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
|
// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfs
import (
"context"
"fmt"
"io"
"github.com/datawire/dlib/derror"
"github.com/datawire/dlib/dlog"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfstree"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
)
type FS struct {
// You should probably not access .LV directly, except when
// implementing special things like fsck.
LV btrfsvol.LogicalVolume[*Device]
cacheSuperblocks []*diskio.Ref[btrfsvol.PhysicalAddr, btrfstree.Superblock]
cacheSuperblock *btrfstree.Superblock
cacheNodes containers.Cache[btrfsvol.LogicalAddr, nodeCacheEntry]
}
var _ diskio.File[btrfsvol.LogicalAddr] = (*FS)(nil)
func (fs *FS) AddDevice(ctx context.Context, dev *Device) error {
sb, err := dev.Superblock()
if err != nil {
return err
}
if err := fs.LV.AddPhysicalVolume(sb.DevItem.DevID, dev); err != nil {
return err
}
fs.cacheSuperblocks = nil
fs.cacheSuperblock = nil
if err := fs.initDev(ctx, *sb); err != nil {
dlog.Errorf(ctx, "error: AddDevice: %q: %v", dev.Name(), err)
}
return nil
}
func (fs *FS) Name() string {
if name := fs.LV.Name(); name != "" {
return name
}
sb, err := fs.Superblock()
if err != nil {
return fmt.Sprintf("fs_uuid=%v", "(unreadable)")
}
name := fmt.Sprintf("fs_uuid=%v", sb.FSUUID)
fs.LV.SetName(name)
return name
}
func (fs *FS) Size() btrfsvol.LogicalAddr {
return fs.LV.Size()
}
func (fs *FS) ReadAt(p []byte, off btrfsvol.LogicalAddr) (int, error) {
return fs.LV.ReadAt(p, off)
}
func (fs *FS) WriteAt(p []byte, off btrfsvol.LogicalAddr) (int, error) {
return fs.LV.WriteAt(p, off)
}
func (fs *FS) Superblocks() ([]*diskio.Ref[btrfsvol.PhysicalAddr, btrfstree.Superblock], error) {
if fs.cacheSuperblocks != nil {
return fs.cacheSuperblocks, nil
}
var ret []*diskio.Ref[btrfsvol.PhysicalAddr, btrfstree.Superblock]
devs := fs.LV.PhysicalVolumes()
if len(devs) == 0 {
return nil, fmt.Errorf("no devices")
}
for _, dev := range devs {
sbs, err := dev.Superblocks()
if err != nil {
return nil, fmt.Errorf("file %q: %w", dev.Name(), err)
}
ret = append(ret, sbs...)
}
fs.cacheSuperblocks = ret
return ret, nil
}
func (fs *FS) Superblock() (*btrfstree.Superblock, error) {
if fs.cacheSuperblock != nil {
return fs.cacheSuperblock, nil
}
sbs, err := fs.Superblocks()
if err != nil {
return nil, err
}
if len(sbs) == 0 {
return nil, fmt.Errorf("no superblocks")
}
fname := ""
sbi := 0
for i, sb := range sbs {
if sb.File.Name() != fname {
fname = sb.File.Name()
sbi = 0
} else {
sbi++
}
if err := sb.Data.ValidateChecksum(); err != nil {
return nil, fmt.Errorf("file %q superblock %v: %w", sb.File.Name(), sbi, err)
}
if i > 0 {
// FIXME(lukeshu): This is probably wrong, but
// lots of my multi-device code is probably
// wrong.
if !sb.Data.Equal(sbs[0].Data) {
return nil, fmt.Errorf("file %q superblock %v and file %q superblock %v disagree",
sbs[0].File.Name(), 0,
sb.File.Name(), sbi)
}
}
}
fs.cacheSuperblock = &sbs[0].Data
return &sbs[0].Data, nil
}
func (fs *FS) ReInit(ctx context.Context) error {
fs.LV.ClearMappings()
for _, dev := range fs.LV.PhysicalVolumes() {
sb, err := dev.Superblock()
if err != nil {
return fmt.Errorf("file %q: %w", dev.Name(), err)
}
if err := fs.initDev(ctx, *sb); err != nil {
return fmt.Errorf("file %q: %w", dev.Name(), err)
}
}
return nil
}
func (fs *FS) initDev(ctx context.Context, sb btrfstree.Superblock) error {
syschunks, err := sb.ParseSysChunkArray()
if err != nil {
return err
}
for _, chunk := range syschunks {
for _, mapping := range chunk.Chunk.Mappings(chunk.Key) {
if err := fs.LV.AddMapping(mapping); err != nil {
return err
}
}
}
chunkTree, err := fs.ForrestLookup(ctx, btrfsprim.CHUNK_TREE_OBJECTID)
if err != nil {
return err
}
var errs derror.MultiError
if err := chunkTree.TreeRange(ctx, func(item btrfstree.Item) bool {
if item.Key.ItemType != btrfsitem.CHUNK_ITEM_KEY {
return true
}
switch itemBody := item.Body.(type) {
case *btrfsitem.Chunk:
for _, mapping := range itemBody.Mappings(item.Key) {
if err := fs.LV.AddMapping(mapping); err != nil {
errs = append(errs, err)
}
}
case *btrfsitem.Error:
// do nothing
default:
// This is a panic because the item decoder should not emit CHUNK_ITEM items as
// anything but btrfsitem.Chunk or btrfsitem.Error without this code also being
// updated.
panic(fmt.Errorf("should not happen: CHUNK_ITEM has unexpected item type: %T", itemBody))
}
return true
}); err != nil {
errs = append(errs, err)
}
if len(errs) > 0 {
return errs
}
return nil
}
func (fs *FS) Close() error {
return fs.LV.Close()
}
var _ io.Closer = (*FS)(nil)
|
