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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
|
package main
import (
"fmt"
"os"
"sort"
"lukeshu.com/btrfs-tools/pkg/binstruct"
"lukeshu.com/btrfs-tools/pkg/btrfs"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsitem"
"lukeshu.com/btrfs-tools/pkg/btrfsmisc"
"lukeshu.com/btrfs-tools/pkg/util"
)
func main() {
if err := Main(os.Args[1]); err != nil {
fmt.Fprintf(os.Stderr, "%s: error: %v\n", os.Args[0], err)
os.Exit(1)
}
}
func Main(imgfilename string) (err error) {
maybeSetErr := func(_err error) {
if _err != nil && err == nil {
err = _err
}
}
fh, err := os.Open(imgfilename)
if err != nil {
return err
}
defer func() {
maybeSetErr(fh.Close())
}()
fs := &btrfs.FS{
Devices: []*btrfs.Device{
{
File: fh,
},
},
}
fmt.Printf("\nPass 0: superblocks...\n") ///////////////////////////////////////////////////
superblock, err := fs.Superblock()
if err != nil {
return fmt.Errorf("superblock: %w", err)
}
fmt.Printf("\nPass 1: chunk mappings...\n") ////////////////////////////////////////////////
fmt.Printf("Pass 1: ... initializing chunk mappings\n")
if err := fs.Init(); err != nil {
fmt.Printf("Pass 1: ... init chunk tree: error: %v\n", err)
}
fmt.Printf("Pass 1: ... walking chunk tree\n")
visitedChunkNodes := make(map[btrfs.LogicalAddr]struct{})
if err := fs.WalkTree(superblock.Data.ChunkTree, btrfs.WalkTreeHandler{
Node: func(node *util.Ref[btrfs.LogicalAddr, btrfs.Node], err error) error {
if err != nil {
fmt.Printf("Pass 1: ... walk chunk tree: error: %v\n", err)
}
if node != nil {
visitedChunkNodes[node.Addr] = struct{}{}
}
return err
},
}); err != nil {
fmt.Printf("Pass 1: ... walk chunk tree: error: %v\n", err)
}
type reconstructedStripe struct {
Size uint64
Addr btrfs.QualifiedPhysicalAddr
}
reconstructedChunks := make(map[btrfs.LogicalAddr][]reconstructedStripe)
for _, dev := range fs.Devices {
fmt.Printf("Pass 1: ... dev[%q] scanning for nodes\n", dev.Name())
superblock, _ := dev.Superblock()
foundNodes := make(map[btrfs.LogicalAddr][]btrfs.PhysicalAddr)
var lostAndFoundChunks []btrfs.SysChunk
if err := btrfsmisc.ScanForNodes(dev, superblock.Data, func(nodeRef *util.Ref[btrfs.PhysicalAddr, btrfs.Node], err error) {
if err != nil {
fmt.Printf("Pass 1: ... dev[%q] error: %v\n", dev.Name(), err)
return
}
foundNodes[nodeRef.Data.Head.Addr] = append(foundNodes[nodeRef.Data.Head.Addr], nodeRef.Addr)
_, alreadyVisited := visitedChunkNodes[nodeRef.Data.Head.Addr]
if nodeRef.Data.Head.Owner == btrfs.CHUNK_TREE_OBJECTID && !alreadyVisited {
for i, item := range nodeRef.Data.BodyLeaf {
if item.Head.Key.ItemType != btrfsitem.CHUNK_ITEM_KEY {
continue
}
chunk, ok := item.Body.(btrfsitem.Chunk)
if !ok {
fmt.Printf("Pass 1: ... dev[%q] node@%d: item %d: error: type is CHUNK_ITEM_KEY, but struct is %T\n",
dev.Name(), nodeRef.Addr, i, item.Body)
continue
}
fmt.Printf("Pass 1: ... dev[%q] node@%d: item %d: found chunk\n",
dev.Name(), nodeRef.Addr, i)
lostAndFoundChunks = append(lostAndFoundChunks, btrfs.SysChunk{
Key: item.Head.Key,
Chunk: chunk,
})
}
}
}); err != nil {
return err
}
fmt.Printf("Pass 1: ... dev[%q] re-inserting lost+found chunks\n", dev.Name())
if len(lostAndFoundChunks) > 0 {
panic("TODO")
}
fmt.Printf("Pass 1: ... dev[%q] re-constructing stripes for lost+found nodes\n", dev.Name())
lostAndFoundNodes := make(map[btrfs.PhysicalAddr]btrfs.LogicalAddr)
for laddr, readPaddrs := range foundNodes {
resolvedPaddrs, _ := fs.Resolve(laddr)
for _, readPaddr := range readPaddrs {
if _, ok := resolvedPaddrs[btrfs.QualifiedPhysicalAddr{
Dev: superblock.Data.DevItem.DevUUID,
Addr: readPaddr,
}]; !ok {
lostAndFoundNodes[readPaddr] = laddr
}
}
}
sortedPaddrs := make([]btrfs.PhysicalAddr, 0, len(lostAndFoundNodes))
for paddr := range lostAndFoundNodes {
sortedPaddrs = append(sortedPaddrs, paddr)
}
sort.Slice(sortedPaddrs, func(i, j int) bool {
return sortedPaddrs[i] < sortedPaddrs[j]
})
type stripe struct {
PAddr btrfs.PhysicalAddr
LAddr btrfs.LogicalAddr
Size uint64
}
var stripes []stripe
for _, paddr := range sortedPaddrs {
var lastStripe *stripe
if len(stripes) > 0 {
lastStripe = &stripes[len(stripes)-1]
}
if lastStripe != nil && (lastStripe.PAddr+btrfs.PhysicalAddr(lastStripe.Size)) == paddr {
lastStripe.Size += uint64(superblock.Data.NodeSize)
} else {
stripes = append(stripes, stripe{
PAddr: paddr,
LAddr: lostAndFoundNodes[paddr],
Size: uint64(superblock.Data.NodeSize),
})
}
}
//fmt.Printf("Pass 1: ... dev[%q] reconstructed stripes: %#v\n", dev.Name(), stripes)
for _, stripe := range stripes {
reconstructedChunks[stripe.LAddr] = append(reconstructedChunks[stripe.LAddr], reconstructedStripe{
Size: stripe.Size,
Addr: btrfs.QualifiedPhysicalAddr{
Dev: superblock.Data.DevItem.DevUUID,
Addr: stripe.PAddr,
},
})
}
}
// FIXME(lukeshu): OK, so this just assumes that all the
// reconstructed stripes fit in one node, and that we can just
// store that node at the root node of the chunk tree. This
// isn't true in general, but it's true of my particular
// filesystem.
reconstructedNode := &util.Ref[btrfs.LogicalAddr, btrfs.Node]{
File: fs,
Addr: superblock.Data.ChunkTree,
Data: btrfs.Node{
Size: superblock.Data.NodeSize,
Head: btrfs.NodeHeader{
MetadataUUID: superblock.Data.EffectiveMetadataUUID(),
Addr: superblock.Data.ChunkTree,
Flags: btrfs.NodeWritten,
//BackrefRef: ???,
//ChunkTreeUUID: ???,
Generation: superblock.Data.ChunkRootGeneration,
Owner: btrfs.CHUNK_TREE_OBJECTID,
Level: 0,
},
},
}
itemOff := uint32(uint64(superblock.Data.NodeSize) - uint64(binstruct.StaticSize(btrfs.ItemHeader{})))
for laddr, stripes := range reconstructedChunks {
stripeSize := stripes[0].Size
for _, stripe := range stripes {
if stripe.Size != stripeSize {
panic("mismatch")
}
}
itemSize := uint32(binstruct.StaticSize(btrfsitem.ChunkHeader{}) + (len(stripes) * binstruct.StaticSize(btrfsitem.ChunkStripe{})))
itemOff -= itemSize
reconstructedNode.Data.BodyLeaf = append(reconstructedNode.Data.BodyLeaf, btrfs.Item{
Head: btrfs.ItemHeader{
Key: btrfs.Key{
ObjectID: TODO,
ItemType: TODO,
Offset: uint64(laddr),
},
DataOffset: itemOff,
DataSize: itemSize,
},
Body: btrfsitem.Chunk{
Head: btrfsitem.ChunkHeader{
Size: stripeSize,
Owner: btrfs.EXTENT_TREE_OBJECTID,
StripeLen: 65536, // ???
Type: TODO,
IOOptimalAlign: TODO,
IOOptimalWidth: TODO,
IOMinSize: TODO,
NumStripes: uint16(len(stripes)),
SubStripes: 1,
},
Stripes: stripes,
},
})
}
reconstructedNode.Data.Head.NumItems = uint32(len(reconstructedNode.Data.BodyLeaf))
reconstructedNode.Data.Head.Checksum, err = reconstructedNode.Data.CalculateChecksum()
if err != nil {
fmt.Printf("Pass 1: ... new node checksum: error: %v\n", err)
}
if err := reconstructedNode.Write(); err != nil {
fmt.Printf("Pass 1: ... write new node: error:: %v\n", err)
}
fmt.Printf("\nPass 2: ?????????????????????????\n") ////////////////////////////////////////
/*
fmt.Printf("node@%d: physical_addr=0x%0X logical_addr=0x%0X generation=%d owner=%v level=%d\n",
nodeRef.Addr,
nodeRef.Addr, nodeRef.Data.Head.Addr,
nodeRef.Data.Head.Generation, nodeRef.Data.Head.Owner, nodeRef.Data.Head.Level)
srcPaddr := btrfs.QualifiedPhysicalAddr{
Dev: superblock.Data.DevItem.DevUUID,
Addr: nodeRef.Addr,
}
resPaddrs, _ := fs.Resolve(nodeRef.Data.Head.Addr)
if len(resPaddrs) == 0 {
fmt.Printf("node@%d: logical_addr=0x%0X is not mapped\n",
nodeRef.Addr, nodeRef.Data.Head.Addr)
} else if _, ok := resPaddrs[srcPaddr]; !ok {
fmt.Printf("node@%d: logical_addr=0x%0X maps to %v, not %v\n",
nodeRef.Addr, nodeRef.Data.Head.Addr, resPaddrs, srcPaddr)
}
*/
return nil
}
|