refactor for reading super block

weed-fs/src/cmd/weed/fix.go

@@ -1,65 +1,70 @@
 package main
 
 import (
-  "pkg/storage"
-  "log"
-  "os"
-  "path"
-  "strconv"
+	"log"
+	"os"
+	"path"
+	"pkg/storage"
+	"strconv"
 )
 
 func init() {
-  cmdFix.Run = runFix // break init cycle
-  IsDebug  = cmdFix.Flag.Bool("debug", false, "enable debug mode")
+	cmdFix.Run = runFix // break init cycle
+	IsDebug = cmdFix.Flag.Bool("debug", false, "enable debug mode")
 }
 
 var cmdFix = &Command{
-  UsageLine: "fix -dir=/tmp -volumeId=234 -debug=1",
-  Short:     "run weed tool fix on index file if corrupted",
-  Long: `Fix runs the WeedFS fix command to re-create the index .idx file.
+	UsageLine: "fix -dir=/tmp -volumeId=234 -debug=1",
+	Short:     "run weed tool fix on index file if corrupted",
+	Long: `Fix runs the WeedFS fix command to re-create the index .idx file.
 
   `,
 }
 
 var (
-  dir      = cmdFix.Flag.String("dir", "/tmp", "data directory to store files")
-  volumeId = cmdFix.Flag.Int("volumeId", -1, "a non-negative volume id. The volume should already exist in the dir. The volume index file should not exist.")
+	dir      = cmdFix.Flag.String("dir", "/tmp", "data directory to store files")
+	volumeId = cmdFix.Flag.Int("volumeId", -1, "a non-negative volume id. The volume should already exist in the dir. The volume index file should not exist.")
 )
 
 func runFix(cmd *Command, args []string) bool {
 
-  if *volumeId == -1 {
-    return false
-  }
+	if *volumeId == -1 {
+		return false
+	}
 
-  fileName := strconv.Itoa(*volumeId)
-  dataFile, e := os.OpenFile(path.Join(*dir, fileName+".dat"), os.O_RDONLY, 0644)
-  if e != nil {
-    log.Fatalf("Read Volume [ERROR] %s\n", e)
-  }
-  defer dataFile.Close()
-  indexFile, ie := os.OpenFile(path.Join(*dir, fileName+".idx"), os.O_WRONLY|os.O_CREATE, 0644)
-  if ie != nil {
-    log.Fatalf("Create Volume Index [ERROR] %s\n", ie)
-  }
-  defer indexFile.Close()
+	fileName := strconv.Itoa(*volumeId)
+	dataFile, e := os.OpenFile(path.Join(*dir, fileName+".dat"), os.O_RDONLY, 0644)
+	if e != nil {
+		log.Fatalf("Read Volume [ERROR] %s\n", e)
+	}
+	defer dataFile.Close()
+	indexFile, ie := os.OpenFile(path.Join(*dir, fileName+".idx"), os.O_WRONLY|os.O_CREATE, 0644)
+	if ie != nil {
+		log.Fatalf("Create Volume Index [ERROR] %s\n", ie)
+	}
+	defer indexFile.Close()
 
-  //skip the volume super block
-  dataFile.Seek(storage.SuperBlockSize, 0)
+	dataFile.Seek(0, 0)
+	header := make([]byte, storage.SuperBlockSize)
+	if _, e := dataFile.Read(header); e != nil {
+		log.Fatalf("cannot read superblock: %s", e)
+	}
 
-  n, rest := storage.ReadNeedle(dataFile)
-  dataFile.Seek(int64(rest), 1)
-  nm := storage.NewNeedleMap(indexFile)
-  offset := uint32(storage.SuperBlockSize)
-  for n != nil {
-    debug("key", n.Id, "volume offset", offset, "data_size", n.Size, "rest", rest)
-    if n.Size > 0 {
-      count, pe := nm.Put(n.Id, offset/8, n.Size)
-      debug("saved", count, "with error", pe)
-    }
-    offset += rest+16
-    n, rest = storage.ReadNeedle(dataFile)
-    dataFile.Seek(int64(rest), 1)
-  }
-  return true
+	ver, _, _ := storage.ParseSuperBlock(header)
+
+	n, rest := storage.ReadNeedle(dataFile, ver)
+	dataFile.Seek(int64(rest), 1)
+	nm := storage.NewNeedleMap(indexFile)
+	offset := uint32(storage.SuperBlockSize)
+	for n != nil {
+		debug("key", n.Id, "volume offset", offset, "data_size", n.Size, "rest", rest)
+		if n.Size > 0 {
+			count, pe := nm.Put(n.Id, offset/8, n.Size)
+			debug("saved", count, "with error", pe)
+		}
+		offset += rest + 16
+		n, rest = storage.ReadNeedle(dataFile, ver)
+		dataFile.Seek(int64(rest), 1)
+	}
+	return true
 }

weed-fs/src/pkg/storage/needle_read_write.go

@@ -1,7 +1,7 @@
 package storage
 
 import (
-    "errors"
+	"errors"
 	"io"
 	"os"
 	"pkg/util"
@@ -15,14 +15,14 @@ func (n *Needle) Append(w io.Writer) uint32 {
 	util.Uint32toBytes(header[12:16], n.Size)
 	w.Write(header)
 	w.Write(n.Data)
-	rest := 8 - ((n.Size + 16 + 4) % 8)
+	rest := 8 - ((16 + n.Size + 4) % 8)
 	util.Uint32toBytes(header[0:4], n.Checksum.Value())
-	w.Write(header[0 : rest+4])
+	w.Write(header[0 : 4+rest])
 	return n.Size
 }
 func (n *Needle) Read(r io.Reader, size uint32, version Version) (int, error) {
 	if version == Version1 {
-		bytes := make([]byte, size+16+4)
+		bytes := make([]byte, 16+size+4)
 		ret, e := r.Read(bytes)
 		n.Cookie = util.BytesToUint32(bytes[0:4])
 		n.Id = util.BytesToUint64(bytes[4:12])
@@ -33,20 +33,24 @@ func (n *Needle) Read(r io.Reader, size uint32, version Version) (int, error) {
 			return 0, errors.New("CRC error! Data On Disk Corrupted!")
 		}
 		return ret, e
-	}else if version == Version2 {
+	} else if version == Version2 {
 	}
 	return 0, errors.New("Unsupported Version!")
 }
-func ReadNeedle(r *os.File) (*Needle, uint32) {
-	n := new(Needle)
-	bytes := make([]byte, 16)
-	count, e := r.Read(bytes)
-	if count <= 0 || e != nil {
-		return nil, 0
+func ReadNeedle(r *os.File, version Version) (n *Needle, bytesTillNextFile uint32) {
+	n = new(Needle)
+	if version == Version1 {
+		bytes := make([]byte, 16)
+		count, e := r.Read(bytes)
+		if count <= 0 || e != nil {
+			return nil, 0
+		}
+		n.Cookie = util.BytesToUint32(bytes[0:4])
+		n.Id = util.BytesToUint64(bytes[4:12])
+		n.Size = util.BytesToUint32(bytes[12:16])
+		rest := 8 - ((n.Size + 16 + 4) % 8)
+		bytesTillNextFile = n.Size + 4 + rest
+	} else if version == Version2 {
 	}
-	n.Cookie = util.BytesToUint32(bytes[0:4])
-	n.Id = util.BytesToUint64(bytes[4:12])
-	n.Size = util.BytesToUint32(bytes[12:16])
-	rest := 8 - ((n.Size + 16 + 4) % 8)
-	return n, n.Size + 4 + rest
+	return
 }

weed-fs/src/pkg/storage/volume.go

@@ -18,8 +18,8 @@ type Volume struct {
 	dataFile *os.File
 	nm       *NeedleMap
 
-	replicaType ReplicationType
 	version     Version
+	replicaType ReplicationType
 
 	accessLock sync.Mutex
 }
@@ -51,11 +51,11 @@ func (v *Volume) load() error {
 	return nil
 }
 func (v *Volume) Version() Version {
-    return CurrentVersion
+	return CurrentVersion
 }
 func (v *Volume) Size() int64 {
-    v.accessLock.Lock()
-    defer v.accessLock.Unlock()
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
 	stat, e := v.dataFile.Stat()
 	if e == nil {
 		return stat.Size()
@@ -64,15 +64,15 @@ func (v *Volume) Size() int64 {
 	return -1
 }
 func (v *Volume) Close() {
-    v.accessLock.Lock()
-    defer v.accessLock.Unlock()
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
 	v.nm.Close()
 	v.dataFile.Close()
 }
 func (v *Volume) maybeWriteSuperBlock() {
 	stat, _ := v.dataFile.Stat()
 	if stat.Size() == 0 {
-        v.version = CurrentVersion
+		v.version = CurrentVersion
 		header := make([]byte, SuperBlockSize)
 		header[0] = byte(v.version)
 		header[1] = v.replicaType.Byte()
@@ -85,12 +85,17 @@ func (v *Volume) readSuperBlock() error {
 	if _, e := v.dataFile.Read(header); e != nil {
 		return fmt.Errorf("cannot read superblock: %s", e)
 	}
-	v.version = Version(header[0])
 	var err error
-	if v.replicaType, err = NewReplicationTypeFromByte(header[1]); err != nil {
-		return fmt.Errorf("cannot read replica type: %s", err)
+	v.version, v.replicaType, err = ParseSuperBlock(header)
+	return err
+}
+func ParseSuperBlock(header []byte) (version Version, replicaType ReplicationType, e error) {
+	version = Version(header[0])
+	var err error
+	if replicaType, err = NewReplicationTypeFromByte(header[1]); err != nil {
+		e = fmt.Errorf("cannot read replica type: %s", err)
 	}
-	return nil
+	return
 }
 func (v *Volume) NeedToReplicate() bool {
 	return v.replicaType.GetCopyCount() > 1
@@ -133,7 +138,7 @@ func (v *Volume) read(n *Needle) (int, error) {
 }
 
 func (v *Volume) garbageLevel() float64 {
-    return float64(v.nm.deletionByteCounter)/float64(v.ContentSize())
+	return float64(v.nm.deletionByteCounter) / float64(v.ContentSize())
 }
 
 func (v *Volume) compact() error {
@@ -143,7 +148,7 @@ func (v *Volume) compact() error {
 	filePath := path.Join(v.dir, v.Id.String())
 	return v.copyDataAndGenerateIndexFile(filePath+".dat", filePath+".cpd", filePath+".cpx")
 }
-func (v *Volume) commitCompact() (error) {
+func (v *Volume) commitCompact() error {
 	v.accessLock.Lock()
 	defer v.accessLock.Unlock()
 	v.dataFile.Close()
@@ -185,7 +190,9 @@ func (v *Volume) copyDataAndGenerateIndexFile(srcName, dstName, idxName string)
 		dst.Write(header)
 	}
 
-	n, rest := ReadNeedle(src)
+	version, _, _ := ParseSuperBlock(header)
+
+	n, rest := ReadNeedle(src, version)
 	nm := NewNeedleMap(idx)
 	old_offset := uint32(SuperBlockSize)
 	new_offset := uint32(SuperBlockSize)
@@ -208,11 +215,11 @@ func (v *Volume) copyDataAndGenerateIndexFile(srcName, dstName, idxName string)
 			src.Seek(int64(rest-n.Size-4), 1)
 		}
 		old_offset += rest + 16
-		n, rest = ReadNeedle(src)
+		n, rest = ReadNeedle(src, version)
 	}
 
 	return nil
 }
-func (v *Volume) ContentSize() uint64{
-    return v.nm.fileByteCounter
+func (v *Volume) ContentSize() uint64 {
+	return v.nm.fileByteCounter
 }