seaweedfs/weed/storage/erasure_coding/ec_shard.go

108 lines
2.8 KiB
Go

package erasure_coding
import (
"fmt"
"os"
"path"
"strconv"
"github.com/chrislusf/seaweedfs/weed/storage/idx"
"github.com/chrislusf/seaweedfs/weed/storage/needle"
"github.com/chrislusf/seaweedfs/weed/storage/types"
)
type ShardId uint8
type EcVolumeShard struct {
VolumeId needle.VolumeId
ShardId ShardId
Collection string
dir string
ecdFile *os.File
ecdFileSize int64
ecxFile *os.File
ecxFileSize int64
}
func NewEcVolumeShard(dirname string, collection string, id needle.VolumeId, shardId ShardId) (v *EcVolumeShard, e error) {
v = &EcVolumeShard{dir: dirname, Collection: collection, VolumeId: id, ShardId: shardId}
baseFileName := v.FileName()
// open ecx file
if v.ecxFile, e = os.OpenFile(baseFileName+".ecx", os.O_RDONLY, 0644); e != nil {
return nil, fmt.Errorf("cannot read ec volume index %s.ecx: %v", baseFileName, e)
}
ecxFi, statErr := v.ecxFile.Stat()
if statErr != nil {
return nil, fmt.Errorf("can not stat ec volume index %s.ecx: %v", baseFileName, statErr)
}
v.ecxFileSize = ecxFi.Size()
// open ecd file
if v.ecdFile, e = os.OpenFile(baseFileName+ToExt(int(shardId)), os.O_RDONLY, 0644); e != nil {
return nil, fmt.Errorf("cannot read ec volume shard %s.%s: %v", baseFileName, ToExt(int(shardId)), e)
}
ecdFi, statErr := v.ecdFile.Stat()
if statErr != nil {
return nil, fmt.Errorf("can not stat ec volume shard %s.%s: %v", baseFileName, ToExt(int(shardId)), statErr)
}
v.ecdFileSize = ecdFi.Size()
return
}
func (shard *EcVolumeShard) String() string {
return fmt.Sprintf("ec shard %v:%v, dir:%s, Collection:%s", shard.VolumeId, shard.ShardId, shard.dir, shard.Collection)
}
func (shard *EcVolumeShard) FileName() (fileName string) {
return EcShardFileName(shard.Collection, shard.dir, int(shard.VolumeId))
}
func EcShardFileName(collection string, dir string, id int) (fileName string) {
idString := strconv.Itoa(id)
if collection == "" {
fileName = path.Join(dir, idString)
} else {
fileName = path.Join(dir, collection+"_"+idString)
}
return
}
func (shard *EcVolumeShard) Close() {
if shard.ecdFile != nil {
_ = shard.ecdFile.Close()
shard.ecdFile = nil
}
if shard.ecxFile != nil {
_ = shard.ecxFile.Close()
shard.ecxFile = nil
}
}
func (shard *EcVolumeShard) findNeedleFromEcx(needleId types.NeedleId) (offset types.Offset, size uint32, err error) {
var key types.NeedleId
buf := make([]byte, types.NeedleMapEntrySize)
l, h := int64(0), shard.ecxFileSize/types.NeedleMapEntrySize
for l < h {
m := (l + h) / 2
if _, err := shard.ecxFile.ReadAt(buf, m*types.NeedleMapEntrySize); err != nil {
return types.Offset{}, 0, err
}
key, offset, size = idx.IdxFileEntry(buf)
if key == needleId {
return
}
if key < needleId {
l = m + 1
} else {
h = m
}
}
err = fmt.Errorf("needle id %d not found", needleId)
return
}