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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsitem
import (
"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
)
// Maps logical address to physical.
//
// key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID
// key.offset = logical_addr
type Chunk struct { // complex CHUNK_ITEM=228
Head ChunkHeader
Stripes []ChunkStripe
}
type ChunkHeader struct {
Size btrfsvol.AddrDelta `bin:"off=0x0, siz=0x8"`
Owner btrfsprim.ObjID `bin:"off=0x8, siz=0x8"` // root referencing this chunk (always EXTENT_TREE_OBJECTID=2)
StripeLen uint64 `bin:"off=0x10, siz=0x8"` // ???
Type btrfsvol.BlockGroupFlags `bin:"off=0x18, siz=0x8"`
IOOptimalAlign uint32 `bin:"off=0x20, siz=0x4"`
IOOptimalWidth uint32 `bin:"off=0x24, siz=0x4"`
IOMinSize uint32 `bin:"off=0x28, siz=0x4"` // sector size
NumStripes uint16 `bin:"off=0x2c, siz=0x2"` // [ignored-when-writing]
SubStripes uint16 `bin:"off=0x2e, siz=0x2"` // ???
binstruct.End `bin:"off=0x30"`
}
type ChunkStripe struct {
DeviceID btrfsvol.DeviceID `bin:"off=0x0, siz=0x8"`
Offset btrfsvol.PhysicalAddr `bin:"off=0x8, siz=0x8"`
DeviceUUID btrfsprim.UUID `bin:"off=0x10, siz=0x10"`
binstruct.End `bin:"off=0x20"`
}
func (chunk Chunk) Mappings(key btrfsprim.Key) []btrfsvol.Mapping {
ret := make([]btrfsvol.Mapping, 0, len(chunk.Stripes))
for _, stripe := range chunk.Stripes {
ret = append(ret, btrfsvol.Mapping{
LAddr: btrfsvol.LogicalAddr(key.Offset),
PAddr: btrfsvol.QualifiedPhysicalAddr{
Dev: stripe.DeviceID,
Addr: stripe.Offset,
},
Size: chunk.Head.Size,
SizeLocked: true,
Flags: containers.Optional[btrfsvol.BlockGroupFlags]{
OK: true,
Val: chunk.Head.Type,
},
})
}
return ret
}
var chunkStripePool containers.SlicePool[ChunkStripe]
func (chunk *Chunk) Free() {
for i := range chunk.Stripes {
chunk.Stripes[i] = ChunkStripe{}
}
chunkStripePool.Put(chunk.Stripes)
*chunk = Chunk{}
chunkPool.Put(chunk)
}
func (chunk Chunk) Clone() Chunk {
ret := chunk
ret.Stripes = chunkStripePool.Get(len(chunk.Stripes))
copy(ret.Stripes, chunk.Stripes)
return ret
}
func (chunk *Chunk) UnmarshalBinary(dat []byte) (int, error) {
n, err := binstruct.Unmarshal(dat, &chunk.Head)
if err != nil {
return n, err
}
chunk.Stripes = chunkStripePool.Get(int(chunk.Head.NumStripes))
for i := range chunk.Stripes {
_n, err := binstruct.Unmarshal(dat[n:], &chunk.Stripes[i])
n += _n
if err != nil {
return n, err
}
}
return n, nil
}
func (chunk Chunk) MarshalBinary() ([]byte, error) {
chunk.Head.NumStripes = uint16(len(chunk.Stripes))
ret, err := binstruct.Marshal(chunk.Head)
if err != nil {
return ret, err
}
for _, stripe := range chunk.Stripes {
_ret, err := binstruct.Marshal(stripe)
ret = append(ret, _ret...)
if err != nil {
return ret, err
}
}
return ret, nil
}
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