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volume.go
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volume.go
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package fs
import (
"fmt"
"io"
"os"
"time"
"github.com/allmad/madq/go/bio"
"github.com/chzyer/flow"
"github.com/chzyer/logex"
)
var ErrFileNotExist = logex.Define("file is not exists")
type Volume struct {
cfg *VolumeConfig
flow *flow.Flow
header *VolumeHeader
delegate VolumeDelegate
fileCache map[string]*File
// init
flusher *Flusher
nameMap *NameMap
}
type VolumeDelegate interface {
bio.ReadWriterAt
ReadData(off int64, n int) ([]byte, error)
}
type VolumeConfig struct {
Delegate VolumeDelegate
FlushInterval time.Duration
FlushSize int
}
func (v *VolumeConfig) init() error {
if v.Delegate == nil {
return fmt.Errorf("volume init error: delegate is empty")
}
if v.FlushInterval == 0 {
v.FlushInterval = time.Second
}
if v.FlushSize == 0 {
v.FlushSize = 10 << 20
}
return nil
}
func NewVolume(f *flow.Flow, cfg *VolumeConfig) (*Volume, error) {
if err := cfg.init(); err != nil {
return nil, err
}
vh, err := ReadVolumeHeader(cfg.Delegate)
if err != nil {
if !logex.Equal(err, io.EOF) {
return nil, logex.Trace(err)
}
// make a new one
vh, err = GenNewVolumeHeader(cfg.Delegate)
if err != nil {
return nil, logex.Trace(err)
}
}
vol := &Volume{
cfg: cfg,
header: vh,
delegate: cfg.Delegate,
fileCache: make(map[string]*File, 16),
}
f.ForkTo(&vol.flow, vol.Close)
if err := vol.init(); err != nil {
return nil, err
}
return vol, nil
}
func (v *Volume) init() (err error) {
v.flusher = v.initFlusher()
v.nameMap, err = v.initNameMap()
if err != nil {
return err
}
return nil
}
func (v *Volume) FlushInodeMap() error {
return v.header.InodeMap.Flush()
}
// require header is inited
func (v *Volume) initFlusher() *Flusher {
f := NewFlusher(v.flow, &FlusherConfig{
Offset: int64(v.header.Checkpoint),
Interval: v.cfg.FlushInterval,
Delegate: &volumeFlusherDelegate{v.header, v.delegate},
})
return f
}
func (v *Volume) initNameMap() (*NameMap, error) {
fd, err := v.inoOpen(0, "/", os.O_CREATE)
if err != nil {
return nil, logex.Trace(err)
}
return NewNameMap(NewHandle(fd, 0), 1)
}
func (v *Volume) removeCache(fd *File) {
delete(v.fileCache, fd.Name())
}
func (v *Volume) addCache(fd *File) {
v.fileCache[fd.Name()] = fd
}
func (v *Volume) getFileInCache(name string) *Handle {
f := v.fileCache[name]
if f != nil {
if !f.AddRef() {
v.removeCache(f)
return nil
}
return NewHandle(f, 0)
}
return nil
}
func (v *Volume) inoOpen(ino int32, name string, flags int) (*File, error) {
fd, err := NewFile(v.flow, &FileConfig{
Ino: ino,
Flags: flags,
Name: name,
Delegate: &volumeFileDelegate{v.delegate, v.header.InodeMap},
FlushInterval: v.cfg.FlushInterval,
FlushSize: v.cfg.FlushSize,
Flusher: v.flusher,
})
if err != nil {
return nil, err
}
v.addCache(fd)
return fd, nil
}
func (v *Volume) Open(name string, flags int) (*Handle, error) {
if fd := v.getFileInCache(name); fd != nil {
return fd, nil
}
ino, err := v.nameMap.GetIno(name)
if err != nil {
return nil, logex.Trace(err)
}
if ino < 0 && !IsFileCreate(flags) {
return nil, ErrFileNotExist.Trace()
}
if ino < 0 {
// alloc ino
ino, err = v.nameMap.GetFreeIno()
if err != nil {
return nil, err
}
if err := v.nameMap.AddIno(name, ino); err != nil {
return nil, err
}
}
fd, err := v.inoOpen(ino, name, flags)
if err != nil {
return nil, logex.Trace(err)
}
if !fd.AddRef() {
panic("can't be fail")
}
// add cache
return NewHandle(fd, 0), nil
}
func (v *Volume) List() []string {
return v.nameMap.List()
}
func (v *Volume) CleanCache() {
v.fileCache = make(map[string]*File)
}
func (v *Volume) Close() {
now := time.Now()
v.nameMap.Close()
v.flusher.Close()
v.flow.Close()
if err := v.header.Flush(v.delegate); err != nil {
println("volume header flush error:", err.Error())
}
Stat.Volume.CloseTime.AddNow(now)
}
// -----------------------------------------------------------------------------
var _ FlushDelegate = new(volumeFlusherDelegate)
type volumeFlusherDelegate struct {
header *VolumeHeader
VolumeDelegate
}
func (v *volumeFlusherDelegate) UpdateCheckpoint(cp int64) {
v.header.Checkpoint.Set(Address(cp))
}
// -----------------------------------------------------------------------------
var _ FileDelegater = new(volumeFileDelegate)
type volumeFileDelegate struct {
v VolumeDelegate
imap *InodeMap
}
func (v *volumeFileDelegate) GetInode(ino int32) (*Inode, error) {
return v.imap.GetInode(ino)
}
func (v *volumeFileDelegate) GetInodeByAddr(addr Address) (*Inode, error) {
return v.imap.GetInodeByAddr(addr)
}
func (v *volumeFileDelegate) ReadData(addr ShortAddr, n int) ([]byte, error) {
return v.v.ReadData(int64(addr), n)
}
func (v *volumeFileDelegate) SaveInode(ino *Inode) {
v.imap.SaveInode(ino)
}
// -----------------------------------------------------------------------------
const (
VolumeHeaderSize = 16
VolumeHeaderMinCheckpoint = VolumeHeaderSize + InodeMapSize
)
type VolumeHeader struct {
Version Int32
Checkpoint Address
InodeMap *InodeMap
}
func (v *VolumeHeader) DiskSize() int {
return VolumeHeaderSize
}
func (v *VolumeHeader) WriteDisk(b []byte) {
dw := NewDiskWriter(b)
dw.WriteMagic(v)
dw.WriteItem(v.Version)
dw.WriteItem(v.Checkpoint)
}
func (v *VolumeHeader) ReadDisk(b []byte) error {
dr := NewDiskReader(b)
if err := dr.ReadMagic(v); err != nil {
return err
}
if err := dr.ReadItem(&v.Version); err != nil {
return err
}
if err := dr.ReadItem(&v.Checkpoint); err != nil {
return err
}
return nil
}
func (v *VolumeHeader) Magic() Magic {
return MagicVolume
}
func (v *VolumeHeader) Flush(w io.WriterAt) error {
if err := WriteDiskAt(w, v, 0); err != nil {
return err
}
if err := v.InodeMap.Flush(); err != nil {
return err
}
return nil
}
func GenNewVolumeHeader(rw bio.ReadWriterAt) (*VolumeHeader, error) {
vh := new(VolumeHeader)
vh.Version = 1
vh.Checkpoint = VolumeHeaderMinCheckpoint
if err := WriteDiskAt(rw, vh, 0); err != nil {
return nil, logex.Trace(err)
}
imap, err := NewInodeMap(VolumeHeaderSize, rw, true)
if err != nil {
return nil, err
}
vh.InodeMap = imap
return vh, nil
}
func ReadVolumeHeader(rw bio.ReadWriterAt) (*VolumeHeader, error) {
vh := new(VolumeHeader)
if err := ReadDisk(rw, vh, 0); err != nil {
return nil, logex.Trace(err)
}
if vh.Checkpoint < VolumeHeaderMinCheckpoint {
return nil, logex.NewError("invalid checkpoint:", vh.Checkpoint)
}
imap, err := NewInodeMap(VolumeHeaderSize, rw, false)
if err != nil {
return nil, err
}
vh.InodeMap = imap
return vh, nil
}