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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsitem
import (
"encoding/binary"
"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
)
// A UUIDMap item goes in the UUID_TREE and maps from a UUID to a
// btrfsprim.ObjID.
//
// The Key for this item is a UUID, and the item is a subvolume ID
// that UUID maps to.
//
// Key:
//
// key.objectid = first half of UUID
// key.offset = second half of UUID
type UUIDMap struct { // trivial UUID_SUBVOL=251 UUID_RECEIVED_SUBVOL=252
ObjID btrfsprim.ObjID `bin:"off=0, siz=8"`
binstruct.End `bin:"off=8"`
}
func KeyToUUID(key btrfsprim.Key) btrfsprim.UUID {
var uuid btrfsprim.UUID
binary.LittleEndian.PutUint64(uuid[:8], uint64(key.ObjectID))
binary.LittleEndian.PutUint64(uuid[8:], key.Offset)
return uuid
}
func UUIDToKey(uuid btrfsprim.UUID) btrfsprim.Key {
return btrfsprim.Key{
ObjectID: btrfsprim.ObjID(binary.LittleEndian.Uint64(uuid[:8])),
ItemType: UUID_SUBVOL_KEY,
Offset: binary.LittleEndian.Uint64(uuid[8:]),
}
}
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