1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
package btrfsitem
import (
"fmt"
"lukeshu.com/btrfs-tools/pkg/binstruct"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsvol"
"lukeshu.com/btrfs-tools/pkg/btrfs/internal"
"lukeshu.com/btrfs-tools/pkg/util"
)
// Maps logical address to physical.
//
// key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID
// key.offset = logical_addr
type Chunk struct { // CHUNK_ITEM=228
Head ChunkHeader
Stripes []ChunkStripe
}
type ChunkHeader struct {
Size btrfsvol.AddrDelta `bin:"off=0x0, siz=0x8"`
Owner internal.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 util.UUID `bin:"off=0x10, siz=0x10"`
binstruct.End `bin:"off=0x20"`
}
func (chunk Chunk) Mappings(key internal.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: &chunk.Head.Type,
})
}
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 = nil
for i := 0; i < int(chunk.Head.NumStripes); i++ {
var stripe ChunkStripe
_n, err := binstruct.Unmarshal(dat[n:], &stripe)
n += _n
if err != nil {
return n, fmt.Errorf("%T.UnmarshalBinary: %w", *chunk, err)
}
chunk.Stripes = append(chunk.Stripes, stripe)
}
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, fmt.Errorf("%T.MarshalBinary: %w", chunk, err)
}
}
return ret, nil
}
|
