command: Introduce functions to obtain command arguments

[thirdparty/u-boot.git] / fs / btrfs / kernel-shared / btrfs_tree.h

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
 * Copied from kernel/include/uapi/linux/btrfs_btree.h.
 *
 * Only modified the header.
 */
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef __BTRFS_TREE_H__
#define __BTRFS_TREE_H__

#include <linux/types.h>

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

/*
 * The max metadata block size (node size).
 *
 * This limit is somewhat artificial. The memmove and tree block locking cost
 * go up with larger node size.
 */
#define BTRFS_MAX_METADATA_BLOCKSIZE 65536

/*
 * We can actually store much bigger names, but lets not confuse the rest
 * of linux.
 *
 * btrfs_dir_item::name_len follows this limitation.
 */
#define BTRFS_NAME_LEN 255

/*
 * Objectids start from here.
 *
 * Check btrfs_disk_key for the meaning of objectids.
 */

/*
 * Root tree holds pointers to all of the tree roots.
 * Without special mention, the root tree contains the root bytenr of all other
 * trees, except the chunk tree and the log tree.
 *
 * The super block contains the root bytenr of this tree.
 */
#define BTRFS_ROOT_TREE_OBJECTID 1ULL

/*
 * Extent tree stores information about which extents are in use, and backrefs
 * for each extent.
 */
#define BTRFS_EXTENT_TREE_OBJECTID 2ULL

/*
 * Chunk tree stores btrfs logical address -> physical address mapping.
 *
 * The super block contains part of chunk tree for bootstrap, and contains
 * the root bytenr of this tree.
 */
#define BTRFS_CHUNK_TREE_OBJECTID 3ULL

/*
 * Device tree stores info about which areas of a given device are in use,
 * and physical address -> btrfs logical address mapping.
 */
#define BTRFS_DEV_TREE_OBJECTID 4ULL

/* The fs tree is the first subvolume tree, storing files and directories. */
#define BTRFS_FS_TREE_OBJECTID 5ULL

/* Shows the directory objectid inside the root tree. */
#define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL

/* Csum tree holds checksums of all the data extents. */
#define BTRFS_CSUM_TREE_OBJECTID 7ULL

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

/* UUID tree stores items that use the BTRFS_UUID_KEY* types. */
#define BTRFS_UUID_TREE_OBJECTID 9ULL

/* Free space cache tree (v2 space cache) tracks free space in block groups. */
#define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL

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

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

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

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

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

/* Extent checksums, shared between the csum tree and log trees. */
#define BTRFS_EXTENT_CSUM_OBJECTID -10ULL

/* For storing free space cache (v1 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
 * (BTRFS_DEV_ITEMS_OBJECTID, 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

/*
 * Types start from here.
 *
 * Check btrfs_disk_key for details about types.
 */

/*
 * 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
/* reserve 2-11 close to the inode for later flexibility */
#define BTRFS_INODE_REF_KEY             12
#define BTRFS_INODE_EXTREF_KEY          13
#define BTRFS_XATTR_ITEM_KEY            24
#define BTRFS_ORPHAN_ITEM_KEY           48

/*
 * 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

/* Stores info (position, size ...) about a data extent of a file */
#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 tree.
 *
 * These record which blocks are used, and how many references there are.
 */
#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.
 *
 * Stores how many free space there is in a block group.
 */
#define BTRFS_BLOCK_GROUP_ITEM_KEY 192

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

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

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

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

/*
 * Records the overall state of the qgroups.
 *
 * There's only one instance of this key present,
 * (0, BTRFS_QGROUP_STATUS_KEY, 0)
 */
#define BTRFS_QGROUP_STATUS_KEY         240
/*
 * Records the currently used space of the qgroup.
 *
 * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid).
 */
#define BTRFS_QGROUP_INFO_KEY           242

/*
 * Contains the user configured limits for the qgroup.
 *
 * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid).
 */
#define BTRFS_QGROUP_LIMIT_KEY          244

/*
 * Records the child-parent relationship of qgroups. For
 * each relation, 2 keys are present:
 * (childid, BTRFS_QGROUP_RELATION_KEY, parentid)
 * (parentid, BTRFS_QGROUP_RELATION_KEY, childid)
 */
#define BTRFS_QGROUP_RELATION_KEY       246

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

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

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

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

/*
 * Persistently 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).
 */
#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


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

/* Csum types */
enum btrfs_csum_type {
        BTRFS_CSUM_TYPE_CRC32   = 0,
        BTRFS_CSUM_TYPE_XXHASH  = 1,
        BTRFS_CSUM_TYPE_SHA256  = 2,
        BTRFS_CSUM_TYPE_BLAKE2  = 3,
};

/*
 * Flags definitions for directory entry item type.
 *
 * Used by:
 * struct btrfs_dir_item.type
 *
 * Values 0..7 must match common file type values in fs_types.h.
 */
#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

#define BTRFS_FSID_SIZE 16
#define BTRFS_UUID_SIZE 16

/*
 * The key defines the order in the tree, and so it also defines (optimal)
 * block layout.
 *
 * Objectid and offset are interpreted based on type.
 * While normally for objectid, it either represents a root number, or an
 * inode number.
 *
 * Type tells us things about the object, and is a kind of stream selector.
 * Check the following URL for full references about btrfs_disk_key/btrfs_key:
 * https://btrfs.wiki.kernel.org/index.php/Btree_Items
 *
 * 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_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;

        /* Optimal seek speed 0-100 where 100 is fastest */
        __u8 seek_speed;

        /* Optimal 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__));

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

/* 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_SUPER_FLAG_METADUMP_V2    (1ULL << 34)
#define BTRFS_SUPER_FLAG_CHANGING_FSID  (1ULL << 35)
#define BTRFS_SUPER_FLAG_CHANGING_FSID_V2 (1ULL << 36)


/*
 * Items in the extent tree 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_EXTENT_FLAG_DATA          (1ULL << 0)
#define BTRFS_EXTENT_FLAG_TREE_BLOCK    (1ULL << 1)

/* 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 used 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__));

/* 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)

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

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

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

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

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

struct btrfs_dir_item {
        struct btrfs_disk_key location;
        __le64 transid;
        __le16 data_len;
        __le16 name_len;
        __u8 type;
} __attribute__ ((__packed__));

#define BTRFS_ROOT_SUBVOL_RDONLY        (1ULL << 0)

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

struct btrfs_root_item {
        struct btrfs_inode_item inode;
        __le64 generation;
        __le64 root_dirid;
        __le64 bytenr;
        __le64 byte_limit;
        __le64 bytes_used;
        __le64 last_snapshot;
        __le64 flags;
        __le32 refs;
        struct btrfs_disk_key drop_progress;
        __u8 drop_level;
        __u8 level;

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

        /*
         * This generation number is used to test if the new fields are valid
         * and up to date while reading the root item. Every time the root item
         * is written out, the "generation" field is copied into this field. If
         * anyone ever mounted the fs with an older kernel, we will have
         * mismatching generation values here and thus must invalidate the
         * new fields. See btrfs_update_root and btrfs_find_last_root for
         * details.
         * The offset of generation_v2 is also used as the start for the memset
         * when invalidating the fields.
         */
        __le64 generation_v2;
        __u8 uuid[BTRFS_UUID_SIZE];
        __u8 parent_uuid[BTRFS_UUID_SIZE];
        __u8 received_uuid[BTRFS_UUID_SIZE];
        __le64 ctransid; /* Updated when an inode changes */
        __le64 otransid; /* Trans when created */
        __le64 stransid; /* Trans when sent. Non-zero for received subvol. */
        __le64 rtransid; /* Trans when received. Non-zero for received subvol.*/
        struct btrfs_timespec ctime;
        struct btrfs_timespec otime;
        struct btrfs_timespec stime;
        struct btrfs_timespec rtime;
        __le64 reserved[8]; /* For future */
} __attribute__ ((__packed__));

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

struct btrfs_disk_balance_args {
        /*
         * Profiles to operate on.
         *
         * SINGLE is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE.
         */
        __le64 profiles;

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

        /* Devid filter */
        __le64 devid;

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

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

        /*
         * Profile to convert to.
         *
         * SINGLE is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE.
         */
        __le64 target;

        /* BTRFS_BALANCE_ARGS_* */
        __le64 flags;

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

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

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

/*
 * Stores 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__));

enum {
        BTRFS_FILE_EXTENT_INLINE   = 0,
        BTRFS_FILE_EXTENT_REG      = 1,
        BTRFS_FILE_EXTENT_PREALLOC = 2,
        BTRFS_NR_FILE_EXTENT_TYPES = 3,
};

enum btrfs_compression_type {
        BTRFS_COMPRESS_NONE  = 0,
        BTRFS_COMPRESS_ZLIB  = 1,
        BTRFS_COMPRESS_LZO   = 2,
        BTRFS_COMPRESS_ZSTD  = 3,
        BTRFS_NR_COMPRESS_TYPES = 4,
};

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 not 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 inside the file extent.
         *
         * 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 bytes this file extent is referencing (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__));

enum btrfs_dev_stat_values {
        /* Disk I/O failure stats */
        BTRFS_DEV_STAT_WRITE_ERRS, /* EIO or EREMOTEIO from lower layers */
        BTRFS_DEV_STAT_READ_ERRS, /* EIO or EREMOTEIO from lower layers */
        BTRFS_DEV_STAT_FLUSH_ERRS, /* EIO or EREMOTEIO from lower layers */

        /* Stats for indirect indications for I/O failures */
        BTRFS_DEV_STAT_CORRUPTION_ERRS, /* Checksum error, bytenr error or
                                         * contents is illegal: this is an
                                         * indication that the block was damaged
                                         * during read or write, or written to
                                         * wrong location or read from wrong
                                         * location */
        BTRFS_DEV_STAT_GENERATION_ERRS, /* An indication that blocks have not
                                         * been written */

        BTRFS_DEV_STAT_VALUES_MAX
};

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

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_RAID1C3       (1ULL << 9)
#define BTRFS_BLOCK_GROUP_RAID1C4       (1ULL << 10)
#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_RAID_RAID1C3,
        BTRFS_RAID_RAID1C4,
        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_RAID1C3 | \
                                         BTRFS_BLOCK_GROUP_RAID1C4 | \
                                         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)

#define BTRFS_BLOCK_GROUP_RAID1_MASK    (BTRFS_BLOCK_GROUP_RAID1 |   \
                                         BTRFS_BLOCK_GROUP_RAID1C3 | \
                                         BTRFS_BLOCK_GROUP_RAID1C4)

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

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

#define BTRFS_EXTENDED_PROFILE_MASK     (BTRFS_BLOCK_GROUP_PROFILE_MASK | \
                                         BTRFS_AVAIL_ALLOC_BIT_SINGLE)

static inline __u64 chunk_to_extended(__u64 flags)
{
        if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0)
                flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;

        return flags;
}
static inline __u64 extended_to_chunk(__u64 flags)
{
        return flags & ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
}

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

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

#define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0)

#define BTRFS_QGROUP_LEVEL_SHIFT                48
static inline __u64 btrfs_qgroup_level(__u64 qgroupid)
{
        return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
}

/* Is subvolume quota turned on? */
#define BTRFS_QGROUP_STATUS_FLAG_ON             (1ULL << 0)

/* Is qgroup rescan running? */
#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.
 */
#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
 *
 * Used by:
 * struct btrfs_qgroup_limit.flags
 * struct btrfs_qgroup_limit_item.flags
 */
#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__));

/*
 * 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__));

/*
 * 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

/* The super block basically lists the main trees of the FS. */
struct btrfs_super_block {
        /* The first 4 fields must match struct btrfs_header */
        u8 csum[BTRFS_CSUM_SIZE];
        /* FS specific UUID, visible to user */
        u8 fsid[BTRFS_FSID_SIZE];
        __le64 bytenr; /* this block number */
        __le64 flags;

        /* Allowed to be different from the btrfs_header from here own down. */
        __le64 magic;
        __le64 generation;
        __le64 root;
        __le64 chunk_root;
        __le64 log_root;

        /* This will help find the new super based on the log root. */
        __le64 log_root_transid;
        __le64 total_bytes;
        __le64 bytes_used;
        __le64 root_dir_objectid;
        __le64 num_devices;
        __le32 sectorsize;
        __le32 nodesize;
        __le32 __unused_leafsize;
        __le32 stripesize;
        __le32 sys_chunk_array_size;
        __le64 chunk_root_generation;
        __le64 compat_flags;
        __le64 compat_ro_flags;
        __le64 incompat_flags;
        __le16 csum_type;
        u8 root_level;
        u8 chunk_root_level;
        u8 log_root_level;
        struct btrfs_dev_item dev_item;

        char label[BTRFS_LABEL_SIZE];

        __le64 cache_generation;
        __le64 uuid_tree_generation;

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

        /* Future expansion */
        __le64 reserved[28];
        u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
        struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
} __attribute__ ((__packed__));

/*
 * Feature flags
 *
 * Used by:
 * struct btrfs_super_block::(compat|compat_ro|incompat)_flags
 * struct btrfs_ioctl_feature_flags
 */
#define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE         (1ULL << 0)

/*
 * Older kernels (< 4.9) on big-endian systems produced broken free space tree
 * bitmaps, and btrfs-progs also used to corrupt the free space tree (versions
 * < 4.7.3).  If this bit is clear, then the free space tree cannot be trusted.
 * btrfs-progs can also intentionally clear this bit to ask the kernel to
 * rebuild the free space tree, however this might not work on older kernels
 * that do not know about this bit. If not sure, clear the cache manually on
 * first mount when booting older kernel versions.
 */
#define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID   (1ULL << 1)

#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)
#define BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD    (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_INCOMPAT_METADATA_UUID    (1ULL << 10)
#define BTRFS_FEATURE_INCOMPAT_RAID1C34         (1ULL << 11)

/*
 * Compat flags that we support.
 *
 * If any incompat flags are set other than the ones specified below then we
 * will fail to mount.
 */
#define BTRFS_FEATURE_COMPAT_SUPP               0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_SET           0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_CLEAR         0ULL

#define BTRFS_FEATURE_COMPAT_RO_SUPP                    \
        (BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE |      \
         BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID)

#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_COMPRESS_ZSTD |         \
         BTRFS_FEATURE_INCOMPAT_RAID56 |                \
         BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |         \
         BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |       \
         BTRFS_FEATURE_INCOMPAT_NO_HOLES        |       \
         BTRFS_FEATURE_INCOMPAT_METADATA_UUID   |       \
         BTRFS_FEATURE_INCOMPAT_RAID1C34)

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

#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

#define BTRFS_MAX_LEVEL 8

/* 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__));

/*
 * 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 children
 * 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__));

#endif /* __BTRFS_TREE_H__ */