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package btrfs
import (
"fmt"
"io"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsitem"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsvol"
"lukeshu.com/btrfs-tools/pkg/util"
)
type FS struct {
// You should probably not access .LV directly, except when
// implementing special things like fsck.
LV btrfsvol.LogicalVolume[*Device]
cacheSuperblocks []*util.Ref[PhysicalAddr, Superblock]
cacheSuperblock *util.Ref[PhysicalAddr, Superblock]
}
var _ util.File[LogicalAddr] = (*FS)(nil)
func (fs *FS) AddDevice(dev *Device) error {
sb, err := dev.Superblock()
if err != nil {
return err
}
if err := fs.LV.AddPhysicalVolume(sb.Data.DevItem.DevID, dev); err != nil {
return err
}
fs.cacheSuperblocks = nil
fs.cacheSuperblock = nil
if err := fs.initDev(sb); err != nil {
return 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.Data.FSUUID)
fs.LV.SetName(name)
return name
}
func (fs *FS) Size() (LogicalAddr, error) {
return fs.LV.Size()
}
func (fs *FS) ReadAt(p []byte, off LogicalAddr) (int, error) {
return fs.LV.ReadAt(p, off)
}
func (fs *FS) WriteAt(p []byte, off LogicalAddr) (int, error) {
return fs.LV.WriteAt(p, off)
}
func (fs *FS) Resolve(laddr LogicalAddr) (paddrs map[QualifiedPhysicalAddr]struct{}, maxlen AddrDelta) {
return fs.LV.Resolve(laddr)
}
func (fs *FS) Superblocks() ([]*util.Ref[PhysicalAddr, Superblock], error) {
if fs.cacheSuperblocks != nil {
return fs.cacheSuperblocks, nil
}
var ret []*util.Ref[PhysicalAddr, 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() (*util.Ref[PhysicalAddr, 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 {
// 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]
return sbs[0], nil
}
func (fs *FS) ReInit() 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(sb); err != nil {
return fmt.Errorf("file %q: %w", dev.Name(), err)
}
}
return nil
}
func (fs *FS) initDev(sb *util.Ref[PhysicalAddr, Superblock]) error {
syschunks, err := sb.Data.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
}
}
}
if err := fs.TreeWalk(sb.Data.ChunkTree, TreeWalkHandler{
Item: func(_ TreeWalkPath, item Item) error {
if item.Head.Key.ItemType != btrfsitem.CHUNK_ITEM_KEY {
return nil
}
for _, mapping := range item.Body.(btrfsitem.Chunk).Mappings(item.Head.Key) {
if err := fs.LV.AddMapping(mapping); err != nil {
return err
}
}
return nil
},
}); err != nil {
return err
}
return nil
}
func (fs *FS) Close() error {
var err error
for _, dev := range fs.LV.PhysicalVolumes() {
if _err := dev.Close(); _err != nil && err == nil {
err = _err
}
}
return err
}
var _ io.Closer = (*FS)(nil)
|
