iputs;
  	struct rw_semaphore delayed_iput_sem;
  
  	/* this protects tree_mod_seq_list */
  	spinlock_t tree_mod_seq_lock;
  	atomic64_t tree_mod_seq;
  	struct list_head tree_mod_seq_list;
  
  	/* this protects tree_mod_log */
  	rwlock_t tree_mod_log_lock;
  	struct rb_root tree_mod_log;
  
  	atomic_t nr_async_submits;
  	atomic_t async_submit_draining;
  	atomic_t nr_async_bios;
  	atomic_t async_delalloc_pages;
  	atomic_t open_ioctl_trans;
  
  	/*
  	 * this is used to protect the following list -- ordered_roots.
  	 */
  	spinlock_t ordered_root_lock;
  
  	/*
  	 * all fs/file tree roots in which there are data=ordered extents
  	 * pending writeback are added into this list.
  	 *
  	 * these can span multiple transactions and basically include
  	 * every dirty data page that isn't from nodatacow
  	 */
  	struct list_head ordered_roots;
  
  	struct mutex delalloc_root_mutex;
  	spinlock_t delalloc_root_lock;
  	/* all fs/file tree roots that have delalloc inodes. */
  	struct list_head delalloc_roots;
  
  	/*
  	 * there is a pool of worker threads for checksumming during writes
  	 * and a pool for checksumming after reads.  This is because readers
  	 * can run with FS locks held, and the writers may be waiting for
  	 * those locks.  We don't want ordering in the pending list to cause
  	 * deadlocks, and so the two are serviced separately.
  	 *
  	 * A third pool does submit_bio to avoid deadlocking with the other
  	 * two
  	 */
  	struct btrfs_workqueue *workers;
  	struct btrfs_workqueue *delalloc_workers;
  	struct btrfs_workqueue *flush_workers;
  	struct btrfs_workqueue *endio_workers;
  	struct btrfs_workqueue *endio_meta_workers;
  	struct btrfs_workqueue *endio_raid56_workers;
  	struct btrfs_workqueue *endio_repair_workers;
  	struct btrfs_workqueue *rmw_workers;
  	struct btrfs_workqueue *endio_meta_write_workers;
  	struct btrfs_workqueue *endio_write_workers;
  	struct btrfs_workqueue *endio_freespace_worker;
  	struct btrfs_workqueue *submit_workers;
  	struct btrfs_workqueue *caching_workers;
  	struct btrfs_workqueue *readahead_workers;
  
  	/*
  	 * fixup workers take dirty pages that didn't properly go through
  	 * the cow mechanism and make them safe to write.  It happens
  	 * for the sys_munmap function call path
  	 */
  	struct btrfs_workqueue *fixup_workers;
  	struct btrfs_workqueue *delayed_workers;
  
  	/* the extent workers do delayed refs on the extent allocation tree */
  	struct btrfs_workqueue *extent_workers;
  	struct task_struct *transaction_kthread;
  	struct task_struct *cleaner_kthread;
  	int thread_pool_size;
  
  	struct kobject *space_info_kobj;
  	int do_barriers;
  	int closing;
  	int log_root_recovering;
  	int open;
  
  	u64 total_pinned;
  
  	/* used to keep from writing metadata until there is a nice batch */
  	struct percpu_counter dirty_metadata_bytes;
  	struct percpu_counter delalloc_bytes;
  	s32 dirty_metadata_batch;
  	s32 delalloc_batch;
  
  	struct list_head dirty_cowonly_roots;
  
  	struct btrfs_fs_devices *fs_devices;
  
  	/*
  	 * the space_info list is almost entirely read only.  It only changes
  	 * when we add a new raid type to the FS, and that happens
  	 * very rarely.  RCU is used to protect it.
  	 */
  	struct list_head space_info;
  
  	struct btrfs_space_info *data_sinfo;
  
  	struct reloc_control *reloc_ctl;
  
  	/* data_alloc_cluster is only used in ssd mode */
  	struct btrfs_free_cluster data_alloc_cluster;
  
  	/* all metadata allocations go through this cluster */
  	struct btrfs_free_cluster meta_alloc_cluster;
  
  	/* auto defrag inodes go here */
  	spinlock_t defrag_inodes_lock;
  	struct rb_root defrag_inodes;
  	atomic_t defrag_running;
  
  	/* Used to protect avail_{data, metadata, system}_alloc_bits */
  	seqlock_t profiles_lock;
  	/*
  	 * these three are in extended format (availability of single
  	 * chunks is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other
  	 * types are denoted by corresponding BTRFS_BLOCK_GROUP_* bits)
  	 */
  	u64 avail_data_alloc_bits;
  	u64 avail_metadata_alloc_bits;
  	u64 avail_system_alloc_bits;
  
  	/* restriper state */
  	spinlock_t balance_lock;
  	struct mutex balance_mutex;
  	atomic_t balance_running;
  	atomic_t balance_pause_req;
  	atomic_t balance_cancel_req;
  	struct btrfs_balance_control *balance_ctl;
  	wait_queue_head_t balance_wait_q;
  
  	unsigned data_chunk_allocations;
  	unsigned metadata_ratio;
  
  	void *bdev_holder;
  
  	/* private scrub information */
  	struct mutex scrub_lock;
  	atomic_t scrubs_running;
  	atomic_t scrub_pause_req;
  	atomic_t scrubs_paused;
  	atomic_t scrub_cancel_req;
  	wait_queue_head_t scrub_pause_wait;
  	int scrub_workers_refcnt;
  	struct btrfs_workqueue *scrub_workers;
  	struct btrfs_workqueue *scrub_wr_completion_workers;
  	struct btrfs_workqueue *scrub_nocow_workers;
  	struct btrfs_workqueue *scrub_parity_workers;
  
  #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
  	u32 check_integrity_print_mask;
  #endif
  	/*
  	 * quota information
  	 */
  	unsigned int quota_enabled:1;
  
  	/*
  	 * quota_enabled only changes state after a commit. This holds the
  	 * next state.
  	 */
  	unsigned int pending_quota_state:1;
  
  	/* is qgroup tracking in a consistent state? */
  	u64 qgroup_flags;
  
  	/* holds configuration and tracking. Protected by qgroup_lock */
  	struct rb_root qgroup_tree;
  	struct rb_root qgroup_op_tree;
  	spinlock_t qgroup_lock;
  	spinlock_t qgroup_op_lock;
  	atomic_t qgroup_op_seq;
  
  	/*
  	 * used to avoid frequently calling ulist_alloc()/ulist_free()
  	 * when doing qgroup accounting, it must be protected by qgroup_lock.
  	 */
  	struct ulist *qgroup_ulist;
  
  	/* protect user change for quota operations */
  	struct mutex qgroup_ioctl_lock;
  
  	/* list of dirty qgroups to be written at next commit */
  	struct list_head dirty_qgroups;
  
  	/* used by qgroup for an efficient tree traversal */
  	u64 qgroup_seq;
  
  	/* qgroup rescan items */
  	struct mutex qgroup_rescan_lock; /* protects the progress item */
  	struct btrfs_key qgroup_rescan_progress;
  	struct btrfs_workqueue *qgroup_rescan_workers;
  	struct completion qgroup_rescan_completion;
  	struct btrfs_work qgroup_rescan_work;
  
  	/* filesystem state */
  	unsigned long fs_state;
  
  	struct btrfs_delayed_root *delayed_root;
  
  	/* readahead tree */
  	spinlock_t reada_lock;
  	struct radix_tree_root reada_tree;
  
  	/* Extent buffer radix tree */
  	spinlock_t buffer_lock;
  	struct radix_tree_root buffer_radix;
  
  	/* next backup root to be overwritten */
  	int backup_root_index;
  
  	int num_tolerated_disk_barrier_failures;
  
  	/* device replace state */
  	struct btrfs_dev_replace dev_replace;
  
  	atomic_t mutually_exclusive_operation_running;
  
  	struct percpu_counter bio_counter;
  	wait_queue_head_t replace_wait;
  
  	struct semaphore uuid_tree_rescan_sem;
  	unsigned int update_uuid_tree_gen:1;
  
  	/* Used to reclaim the metadata space in the background. */
  	struct work_struct async_reclaim_work;
  
  	spinlock_t unused_bgs_lock;
  	struct list_head unused_bgs;
  	struct mutex unused_bg_unpin_mutex;
  	struct mutex delete_unused_bgs_mutex;
  
  	/* For btrfs to record security options */
  	struct security_mnt_opts security_opts;
  
  	/*
  	 * Chunks that can't be freed yet (under a trim/discard operation)
  	 * and will be latter freed. Protected by fs_info->chunk_mutex.
  	 */
  	struct list_head pinned_chunks;
  };
  
  struct btrfs_subvolume_writers {
  	struct percpu_counter	counter;
  	wait_queue_head_t	wait;
  };
  
  /*
   * The state of btrfs root
   */
  /*
   * btrfs_record_root_in_trans is a multi-step process,
   * and it can race with the balancing code.   But the
   * race is very small, and only the first time the root
   * is added to each transaction.  So IN_TRANS_SETUP
   * is used to tell us when more checks are required
   */
  #define BTRFS_ROOT_IN_TRANS_SETUP	0
  #define BTRFS_ROOT_REF_COWS		1
  #define BTRFS_ROOT_TRACK_DIRTY		2
  #define BTRFS_ROOT_IN_RADIX		3
  #define BTRFS_ROOT_DUMMY_ROOT		4
  #define BTRFS_ROOT_ORPHAN_ITEM_INSERTED	5
  #define BTRFS_ROOT_DEFRAG_RUNNING	6
  #define BTRFS_ROOT_FORCE_COW		7
  #define BTRFS_ROOT_MULTI_LOG_TASKS	8
  #define BTRFS_ROOT_DIRTY		9
  
  /*
   * in ram representation of the tree.  extent_root is used for all allocations
   * and for the extent tree extent_root root.
   */
  struct btrfs_root {
  	struct extent_buffer *node;
  
  	struct extent_buffer *commit_root;
  	struct btrfs_root *log_root;
  	struct btrfs_root *reloc_root;
  
  	unsigned long state;
  	struct btrfs_root_item root_item;
  	struct btrfs_key root_key;
  	struct btrfs_fs_info *fs_info;
  	struct extent_io_tree dirty_log_pages;
  
  	struct mutex objectid_mutex;
  
  	spinlock_t accounting_lock;
  	struct btrfs_block_rsv *block_rsv;
  
  	/* free ino cache stuff */
  	struct btrfs_free_space_ctl *free_ino_ctl;
  	enum btrfs_caching_type ino_cache_state;
  	spinlock_t ino_cache_lock;
  	wait_queue_head_t ino_cache_wait;
  	struct btrfs_free_space_ctl *free_ino_pinned;
  	u64 ino_cache_progress;
  	struct inode *ino_cache_inode;
  
  	struct mutex log_mutex;
  	wait_queue_head_t log_writer_wait;
  	wait_queue_head_t log_commit_wait[2];
  	struct list_head log_ctxs[2];
  	atomic_t log_writers;
  	atomic_t log_commit[2];
  	atomic_t log_batch;
  	int log_transid;
  	/* No matter the commit succeeds or not*/
  	int log_transid_committed;
  	/* Just be updated when the commit succeeds. */
  	int last_log_commit;
  	pid_t log_start_pid;
  
  	u64 objectid;
  	u64 last_trans;
  
  	/* data allocations are done in sectorsize units */
  	u32 sectorsize;
  
  	/* node allocations are done in nodesize units */
  	u32 nodesize;
  
  	u32 stripesize;
  
  	u32 type;
  
  	u64 highest_objectid;
  
  	/* only used with CONFIG_BTRFS_FS_RUN_SANITY_TESTS is enabled */
  	u64 alloc_bytenr;
  
  	u64 defrag_trans_start;
  	struct btrfs_key defrag_progress;
  	struct btrfs_key defrag_max;
  	char *name;
  
  	/* the dirty list is only used by non-reference counted roots */
  	struct list_head dirty_list;
  
  	struct list_head root_list;
  
  	spinlock_t log_extents_lock[2];
  	struct list_head logged_list[2];
  
  	spinlock_t orphan_lock;
  	atomic_t orphan_inodes;
  	struct btrfs_block_rsv *orphan_block_rsv;
  	int orphan_cleanup_state;
  
  	spinlock_t inode_lock;
  	/* red-black tree that keeps track of in-memory inodes */
  	struct rb_root inode_tree;
  
  	/*
  	 * radix tree that keeps track of delayed nodes of every inode,
  	 * protected by inode_lock
  	 */
  	struct radix_tree_root delayed_nodes_tree;
  	/*
  	 * right now this just gets used so that a root has its own devid
  	 * for stat.  It may be used for more later
  	 */
  	dev_t anon_dev;
  
  	spinlock_t root_item_lock;
  	atomic_t refs;
  
  	struct mutex delalloc_mutex;
  	spinlock_t delalloc_lock;
  	/*
  	 * all of the inodes that have delalloc bytes.  It is possible for
  	 * this list to be empty even when there is still dirty data=ordered
  	 * extents waiting to finish IO.
  	 */
  	struct list_head delalloc_inodes;
  	struct list_head delalloc_root;
  	u64 nr_delalloc_inodes;
  
  	struct mutex ordered_extent_mutex;
  	/*
  	 * this is used by the balancing code to wait for all the pending
  	 * ordered extents
  	 */
  	spinlock_t ordered_extent_lock;
  
  	/*
  	 * all of the data=ordered extents pending writeback
  	 * these can span multiple transactions and basically include
  	 * every dirty data page that isn't from nodatacow
  	 */
  	struct list_head ordered_extents;
  	struct list_head ordered_root;
  	u64 nr_ordered_extents;
  
  	/*
  	 * Number of currently running SEND ioctls to prevent
  	 * manipulation with the read-only status via SUBVOL_SETFLAGS
  	 */
  	int send_in_progress;
  	struct btrfs_subvolume_writers *subv_writers;
  	atomic_t will_be_snapshoted;
  
  	/* For qgroup metadata space reserve */
  	atomic_t qgroup_meta_rsv;
  };
  
  struct btrfs_ioctl_defrag_range_args {
  	/* start of the defrag operation */
  	__u64 start;
  
  	/* number of bytes to defrag, use (u64)-1 to say all */
  	__u64 len;
  
  	/*
  	 * flags for the operation, which can include turning
  	 * on compression for this one defrag
  	 */
  	__u64 flags;
  
  	/*
  	 * any extent bigger than this will be considered
  	 * already defragged.  Use 0 to take the kernel default
  	 * Use 1 to say every single extent must be rewritten
  	 */
  	__u32 extent_thresh;
  
  	/*
  	 * which compression method to use if turning on compression
  	 * for this defrag operation.  If unspecified, zlib will
  	 * be used
  	 */
  	__u32 compress_type;
  
  	/* spare for later */
  	__u32 unused[4];
  };
  
  
  /*
   * inode items have the data typically returned from stat and store other
   * info about object characteristics.  There is one for every file and dir in
   * the FS
   */
  #define BTRFS_INODE_ITEM_KEY		1
  #define BTRFS_INODE_REF_KEY		12
  #define BTRFS_INODE_EXTREF_KEY		13
  #define BTRFS_XATTR_ITEM_KEY		24
  #define BTRFS_ORPHAN_ITEM_KEY		48
  /* reserve 2-15 close to the inode for later flexibility */
  
  /*
   * dir items are the name -> inode pointers in a directory.  There is one
   * for every name in a directory.
   */
  #define BTRFS_DIR_LOG_ITEM_KEY  60
  #define BTRFS_DIR_LOG_INDEX_KEY 72
  #define BTRFS_DIR_ITEM_KEY	84
  #define BTRFS_DIR_INDEX_KEY	96
  /*
   * extent data is for file data
   */
  #define BTRFS_EXTENT_DATA_KEY	108
  
  /*
   * extent csums are stored in a separate tree and hold csums for
   * an entire extent on disk.
   */
  #define BTRFS_EXTENT_CSUM_KEY	128
  
  /*
   * root items point to tree roots.  They are typically in the root
   * tree used by the super block to find all the other trees
   */
  #define BTRFS_ROOT_ITEM_KEY	132
  
  /*
   * root backrefs tie subvols and snapshots to the directory entries that
   * reference them
   */
  #define BTRFS_ROOT_BACKREF_KEY	144
  
  /*
   * root refs make a fast index for listing all of the snapshots and
   * subvolumes referenced by a given root.  They point directly to the
   * directory item in the root that references the subvol
   */
  #define BTRFS_ROOT_REF_KEY	156
  
  /*
   * extent items are in the extent map tree.  These record which blocks
   * are used, and how many references there are to each block
   */
  #define BTRFS_EXTENT_ITEM_KEY	168
  
  /*
   * The same as the BTRFS_EXTENT_ITEM_KEY, except it's metadata we already know
   * the length, so we save the level in key->offset instead of the length.
   */
  #define BTRFS_METADATA_ITEM_KEY	169
  
  #define BTRFS_TREE_BLOCK_REF_KEY	176
  
  #define BTRFS_EXTENT_DATA_REF_KEY	178
  
  #define BTRFS_EXTENT_REF_V0_KEY		180
  
  #define BTRFS_SHARED_BLOCK_REF_KEY	182
  
  #define BTRFS_SHARED_DATA_REF_KEY	184
  
  /*
   * block groups give us hints into the extent allocation trees.  Which
   * blocks are free etc etc
   */
  #define BTRFS_BLOCK_GROUP_ITEM_KEY 192
  
  #define BTRFS_DEV_EXTENT_KEY	204
  #define BTRFS_DEV_ITEM_KEY	216
  #define BTRFS_CHUNK_ITEM_KEY	228
  
  /*
   * Records the overall state of the qgroups.
   * There's only one instance of this key present,
   * (0, BTRFS_QGROUP_STATUS_KEY, 0)
   */
  #define BTRFS_QGROUP_STATUS_KEY         240
  /*
   * Records the currently used space of the qgroup.
   * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid).
   */
  #define BTRFS_QGROUP_INFO_KEY           242
  /*
   * Contains the user configured limits for the qgroup.
   * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid).
   */
  #define BTRFS_QGROUP_LIMIT_KEY          244
  /*
   * Records the child-parent relationship of qgroups. For
   * each relation, 2 keys are present:
   * (childid, BTRFS_QGROUP_RELATION_KEY, parentid)
   * (parentid, BTRFS_QGROUP_RELATION_KEY, childid)
   */
  #define BTRFS_QGROUP_RELATION_KEY       246
  
  #define BTRFS_BALANCE_ITEM_KEY	248
  
  /*
   * Persistantly stores the io stats in the device tree.
   * One key for all stats, (0, BTRFS_DEV_STATS_KEY, devid).
   */
  #define BTRFS_DEV_STATS_KEY	249
  
  /*
   * Persistantly stores the device replace state in the device tree.
   * The key is built like this: (0, BTRFS_DEV_REPLACE_KEY, 0).
   */
  #define BTRFS_DEV_REPLACE_KEY	250
  
  /*
   * Stores items that allow to quickly map UUIDs to something else.
   * These items are part of the filesystem UUID tree.
   * The key is built like this:
   * (UUID_upper_64_bits, BTRFS_UUID_KEY*, UUID_lower_64_bits).
   */
  #if BTRFS_UUID_SIZE != 16
  #error "UUID items require BTRFS_UUID_SIZE == 16!"
  #endif
  #define BTRFS_UUID_KEY_SUBVOL	251	/* for UUIDs assigned to subvols */
  #define BTRFS_UUID_KEY_RECEIVED_SUBVOL	252	/* for UUIDs assigned to
  						 * received subvols */
  
  /*
   * string items are for debugging.  They just store a short string of
   * data in the FS
   */
  #define BTRFS_STRING_ITEM_KEY	253
  
  /*
   * Flags for mount options.
   *
   * Note: don't forget to add new options to btrfs_show_options()
   */
  #define BTRFS_MOUNT_NODATASUM		(1 << 0)
  #define BTRFS_MOUNT_NODATACOW		(1 << 1)
  #define BTRFS_MOUNT_NOBARRIER		(1 << 2)
  #define BTRFS_MOUNT_SSD			(1 << 3)
  #define BTRFS_MOUNT_DEGRADED		(1 << 4)
  #define BTRFS_MOUNT_COMPRESS		(1 << 5)
  #define BTRFS_MOUNT_NOTREELOG           (1 << 6)
  #define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)
  #define BTRFS_MOUNT_SSD_SPREAD		(1 << 8)
  #define BTRFS_MOUNT_NOSSD		(1 << 9)
  #define BTRFS_MOUNT_DISCARD		(1 << 10)
  #define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
  #define BTRFS_MOUNT_SPACE_CACHE		(1 << 12)
  #define BTRFS_MOUNT_CLEAR_CACHE		(1 << 13)
  #define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
  #define BTRFS_MOUNT_ENOSPC_DEBUG	 (1 << 15)
  #define BTRFS_MOUNT_AUTO_DEFRAG		(1 << 16)
  #define BTRFS_MOUNT_INODE_MAP_CACHE	(1 << 17)
  #define BTRFS_MOUNT_RECOVERY		(1 << 18)
  #define BTRFS_MOUNT_SKIP_BALANCE	(1 << 19)
  #define BTRFS_MOUNT_CHECK_INTEGRITY	(1 << 20)
  #define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
  #define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR	(1 << 22)
  #define BTRFS_MOUNT_RESCAN_UUID_TREE	(1 << 23)
  #define BTRFS_MOUNT_FRAGMENT_DATA	(1 << 24)
  #define BTRFS_MOUNT_FRAGMENT_METADATA	(1 << 25)
  
  #define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)
  #define BTRFS_DEFAULT_MAX_INLINE	(8192)
  
  #define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
  #define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
  #define btrfs_raw_test_opt(o, opt)	((o) & BTRFS_MOUNT_##opt)
  #define btrfs_test_opt(root, opt)	((root)->fs_info->mount_opt & \
  					 BTRFS_MOUNT_##opt)
  
  #define btrfs_set_and_info(root, opt, fmt, args...)			\
  {									\
  	if (!btrfs_test_opt(root, opt))					\
  		btrfs_info(root->fs_info, fmt, ##args);			\
  	btrfs_set_opt(root->fs_info->mount_opt, opt);			\
  }
  
  #define btrfs_clear_and_info(root, opt, fmt, args...)			\
  {									\
  	if (btrfs_test_opt(root, opt))					\
  		btrfs_info(root->fs_info, fmt, ##args);			\
  	btrfs_clear_opt(root->fs_info->mount_opt, opt);			\
  }
  
  #ifdef CONFIG_BTRFS_DEBUG
  static inline int
  btrfs_should_fragment_free_space(struct btrfs_root *root,
  				 struct btrfs_block_group_cache *block_group)
  {
  	return (btrfs_test_opt(root, FRAGMENT_METADATA) &&
  		block_group->flags & BTRFS_BLOCK_GROUP_METADATA) ||
  	       (btrfs_test_opt(root, FRAGMENT_DATA) &&
  		block_group->flags &  BTRFS_BLOCK_GROUP_DATA);
  }
  #endif
  
  /*
   * Requests for changes that need to be done during transaction commit.
   *
   * Internal mount options that are used for special handling of the real
   * mount options (eg. cannot be set during remount and have to be set during
   * transaction commit)
   */
  
  #define BTRFS_PENDING_SET_INODE_MAP_CACHE	(0)
  #define BTRFS_PENDING_CLEAR_INODE_MAP_CACHE	(1)
  #define BTRFS_PENDING_COMMIT			(2)
  
  #define btrfs_test_pending(info, opt)	\
  	test_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)
  #define btrfs_set_pending(info, opt)	\
  	set_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)
  #define btrfs_clear_pending(info, opt)	\
  	clear_bit(BTRFS_PENDING_##opt, &(info)->pending_changes)
  
  /*
   * Helpers for setting pending mount option changes.
   *
   * Expects corresponding macros
   * BTRFS_PENDING_SET_ and CLEAR_ + short mount option name
   */
  #define btrfs_set_pending_and_info(info, opt, fmt, args...)            \
  do {                                                                   \
         if (!btrfs_raw_test_opt((info)->mount_opt, opt)) {              \
                 btrfs_info((info), fmt, ##args);                        \
                 btrfs_set_pending((info), SET_##opt);                   \
                 btrfs_clear_pending((info), CLEAR_##opt);               \
         }                                                               \
  } while(0)
  
  #define btrfs_clear_pending_and_info(info, opt, fmt, args...)          \
  do {                                                                   \
         if (btrfs_raw_test_opt((info)->mount_opt, opt)) {               \
                 btrfs_info((info), fmt, ##args);                        \
                 btrfs_set_pending((info), CLEAR_##opt);                 \
                 btrfs_clear_pending((info), SET_##opt);                 \
         }                                                               \
  } while(0)
  
  /*
   * Inode flags
   */
  #define BTRFS_INODE_NODATASUM		(1 << 0)
  #define BTRFS_INODE_NODATACOW		(1 << 1)
  #define BTRFS_INODE_READONLY		(1 << 2)
  #define BTRFS_INODE_NOCOMPRESS		(1 << 3)
  #define BTRFS_INODE_PREALLOC		(1 << 4)
  #define BTRFS_INODE_SYNC		(1 << 5)
  #define BTRFS_INODE_IMMUTABLE		(1 << 6)
  #define BTRFS_INODE_APPEND		(1 << 7)
  #define BTRFS_INODE_NODUMP		(1 << 8)
  #define BTRFS_INODE_NOATIME		(1 << 9)
  #define BTRFS_INODE_DIRSYNC		(1 << 10)
  #define BTRFS_INODE_COMPRESS		(1 << 11)
  
  #define BTRFS_INODE_ROOT_ITEM_INIT	(1 << 31)
  
  struct btrfs_map_token {
  	struct extent_buffer *eb;
  	char *kaddr;
  	unsigned long offset;
  };
  
  static inline void btrfs_init_map_token (struct btrfs_map_token *token)
  {
  	token->kaddr = NULL;
  }
  
  /* some macros to generate set/get funcs for the struct fields.  This
   * assumes there is a lefoo_to_cpu for every type, so lets make a simple
   * one for u8:
   */
  #define le8_to_cpu(v) (v)
  #define cpu_to_le8(v) (v)
  #define __le8 u8
  
  #define read_eb_member(eb, ptr, type, member, result) (			\
  	read_extent_buffer(eb, (char *)(result),			\
  			   ((unsigned long)(ptr)) +			\
  			    offsetof(type, member),			\
  			   sizeof(((type *)0)->member)))
  
  #define write_eb_member(eb, ptr, type, member, result) (		\
  	write_extent_buffer(eb, (char *)(result),			\
  			   ((unsigned long)(ptr)) +			\
  			    offsetof(type, member),			\
  			   sizeof(((type *)0)->member)))
  
  #define DECLARE_BTRFS_SETGET_BITS(bits)					\
  u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr,	\
  			       unsigned long off,			\
                                struct btrfs_map_token *token);		\
  void btrfs_set_token_##bits(struct extent_buffer *eb, void *ptr,	\
  			    unsigned long off, u##bits val,		\
  			    struct btrfs_map_token *token);		\
  static inline u##bits btrfs_get_##bits(struct extent_buffer *eb, void *ptr, \
  				       unsigned long off)		\
  {									\
  	return btrfs_get_token_##bits(eb, ptr, off, NULL);		\
  }									\
  static inline void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
  				    unsigned long off, u##bits val)	\
  {									\
         btrfs_set_token_##bits(eb, ptr, off, val, NULL);			\
  }
  
  DECLARE_BTRFS_SETGET_BITS(8)
  DECLARE_BTRFS_SETGET_BITS(16)
  DECLARE_BTRFS_SETGET_BITS(32)
  DECLARE_BTRFS_SETGET_BITS(64)
  
  #define BTRFS_SETGET_FUNCS(name, type, member, bits)			\
  static inline u##bits btrfs_##name(struct extent_buffer *eb, type *s)	\
  {									\
  	BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);	\
  	return btrfs_get_##bits(eb, s, offsetof(type, member));		\
  }									\
  static inline void btrfs_set_##name(struct extent_buffer *eb, type *s,	\
  				    u##bits val)			\
  {									\
  	BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);	\
  	btrfs_set_##bits(eb, s, offsetof(type, member), val);		\
  }									\
  static inline u##bits btrfs_token_##name(struct extent_buffer *eb, type *s, \
  					 struct btrfs_map_token *token)	\
  {									\
  	BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);	\
  	return btrfs_get_token_##bits(eb, s, offsetof(type, member), token); \
  }									\
  static inline void btrfs_set_token_##name(struct extent_buffer *eb,	\
  					  type *s, u##bits val,		\
                                           struct btrfs_map_token *token)	\
  {									\
  	BUILD_BUG_ON(sizeof(u##bits) != sizeof(((type *)0))->member);	\
  	btrfs_set_token_##bits(eb, s, offsetof(type, member), val, token); \
  }
  
  #define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits)		\
  static inline u##bits btrfs_##name(struct extent_buffer *eb)		\
  {									\
  	type *p = page_address(eb->pages[0]);				\
  	u##bits res = le##bits##_to_cpu(p->member);			\
  	return res;							\
  }									\
  static inline void btrfs_set_##name(struct extent_buffer *eb,		\
  				    u##bits val)			\
  {									\
  	type *p = page_address(eb->pages[0]);				\
  	p->member = cpu_to_le##bits(val);				\
  }
  
  #define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits)		\
  static inline u##bits btrfs_##name(type *s)				\
  {									\
  	return le##bits##_to_cpu(s->member);				\
  }									\
  static inline void btrfs_set_##name(type *s, u##bits val)		\
  {									\
  	s->member = cpu_to_le##bits(val);				\
  }
  
  BTRFS_SETGET_FUNCS(device_type, struct btrfs_dev_item, type, 64);
  BTRFS_SETGET_FUNCS(device_total_bytes, struct btrfs_dev_item, total_bytes, 64);
  BTRFS_SETGET_FUNCS(device_bytes_used, struct btrfs_dev_item, bytes_used, 64);
  BTRFS_SETGET_FUNCS(device_io_align, struct btrfs_dev_item, io_align, 32);
  BTRFS_SETGET_FUNCS(device_io_width, struct btrfs_dev_item, io_width, 32);
  BTRFS_SETGET_FUNCS(device_start_offset, struct btrfs_dev_item,
  		   start_offset, 64);
  BTRFS_SETGET_FUNCS(device_sector_size, struct btrfs_dev_item, sector_size, 32);
  BTRFS_SETGET_FUNCS(device_id, struct btrfs_dev_item, devid, 64);
  BTRFS_SETGET_FUNCS(device_group, struct btrfs_dev_item, dev_group, 32);
  BTRFS_SETGET_FUNCS(device_seek_speed, struct btrfs_dev_item, seek_speed, 8);
  BTRFS_SETGET_FUNCS(device_bandwidth, struct btrfs_dev_item, bandwidth, 8);
  BTRFS_SETGET_FUNCS(device_generation, struct btrfs_dev_item, generation, 64);
  
  BTRFS_SETGET_STACK_FUNCS(stack_device_type, struct btrfs_dev_item, type, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_device_total_bytes, struct btrfs_dev_item,
  			 total_bytes, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_device_bytes_used, struct btrfs_dev_item,
  			 bytes_used, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_device_io_align, struct btrfs_dev_item,
  			 io_align, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_device_io_width, struct btrfs_dev_item,
  			 io_width, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_device_sector_size, struct btrfs_dev_item,
  			 sector_size, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_device_id, struct btrfs_dev_item, devid, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_device_group, struct btrfs_dev_item,
  			 dev_group, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_device_seek_speed, struct btrfs_dev_item,
  			 seek_speed, 8);
  BTRFS_SETGET_STACK_FUNCS(stack_device_bandwidth, struct btrfs_dev_item,
  			 bandwidth, 8);
  BTRFS_SETGET_STACK_FUNCS(stack_device_generation, struct btrfs_dev_item,
  			 generation, 64);
  
  static inline unsigned long btrfs_device_uuid(struct btrfs_dev_item *d)
  {
  	return (unsigned long)d + offsetof(struct btrfs_dev_item, uuid);
  }
  
  static inline unsigned long btrfs_device_fsid(struct btrfs_dev_item *d)
  {
  	return (unsigned long)d + offsetof(struct btrfs_dev_item, fsid);
  }
  
  BTRFS_SETGET_FUNCS(chunk_length, struct btrfs_chunk, length, 64);
  BTRFS_SETGET_FUNCS(chunk_owner, struct btrfs_chunk, owner, 64);
  BTRFS_SETGET_FUNCS(chunk_stripe_len, struct btrfs_chunk, stripe_len, 64);
  BTRFS_SETGET_FUNCS(chunk_io_align, struct btrfs_chunk, io_align, 32);
  BTRFS_SETGET_FUNCS(chunk_io_width, struct btrfs_chunk, io_width, 32);
  BTRFS_SETGET_FUNCS(chunk_sector_size, struct btrfs_chunk, sector_size, 32);
  BTRFS_SETGET_FUNCS(chunk_type, struct btrfs_chunk, type, 64);
  BTRFS_SETGET_FUNCS(chunk_num_stripes, struct btrfs_chunk, num_stripes, 16);
  BTRFS_SETGET_FUNCS(chunk_sub_stripes, struct btrfs_chunk, sub_stripes, 16);
  BTRFS_SETGET_FUNCS(stripe_devid, struct btrfs_stripe, devid, 64);
  BTRFS_SETGET_FUNCS(stripe_offset, struct btrfs_stripe, offset, 64);
  
  static inline char *btrfs_stripe_dev_uuid(struct btrfs_stripe *s)
  {
  	return (char *)s + offsetof(struct btrfs_stripe, dev_uuid);
  }
  
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_length, struct btrfs_chunk, length, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_owner, struct btrfs_chunk, owner, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_stripe_len, struct btrfs_chunk,
  			 stripe_len, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_io_align, struct btrfs_chunk,
  			 io_align, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_io_width, struct btrfs_chunk,
  			 io_width, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_sector_size, struct btrfs_chunk,
  			 sector_size, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_type, struct btrfs_chunk, type, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_num_stripes, struct btrfs_chunk,
  			 num_stripes, 16);
  BTRFS_SETGET_STACK_FUNCS(stack_chunk_sub_stripes, struct btrfs_chunk,
  			 sub_stripes, 16);
  BTRFS_SETGET_STACK_FUNCS(stack_stripe_devid, struct btrfs_stripe, devid, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_stripe_offset, struct btrfs_stripe, offset, 64);
  
  static inline struct btrfs_stripe *btrfs_stripe_nr(struct btrfs_chunk *c,
  						   int nr)
  {
  	unsigned long offset = (unsigned long)c;
  	offset += offsetof(struct btrfs_chunk, stripe);
  	offset += nr * sizeof(struct btrfs_stripe);
  	return (struct btrfs_stripe *)offset;
  }
  
  static inline char *btrfs_stripe_dev_uuid_nr(struct btrfs_chunk *c, int nr)
  {
  	return btrfs_stripe_dev_uuid(btrfs_stripe_nr(c, nr));
  }
  
  static inline u64 btrfs_stripe_offset_nr(struct extent_buffer *eb,
  					 struct btrfs_chunk *c, int nr)
  {
  	return btrfs_stripe_offset(eb, btrfs_stripe_nr(c, nr));
  }
  
  static inline u64 btrfs_stripe_devid_nr(struct extent_buffer *eb,
  					 struct btrfs_chunk *c, int nr)
  {
  	return btrfs_stripe_devid(eb, btrfs_stripe_nr(c, nr));
  }
  
  /* struct btrfs_block_group_item */
  BTRFS_SETGET_STACK_FUNCS(block_group_used, struct btrfs_block_group_item,
  			 used, 64);
  BTRFS_SETGET_FUNCS(disk_block_group_used, struct btrfs_block_group_item,
  			 used, 64);
  BTRFS_SETGET_STACK_FUNCS(block_group_chunk_objectid,
  			struct btrfs_block_group_item, chunk_objectid, 64);
  
  BTRFS_SETGET_FUNCS(disk_block_group_chunk_objectid,
  		   struct btrfs_block_group_item, chunk_objectid, 64);
  BTRFS_SETGET_FUNCS(disk_block_group_flags,
  		   struct btrfs_block_group_item, flags, 64);
  BTRFS_SETGET_STACK_FUNCS(block_group_flags,
  			struct btrfs_block_group_item, flags, 64);
  
  /* struct btrfs_inode_ref */
  BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
  BTRFS_SETGET_FUNCS(inode_ref_index, struct btrfs_inode_ref, index, 64);
  
  /* struct btrfs_inode_extref */
  BTRFS_SETGET_FUNCS(inode_extref_parent, struct btrfs_inode_extref,
  		   parent_objectid, 64);
  BTRFS_SETGET_FUNCS(inode_extref_name_len, struct btrfs_inode_extref,
  		   name_len, 16);
  BTRFS_SETGET_FUNCS(inode_extref_index, struct btrfs_inode_extref, index, 64);
  
  /* struct btrfs_inode_item */
  BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
  BTRFS_SETGET_FUNCS(inode_sequence, struct btrfs_inode_item, sequence, 64);
  BTRFS_SETGET_FUNCS(inode_transid, struct btrfs_inode_item, transid, 64);
  BTRFS_SETGET_FUNCS(inode_size, struct btrfs_inode_item, size, 64);
  BTRFS_SETGET_FUNCS(inode_nbytes, struct btrfs_inode_item, nbytes, 64);
  BTRFS_SETGET_FUNCS(inode_block_group, struct btrfs_inode_item, block_group, 64);
  BTRFS_SETGET_FUNCS(inode_nlink, struct btrfs_inode_item, nlink, 32);
  BTRFS_SETGET_FUNCS(inode_uid, struct btrfs_inode_item, uid, 32);
  BTRFS_SETGET_FUNCS(inode_gid, struct btrfs_inode_item, gid, 32);
  BTRFS_SETGET_FUNCS(inode_mode, struct btrfs_inode_item, mode, 32);
  BTRFS_SETGET_FUNCS(inode_rdev, struct btrfs_inode_item, rdev, 64);
  BTRFS_SETGET_FUNCS(inode_flags, struct btrfs_inode_item, flags, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_generation, struct btrfs_inode_item,
  			 generation, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_sequence, struct btrfs_inode_item,
  			 sequence, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_transid, struct btrfs_inode_item,
  			 transid, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_size, struct btrfs_inode_item, size, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_nbytes, struct btrfs_inode_item,
  			 nbytes, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_block_group, struct btrfs_inode_item,
  			 block_group, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_nlink, struct btrfs_inode_item, nlink, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_uid, struct btrfs_inode_item, uid, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_gid, struct btrfs_inode_item, gid, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_mode, struct btrfs_inode_item, mode, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_rdev, struct btrfs_inode_item, rdev, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_inode_flags, struct btrfs_inode_item, flags, 64);
  BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
  BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);
  
  /* struct btrfs_dev_extent */
  BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
  		   chunk_tree, 64);
  BTRFS_SETGET_FUNCS(dev_extent_chunk_objectid, struct btrfs_dev_extent,
  		   chunk_objectid, 64);
  BTRFS_SETGET_FUNCS(dev_extent_chunk_offset, struct btrfs_dev_extent,
  		   chunk_offset, 64);
  BTRFS_SETGET_FUNCS(dev_extent_length, struct btrfs_dev_extent, length, 64);
  
  static inline unsigned long btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
  {
  	unsigned long ptr = offsetof(struct btrfs_dev_extent, chunk_tree_uuid);
  	return (unsigned long)dev + ptr;
  }
  
  BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 64);
  BTRFS_SETGET_FUNCS(extent_generation, struct btrfs_extent_item,
  		   generation, 64);
  BTRFS_SETGET_FUNCS(extent_flags, struct btrfs_extent_item, flags, 64);
  
  BTRFS_SETGET_FUNCS(extent_refs_v0, struct btrfs_extent_item_v0, refs, 32);
  
  
  BTRFS_SETGET_FUNCS(tree_block_level, struct btrfs_tree_block_info, level, 8);
  
  static inline void btrfs_tree_block_key(struct extent_buffer *eb,
  					struct btrfs_tree_block_info *item,
  					struct btrfs_disk_key *key)
  {
  	read_eb_member(eb, item, struct btrfs_tree_block_info, key, key);
  }
  
  static inline void btrfs_set_tree_block_key(struct extent_buffer *eb,
  					    struct btrfs_tree_block_info *item,
  					    struct btrfs_disk_key *key)
  {
  	write_eb_member(eb, item, struct btrfs_tree_block_info, key, key);
  }
  
  BTRFS_SETGET_FUNCS(extent_data_ref_root, struct btrfs_extent_data_ref,
  		   root, 64);
  BTRFS_SETGET_FUNCS(extent_data_ref_objectid, struct btrfs_extent_data_ref,
  		   objectid, 64);
  BTRFS_SETGET_FUNCS(extent_data_ref_offset, struct btrfs_extent_data_ref,
  		   offset, 64);
  BTRFS_SETGET_FUNCS(extent_data_ref_count, struct btrfs_extent_data_ref,
  		   count, 32);
  
  BTRFS_SETGET_FUNCS(shared_data_ref_count, struct btrfs_shared_data_ref,
  		   count, 32);
  
  BTRFS_SETGET_FUNCS(extent_inline_ref_type, struct btrfs_extent_inline_ref,
  		   type, 8);
  BTRFS_SETGET_FUNCS(extent_inline_ref_offset, struct btrfs_extent_inline_ref,
  		   offset, 64);
  
  static inline u32 btrfs_extent_inline_ref_size(int type)
  {
  	if (type == BTRFS_TREE_BLOCK_REF_KEY ||
  	    type == BTRFS_SHARED_BLOCK_REF_KEY)
  		return sizeof(struct btrfs_extent_inline_ref);
  	if (type == BTRFS_SHARED_DATA_REF_KEY)
  		return sizeof(struct btrfs_shared_data_ref) +
  		       sizeof(struct btrfs_extent_inline_ref);
  	if (type == BTRFS_EXTENT_DATA_REF_KEY)
  		return sizeof(struct btrfs_extent_data_ref) +
  		       offsetof(struct btrfs_extent_inline_ref, offset);
  	BUG();
  	return 0;
  }
  
  BTRFS_SETGET_FUNCS(ref_root_v0, struct btrfs_extent_ref_v0, root, 64);
  BTRFS_SETGET_FUNCS(ref_generation_v0, struct btrfs_extent_ref_v0,
  		   generation, 64);
  BTRFS_SETGET_FUNCS(ref_objectid_v0, struct btrfs_extent_ref_v0, objectid, 64);
  BTRFS_SETGET_FUNCS(ref_count_v0, struct btrfs_extent_ref_v0, count, 32);
  
  /* struct btrfs_node */
  BTRFS_SETGET_FUNCS(key_blockptr, struct btrfs_key_ptr, blockptr, 64);
  BTRFS_SETGET_FUNCS(key_generation, struct btrfs_key_ptr, generation, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_key_blockptr, struct btrfs_key_ptr,
  			 blockptr, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_key_generation, struct btrfs_key_ptr,
  			 generation, 64);
  
  static inline u64 btrfs_node_blockptr(struct extent_buffer *eb, int nr)
  {
  	unsigned long ptr;
  	ptr = offsetof(struct btrfs_node, ptrs) +
  		sizeof(struct btrfs_key_ptr) * nr;
  	return btrfs_key_blockptr(eb, (struct btrfs_key_ptr *)ptr);
  }
  
  static inline void btrfs_set_node_blockptr(struct extent_buffer *eb,
  					   int nr, u64 val)
  {
  	unsigned long ptr;
  	ptr = offsetof(struct btrfs_node, ptrs) +
  		sizeof(struct btrfs_key_ptr) * nr;
  	btrfs_set_key_blockptr(eb, (struct btrfs_key_ptr *)ptr, val);
  }
  
  static inline u64 btrfs_node_ptr_generation(struct extent_buffer *eb, int nr)
  {
  	unsigned long ptr;
  	ptr = offsetof(struct btrfs_node, ptrs) +
  		sizeof(struct btrfs_key_ptr) * nr;
  	return btrfs_key_generation(eb, (struct btrfs_key_ptr *)ptr);
  }
  
  static inline void btrfs_set_node_ptr_generation(struct extent_buffer *eb,
  						 int nr, u64 val)
  {
  	unsigned long ptr;
  	ptr = offsetof(struct btrfs_node, ptrs) +
  		sizeof(struct btrfs_key_ptr) * nr;
  	btrfs_set_key_generation(eb, (struct btrfs_key_ptr *)ptr, val);
  }
  
  static inline unsigned long btrfs_node_key_ptr_offset(int nr)
  {
  	return offsetof(struct btrfs_node, ptrs) +
  		sizeof(struct btrfs_key_ptr) * nr;
  }
  
  void btrfs_node_key(struct extent_buffer *eb,
  		    struct btrfs_disk_key *disk_key, int nr);
  
  static inline void btrfs_set_node_key(struct extent_buffer *eb,
  				      struct btrfs_disk_key *disk_key, int nr)
  {
  	unsigned long ptr;
  	ptr = btrfs_node_key_ptr_offset(nr);
  	write_eb_member(eb, (struct btrfs_key_ptr *)ptr,
  		       struct btrfs_key_ptr, key, disk_key);
  }
  
  /* struct btrfs_item */
  BTRFS_SETGET_FUNCS(item_offset, struct btrfs_item, offset, 32);
  BTRFS_SETGET_FUNCS(item_size, struct btrfs_item, size, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_item_offset, struct btrfs_item, offset, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_item_size, struct btrfs_item, size, 32);
  
  static inline unsigned long btrfs_item_nr_offset(int nr)
  {
  	return offsetof(struct btrfs_leaf, items) +
  		sizeof(struct btrfs_item) * nr;
  }
  
  static inline struct btrfs_item *btrfs_item_nr(int nr)
  {
  	return (struct btrfs_item *)btrfs_item_nr_offset(nr);
  }
  
  static inline u32 btrfs_item_end(struct extent_buffer *eb,
  				 struct btrfs_item *item)
  {
  	return btrfs_item_offset(eb, item) + btrfs_item_size(eb, item);
  }
  
  static inline u32 btrfs_item_end_nr(struct extent_buffer *eb, int nr)
  {
  	return btrfs_item_end(eb, btrfs_item_nr(nr));
  }
  
  static inline u32 btrfs_item_offset_nr(struct extent_buffer *eb, int nr)
  {
  	return btrfs_item_offset(eb, btrfs_item_nr(nr));
  }
  
  static inline u32 btrfs_item_size_nr(struct extent_buffer *eb, int nr)
  {
  	return btrfs_item_size(eb, btrfs_item_nr(nr));
  }
  
  static inline void btrfs_item_key(struct extent_buffer *eb,
  			   struct btrfs_disk_key *disk_key, int nr)
  {
  	struct btrfs_item *item = btrfs_item_nr(nr);
  	read_eb_member(eb, item, struct btrfs_item, key, disk_key);
  }
  
  static inline void btrfs_set_item_key(struct extent_buffer *eb,
  			       struct btrfs_disk_key *disk_key, int nr)
  {
  	struct btrfs_item *item = btrfs_item_nr(nr);
  	write_eb_member(eb, item, struct btrfs_item, key, disk_key);
  }
  
  BTRFS_SETGET_FUNCS(dir_log_end, struct btrfs_dir_log_item, end, 64);
  
  /*
   * struct btrfs_root_ref
   */
  BTRFS_SETGET_FUNCS(root_ref_dirid, struct btrfs_root_ref, dirid, 64);
  BTRFS_SETGET_FUNCS(root_ref_sequence, struct btrfs_root_ref, sequence, 64);
  BTRFS_SETGET_FUNCS(root_ref_name_len, struct btrfs_root_ref, name_len, 16);
  
  /* struct btrfs_dir_item */
  BTRFS_SETGET_FUNCS(dir_data_len, struct btrfs_dir_item, data_len, 16);
  BTRFS_SETGET_FUNCS(dir_type, struct btrfs_dir_item, type, 8);
  BTRFS_SETGET_FUNCS(dir_name_len, struct btrfs_dir_item, name_len, 16);
  BTRFS_SETGET_FUNCS(dir_transid, struct btrfs_dir_item, transid, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dir_type, struct btrfs_dir_item, type, 8);
  BTRFS_SETGET_STACK_FUNCS(stack_dir_data_len, struct btrfs_dir_item,
  			 data_len, 16);
  BTRFS_SETGET_STACK_FUNCS(stack_dir_name_len, struct btrfs_dir_item,
  			 name_len, 16);
  BTRFS_SETGET_STACK_FUNCS(stack_dir_transid, struct btrfs_dir_item,
  			 transid, 64);
  
  static inline void btrfs_dir_item_key(struct extent_buffer *eb,
  				      struct btrfs_dir_item *item,
  				      struct btrfs_disk_key *key)
  {
  	read_eb_member(eb, item, struct btrfs_dir_item, location, key);
  }
  
  static inline void btrfs_set_dir_item_key(struct extent_buffer *eb,
  					  struct btrfs_dir_item *item,
  					  struct btrfs_disk_key *key)
  {
  	write_eb_member(eb, item, struct btrfs_dir_item, location, key);
  }
  
  BTRFS_SETGET_FUNCS(free_space_entries, struct btrfs_free_space_header,
  		   num_entries, 64);
  BTRFS_SETGET_FUNCS(free_space_bitmaps, struct btrfs_free_space_header,
  		   num_bitmaps, 64);
  BTRFS_SETGET_FUNCS(free_space_generation, struct btrfs_free_space_header,
  		   generation, 64);
  
  static inline void btrfs_free_space_key(struct extent_buffer *eb,
  					struct btrfs_free_space_header *h,
  					struct btrfs_disk_key *key)
  {
  	read_eb_member(eb, h, struct btrfs_free_space_header, location, key);
  }
  
  static inline void btrfs_set_free_space_key(struct extent_buffer *eb,
  					    struct btrfs_free_space_header *h,
  					    struct btrfs_disk_key *key)
  {
  	write_eb_member(eb, h, struct btrfs_free_space_header, location, key);
  }
  
  /* struct btrfs_disk_key */
  BTRFS_SETGET_STACK_FUNCS(disk_key_objectid, struct btrfs_disk_key,
  			 objectid, 64);
  BTRFS_SETGET_STACK_FUNCS(disk_key_offset, struct btrfs_disk_key, offset, 64);
  BTRFS_SETGET_STACK_FUNCS(disk_key_type, struct btrfs_disk_key, type, 8);
  
  static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
  					 struct btrfs_disk_key *disk)
  {
  	cpu->offset = le64_to_cpu(disk->offset);
  	cpu->type = disk->type;
  	cpu->objectid = le64_to_cpu(disk->objectid);
  }
  
  static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
  					 struct btrfs_key *cpu)
  {
  	disk->offset = cpu_to_le64(cpu->offset);
  	disk->type = cpu->type;
  	disk->objectid = cpu_to_le64(cpu->objectid);
  }
  
  static inline void btrfs_node_key_to_cpu(struct extent_buffer *eb,
  				  struct btrfs_key *key, int nr)
  {
  	struct btrfs_disk_key disk_key;
  	btrfs_node_key(eb, &disk_key, nr);
  	btrfs_disk_key_to_cpu(key, &disk_key);
  }
  
  static inline void btrfs_item_key_to_cpu(struct extent_buffer *eb,
  				  struct btrfs_key *key, int nr)
  {
  	struct btrfs_disk_key disk_key;
  	btrfs_item_key(eb, &disk_key, nr);
  	btrfs_disk_key_to_cpu(key, &disk_key);
  }
  
  static inline void btrfs_dir_item_key_to_cpu(struct extent_buffer *eb,
  				      struct btrfs_dir_item *item,
  				      struct btrfs_key *key)
  {
  	struct btrfs_disk_key disk_key;
  	btrfs_dir_item_key(eb, item, &disk_key);
  	btrfs_disk_key_to_cpu(key, &disk_key);
  }
  
  
  static inline u8 btrfs_key_type(struct btrfs_key *key)
  {
  	return key->type;
  }
  
  static inline void btrfs_set_key_type(struct btrfs_key *key, u8 val)
  {
  	key->type = val;
  }
  
  /* struct btrfs_header */
  BTRFS_SETGET_HEADER_FUNCS(header_bytenr, struct btrfs_header, bytenr, 64);
  BTRFS_SETGET_HEADER_FUNCS(header_generation, struct btrfs_header,
  			  generation, 64);
  BTRFS_SETGET_HEADER_FUNCS(header_owner, struct btrfs_header, owner, 64);
  BTRFS_SETGET_HEADER_FUNCS(header_nritems, struct btrfs_header, nritems, 32);
  BTRFS_SETGET_HEADER_FUNCS(header_flags, struct btrfs_header, flags, 64);
  BTRFS_SETGET_HEADER_FUNCS(header_level, struct btrfs_header, level, 8);
  BTRFS_SETGET_STACK_FUNCS(stack_header_generation, struct btrfs_header,
  			 generation, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_header_owner, struct btrfs_header, owner, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_header_nritems, struct btrfs_header,
  			 nritems, 32);
  BTRFS_SETGET_STACK_FUNCS(stack_header_bytenr, struct btrfs_header, bytenr, 64);
  
  static inline int btrfs_header_flag(struct extent_buffer *eb, u64 flag)
  {
  	return (btrfs_header_flags(eb) & flag) == flag;
  }
  
  static inline int btrfs_set_header_flag(struct extent_buffer *eb, u64 flag)
  {
  	u64 flags = btrfs_header_flags(eb);
  	btrfs_set_header_flags(eb, flags | flag);
  	return (flags & flag) == flag;
  }
  
  static inline int btrfs_clear_header_flag(struct extent_buffer *eb, u64 flag)
  {
  	u64 flags = btrfs_header_flags(eb);
  	btrfs_set_header_flags(eb, flags & ~flag);
  	return (flags & flag) == flag;
  }
  
  static inline int btrfs_header_backref_rev(struct extent_buffer *eb)
  {
  	u64 flags = btrfs_header_flags(eb);
  	return flags >> BTRFS_BACKREF_REV_SHIFT;
  }
  
  static inline void btrfs_set_header_backref_rev(struct extent_buffer *eb,
  						int rev)
  {
  	u64 flags = btrfs_header_flags(eb);
  	flags &= ~BTRFS_BACKREF_REV_MASK;
  	flags |= (u64)rev << BTRFS_BACKREF_REV_SHIFT;
  	btrfs_set_header_flags(eb, flags);
  }
  
  static inline unsigned long btrfs_header_fsid(void)
  {
  	return offsetof(struct btrfs_header, fsid);
  }
  
  static inline unsigned long btrfs_header_chunk_tree_uuid(struct extent_buffer *eb)
  {
  	return offsetof(struct btrfs_header, chunk_tree_uuid);
  }
  
  static inline int btrfs_is_leaf(struct extent_buffer *eb)
  {
  	return btrfs_header_level(eb) == 0;
  }
  
  /* struct btrfs_root_item */
  BTRFS_SETGET_FUNCS(disk_root_generation, struct btrfs_root_item,
  		   generation, 64);
  BTRFS_SETGET_FUNCS(disk_root_refs, struct btrfs_root_item, refs, 32);
  BTRFS_SETGET_FUNCS(disk_root_bytenr, struct btrfs_root_item, bytenr, 64);
  BTRFS_SETGET_FUNCS(disk_root_level, struct btrfs_root_item, level, 8);
  
  BTRFS_SETGET_STACK_FUNCS(root_generation, struct btrfs_root_item,
  			 generation, 64);
  BTRFS_SETGET_STACK_FUNCS(root_bytenr, struct btrfs_root_item, bytenr, 64);
  BTRFS_SETGET_STACK_FUNCS(root_level, struct btrfs_root_item, level, 8);
  BTRFS_SETGET_STACK_FUNCS(root_dirid, struct btrfs_root_item, root_dirid, 64);
  BTRFS_SETGET_STACK_FUNCS(root_refs, struct btrfs_root_item, refs, 32);
  BTRFS_SETGET_STACK_FUNCS(root_flags, struct btrfs_root_item, flags, 64);
  BTRFS_SETGET_STACK_FUNCS(root_used, struct btrfs_root_item, bytes_used, 64);
  BTRFS_SETGET_STACK_FUNCS(root_limit, struct btrfs_root_item, byte_limit, 64);
  BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item,
  			 last_snapshot, 64);
  BTRFS_SETGET_STACK_FUNCS(root_generation_v2, struct btrfs_root_item,
  			 generation_v2, 64);
  BTRFS_SETGET_STACK_FUNCS(root_ctransid, struct btrfs_root_item,
  			 ctransid, 64);
  BTRFS_SETGET_STACK_FUNCS(root_otransid, struct btrfs_root_item,
  			 otransid, 64);
  BTRFS_SETGET_STACK_FUNCS(root_stransid, struct btrfs_root_item,
  			 stransid, 64);
  BTRFS_SETGET_STACK_FUNCS(root_rtransid, struct btrfs_root_item,
  			 rtransid, 64);
  
  static inline bool btrfs_root_readonly(struct btrfs_root *root)
  {
  	return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
  }
  
  static inline bool btrfs_root_dead(struct btrfs_root *root)
  {
  	return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
  }
  
  /* struct btrfs_root_backup */
  BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
  		   tree_root, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_tree_root_gen, struct btrfs_root_backup,
  		   tree_root_gen, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_tree_root_level, struct btrfs_root_backup,
  		   tree_root_level, 8);
  
  BTRFS_SETGET_STACK_FUNCS(backup_chunk_root, struct btrfs_root_backup,
  		   chunk_root, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_gen, struct btrfs_root_backup,
  		   chunk_root_gen, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_level, struct btrfs_root_backup,
  		   chunk_root_level, 8);
  
  BTRFS_SETGET_STACK_FUNCS(backup_extent_root, struct btrfs_root_backup,
  		   extent_root, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_extent_root_gen, struct btrfs_root_backup,
  		   extent_root_gen, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_extent_root_level, struct btrfs_root_backup,
  		   extent_root_level, 8);
  
  BTRFS_SETGET_STACK_FUNCS(backup_fs_root, struct btrfs_root_backup,
  		   fs_root, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_fs_root_gen, struct btrfs_root_backup,
  		   fs_root_gen, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_fs_root_level, struct btrfs_root_backup,
  		   fs_root_level, 8);
  
  BTRFS_SETGET_STACK_FUNCS(backup_dev_root, struct btrfs_root_backup,
  		   dev_root, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_dev_root_gen, struct btrfs_root_backup,
  		   dev_root_gen, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_dev_root_level, struct btrfs_root_backup,
  		   dev_root_level, 8);
  
  BTRFS_SETGET_STACK_FUNCS(backup_csum_root, struct btrfs_root_backup,
  		   csum_root, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_csum_root_gen, struct btrfs_root_backup,
  		   csum_root_gen, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_csum_root_level, struct btrfs_root_backup,
  		   csum_root_level, 8);
  BTRFS_SETGET_STACK_FUNCS(backup_total_bytes, struct btrfs_root_backup,
  		   total_bytes, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_bytes_used, struct btrfs_root_backup,
  		   bytes_used, 64);
  BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
  		   num_devices, 64);
  
  /* struct btrfs_balance_item */
  BTRFS_SETGET_FUNCS(balance_flags, struct btrfs_balance_item, flags, 64);
  
  static inline void btrfs_balance_data(struct extent_buffer *eb,
  				      struct btrfs_balance_item *bi,
  				      struct btrfs_disk_balance_args *ba)
  {
  	read_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
  }
  
  static inline void btrfs_set_balance_data(struct extent_buffer *eb,
  					  struct btrfs_balance_item *bi,
  					  struct btrfs_disk_balance_args *ba)
  {
  	write_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
  }
  
  static inline void btrfs_balance_meta(struct extent_buffer *eb,
  				      struct btrfs_balance_item *bi,
  				      struct btrfs_disk_balance_args *ba)
  {
  	read_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
  }
  
  static inline void btrfs_set_balance_meta(struct extent_buffer *eb,
  					  struct btrfs_balance_item *bi,
  					  struct btrfs_disk_balance_args *ba)
  {
  	write_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
  }
  
  static inline void btrfs_balance_sys(struct extent_buffer *eb,
  				     struct btrfs_balance_item *bi,
  				     struct btrfs_disk_balance_args *ba)
  {
  	read_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
  }
  
  static inline void btrfs_set_balance_sys(struct extent_buffer *eb,
  					 struct btrfs_balance_item *bi,
  					 struct btrfs_disk_balance_args *ba)
  {
  	write_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
  }
  
  static inline void
  btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,
  			       struct btrfs_disk_balance_args *disk)
  {
  	memset(cpu, 0, sizeof(*cpu));
  
  	cpu->profiles = le64_to_cpu(disk->profiles);
  	cpu->usage = le64_to_cpu(disk->usage);
  	cpu->devid = le64_to_cpu(disk->devid);
  	cpu->pstart = le64_to_cpu(disk->pstart);
  	cpu->pend = le64_to_cpu(disk->pend);
  	cpu->vstart = le64_to_cpu(disk->vstart);
  	cpu->vend = le64_to_cpu(disk->vend);
  	cpu->target = le64_to_cpu(disk->target);
  	cpu->flags = le64_to_cpu(disk->flags);
  	cpu->limit = le64_to_cpu(disk->limit);
  }
  
  static inline void
  btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,
  			       struct btrfs_balance_args *cpu)
  {
  	memset(disk, 0, sizeof(*disk));
  
  	disk->profiles = cpu_to_le64(cpu->profiles);
  	disk->usage = cpu_to_le64(cpu->usage);
  	disk->devid = cpu_to_le64(cpu->devid);
  	disk->pstart = cpu_to_le64(cpu->pstart);
  	disk->pend = cpu_to_le64(cpu->pend);
  	disk->vstart = cpu_to_le64(cpu->vstart);
  	disk->vend = cpu_to_le64(cpu->vend);
  	disk->target = cpu_to_le64(cpu->target);
  	disk->flags = cpu_to_le64(cpu->flags);
  	disk->limit = cpu_to_le64(cpu->limit);
  }
  
  /* struct btrfs_super_block */
  BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);
  BTRFS_SETGET_STACK_FUNCS(super_flags, struct btrfs_super_block, flags, 64);
  BTRFS_SETGET_STACK_FUNCS(super_generation, struct btrfs_super_block,
  			 generation, 64);
  BTRFS_SETGET_STACK_FUNCS(super_root, struct btrfs_super_block, root, 64);
  BTRFS_SETGET_STACK_FUNCS(super_sys_array_size,
  			 struct btrfs_super_block, sys_chunk_array_size, 32);
  BTRFS_SETGET_STACK_FUNCS(super_chunk_root_generation,
  			 struct btrfs_super_block, chunk_root_generation, 64);
  BTRFS_SETGET_STACK_FUNCS(super_root_level, struct btrfs_super_block,
  			 root_level, 8);
  BTRFS_SETGET_STACK_FUNCS(super_chunk_root, struct btrfs_super_block,
  			 chunk_root, 64);
  BTRFS_SETGET_STACK_FUNCS(super_chunk_root_level, struct btrfs_super_block,
  			 chunk_root_level, 8);
  BTRFS_SETGET_STACK_FUNCS(super_log_root, struct btrfs_super_block,
  			 log_root, 64);
  BTRFS_SETGET_STACK_FUNCS(super_log_root_transid, struct btrfs_super_block,
  			 log_root_transid, 64);
  BTRFS_SETGET_STACK_FUNCS(super_log_root_level, struct btrfs_super_block,
  			 log_root_level, 8);
  BTRFS_SETGET_STACK_FUNCS(super_total_bytes, struct btrfs_super_block,
  			 total_bytes, 64);
  BTRFS_SETGET_STACK_FUNCS(super_bytes_used, struct btrfs_super_block,
  			 bytes_used, 64);
  BTRFS_SETGET_STACK_FUNCS(super_sectorsize, struct btrfs_super_block,
  			 sectorsize, 32);
  BTRFS_SETGET_STACK_FUNCS(super_nodesize, struct btrfs_super_block,
  			 nodesize, 32);
  BTRFS_SETGET_STACK_FUNCS(super_stripesize, struct btrfs_super_block,
  			 stripesize, 32);
  BTRFS_SETGET_STACK_FUNCS(super_root_dir, struct btrfs_super_block,
  			 root_dir_objectid, 64);
  BTRFS_SETGET_STACK_FUNCS(super_num_devices, struct btrfs_super_block,
  			 num_devices, 64);
  BTRFS_SETGET_STACK_FUNCS(super_compat_flags, struct btrfs_super_block,
  			 compat_flags, 64);
  BTRFS_SETGET_STACK_FUNCS(super_compat_ro_flags, struct btrfs_super_block,
  			 compat_ro_flags, 64);
  BTRFS_SETGET_STACK_FUNCS(super_incompat_flags, struct btrfs_super_block,
  			 incompat_flags, 64);
  BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block,
  			 csum_type, 16);
  BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block,
  			 cache_generation, 64);
  BTRFS_SETGET_STACK_FUNCS(super_magic, struct btrfs_super_block, magic, 64);
  BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block,
  			 uuid_tree_generation, 64);
  
  static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
  {
  	u16 t = btrfs_super_csum_type(s);
  	/*
  	 * csum type is validated at mount time
  	 */
  	return btrfs_csum_sizes[t];
  }
  
  static inline unsigned long btrfs_leaf_data(struct extent_buffer *l)
  {
  	return offsetof(struct btrfs_leaf, items);
  }
  
  /* struct btrfs_file_extent_item */
  BTRFS_SETGET_FUNCS(file_extent_type, struct btrfs_file_extent_item, type, 8);
  BTRFS_SETGET_STACK_FUNCS(stack_file_extent_disk_bytenr,
  			 struct btrfs_file_extent_item, disk_bytenr, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_file_extent_offset,
  			 struct btrfs_file_extent_item, offset, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_file_extent_generation,
  			 struct btrfs_file_extent_item, generation, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_file_extent_num_bytes,
  			 struct btrfs_file_extent_item, num_bytes, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_file_extent_disk_num_bytes,
  			 struct btrfs_file_extent_item, disk_num_bytes, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_file_extent_compression,
  			 struct btrfs_file_extent_item, compression, 8);
  
  static inline unsigned long
  btrfs_file_extent_inline_start(struct btrfs_file_extent_item *e)
  {
  	return (unsigned long)e + BTRFS_FILE_EXTENT_INLINE_DATA_START;
  }
  
  static inline u32 btrfs_file_extent_calc_inline_size(u32 datasize)
  {
  	return BTRFS_FILE_EXTENT_INLINE_DATA_START + datasize;
  }
  
  BTRFS_SETGET_FUNCS(file_extent_disk_bytenr, struct btrfs_file_extent_item,
  		   disk_bytenr, 64);
  BTRFS_SETGET_FUNCS(file_extent_generation, struct btrfs_file_extent_item,
  		   generation, 64);
  BTRFS_SETGET_FUNCS(file_extent_disk_num_bytes, struct btrfs_file_extent_item,
  		   disk_num_bytes, 64);
  BTRFS_SETGET_FUNCS(file_extent_offset, struct btrfs_file_extent_item,
  		  offset, 64);
  BTRFS_SETGET_FUNCS(file_extent_num_bytes, struct btrfs_file_extent_item,
  		   num_bytes, 64);
  BTRFS_SETGET_FUNCS(file_extent_ram_bytes, struct btrfs_file_extent_item,
  		   ram_bytes, 64);
  BTRFS_SETGET_FUNCS(file_extent_compression, struct btrfs_file_extent_item,
  		   compression, 8);
  BTRFS_SETGET_FUNCS(file_extent_encryption, struct btrfs_file_extent_item,
  		   encryption, 8);
  BTRFS_SETGET_FUNCS(file_extent_other_encoding, struct btrfs_file_extent_item,
  		   other_encoding, 16);
  
  /*
   * this returns the number of bytes used by the item on disk, minus the
   * size of any extent headers.  If a file is compressed on disk, this is
   * the compressed size
   */
  static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
  						    struct btrfs_item *e)
  {
  	return btrfs_item_size(eb, e) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
  }
  
  /* this returns the number of file bytes represented by the inline item.
   * If an item is compressed, this is the uncompressed size
   */
  static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
  					       int slot,
  					       struct btrfs_file_extent_item *fi)
  {
  	struct btrfs_map_token token;
  
  	btrfs_init_map_token(&token);
  	/*
  	 * return the space used on disk if this item isn't
  	 * compressed or encoded
  	 */
  	if (btrfs_token_file_extent_compression(eb, fi, &token) == 0 &&
  	    btrfs_token_file_extent_encryption(eb, fi, &token) == 0 &&
  	    btrfs_token_file_extent_other_encoding(eb, fi, &token) == 0) {
  		return btrfs_file_extent_inline_item_len(eb,
  							 btrfs_item_nr(slot));
  	}
  
  	/* otherwise use the ram bytes field */
  	return btrfs_token_file_extent_ram_bytes(eb, fi, &token);
  }
  
  
  /* btrfs_dev_stats_item */
  static inline u64 btrfs_dev_stats_value(struct extent_buffer *eb,
  					struct btrfs_dev_stats_item *ptr,
  					int index)
  {
  	u64 val;
  
  	read_extent_buffer(eb, &val,
  			   offsetof(struct btrfs_dev_stats_item, values) +
  			    ((unsigned long)ptr) + (index * sizeof(u64)),
  			   sizeof(val));
  	return val;
  }
  
  static inline void btrfs_set_dev_stats_value(struct extent_buffer *eb,
  					     struct btrfs_dev_stats_item *ptr,
  					     int index, u64 val)
  {
  	write_extent_buffer(eb, &val,
  			    offsetof(struct btrfs_dev_stats_item, values) +
  			     ((unsigned long)ptr) + (index * sizeof(u64)),
  			    sizeof(val));
  }
  
  /* btrfs_qgroup_status_item */
  BTRFS_SETGET_FUNCS(qgroup_status_generation, struct btrfs_qgroup_status_item,
  		   generation, 64);
  BTRFS_SETGET_FUNCS(qgroup_status_version, struct btrfs_qgroup_status_item,
  		   version, 64);
  BTRFS_SETGET_FUNCS(qgroup_status_flags, struct btrfs_qgroup_status_item,
  		   flags, 64);
  BTRFS_SETGET_FUNCS(qgroup_status_rescan, struct btrfs_qgroup_status_item,
  		   rescan, 64);
  
  /* btrfs_qgroup_info_item */
  BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,
  		   generation, 64);
  BTRFS_SETGET_FUNCS(qgroup_info_rfer, struct btrfs_qgroup_info_item, rfer, 64);
  BTRFS_SETGET_FUNCS(qgroup_info_rfer_cmpr, struct btrfs_qgroup_info_item,
  		   rfer_cmpr, 64);
  BTRFS_SETGET_FUNCS(qgroup_info_excl, struct btrfs_qgroup_info_item, excl, 64);
  BTRFS_SETGET_FUNCS(qgroup_info_excl_cmpr, struct btrfs_qgroup_info_item,
  		   excl_cmpr, 64);
  
  BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_generation,
  			 struct btrfs_qgroup_info_item, generation, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_rfer, struct btrfs_qgroup_info_item,
  			 rfer, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_rfer_cmpr,
  			 struct btrfs_qgroup_info_item, rfer_cmpr, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_excl, struct btrfs_qgroup_info_item,
  			 excl, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_qgroup_info_excl_cmpr,
  			 struct btrfs_qgroup_info_item, excl_cmpr, 64);
  
  /* btrfs_qgroup_limit_item */
  BTRFS_SETGET_FUNCS(qgroup_limit_flags, struct btrfs_qgroup_limit_item,
  		   flags, 64);
  BTRFS_SETGET_FUNCS(qgroup_limit_max_rfer, struct btrfs_qgroup_limit_item,
  		   max_rfer, 64);
  BTRFS_SETGET_FUNCS(qgroup_limit_max_excl, struct btrfs_qgroup_limit_item,
  		   max_excl, 64);
  BTRFS_SETGET_FUNCS(qgroup_limit_rsv_rfer, struct btrfs_qgroup_limit_item,
  		   rsv_rfer, 64);
  BTRFS_SETGET_FUNCS(qgroup_limit_rsv_excl, struct btrfs_qgroup_limit_item,
  		   rsv_excl, 64);
  
  /* btrfs_dev_replace_item */
  BTRFS_SETGET_FUNCS(dev_replace_src_devid,
  		   struct btrfs_dev_replace_item, src_devid, 64);
  BTRFS_SETGET_FUNCS(dev_replace_cont_reading_from_srcdev_mode,
  		   struct btrfs_dev_replace_item, cont_reading_from_srcdev_mode,
  		   64);
  BTRFS_SETGET_FUNCS(dev_replace_replace_state, struct btrfs_dev_replace_item,
  		   replace_state, 64);
  BTRFS_SETGET_FUNCS(dev_replace_time_started, struct btrfs_dev_replace_item,
  		   time_started, 64);
  BTRFS_SETGET_FUNCS(dev_replace_time_stopped, struct btrfs_dev_replace_item,
  		   time_stopped, 64);
  BTRFS_SETGET_FUNCS(dev_replace_num_write_errors, struct btrfs_dev_replace_item,
  		   num_write_errors, 64);
  BTRFS_SETGET_FUNCS(dev_replace_num_uncorrectable_read_errors,
  		   struct btrfs_dev_replace_item, num_uncorrectable_read_errors,
  		   64);
  BTRFS_SETGET_FUNCS(dev_replace_cursor_left, struct btrfs_dev_replace_item,
  		   cursor_left, 64);
  BTRFS_SETGET_FUNCS(dev_replace_cursor_right, struct btrfs_dev_replace_item,
  		   cursor_right, 64);
  
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_src_devid,
  			 struct btrfs_dev_replace_item, src_devid, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cont_reading_from_srcdev_mode,
  			 struct btrfs_dev_replace_item,
  			 cont_reading_from_srcdev_mode, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_replace_state,
  			 struct btrfs_dev_replace_item, replace_state, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_time_started,
  			 struct btrfs_dev_replace_item, time_started, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_time_stopped,
  			 struct btrfs_dev_replace_item, time_stopped, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_num_write_errors,
  			 struct btrfs_dev_replace_item, num_write_errors, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_num_uncorrectable_read_errors,
  			 struct btrfs_dev_replace_item,
  			 num_uncorrectable_read_errors, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cursor_left,
  			 struct btrfs_dev_replace_item, cursor_left, 64);
  BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cursor_right,
  			 struct btrfs_dev_replace_item, cursor_right, 64);
  
  static inline struct btrfs_fs_info *btrfs_sb(struct super_block *sb)
  {
  	return sb->s_fs_info;
  }
  
  /* helper function to cast into the data area of the leaf. */
  #define btrfs_item_ptr(leaf, slot, type) \
  	((type *)(btrfs_leaf_data(leaf) + \
  	btrfs_item_offset_nr(leaf, slot)))
  
  #define btrfs_item_ptr_offset(leaf, slot) \
  	((unsigned long)(btrfs_leaf_data(leaf) + \
  	btrfs_item_offset_nr(leaf, slot)))
  
  static inline bool btrfs_mixed_space_info(struct btrfs_space_info *space_info)
  {
  	return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) &&
  		(space_info->flags & BTRFS_BLOCK_GROUP_DATA));
  }
  
  static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
  {
  	return mapping_gfp_constraint(mapping, ~__GFP_FS);
  }
  
  /* extent-tree.c */
  
  u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes);
  
  static inline u64 btrfs_calc_trans_metadata_size(struct btrfs_root *root,
  						 unsigned num_items)
  {
  	return (root->nodesize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
  		2 * num_items;
  }
  
  /*
   * Doing a truncate won't result in new nodes or leaves, just what we need for
   * COW.
   */
  static inline u64 btrfs_calc_trunc_metadata_size(struct btrfs_root *root,
  						 unsigned num_items)
  {
  	return root->nodesize * BTRFS_MAX_LEVEL * num_items;
  }
  
  int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
  				       struct btrfs_root *root);
  int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
  				       struct btrfs_root *root);
  void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
  int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root, unsigned long count);
  int btrfs_async_run_delayed_refs(struct btrfs_root *root,
  				 unsigned long count, int wait);
  int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len);
  int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root, u64 bytenr,
  			     u64 offset, int metadata, u64 *refs, u64 *flags);
  int btrfs_pin_extent(struct btrfs_root *root,
  		     u64 bytenr, u64 num, int reserved);
  int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
  				    u64 bytenr, u64 num_bytes);
  int btrfs_exclude_logged_extents(struct btrfs_root *root,
  				 struct extent_buffer *eb);
  int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
  			  struct btrfs_root *root,
  			  u64 objectid, u64 offset, u64 bytenr);
  struct btrfs_block_group_cache *btrfs_lookup_block_group(
  						 struct btrfs_fs_info *info,
  						 u64 bytenr);
  void btrfs_get_block_group(struct btrfs_block_group_cache *cache);
  void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
  int get_block_group_index(struct btrfs_block_group_cache *cache);
  struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
  					struct btrfs_root *root, u64 parent,
  					u64 root_objectid,
  					struct btrfs_disk_key *key, int level,
  					u64 hint, u64 empty_size);
  void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root,
  			   struct extent_buffer *buf,
  			   u64 parent, int last_ref);
  int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  				     struct btrfs_root *root,
  				     u64 root_objectid, u64 owner,
  				     u64 offset, u64 ram_bytes,
  				     struct btrfs_key *ins);
  int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
  				   struct btrfs_root *root,
  				   u64 root_objectid, u64 owner, u64 offset,
  				   struct btrfs_key *ins);
  int btrfs_reserve_extent(struct btrfs_root *root, u64 num_bytes,
  			 u64 min_alloc_size, u64 empty_size, u64 hint_byte,
  			 struct btrfs_key *ins, int is_data, int delalloc);
  int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  		  struct extent_buffer *buf, int full_backref);
  int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  		  struct extent_buffer *buf, int full_backref);
  int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
  				struct btrfs_root *root,
  				u64 bytenr, u64 num_bytes, u64 flags,
  				int level, int is_data);
  int btrfs_free_extent(struct btrfs_trans_handle *trans,
  		      struct btrfs_root *root,
  		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
  		      u64 owner, u64 offset);
  
  int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len,
  			       int delalloc);
  int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
  				       u64 start, u64 len);
  void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
  				 struct btrfs_root *root);
  int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
  			       struct btrfs_root *root);
  int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
  			 struct btrfs_root *root,
  			 u64 bytenr, u64 num_bytes, u64 parent,
  			 u64 root_objectid, u64 owner, u64 offset);
  
  int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
  				   struct btrfs_root *root);
  int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
  				    struct btrfs_root *root);
  int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
  			    struct btrfs_root *root);
  int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr);
  int btrfs_free_block_groups(struct btrfs_fs_info *info);
  int btrfs_read_block_groups(struct btrfs_root *root);
  int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr);
  int btrfs_make_block_group(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root, u64 bytes_used,
  			   u64 type, u64 chunk_objectid, u64 chunk_offset,
  			   u64 size);
  struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
  				struct btrfs_fs_info *fs_info,
  				const u64 chunk_offset);
  int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root, u64 group_start,
  			     struct extent_map *em);
  void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info);
  void btrfs_get_block_group_trimming(struct btrfs_block_group_cache *cache);
  void btrfs_put_block_group_trimming(struct btrfs_block_group_cache *cache);
  void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
  				       struct btrfs_root *root);
  u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data);
  void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
  
  enum btrfs_reserve_flush_enum {
  	/* If we are in the transaction, we can't flush anything.*/
  	BTRFS_RESERVE_NO_FLUSH,
  	/*
  	 * Flushing delalloc may cause deadlock somewhere, in this
  	 * case, use FLUSH LIMIT
  	 */
  	BTRFS_RESERVE_FLUSH_LIMIT,
  	BTRFS_RESERVE_FLUSH_ALL,
  };
  
  int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len);
  int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes);
  void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len);
  void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
  					    u64 len);
  void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
  				struct btrfs_root *root);
  void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
  int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
  				  struct inode *inode);
  void btrfs_orphan_release_metadata(struct inode *inode);
  int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
  				     struct btrfs_block_rsv *rsv,
  				     int nitems,
  				     u64 *qgroup_reserved, bool use_global_rsv);
  void btrfs_subvolume_release_metadata(struct btrfs_root *root,
  				      struct btrfs_block_rsv *rsv,
  				      u64 qgroup_reserved);
  int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes);
  void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes);
  int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len);
  void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len);
  void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type);
  struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
  					      unsigned short type);
  void btrfs_free_block_rsv(struct btrfs_root *root,
  			  struct btrfs_block_rsv *rsv);
  void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv);
  int btrfs_block_rsv_add(struct btrfs_root *root,
  			struct btrfs_block_rsv *block_rsv, u64 num_bytes,
  			enum btrfs_reserve_flush_enum flush);
  int btrfs_block_rsv_check(struct btrfs_root *root,
  			  struct btrfs_block_rsv *block_rsv, int min_factor);
  int btrfs_block_rsv_refill(struct btrfs_root *root,
  			   struct btrfs_block_rsv *block_rsv, u64 min_reserved,
  			   enum btrfs_reserve_flush_enum flush);
  int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
  			    struct btrfs_block_rsv *dst_rsv,
  			    u64 num_bytes);
  int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
  			     struct btrfs_block_rsv *dest, u64 num_bytes,
  			     int min_factor);
  void btrfs_block_rsv_release(struct btrfs_root *root,
  			     struct btrfs_block_rsv *block_rsv,
  			     u64 num_bytes);
  int btrfs_inc_block_group_ro(struct btrfs_root *root,
  			     struct btrfs_block_group_cache *cache);
  void btrfs_dec_block_group_ro(struct btrfs_root *root,
  			      struct btrfs_block_group_cache *cache);
  void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
  u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
  int btrfs_error_unpin_extent_range(struct btrfs_root *root,
  				   u64 start, u64 end);
  int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
  			 u64 num_bytes, u64 *actual_bytes);
  int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
  			    struct btrfs_root *root, u64 type);
  int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range);
  
  int btrfs_init_space_info(struct btrfs_fs_info *fs_info);
  int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
  					 struct btrfs_fs_info *fs_info);
  int __get_raid_index(u64 flags);
  int btrfs_start_write_no_snapshoting(struct btrfs_root *root);
  void btrfs_end_write_no_snapshoting(struct btrfs_root *root);
  void check_system_chunk(struct btrfs_trans_handle *trans,
  			struct btrfs_root *root,
  			const u64 type);
  /* ctree.c */
  int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
  		     int level, int *slot);
  int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2);
  int btrfs_previous_item(struct btrfs_root *root,
  			struct btrfs_path *path, u64 min_objectid,
  			int type);
  int btrfs_previous_extent_item(struct btrfs_root *root,
  			struct btrfs_path *path, u64 min_objectid);
  void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
  			     struct btrfs_path *path,
  			     struct btrfs_key *new_key);
  struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
  struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
  int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
  			struct btrfs_key *key, int lowest_level,
  			u64 min_trans);
  int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
  			 struct btrfs_path *path,
  			 u64 min_trans);
  enum btrfs_compare_tree_result {
  	BTRFS_COMPARE_TREE_NEW,
  	BTRFS_COMPARE_TREE_DELETED,
  	BTRFS_COMPARE_TREE_CHANGED,
  	BTRFS_COMPARE_TREE_SAME,
  };
  typedef int (*btrfs_changed_cb_t)(struct btrfs_root *left_root,
  				  struct btrfs_root *right_root,
  				  struct btrfs_path *left_path,
  				  struct btrfs_path *right_path,
  				  struct btrfs_key *key,
  				  enum btrfs_compare_tree_result result,
  				  void *ctx);
  int btrfs_compare_trees(struct btrfs_root *left_root,
  			struct btrfs_root *right_root,
  			btrfs_changed_cb_t cb, void *ctx);
  int btrfs_cow_block(struct btrfs_trans_handle *trans,
  		    struct btrfs_root *root, struct extent_buffer *buf,
  		    struct extent_buffer *parent, int parent_slot,
  		    struct extent_buffer **cow_ret);
  int btrfs_copy_root(struct btrfs_trans_handle *trans,
  		      struct btrfs_root *root,
  		      struct extent_buffer *buf,
  		      struct extent_buffer **cow_ret, u64 new_root_objectid);
  int btrfs_block_can_be_shared(struct btrfs_root *root,
  			      struct extent_buffer *buf);
  void btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
  		       u32 data_size);
  void btrfs_truncate_item(struct btrfs_root *root, struct btrfs_path *path,
  			 u32 new_size, int from_end);
  int btrfs_split_item(struct btrfs_trans_handle *trans,
  		     struct btrfs_root *root,
  		     struct btrfs_path *path,
  		     struct btrfs_key *new_key,
  		     unsigned long split_offset);
  int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
  			 struct btrfs_root *root,
  			 struct btrfs_path *path,
  			 struct btrfs_key *new_key);
  int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
  		u64 inum, u64 ioff, u8 key_type, struct btrfs_key *found_key);
  int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
  		      *root, struct btrfs_key *key, struct btrfs_path *p, int
  		      ins_len, int cow);
  int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
  			  struct btrfs_path *p, u64 time_seq);
  int btrfs_search_slot_for_read(struct btrfs_root *root,
  			       struct btrfs_key *key, struct btrfs_path *p,
  			       int find_higher, int return_any);
  int btrfs_realloc_node(struct btrfs_trans_handle *trans,
  		       struct btrfs_root *root, struct extent_buffer *parent,
  		       int start_slot, u64 *last_ret,
  		       struct btrfs_key *progress);
  void btrfs_release_path(struct btrfs_path *p);
  struct btrfs_path *btrfs_alloc_path(void);
  void btrfs_free_path(struct btrfs_path *p);
  void btrfs_set_path_blocking(struct btrfs_path *p);
  void btrfs_clear_path_blocking(struct btrfs_path *p,
  			       struct extent_buffer *held, int held_rw);
  void btrfs_unlock_up_safe(struct btrfs_path *p, int level);
  
  int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  		   struct btrfs_path *path, int slot, int nr);
  static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
  				 struct btrfs_root *root,
  				 struct btrfs_path *path)
  {
  	return btrfs_del_items(trans, root, path, path->slots[0], 1);
  }
  
  void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
  			    struct btrfs_key *cpu_key, u32 *data_size,
  			    u32 total_data, u32 total_size, int nr);
  int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
  		      *root, struct btrfs_key *key, void *data, u32 data_size);
  int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root,
  			     struct btrfs_path *path,
  			     struct btrfs_key *cpu_key, u32 *data_size, int nr);
  
  static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
  					  struct btrfs_root *root,
  					  struct btrfs_path *path,
  					  struct btrfs_key *key,
  					  u32 data_size)
  {
  	return btrfs_insert_empty_items(trans, root, path, key, &data_size, 1);
  }
  
  int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
  int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
  int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
  			u64 time_seq);
  static inline int btrfs_next_old_item(struct btrfs_root *root,
  				      struct btrfs_path *p, u64 time_seq)
  {
  	++p->slots[0];
  	if (p->slots[0] >= btrfs_header_nritems(p->nodes[0]))
  		return btrfs_next_old_leaf(root, p, time_seq);
  	return 0;
  }
  static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
  {
  	return btrfs_next_old_item(root, p, 0);
  }
  int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
  int __must_check btrfs_drop_snapshot(struct btrfs_root *root,
  				     struct btrfs_block_rsv *block_rsv,
  				     int update_ref, int for_reloc);
  int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
  			struct btrfs_root *root,
  			struct extent_buffer *node,
  			struct extent_buffer *parent);
  static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
  {
  	/*
  	 * Get synced with close_ctree()
  	 */
  	smp_mb();
  	return fs_info->closing;
  }
  
  /*
   * If we remount the fs to be R/O or umount the fs, the cleaner needn't do
   * anything except sleeping. This function is used to check the status of
   * the fs.
   */
  static inline int btrfs_need_cleaner_sleep(struct btrfs_root *root)
  {
  	return (root->fs_info->sb->s_flags & MS_RDONLY ||
  		btrfs_fs_closing(root->fs_info));
  }
  
  static inline void free_fs_info(struct btrfs_fs_info *fs_info)
  {
  	kfree(fs_info->balance_ctl);
  	kfree(fs_info->delayed_root);
  	kfree(fs_info->extent_root);
  	kfree(fs_info->tree_root);
  	kfree(fs_info->chunk_root);
  	kfree(fs_info->dev_root);
  	kfree(fs_info->csum_root);
  	kfree(fs_info->quota_root);
  	kfree(fs_info->uuid_root);
  	kfree(fs_info->super_copy);
  	kfree(fs_info->super_for_commit);
  	security_free_mnt_opts(&fs_info->security_opts);
  	kfree(fs_info);
  }
  
  /* tree mod log functions from ctree.c */
  u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
  			   struct seq_list *elem);
  void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
  			    struct seq_list *elem);
  int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq);
  
  /* root-item.c */
  int btrfs_find_root_ref(struct btrfs_root *tree_root,
  			struct btrfs_path *path,
  			u64 root_id, u64 ref_id);
  int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
  		       struct btrfs_root *tree_root,
  		       u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
  		       const char *name, int name_len);
  int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
  		       struct btrfs_root *tree_root,
  		       u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
  		       const char *name, int name_len);
  int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  		   struct btrfs_key *key);
  int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
  		      *root, struct btrfs_key *key, struct btrfs_root_item
  		      *item);
  int __must_check btrfs_update_root(struct btrfs_trans_handle *trans,
  				   struct btrfs_root *root,
  				   struct btrfs_key *key,
  				   struct btrfs_root_item *item);
  int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
  		    struct btrfs_path *path, struct btrfs_root_item *root_item,
  		    struct btrfs_key *root_key);
  int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
  void btrfs_set_root_node(struct btrfs_root_item *item,
  			 struct extent_buffer *node);
  void btrfs_check_and_init_root_item(struct btrfs_root_item *item);
  void btrfs_update_root_times(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root);
  
  /* uuid-tree.c */
  int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans,
  			struct btrfs_root *uuid_root, u8 *uuid, u8 type,
  			u64 subid);
  int btrfs_uuid_tree_rem(struct btrfs_trans_handle *trans,
  			struct btrfs_root *uuid_root, u8 *uuid, u8 type,
  			u64 subid);
  int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info,
  			    int (*check_func)(struct btrfs_fs_info *, u8 *, u8,
  					      u64));
  
  /* dir-item.c */
  int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
  			  const char *name, int name_len);
  int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
  			  struct btrfs_root *root, const char *name,
  			  int name_len, struct inode *dir,
  			  struct btrfs_key *location, u8 type, u64 index);
  struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
  					     struct btrfs_root *root,
  					     struct btrfs_path *path, u64 dir,
  					     const char *name, int name_len,
  					     int mod);
  struct btrfs_dir_item *
  btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
  			    struct btrfs_root *root,
  			    struct btrfs_path *path, u64 dir,
  			    u64 objectid, const char *name, int name_len,
  			    int mod);
  struct btrfs_dir_item *
  btrfs_search_dir_index_item(struct btrfs_root *root,
  			    struct btrfs_path *path, u64 dirid,
  			    const char *name, int name_len);
  int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
  			      struct btrfs_root *root,
  			      struct btrfs_path *path,
  			      struct btrfs_dir_item *di);
  int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  			    struct btrfs_root *root,
  			    struct btrfs_path *path, u64 objectid,
  			    const char *name, u16 name_len,
  			    const void *data, u16 data_len);
  struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
  					  struct btrfs_root *root,
  					  struct btrfs_path *path, u64 dir,
  					  const char *name, u16 name_len,
  					  int mod);
  int verify_dir_item(struct btrfs_root *root,
  		    struct extent_buffer *leaf,
  		    struct btrfs_dir_item *dir_item);
  struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
  						 struct btrfs_path *path,
  						 const char *name,
  						 int name_len);
  
  /* orphan.c */
  int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root, u64 offset);
  int btrfs_del_orphan_item(struct btrfs_trans_handle *trans,
  			  struct btrfs_root *root, u64 offset);
  int btrfs_find_orphan_item(struct btrfs_root *root, u64 offset);
  
  /* inode-item.c */
  int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root,
  			   const char *name, int name_len,
  			   u64 inode_objectid, u64 ref_objectid, u64 index);
  int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root,
  			   const char *name, int name_len,
  			   u64 inode_objectid, u64 ref_objectid, u64 *index);
  int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root,
  			     struct btrfs_path *path, u64 objectid);
  int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
  		       *root, struct btrfs_path *path,
  		       struct btrfs_key *location, int mod);
  
  struct btrfs_inode_extref *
  btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
  			  struct btrfs_root *root,
  			  struct btrfs_path *path,
  			  const char *name, int name_len,
  			  u64 inode_objectid, u64 ref_objectid, int ins_len,
  			  int cow);
  
  int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
  				   u64 ref_objectid, const char *name,
  				   int name_len,
  				   struct btrfs_inode_extref **extref_ret);
  
  /* file-item.c */
  struct btrfs_dio_private;
  int btrfs_del_csums(struct btrfs_trans_handle *trans,
  		    struct btrfs_root *root, u64 bytenr, u64 len);
  int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
  			  struct bio *bio, u32 *dst);
  int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
  			      struct bio *bio, u64 logical_offset);
  int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root,
  			     u64 objectid, u64 pos,
  			     u64 disk_offset, u64 disk_num_bytes,
  			     u64 num_bytes, u64 offset, u64 ram_bytes,
  			     u8 compression, u8 encryption, u16 other_encoding);
  int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *root,
  			     struct btrfs_path *path, u64 objectid,
  			     u64 bytenr, int mod);
  int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
  			   struct btrfs_root *root,
  			   struct btrfs_ordered_sum *sums);
  int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
  		       struct bio *bio, u64 file_start, int contig);
  int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
  			     struct list_head *list, int search_commit);
  void btrfs_extent_item_to_extent_map(struct inode *inode,
  				     const struct btrfs_path *path,
  				     struct btrfs_file_extent_item *fi,
  				     const bool new_inline,
  				     struct extent_map *em);
  
  /* inode.c */
  struct btrfs_delalloc_work {
  	struct inode *inode;
  	int wait;
  	int delay_iput;
  	struct completion completion;
  	struct list_head list;
  	struct btrfs_work work;
  };
  
  struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
  						    int wait, int delay_iput);
  void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work);
  
  struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
  					   size_t pg_offset, u64 start, u64 len,
  					   int create);
  noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
  			      u64 *orig_start, u64 *orig_block_len,
  			      u64 *ram_bytes);
  
  /* RHEL and EL kernels have a patch that renames PG_checked to FsMisc */
  #if defined(ClearPageFsMisc) && !defined(ClearPageChecked)
  #define ClearPageChecked ClearPageFsMisc
  #define SetPageChecked SetPageFsMisc
  #define PageChecked PageFsMisc
  #endif
  
  /* This forces readahead on a given range of bytes in an inode */
  static inline void btrfs_force_ra(struct address_space *mapping,
  				  struct file_ra_state *ra, struct file *file,
  				  pgoff_t offset, unsigned long req_size)
  {
  	page_cache_sync_readahead(mapping, ra, file, offset, req_size);
  }
  
  struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
  int btrfs_set_inode_index(struct inode *dir, u64 *index);
  int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
  		       struct btrfs_root *root,
  		       struct inode *dir, struct inode *inode,
  		       const char *name, int name_len);
  int btrfs_add_link(struct btrfs_trans_handle *trans,
  		   struct inode *parent_inode, struct inode *inode,
  		   const char *name, int name_len, int add_backref, u64 index);
  int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
  			struct btrfs_root *root,
  			struct inode *dir, u64 objectid,
  			const char *name, int name_len);
  int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
  			int front);
  int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
  			       struct btrfs_root *root,
  			       struct inode *inode, u64 new_size,
  			       u32 min_type);
  
  int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput);
  int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
  			       int nr);
  int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
  			      struct extent_state **cached_state);
  int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
  			     struct btrfs_root *new_root,
  			     struct btrfs_root *parent_root,
  			     u64 new_dirid);
  int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
  			 size_t size, struct bio *bio,
  			 unsigned long bio_flags);
  int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
  int btrfs_readpage(struct file *file, struct page *page);
  void btrfs_evict_inode(struct inode *inode);
  int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc);
  struct inode *btrfs_alloc_inode(struct super_block *sb);
  void btrfs_destroy_inode(struct inode *inode);
  int btrfs_drop_inode(struct inode *inode);
  int btrfs_init_cachep(void);
  void btrfs_destroy_cachep(void);
  long btrfs_ioctl_trans_end(struct file *file);
  struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
  			 struct btrfs_root *root, int *was_new);
  struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
  				    size_t pg_offset, u64 start, u64 end,
  				    int create);
  int btrfs_update_inode(struct btrfs_trans_handle *trans,
  			      struct btrfs_root *root,
  			      struct inode *inode);
  int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
  				struct btrfs_root *root, struct inode *inode);
  int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode);
  int btrfs_orphan_cleanup(struct btrfs_root *root);
  void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
  			      struct btrfs_root *root);
  int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size);
  void btrfs_invalidate_inodes(struct btrfs_root *root);
  void btrfs_add_delayed_iput(struct inode *inode);
  void btrfs_run_delayed_iputs(struct btrfs_root *root);
  int btrfs_prealloc_file_range(struct inode *inode, int mode,
  			      u64 start, u64 num_bytes, u64 min_size,
  			      loff_t actual_len, u64 *alloc_hint);
  int btrfs_prealloc_file_range_trans(struct inode *inode,
  				    struct btrfs_trans_handle *trans, int mode,
  				    u64 start, u64 num_bytes, u64 min_size,
  				    loff_t actual_len, u64 *alloc_hint);
  int btrfs_inode_check_errors(struct inode *inode);
  extern const struct dentry_operations btrfs_dentry_operations;
  #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
  void btrfs_test_inode_set_ops(struct inode *inode);
  #endif
  
  /* ioctl.c */
  long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
  void btrfs_update_iflags(struct inode *inode);
  void btrfs_inherit_iflags(struct inode *inode, struct inode *dir);
  int btrfs_is_empty_uuid(u8 *uuid);
  int btrfs_defrag_file(struct inode *inode, struct file *file,
  		      struct btrfs_ioctl_defrag_range_args *range,
  		      u64 newer_than, unsigned long max_pages);
  void btrfs_get_block_group_info(struct list_head *groups_list,
  				struct btrfs_ioctl_space_info *space);
  void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
  			       struct btrfs_ioctl_balance_args *bargs);
  
  
  /* file.c */
  int btrfs_auto_defrag_init(void);
  void btrfs_auto_defrag_exit(void);
  int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
  			   struct inode *inode);
  int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info);
  void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info);
  int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync);
  void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
  			     int skip_pinned);
  extern const struct file_operations btrfs_file_operations;
  int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
  			 struct btrfs_root *root, struct inode *inode,
  			 struct btrfs_path *path, u64 start, u64 end,
  			 u64 *drop_end, int drop_cache,
  			 int replace_extent,
  			 u32 extent_item_size,
  			 int *key_inserted);
  int btrfs_drop_extents(struct btrfs_trans_handle *trans,
  		       struct btrfs_root *root, struct inode *inode, u64 start,
  		       u64 end, int drop_cache);
  int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
  			      struct inode *inode, u64 start, u64 end);
  int btrfs_release_file(struct inode *inode, struct file *file);
  int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
  		      struct page **pages, size_t num_pages,
  		      loff_t pos, size_t write_bytes,
  		      struct extent_state **cached);
  int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end);
  
  /* tree-defrag.c */
  int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
  			struct btrfs_root *root);
  
  /* sysfs.c */
  int btrfs_init_sysfs(void);
  void btrfs_exit_sysfs(void);
  int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info);
  void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info);
  
  /* xattr.c */
  ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
  
  /* super.c */
  int btrfs_parse_options(struct btrfs_root *root, char *options);
  int btrfs_sync_fs(struct super_block *sb, int wait);
  
  #ifdef CONFIG_PRINTK
  __printf(2, 3)
  void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...);
  #else
  static inline __printf(2, 3)
  void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
  {
  }
  #endif
  
  #define btrfs_emerg(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_EMERG fmt, ##args)
  #define btrfs_alert(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_ALERT fmt, ##args)
  #define btrfs_crit(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_CRIT fmt, ##args)
  #define btrfs_err(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_ERR fmt, ##args)
  #define btrfs_warn(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_WARNING fmt, ##args)
  #define btrfs_notice(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_NOTICE fmt, ##args)
  #define btrfs_info(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_INFO fmt, ##args)
  
  /*
   * Wrappers that use printk_in_rcu
   */
  #define btrfs_emerg_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_EMERG fmt, ##args)
  #define btrfs_alert_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_ALERT fmt, ##args)
  #define btrfs_crit_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_CRIT fmt, ##args)
  #define btrfs_err_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_ERR fmt, ##args)
  #define btrfs_warn_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_WARNING fmt, ##args)
  #define btrfs_notice_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_NOTICE fmt, ##args)
  #define btrfs_info_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_INFO fmt, ##args)
  
  /*
   * Wrappers that use a ratelimited printk_in_rcu
   */
  #define btrfs_emerg_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_EMERG fmt, ##args)
  #define btrfs_alert_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_ALERT fmt, ##args)
  #define btrfs_crit_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_CRIT fmt, ##args)
  #define btrfs_err_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_ERR fmt, ##args)
  #define btrfs_warn_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_WARNING fmt, ##args)
  #define btrfs_notice_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_NOTICE fmt, ##args)
  #define btrfs_info_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_INFO fmt, ##args)
  
  /*
   * Wrappers that use a ratelimited printk
   */
  #define btrfs_emerg_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_EMERG fmt, ##args)
  #define btrfs_alert_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_ALERT fmt, ##args)
  #define btrfs_crit_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_CRIT fmt, ##args)
  #define btrfs_err_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_ERR fmt, ##args)
  #define btrfs_warn_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_WARNING fmt, ##args)
  #define btrfs_notice_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_NOTICE fmt, ##args)
  #define btrfs_info_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_INFO fmt, ##args)
  #ifdef DEBUG
  #define btrfs_debug(fs_info, fmt, args...) \
  	btrfs_printk(fs_info, KERN_DEBUG fmt, ##args)
  #define btrfs_debug_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
  #define btrfs_debug_rl_in_rcu(fs_info, fmt, args...) \
  	btrfs_printk_rl_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
  #define btrfs_debug_rl(fs_info, fmt, args...) \
  	btrfs_printk_ratelimited(fs_info, KERN_DEBUG fmt, ##args)
  #else
  #define btrfs_debug(fs_info, fmt, args...) \
      no_printk(KERN_DEBUG fmt, ##args)
  #define btrfs_debug_in_rcu(fs_info, fmt, args...) \
  	no_printk(KERN_DEBUG fmt, ##args)
  #define btrfs_debug_rl_in_rcu(fs_info, fmt, args...) \
  	no_printk(KERN_DEBUG fmt, ##args)
  #define btrfs_debug_rl(fs_info, fmt, args...) \
  	no_printk(KERN_DEBUG fmt, ##args)
  #endif
  
  #define btrfs_printk_in_rcu(fs_info, fmt, args...)	\
  do {							\
  	rcu_read_lock();				\
  	btrfs_printk(fs_info, fmt, ##args);		\
  	rcu_read_unlock();				\
  } while (0)
  
  #define btrfs_printk_ratelimited(fs_info, fmt, args...)		\
  do {								\
  	static DEFINE_RATELIMIT_STATE(_rs,			\
  		DEFAULT_RATELIMIT_INTERVAL,			\
  		DEFAULT_RATELIMIT_BURST);       		\
  	if (__ratelimit(&_rs))					\
  		btrfs_printk(fs_info, fmt, ##args);		\
  } while (0)
  
  #define btrfs_printk_rl_in_rcu(fs_info, fmt, args...)		\
  do {								\
  	rcu_read_lock();					\
  	btrfs_printk_ratelimited(fs_info, fmt, ##args);		\
  	rcu_read_unlock();					\
  } while (0)
  
  #ifdef CONFIG_BTRFS_ASSERT
  
  __cold
  static inline void assfail(char *expr, char *file, int line)
  {
  	pr_err("BTRFS: assertion failed: %s, file: %s, line: %d",
  	       expr, file, line);
  	BUG();
  }
  
  #define ASSERT(expr)	\
  	(likely(expr) ? (void)0 : assfail(#expr, __FILE__, __LINE__))
  #else
  #define ASSERT(expr)	((void)0)
  #endif
  
  #define btrfs_assert()
  __printf(5, 6)
  __cold
  void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
  		     unsigned int line, int errno, const char *fmt, ...);
  
  const char *btrfs_decode_error(int errno);
  
  __cold
  void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
  			       struct btrfs_root *root, const char *function,
  			       unsigned int line, int errno);
  
  #define btrfs_set_fs_incompat(__fs_info, opt) \
  	__btrfs_set_fs_incompat((__fs_info), BTRFS_FEATURE_INCOMPAT_##opt)
  
  static inline void __btrfs_set_fs_incompat(struct btrfs_fs_info *fs_info,
  					   u64 flag)
  {
  	struct btrfs_super_block *disk_super;
  	u64 features;
  
  	disk_super = fs_info->super_copy;
  	features = btrfs_super_incompat_flags(disk_super);
  	if (!(features & flag)) {
  		spin_lock(&fs_info->super_lock);
  		features = btrfs_super_incompat_flags(disk_super);
  		if (!(features & flag)) {
  			features |= flag;
  			btrfs_set_super_incompat_flags(disk_super, features);
  			btrfs_info(fs_info, "setting %llu feature flag",
  					 flag);
  		}
  		spin_unlock(&fs_info->super_lock);
  	}
  }
  
  #define btrfs_fs_incompat(fs_info, opt) \
  	__btrfs_fs_incompat((fs_info), BTRFS_FEATURE_INCOMPAT_##opt)
  
  static inline int __btrfs_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag)
  {
  	struct btrfs_super_block *disk_super;
  	disk_super = fs_info->super_copy;
  	return !!(btrfs_super_incompat_flags(disk_super) & flag);
  }
  
  /*
   * Call btrfs_abort_transaction as early as possible when an error condition is
   * detected, that way the exact line number is reported.
   */
  #define btrfs_abort_transaction(trans, root, errno)		\
  do {								\
  	/* Report first abort since mount */			\
  	if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,	\
  			&((root)->fs_info->fs_state))) {	\
  		WARN(1, KERN_DEBUG				\
  		"BTRFS: Transaction aborted (error %d)\n",	\
  		(errno));					\
  	}							\
  	__btrfs_abort_transaction((trans), (root), __func__,	\
  				  __LINE__, (errno));		\
  } while (0)
  
  #define btrfs_std_error(fs_info, errno, fmt, args...)		\
  do {								\
  	__btrfs_std_error((fs_info), __func__, __LINE__,	\
  			  (errno), fmt, ##args);		\
  } while (0)
  
  __printf(5, 6)
  __cold
  void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
  		   unsigned int line, int errno, const char *fmt, ...);
  
  /*
   * If BTRFS_MOUNT_PANIC_ON_FATAL_ERROR is in mount_opt, __btrfs_panic
   * will panic().  Otherwise we BUG() here.
   */
  #define btrfs_panic(fs_info, errno, fmt, args...)			\
  do {									\
  	__btrfs_panic(fs_info, __func__, __LINE__, errno, fmt, ##args);	\
  	BUG();								\
  } while (0)
  
  /* acl.c */
  #ifdef CONFIG_BTRFS_FS_POSIX_ACL
  struct posix_acl *btrfs_get_acl(struct inode *inode, int type);
  int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
  int btrfs_init_acl(struct btrfs_trans_handle *trans,
  		   struct inode *inode, struct inode *dir);
  #else
  #define btrfs_get_acl NULL
  #define btrfs_set_acl NULL
  static inline int btrfs_init_acl(struct btrfs_trans_handle *trans,
  				 struct inode *inode, struct inode *dir)
  {
  	return 0;
  }
  #endif
  
  /* relocation.c */
  int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start);
  int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
  			  struct btrfs_root *root);
  int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
  			    struct btrfs_root *root);
  int btrfs_recover_relocation(struct btrfs_root *root);
  int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len);
  int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
  			  struct btrfs_root *root, struct extent_buffer *buf,
  			  struct extent_buffer *cow);
  void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
  			      u64 *bytes_to_reserve);
  int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
  			      struct btrfs_pending_snapshot *pending);
  
  /* scrub.c */
  int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
  		    u64 end, struct btrfs_scrub_progress *progress,
  		    int readonly, int is_dev_replace);
  void btrfs_scrub_pause(struct btrfs_root *root);
  void btrfs_scrub_continue(struct btrfs_root *root);
  int btrfs_scrub_cancel(struct btrfs_fs_info *info);
  int btrfs_scrub_cancel_dev(struct btrfs_fs_info *info,
  			   struct btrfs_device *dev);
  int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
  			 struct btrfs_scrub_progress *progress);
  
  /* dev-replace.c */
  void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info);
  void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info);
  void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount);
  
  static inline void btrfs_bio_counter_dec(struct btrfs_fs_info *fs_info)
  {
  	btrfs_bio_counter_sub(fs_info, 1);
  }
  
  /* reada.c */
  struct reada_control {
  	struct btrfs_root	*root;		/* tree to prefetch */
  	struct btrfs_key	key_start;
  	struct btrfs_key	key_end;	/* exclusive */
  	atomic_t		elems;
  	struct kref		refcnt;
  	wait_queue_head_t	wait;
  };
  struct reada_control *btrfs_reada_add(struct btrfs_root *root,
  			      struct btrfs_key *start, struct btrfs_key *end);
  int btrfs_reada_wait(void *handle);
  void btrfs_reada_detach(void *handle);
  int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
  			 u64 start, int err);
  
  static inline int is_fstree(u64 rootid)
  {
  	if (rootid == BTRFS_FS_TREE_OBJECTID ||
  	    ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID &&
  	      !btrfs_qgroup_level(rootid)))
  		return 1;
  	return 0;
  }
  
  static inline int btrfs_defrag_cancelled(struct btrfs_fs_info *fs_info)
  {
  	return signal_pending(current);
  }
  
  /* Sanity test specific functions */
  #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
  void btrfs_test_destroy_inode(struct inode *inode);
  #endif
  
  static inline int btrfs_test_is_dummy_root(struct btrfs_root *root)
  {
  #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
  	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
  		return 1;
  #endif
  	return 0;
  }
  
  #endif
  