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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsitem
import (
"fmt"
"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/fmtutil"
)
// Extent items map from regions in the logical address space to
// regions in a file.
//
// Compare with:
//
// - Metadata, which are like Extents but without .Info.
// - FileExtents, which map from regions in a file to regions in the
// logical address space.
//
// An Extent may contain (inline or not) several ExtentDataRef items
// and/or ShareDataRef items.
//
// Key:
//
// key.objectid = laddr of the extent
// key.offset = length of the extent
type Extent struct { // complex EXTENT_ITEM=168
Head ExtentHeader
Info TreeBlockInfo // only if .Head.Flags.Has(EXTENT_FLAG_TREE_BLOCK)
Refs []ExtentInlineRef
}
var extentInlineRefPool containers.SlicePool[ExtentInlineRef]
func (o *Extent) Free() {
for i := range o.Refs {
if o.Refs[i].Body != nil {
o.Refs[i].Body.Free()
}
o.Refs[i] = ExtentInlineRef{}
}
extentInlineRefPool.Put(o.Refs)
*o = Extent{}
extentPool.Put(o)
}
func (o Extent) Clone() Extent {
ret := o
ret.Refs = extentInlineRefPool.Get(len(o.Refs))
copy(ret.Refs, o.Refs)
for i := range ret.Refs {
ret.Refs[i].Body = o.Refs[i].Body.CloneItem()
}
return ret
}
func (o *Extent) UnmarshalBinary(dat []byte) (int, error) {
*o = Extent{}
n, err := binstruct.Unmarshal(dat, &o.Head)
if err != nil {
return n, err
}
if o.Head.Flags.Has(EXTENT_FLAG_TREE_BLOCK) {
_n, err := binstruct.Unmarshal(dat[n:], &o.Info)
n += _n
if err != nil {
return n, err
}
}
if n < len(dat) {
o.Refs = extentInlineRefPool.Get(1)[:0]
}
for n < len(dat) {
var ref ExtentInlineRef
_n, err := binstruct.Unmarshal(dat[n:], &ref)
n += _n
o.Refs = append(o.Refs, ref)
if err != nil {
return n, err
}
}
return n, nil
}
func (o Extent) MarshalBinary() ([]byte, error) {
dat, err := binstruct.Marshal(o.Head)
if err != nil {
return dat, err
}
if o.Head.Flags.Has(EXTENT_FLAG_TREE_BLOCK) {
bs, err := binstruct.Marshal(o.Info)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
}
for _, ref := range o.Refs {
bs, err := binstruct.Marshal(ref)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
}
return dat, nil
}
type ExtentHeader struct {
Refs int64 `bin:"off=0, siz=8"`
Generation btrfsprim.Generation `bin:"off=8, siz=8"`
Flags ExtentFlags `bin:"off=16, siz=8"`
binstruct.End `bin:"off=24"`
}
type TreeBlockInfo struct {
Key btrfsprim.Key `bin:"off=0, siz=0x11"`
Level uint8 `bin:"off=0x11, siz=0x1"`
binstruct.End `bin:"off=0x12"`
}
type ExtentFlags uint64
const (
EXTENT_FLAG_DATA ExtentFlags = 1 << iota
EXTENT_FLAG_TREE_BLOCK
)
var extentFlagNames = []string{
"DATA",
"TREE_BLOCK",
}
func (f ExtentFlags) Has(req ExtentFlags) bool { return f&req == req }
func (f ExtentFlags) String() string {
return fmtutil.BitfieldString(f, extentFlagNames, fmtutil.HexNone)
}
type ExtentInlineRef struct {
Type Type // only 4 valid values: {TREE,SHARED}_BLOCK_REF_KEY, {EXTENT,SHARED}_DATA_REF_KEY
Offset uint64 // only when Type != EXTENT_DATA_REF_KEY
Body Item // only when Type == *_DATA_REF_KEY
}
func (o *ExtentInlineRef) UnmarshalBinary(dat []byte) (int, error) {
o.Type = Type(dat[0])
n := 1
switch o.Type {
case TREE_BLOCK_REF_KEY, SHARED_BLOCK_REF_KEY:
_n, err := binstruct.Unmarshal(dat[n:], &o.Offset)
n += _n
if err != nil {
return n, err
}
case EXTENT_DATA_REF_KEY:
dref, _ := extentDataRefPool.Get()
_n, err := binstruct.Unmarshal(dat[n:], dref)
n += _n
o.Body = dref
if err != nil {
return n, err
}
case SHARED_DATA_REF_KEY:
_n, err := binstruct.Unmarshal(dat[n:], &o.Offset)
n += _n
if err != nil {
return n, err
}
sref, _ := sharedDataRefPool.Get()
_n, err = binstruct.Unmarshal(dat[n:], sref)
n += _n
o.Body = sref
if err != nil {
return n, err
}
default:
return n, fmt.Errorf("unexpected item type %v", o.Type)
}
return n, nil
}
func (o ExtentInlineRef) MarshalBinary() ([]byte, error) {
dat := []byte{byte(o.Type)}
switch o.Type {
case TREE_BLOCK_REF_KEY, SHARED_BLOCK_REF_KEY:
_dat, err := binstruct.Marshal(o.Offset)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
case EXTENT_DATA_REF_KEY:
_dat, err := binstruct.Marshal(o.Body)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
case SHARED_DATA_REF_KEY:
_dat, err := binstruct.Marshal(o.Offset)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
_dat, err = binstruct.Marshal(o.Body)
dat = append(dat, _dat...)
if err != nil {
return dat, err
}
default:
return dat, fmt.Errorf("unexpected item type %v", o.Type)
}
return dat, nil
}
|
