diff options
Diffstat (limited to 'pkg/btrfs/types.go')
| -rw-r--r-- | pkg/btrfs/types.go | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/pkg/btrfs/types.go b/pkg/btrfs/types.go new file mode 100644 index 0000000..2949a8b --- /dev/null +++ b/pkg/btrfs/types.go @@ -0,0 +1,132 @@ +package btrfs + +import ( + "time" + + "lukeshu.com/btrfs-tools/pkg/binstruct" +) + +type ( + PhysicalAddr int64 + LogicalAddr int64 + ObjID int64 +) + +type Key struct { + ObjectID ObjID `bin:"off=0, siz=8, desc=Object ID. Each tree has its own set of Object IDs."` + ItemType uint8 `bin:"off=8, siz=1, desc=Item type."` + Offset uint64 `bin:"off=9, siz=8, desc=Offset. The meaning depends on the item type."` + binstruct.End `bin:"off=11"` +} + +type Time struct { + Sec int64 `bin:"off=0, siz=8, desc=Number of seconds since 1970-01-01T00:00:00Z."` + NSec uint64 `bin:"off=8, siz=4, desc=Number of nanoseconds since the beginning of the second."` + binstruct.End `bin:"off=c"` +} + +func (t Time) ToStd() time.Time { + return time.Unix(t.Sec, int64(t.NSec)) +} + +type Superblock struct { + Checksum CSum `bin:"off=0, siz=20, desc=Checksum of everything past this field (from 20 to 1000)"` + FSUUID UUID `bin:"off=20, siz=10, desc=FS UUID"` + Self PhysicalAddr `bin:"off=30, siz=8, desc=physical address of this block (different for mirrors)"` + Flags uint64 `bin:"off=38, siz=8, desc=flags"` + Magic [8]byte `bin:"off=40, siz=8, desc=magic ('_BHRfS_M')"` + Generation uint64 `bin:"off=48, siz=8, desc=generation"` + + RootTree LogicalAddr `bin:"off=50, siz=8, desc=logical address of the root tree root"` + ChunkTree LogicalAddr `bin:"off=58, siz=8, desc=logical address of the chunk tree root"` + LogTree LogicalAddr `bin:"off=60, siz=8, desc=logical address of the log tree root"` + + LogRootTransID uint64 `bin:"off=68, siz=8, desc=log_root_transid"` + TotalBytes uint64 `bin:"off=70, siz=8, desc=total_bytes"` + BytesUsed uint64 `bin:"off=78, siz=8, desc=bytes_used"` + RootDirObjectID uint64 `bin:"off=80, siz=8, desc=root_dir_objectid (usually 6)"` + NumDevices uint64 `bin:"off=88, siz=8, desc=num_devices"` + + SectorSize uint32 `bin:"off=90, siz=4, desc=sectorsize"` + NodeSize uint32 `bin:"off=94, siz=4, desc=nodesize"` + LeafSize uint32 `bin:"off=98, siz=4, desc=leafsize"` + StripeSize uint32 `bin:"off=9c, siz=4, desc=stripesize"` + SysChunkArraySize uint32 `bin:"off=a0, siz=4, desc=sys_chunk_array_size"` + + ChunkRootGeneration uint64 `bin:"off=a4, siz=8, desc=chunk_root_generation"` + CompatFlags uint64 `bin:"off=ac, siz=8, desc=compat_flags"` + CompatROFlags uint64 `bin:"off=b4, siz=8, desc=compat_ro_flags - only implementations that support the flags can write to the filesystem"` + IncompatFlags uint64 `bin:"off=bc, siz=8, desc=incompat_flags - only implementations that support the flags can use the filesystem"` + ChecksumType uint16 `bin:"off=c4, siz=2, desc=csum_type - Btrfs currently uses the CRC32c little-endian hash function with seed -1."` + + RootLevel uint8 `bin:"off=c6, siz=1, desc=root_level"` + ChunkLevel uint8 `bin:"off=c7, siz=1, desc=chunk_root_level"` + LogLevel uint8 `bin:"off=c8, siz=1, desc=log_root_level"` + + DevItem DevItem `bin:"off=c9, siz=62, desc=DEV_ITEM data for this device"` + Label [0x100]byte `bin:"off=12b, siz=100, desc=label (may not contain '/' or '\\')"` + CacheGeneration uint64 `bin:"off=22b, siz=8, desc=cache_generation"` + UUIDTreeGeneration uint64 `bin:"off=233, siz=8, desc=uuid_tree_generation"` + + Reserved [0xf0]byte `bin:"off=23b, siz=f0, desc=reserved /* future expansion */"` + + TODOSysChunkArray [0x800]byte `bin:"off=32b, siz=800, desc=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. "` + TODOSuperRoots [0x2a0]byte `bin:"off=b2b, siz=2a0, desc=Contain super_roots (4 btrfs_root_backup)"` + + Unused [0x235]byte `bin:"off=dcb, siz=235, desc=current unused"` + + binstruct.End `bin:"off=1000"` +} + +func (sb Superblock) CalculateChecksum() (CSum, error) { + data, err := binstruct.Marshal(sb) + if err != nil { + return CSum{}, err + } + return CRC32c(data[0x20:]), nil +} + +type DevItem struct { + DeviceID uint64 `bin:"off=0, siz=8, desc=device id"` + + NumBytes uint64 `bin:"off=8, siz=8, desc=number of bytes"` + NumBytesUsed uint64 `bin:"off=10, siz=8, desc=number of bytes used"` + + IOOptimalAlign uint32 `bin:"off=18, siz=4, desc=optimal I/O align"` + IOOptimalWidth uint32 `bin:"off=1c, siz=4, desc=optimal I/O width"` + IOMinSize uint32 `bin:"off=20, siz=4, desc=minimal I/O size (sector size)"` + + Type uint64 `bin:"off=24, siz=8, desc=type"` + Generation uint64 `bin:"off=2c, siz=8, desc=generation"` + StartOffset uint64 `bin:"off=34, siz=8, desc=start offset"` + DevGroup uint32 `bin:"off=3c, siz=4, desc=dev group"` + SeekSpeed uint8 `bin:"off=40, siz=1, desc=seek speed"` + Bandwidth uint8 `bin:"off=41, siz=1, desc=bandwidth"` + + DevUUID UUID `bin:"off=42, siz=10, desc=device UUID"` + FSUUID UUID `bin:"off=52, siz=10, desc=FS UUID"` + + binstruct.End `bin:"off=62"` +} + +type ChunkItem struct { + // Maps logical address to physical. + Size uint64 `bin:"off=0, siz=8, desc=size of chunk (bytes)"` + Root ObjID `bin:"off=8, siz=8, desc=root referencing this chunk (2)"` + StripeLen uint64 `bin:"off=10, siz=8, desc=stripe length"` + Type uint64 `bin:"off=18, siz=8, desc=type (same as flags for block group?)"` + IOOptimalAlign uint32 `bin:"off=20, siz=4, desc=optimal io alignment"` + IOOptimalWidth uint32 `bin:"off=24, siz=4, desc=optimal io width"` + IoMinSize uint32 `bin:"off=28, siz=4, desc=minimal io size (sector size)"` + NumStripes uint16 `bin:"off=2c, siz=2, desc=number of stripes"` + SubStripes uint16 `bin:"off=2e, siz=2, desc=sub stripes"` + binstruct.End `bin:"off=30"` +} + +type ChunkItemStripe struct { + // Stripes follow (for each number of stripes): + DeviceID ObjID `bin:"off=0, siz=8, desc=device id"` + Offset uint64 `bin:"off=8, siz=8, desc=offset"` + DeviceUUID UUID `bin:"off=10, siz=10, desc=device UUID"` + binstruct.End `bin:"off=20"` +} |