diff options
Diffstat (limited to 'lib/btrfs/types_superblock.go')
| -rw-r--r-- | lib/btrfs/types_superblock.go | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/lib/btrfs/types_superblock.go b/lib/btrfs/types_superblock.go new file mode 100644 index 0000000..373de48 --- /dev/null +++ b/lib/btrfs/types_superblock.go @@ -0,0 +1,233 @@ +package btrfs + +import ( + "fmt" + "reflect" + + "git.lukeshu.com/btrfs-progs-ng/lib/binstruct" + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem" + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum" + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol" + "git.lukeshu.com/btrfs-progs-ng/lib/util" +) + +type Superblock struct { + Checksum btrfssum.CSum `bin:"off=0x0, siz=0x20"` // Checksum of everything past this field (from 0x20 to 0x1000) + FSUUID UUID `bin:"off=0x20, siz=0x10"` // FS UUID + Self btrfsvol.PhysicalAddr `bin:"off=0x30, siz=0x8"` // physical address of this block (different for mirrors) + Flags uint64 `bin:"off=0x38, siz=0x8"` // flags + Magic [8]byte `bin:"off=0x40, siz=0x8"` // magic ('_BHRfS_M') + Generation Generation `bin:"off=0x48, siz=0x8"` + + RootTree btrfsvol.LogicalAddr `bin:"off=0x50, siz=0x8"` // logical address of the root tree root + ChunkTree btrfsvol.LogicalAddr `bin:"off=0x58, siz=0x8"` // logical address of the chunk tree root + LogTree btrfsvol.LogicalAddr `bin:"off=0x60, siz=0x8"` // logical address of the log tree root + + LogRootTransID uint64 `bin:"off=0x68, siz=0x8"` // log_root_transid + TotalBytes uint64 `bin:"off=0x70, siz=0x8"` // total_bytes + BytesUsed uint64 `bin:"off=0x78, siz=0x8"` // bytes_used + RootDirObjectID ObjID `bin:"off=0x80, siz=0x8"` // root_dir_objectid (usually 6) + NumDevices uint64 `bin:"off=0x88, siz=0x8"` // num_devices + + SectorSize uint32 `bin:"off=0x90, siz=0x4"` + NodeSize uint32 `bin:"off=0x94, siz=0x4"` + LeafSize uint32 `bin:"off=0x98, siz=0x4"` // unused; must be the same as NodeSize + StripeSize uint32 `bin:"off=0x9c, siz=0x4"` + SysChunkArraySize uint32 `bin:"off=0xa0, siz=0x4"` + + ChunkRootGeneration Generation `bin:"off=0xa4, siz=0x8"` + CompatFlags uint64 `bin:"off=0xac, siz=0x8"` // compat_flags + CompatROFlags uint64 `bin:"off=0xb4, siz=0x8"` // compat_ro_flags - only implementations that support the flags can write to the filesystem + IncompatFlags IncompatFlags `bin:"off=0xbc, siz=0x8"` // incompat_flags - only implementations that support the flags can use the filesystem + ChecksumType btrfssum.CSumType `bin:"off=0xc4, siz=0x2"` + + RootLevel uint8 `bin:"off=0xc6, siz=0x1"` // root_level + ChunkLevel uint8 `bin:"off=0xc7, siz=0x1"` // chunk_root_level + LogLevel uint8 `bin:"off=0xc8, siz=0x1"` // log_root_level + + DevItem btrfsitem.Dev `bin:"off=0xc9, siz=0x62"` // DEV_ITEM data for this device + Label [0x100]byte `bin:"off=0x12b, siz=0x100"` // label (may not contain '/' or '\\') + CacheGeneration Generation `bin:"off=0x22b, siz=0x8"` + UUIDTreeGeneration Generation `bin:"off=0x233, siz=0x8"` + + // FeatureIncompatMetadataUUID + MetadataUUID UUID `bin:"off=0x23b, siz=0x10"` + + // FeatureIncompatExtentTreeV2 + NumGlobalRoots uint64 `bin:"off=0x24b, siz=0x8"` + + // FeatureIncompatExtentTreeV2 + BlockGroupRoot btrfsvol.LogicalAddr `bin:"off=0x253, siz=0x8"` + BlockGroupRootGeneration Generation `bin:"off=0x25b, siz=0x8"` + BlockGroupRootLevel uint8 `bin:"off=0x263, siz=0x1"` + + Reserved [199]byte `bin:"off=0x264, siz=0xc7"` // future expansion + + SysChunkArray [0x800]byte `bin:"off=0x32b, siz=0x800"` // sys_chunk_array:(n bytes valid) Contains (KEY . CHUNK_ITEM) pairs for all SYSTEM chunks. This is needed to bootstrap the mapping from logical addresses to physical. + SuperRoots [4]RootBackup `bin:"off=0xb2b, siz=0x2a0"` + + // Padded to 4096 bytes + Padding [565]byte `bin:"off=0xdcb, siz=0x235"` + binstruct.End `bin:"off=0x1000"` +} + +func (sb Superblock) CalculateChecksum() (btrfssum.CSum, error) { + data, err := binstruct.Marshal(sb) + if err != nil { + return btrfssum.CSum{}, err + } + return sb.ChecksumType.Sum(data[binstruct.StaticSize(btrfssum.CSum{}):]) +} + +func (sb Superblock) ValidateChecksum() error { + stored := sb.Checksum + calced, err := sb.CalculateChecksum() + if err != nil { + return err + } + if calced != stored { + return fmt.Errorf("superblock checksum mismatch: stored=%v calculated=%v", + stored, calced) + } + return nil +} + +func (a Superblock) Equal(b Superblock) bool { + a.Checksum = btrfssum.CSum{} + a.Self = 0 + + b.Checksum = btrfssum.CSum{} + b.Self = 0 + + return reflect.DeepEqual(a, b) +} + +func (sb Superblock) EffectiveMetadataUUID() UUID { + if !sb.IncompatFlags.Has(FeatureIncompatMetadataUUID) { + return sb.FSUUID + } + return sb.MetadataUUID +} + +type SysChunk struct { + Key Key + Chunk btrfsitem.Chunk +} + +func (sc SysChunk) MarshalBinary() ([]byte, error) { + dat, err := binstruct.Marshal(sc.Key) + if err != nil { + return dat, fmt.Errorf("%T.MarshalBinary: %w", sc, err) + } + _dat, err := binstruct.Marshal(sc.Chunk) + dat = append(dat, _dat...) + if err != nil { + return dat, fmt.Errorf("%T.MarshalBinary: %w", sc, err) + } + return dat, nil +} + +func (sc *SysChunk) UnmarshalBinary(dat []byte) (int, error) { + n, err := binstruct.Unmarshal(dat, &sc.Key) + if err != nil { + return n, fmt.Errorf("%T.UnmarshalBinary: %w", *sc, err) + } + _n, err := binstruct.Unmarshal(dat[n:], &sc.Chunk) + n += _n + if err != nil { + return n, fmt.Errorf("%T.UnmarshalBinary: %w", *sc, err) + } + return n, nil +} + +func (sb Superblock) ParseSysChunkArray() ([]SysChunk, error) { + dat := sb.SysChunkArray[:sb.SysChunkArraySize] + var ret []SysChunk + for len(dat) > 0 { + var pair SysChunk + n, err := binstruct.Unmarshal(dat, &pair) + dat = dat[n:] + if err != nil { + return nil, err + } + ret = append(ret, pair) + } + return ret, nil +} + +type RootBackup struct { + TreeRoot ObjID `bin:"off=0x0, siz=0x8"` + TreeRootGen Generation `bin:"off=0x8, siz=0x8"` + + ChunkRoot ObjID `bin:"off=0x10, siz=0x8"` + ChunkRootGen Generation `bin:"off=0x18, siz=0x8"` + + ExtentRoot ObjID `bin:"off=0x20, siz=0x8"` + ExtentRootGen Generation `bin:"off=0x28, siz=0x8"` + + FSRoot ObjID `bin:"off=0x30, siz=0x8"` + FSRootGen Generation `bin:"off=0x38, siz=0x8"` + + DevRoot ObjID `bin:"off=0x40, siz=0x8"` + DevRootGen Generation `bin:"off=0x48, siz=0x8"` + + ChecksumRoot ObjID `bin:"off=0x50, siz=0x8"` + ChecksumRootGen Generation `bin:"off=0x58, siz=0x8"` + + TotalBytes uint64 `bin:"off=0x60, siz=0x8"` + BytesUsed uint64 `bin:"off=0x68, siz=0x8"` + NumDevices uint64 `bin:"off=0x70, siz=0x8"` + + Unused [8 * 4]byte `bin:"off=0x78, siz=0x20"` + + TreeRootLevel uint8 `bin:"off=0x98, siz=0x1"` + ChunkRootLevel uint8 `bin:"off=0x99, siz=0x1"` + ExtentRootLevel uint8 `bin:"off=0x9a, siz=0x1"` + FSRootLevel uint8 `bin:"off=0x9b, siz=0x1"` + DevRootLevel uint8 `bin:"off=0x9c, siz=0x1"` + ChecksumRootLevel uint8 `bin:"off=0x9d, siz=0x1"` + + Padding [10]byte `bin:"off=0x9e, siz=0xa"` + binstruct.End `bin:"off=0xa8"` +} + +type IncompatFlags uint64 + +const ( + FeatureIncompatMixedBackref = IncompatFlags(1 << iota) + FeatureIncompatDefaultSubvol + FeatureIncompatMixedGroups + FeatureIncompatCompressLZO + FeatureIncompatCompressZSTD + FeatureIncompatBigMetadata // buggy + FeatureIncompatExtendedIRef + FeatureIncompatRAID56 + FeatureIncompatSkinnyMetadata + FeatureIncompatNoHoles + FeatureIncompatMetadataUUID + FeatureIncompatRAID1C34 + FeatureIncompatZoned + FeatureIncompatExtentTreeV2 +) + +var incompatFlagNames = []string{ + "FeatureIncompatMixedBackref", + "FeatureIncompatDefaultSubvol", + "FeatureIncompatMixedGroups", + "FeatureIncompatCompressLZO", + "FeatureIncompatCompressZSTD", + "FeatureIncompatBigMetadata ", + "FeatureIncompatExtendedIRef", + "FeatureIncompatRAID56", + "FeatureIncompatSkinnyMetadata", + "FeatureIncompatNoHoles", + "FeatureIncompatMetadataUUID", + "FeatureIncompatRAID1C34", + "FeatureIncompatZoned", + "FeatureIncompatExtentTreeV2", +} + +func (f IncompatFlags) Has(req IncompatFlags) bool { return f&req == req } +func (f IncompatFlags) String() string { + return util.BitfieldString(f, incompatFlagNames, util.HexLower) +} |