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
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
|
// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package rebuildnodes
import (
"context"
"fmt"
"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"
)
type rebuildCallbacks interface {
fsErr(ctx context.Context, e error)
want(ctx context.Context, reason string, treeID btrfsprim.ObjID, objID btrfsprim.ObjID, typ btrfsprim.ItemType)
wantOff(ctx context.Context, reason string, treeID btrfsprim.ObjID, objID btrfsprim.ObjID, typ btrfsprim.ItemType, off uint64)
wantDirIndex(ctx context.Context, reason string, treeID btrfsprim.ObjID, objID btrfsprim.ObjID, name []byte)
wantCSum(ctx context.Context, reason string, inodeTree, inodeItem btrfsprim.ObjID, beg, end btrfsvol.LogicalAddr) // interval is [beg, end)
wantFileExt(ctx context.Context, reason string, treeID btrfsprim.ObjID, ino btrfsprim.ObjID, size int64)
}
func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID, item btrfstree.Item) {
// Notionally, just express the relationships shown in
// https://btrfs.wiki.kernel.org/index.php/File:References.png (from the page
// https://btrfs.wiki.kernel.org/index.php/Data_Structures )
switch body := item.Body.(type) {
case btrfsitem.BlockGroup:
o.want(ctx, "Chunk",
btrfsprim.CHUNK_TREE_OBJECTID,
body.ChunkObjectID,
btrfsitem.CHUNK_ITEM_KEY)
o.wantOff(ctx, "FreeSpaceInfo",
btrfsprim.FREE_SPACE_TREE_OBJECTID,
item.Key.ObjectID,
btrfsitem.FREE_SPACE_INFO_KEY,
item.Key.Offset)
case btrfsitem.Chunk:
o.want(ctx, "owning Root",
btrfsprim.ROOT_TREE_OBJECTID,
body.Head.Owner,
btrfsitem.ROOT_ITEM_KEY)
case btrfsitem.Dev:
// nothing
case btrfsitem.DevExtent:
o.wantOff(ctx, "Chunk",
body.ChunkTree,
body.ChunkObjectID,
btrfsitem.CHUNK_ITEM_KEY,
uint64(body.ChunkOffset))
case btrfsitem.DevStats:
// nothing
case btrfsitem.DirEntry:
// containing-directory
o.wantOff(ctx, "containing dir inode",
treeID,
item.Key.ObjectID,
btrfsitem.INODE_ITEM_KEY,
0)
// siblings
switch item.Key.ItemType {
case btrfsitem.DIR_ITEM_KEY:
o.wantDirIndex(ctx, "corresponding DIR_INDEX",
treeID,
item.Key.ObjectID,
body.Name)
case btrfsitem.DIR_INDEX_KEY:
o.wantOff(ctx, "corresponding DIR_ITEM",
treeID,
item.Key.ObjectID,
btrfsitem.DIR_ITEM_KEY,
btrfsitem.NameHash(body.Name))
case btrfsitem.XATTR_ITEM_KEY:
// nothing
default:
// This is a panic because the item decoder should not emit a
// btrfsitem.DirEntry for other item types without this code also being
// updated.
panic(fmt.Errorf("should not happen: DirEntry: unexpected ItemType=%v", item.Key.ItemType))
}
// item-within-directory
if body.Location != (btrfsprim.Key{}) {
switch body.Location.ItemType {
case btrfsitem.INODE_ITEM_KEY:
o.wantOff(ctx, "item being pointed to",
treeID,
body.Location.ObjectID,
body.Location.ItemType,
body.Location.Offset)
o.wantOff(ctx, "backref from item being pointed to",
treeID,
body.Location.ObjectID,
btrfsitem.INODE_REF_KEY,
uint64(item.Key.ObjectID))
case btrfsitem.ROOT_ITEM_KEY:
o.want(ctx, "Root of subvolume being pointed to",
btrfsprim.ROOT_TREE_OBJECTID,
body.Location.ObjectID,
body.Location.ItemType)
default:
o.fsErr(ctx, fmt.Errorf("DirEntry: unexpected .Location.ItemType=%v", body.Location.ItemType))
}
}
case btrfsitem.Empty:
// nothing
case btrfsitem.Extent:
// if body.Head.Flags.Has(btrfsitem.EXTENT_FLAG_TREE_BLOCK) {
// // Supposedly this flag indicates that
// // body.Info.Key identifies a node by the
// // first key in the node. But nothing in the
// // kernel ever reads this, so who knows if it
// // always gets updated correctly?
// }
for i, ref := range body.Refs {
switch refBody := ref.Body.(type) {
case nil:
// nothing
case btrfsitem.ExtentDataRef:
o.wantOff(ctx, "referencing Inode",
refBody.Root,
refBody.ObjectID,
btrfsitem.INODE_ITEM_KEY,
0)
o.wantOff(ctx, "referencing FileExtent",
refBody.Root,
refBody.ObjectID,
btrfsitem.EXTENT_DATA_KEY,
uint64(refBody.Offset))
case btrfsitem.SharedDataRef:
// nothing
default:
// This is a panic because the item decoder should not emit a new
// type to ref.Body without this code also being updated.
panic(fmt.Errorf("should not happen: Extent: unexpected .Refs[%d].Body type %T", i, refBody))
}
}
case btrfsitem.ExtentCSum:
// nothing
case btrfsitem.ExtentDataRef:
o.want(ctx, "Extent being referenced",
btrfsprim.EXTENT_TREE_OBJECTID,
item.Key.ObjectID,
btrfsitem.EXTENT_ITEM_KEY)
o.wantOff(ctx, "referencing Inode",
body.Root,
body.ObjectID,
btrfsitem.INODE_ITEM_KEY,
0)
o.wantOff(ctx, "referencing FileExtent",
body.Root,
body.ObjectID,
btrfsitem.EXTENT_DATA_KEY,
uint64(body.Offset))
case btrfsitem.FileExtent:
o.wantOff(ctx, "containing Inode",
treeID,
item.Key.ObjectID,
btrfsitem.INODE_ITEM_KEY,
0)
switch body.Type {
case btrfsitem.FILE_EXTENT_INLINE:
// nothing
case btrfsitem.FILE_EXTENT_REG, btrfsitem.FILE_EXTENT_PREALLOC:
// NB: o.wantCSum checks inodeBody.Flags.Has(btrfsitem.INODE_NODATASUM) for us.
o.wantCSum(ctx, "data sum",
treeID, item.Key.ObjectID,
body.BodyExtent.DiskByteNr,
body.BodyExtent.DiskByteNr.Add(body.BodyExtent.DiskNumBytes))
default:
o.fsErr(ctx, fmt.Errorf("FileExtent: unexpected body.Type=%v", body.Type))
}
case btrfsitem.FreeSpaceBitmap:
o.wantOff(ctx, "FreeSpaceInfo",
treeID,
item.Key.ObjectID,
btrfsitem.FREE_SPACE_INFO_KEY,
item.Key.Offset)
case btrfsitem.FreeSpaceHeader:
o.wantOff(ctx, ".Location",
treeID,
body.Location.ObjectID,
body.Location.ItemType,
body.Location.Offset)
case btrfsitem.FreeSpaceInfo:
if body.Flags.Has(btrfsitem.FREE_SPACE_USING_BITMAPS) {
o.wantOff(ctx, "FreeSpaceBitmap",
treeID,
item.Key.ObjectID,
btrfsitem.FREE_SPACE_BITMAP_KEY,
item.Key.Offset)
}
case btrfsitem.Inode:
o.want(ctx, "backrefs",
treeID, // TODO: validate the number of these against body.NLink
item.Key.ObjectID,
btrfsitem.INODE_REF_KEY)
o.wantFileExt(ctx, "FileExtents",
treeID, item.Key.ObjectID, body.Size)
if body.BlockGroup != 0 {
o.want(ctx, "BlockGroup",
btrfsprim.EXTENT_TREE_OBJECTID,
body.BlockGroup,
btrfsitem.BLOCK_GROUP_ITEM_KEY)
}
case btrfsitem.InodeRefs:
o.wantOff(ctx, "child Inode",
treeID,
item.Key.ObjectID,
btrfsitem.INODE_ITEM_KEY,
0)
o.wantOff(ctx, "parent Inode",
treeID,
btrfsprim.ObjID(item.Key.Offset),
btrfsitem.INODE_ITEM_KEY,
0)
for _, ref := range body {
o.wantOff(ctx, "DIR_ITEM",
treeID,
btrfsprim.ObjID(item.Key.Offset),
btrfsitem.DIR_ITEM_KEY,
btrfsitem.NameHash(ref.Name))
o.wantOff(ctx, "DIR_INDEX",
treeID,
btrfsprim.ObjID(item.Key.Offset),
btrfsitem.DIR_INDEX_KEY,
uint64(ref.Index))
}
case btrfsitem.Metadata:
for i, ref := range body.Refs {
switch refBody := ref.Body.(type) {
case nil:
// nothing
case btrfsitem.ExtentDataRef:
o.wantOff(ctx, "referencing INode",
refBody.Root,
refBody.ObjectID,
btrfsitem.INODE_ITEM_KEY,
0)
o.wantOff(ctx, "referencing FileExtent",
refBody.Root,
refBody.ObjectID,
btrfsitem.EXTENT_DATA_KEY,
uint64(refBody.Offset))
case btrfsitem.SharedDataRef:
// nothing
default:
// This is a panic because the item decoder should not emit a new
// type to ref.Body without this code also being updated.
panic(fmt.Errorf("should not happen: Metadata: unexpected .Refs[%d].Body type %T", i, refBody))
}
}
case btrfsitem.Root:
if body.RootDirID != 0 {
o.wantOff(ctx, "root directory",
item.Key.ObjectID,
body.RootDirID,
btrfsitem.INODE_ITEM_KEY,
0)
}
if body.UUID != (btrfsprim.UUID{}) {
key := btrfsitem.UUIDToKey(body.UUID)
o.wantOff(ctx, "uuid",
btrfsprim.UUID_TREE_OBJECTID,
key.ObjectID,
key.ItemType,
key.Offset)
}
if body.ParentUUID != (btrfsprim.UUID{}) {
key := btrfsitem.UUIDToKey(body.ParentUUID)
o.wantOff(ctx, "parent uuid",
btrfsprim.UUID_TREE_OBJECTID,
key.ObjectID,
key.ItemType,
key.Offset)
}
case btrfsitem.RootRef:
var otherType btrfsprim.ItemType
var parent, child btrfsprim.ObjID
switch item.Key.ItemType {
case btrfsitem.ROOT_REF_KEY:
otherType = btrfsitem.ROOT_BACKREF_KEY
parent = item.Key.ObjectID
child = btrfsprim.ObjID(item.Key.Offset)
case btrfsitem.ROOT_BACKREF_KEY:
otherType = btrfsitem.ROOT_REF_KEY
parent = btrfsprim.ObjID(item.Key.Offset)
child = item.Key.ObjectID
default:
// This is a panic because the item decoder should not emit a
// btrfsitem.RootRef for other item types without this code also being
// updated.
panic(fmt.Errorf("should not happen: RootRef: unexpected ItemType=%v", item.Key.ItemType))
}
// sibling
o.wantOff(ctx, fmt.Sprintf("corresponding %v", otherType),
treeID,
btrfsprim.ObjID(item.Key.Offset),
otherType,
uint64(item.Key.ObjectID))
// parent
o.want(ctx, "parent subvolume: Root",
treeID,
parent,
btrfsitem.ROOT_ITEM_KEY)
o.wantOff(ctx, "parent subvolume: Inode of parent dir",
parent,
body.DirID,
btrfsitem.INODE_ITEM_KEY,
0)
o.wantOff(ctx, "parent subvolume: DIR_ITEM in parent dir",
parent,
body.DirID,
btrfsitem.DIR_ITEM_KEY,
btrfsitem.NameHash(body.Name))
o.wantOff(ctx, "parent subvolume: DIR_INDEX in parent dir",
parent,
body.DirID,
btrfsitem.DIR_INDEX_KEY,
uint64(body.Sequence))
// child
o.want(ctx, "child subvolume: Root",
treeID,
child,
btrfsitem.ROOT_ITEM_KEY)
case btrfsitem.SharedDataRef:
o.want(ctx, "Extent",
btrfsprim.EXTENT_TREE_OBJECTID,
item.Key.ObjectID,
btrfsitem.EXTENT_ITEM_KEY)
case btrfsitem.UUIDMap:
o.want(ctx, "subvolume Root",
btrfsprim.ROOT_TREE_OBJECTID,
body.ObjID,
btrfsitem.ROOT_ITEM_KEY)
case btrfsitem.Error:
o.fsErr(ctx, fmt.Errorf("error decoding item: %w", body.Err))
default:
// This is a panic because the item decoder should not emit new types without this
// code also being updated.
panic(fmt.Errorf("should not happen: unexpected item type: %T", body))
}
}
|