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package storage
import ( "fmt" "github.com/seaweedfs/seaweedfs/weed/util/mem" "io" "time"
"github.com/seaweedfs/seaweedfs/weed/glog" "github.com/seaweedfs/seaweedfs/weed/storage/backend" "github.com/seaweedfs/seaweedfs/weed/storage/needle" "github.com/seaweedfs/seaweedfs/weed/storage/super_block" . "github.com/seaweedfs/seaweedfs/weed/storage/types" )
const PagedReadLimit = 1024 * 1024
// read fills in Needle content by looking up n.Id from NeedleMapper
func (v *Volume) readNeedle(n *needle.Needle, readOption *ReadOption, onReadSizeFn func(size Size)) (count int, err error) { v.dataFileAccessLock.RLock() defer v.dataFileAccessLock.RUnlock()
nv, ok := v.nm.Get(n.Id) if !ok || nv.Offset.IsZero() { return -1, ErrorNotFound } readSize := nv.Size if readSize.IsDeleted() { if readOption != nil && readOption.ReadDeleted && readSize != TombstoneFileSize { glog.V(3).Infof("reading deleted %s", n.String()) readSize = -readSize } else { return -1, ErrorDeleted } } if readSize == 0 { return 0, nil } if onReadSizeFn != nil { onReadSizeFn(readSize) } if readOption != nil && readOption.AttemptMetaOnly && readSize > PagedReadLimit { readOption.VolumeRevision = v.SuperBlock.CompactionRevision err = n.ReadNeedleMeta(v.DataBackend, nv.Offset.ToActualOffset(), readSize, v.Version()) if err == needle.ErrorSizeMismatch && OffsetSize == 4 { readOption.IsOutOfRange = true err = n.ReadNeedleMeta(v.DataBackend, nv.Offset.ToActualOffset()+int64(MaxPossibleVolumeSize), readSize, v.Version()) } if err != nil { return 0, err } if !n.IsCompressed() && !n.IsChunkedManifest() { readOption.IsMetaOnly = true } } if readOption == nil || !readOption.IsMetaOnly { err = n.ReadData(v.DataBackend, nv.Offset.ToActualOffset(), readSize, v.Version()) if err == needle.ErrorSizeMismatch && OffsetSize == 4 { err = n.ReadData(v.DataBackend, nv.Offset.ToActualOffset()+int64(MaxPossibleVolumeSize), readSize, v.Version()) } v.checkReadWriteError(err) if err != nil { return 0, err } } count = int(n.DataSize) if !n.HasTtl() { return } ttlMinutes := n.Ttl.Minutes() if ttlMinutes == 0 { return } if !n.HasLastModifiedDate() { return } if time.Now().Before(time.Unix(0, int64(n.AppendAtNs)).Add(time.Duration(ttlMinutes) * time.Minute)) { return } return -1, ErrorNotFound }
// read needle at a specific offset
func (v *Volume) readNeedleMetaAt(n *needle.Needle, offset int64, size int32) (err error) { v.dataFileAccessLock.RLock() defer v.dataFileAccessLock.RUnlock() // read deleted meta data
if size < 0 { size = -size } err = n.ReadNeedleMeta(v.DataBackend, offset, Size(size), v.Version()) if err == needle.ErrorSizeMismatch && OffsetSize == 4 { err = n.ReadNeedleMeta(v.DataBackend, offset+int64(MaxPossibleVolumeSize), Size(size), v.Version()) } if err != nil { return err } return nil }
// read fills in Needle content by looking up n.Id from NeedleMapper
func (v *Volume) readNeedleDataInto(n *needle.Needle, readOption *ReadOption, writer io.Writer, offset int64, size int64) (err error) {
if !readOption.HasSlowRead { v.dataFileAccessLock.RLock() defer v.dataFileAccessLock.RUnlock() }
if readOption.HasSlowRead { v.dataFileAccessLock.RLock() } nv, ok := v.nm.Get(n.Id) if readOption.HasSlowRead { v.dataFileAccessLock.RUnlock() }
if !ok || nv.Offset.IsZero() { return ErrorNotFound } readSize := nv.Size if readSize.IsDeleted() { if readOption != nil && readOption.ReadDeleted && readSize != TombstoneFileSize { glog.V(3).Infof("reading deleted %s", n.String()) readSize = -readSize } else { return ErrorDeleted } } if readSize == 0 { return nil }
actualOffset := nv.Offset.ToActualOffset() if readOption.IsOutOfRange { actualOffset += int64(MaxPossibleVolumeSize) }
buf := mem.Allocate(min(readOption.ReadBufferSize, int(size))) defer mem.Free(buf)
// read needle data
crc := needle.CRC(0) for x := offset; x < offset+size; x += int64(len(buf)) {
if readOption.HasSlowRead { v.dataFileAccessLock.RLock() } // possibly re-read needle offset if volume is compacted
if readOption.VolumeRevision != v.SuperBlock.CompactionRevision { // the volume is compacted
nv, ok = v.nm.Get(n.Id) if !ok || nv.Offset.IsZero() { if readOption.HasSlowRead { v.dataFileAccessLock.RUnlock() } return ErrorNotFound } actualOffset = nv.Offset.ToActualOffset() readOption.VolumeRevision = v.SuperBlock.CompactionRevision } count, err := n.ReadNeedleData(v.DataBackend, actualOffset, buf, x) if readOption.HasSlowRead { v.dataFileAccessLock.RUnlock() }
toWrite := min(count, int(offset+size-x)) if toWrite > 0 { crc = crc.Update(buf[0:toWrite]) if _, err = writer.Write(buf[0:toWrite]); err != nil { return fmt.Errorf("ReadNeedleData write: %v", err) } } if err != nil { if err == io.EOF { err = nil break } return fmt.Errorf("ReadNeedleData: %v", err) } if count <= 0 { break } } if offset == 0 && size == int64(n.DataSize) && (n.Checksum != crc && uint32(n.Checksum) != crc.Value()) { // the crc.Value() function is to be deprecated. this double checking is for backward compatible.
return fmt.Errorf("ReadNeedleData checksum %v expected %v", crc, n.Checksum) } return nil
}
func min(x, y int) int { if x < y { return x } return y }
// read fills in Needle content by looking up n.Id from NeedleMapper
func (v *Volume) ReadNeedleBlob(offset int64, size Size) ([]byte, error) { v.dataFileAccessLock.RLock() defer v.dataFileAccessLock.RUnlock()
return needle.ReadNeedleBlob(v.DataBackend, offset, size, v.Version()) }
type VolumeFileScanner interface { VisitSuperBlock(super_block.SuperBlock) error ReadNeedleBody() bool VisitNeedle(n *needle.Needle, offset int64, needleHeader, needleBody []byte) error }
func ScanVolumeFile(dirname string, collection string, id needle.VolumeId, needleMapKind NeedleMapKind, volumeFileScanner VolumeFileScanner) (err error) { var v *Volume if v, err = loadVolumeWithoutIndex(dirname, collection, id, needleMapKind); err != nil { return fmt.Errorf("failed to load volume %d: %v", id, err) } if err = volumeFileScanner.VisitSuperBlock(v.SuperBlock); err != nil { return fmt.Errorf("failed to process volume %d super block: %v", id, err) } defer v.Close()
version := v.Version()
offset := int64(v.SuperBlock.BlockSize())
return ScanVolumeFileFrom(version, v.DataBackend, offset, volumeFileScanner) }
func ScanVolumeFileFrom(version needle.Version, datBackend backend.BackendStorageFile, offset int64, volumeFileScanner VolumeFileScanner) (err error) { n, nh, rest, e := needle.ReadNeedleHeader(datBackend, version, offset) if e != nil { if e == io.EOF { return nil } return fmt.Errorf("cannot read %s at offset %d: %v", datBackend.Name(), offset, e) } for n != nil { var needleBody []byte if volumeFileScanner.ReadNeedleBody() { // println("needle", n.Id.String(), "offset", offset, "size", n.Size, "rest", rest)
if needleBody, err = n.ReadNeedleBody(datBackend, version, offset+NeedleHeaderSize, rest); err != nil { glog.V(0).Infof("cannot read needle head [%d, %d) body [%d, %d) body length %d: %v", offset, offset+NeedleHeaderSize, offset+NeedleHeaderSize, offset+NeedleHeaderSize+rest, rest, err) // err = fmt.Errorf("cannot read needle body: %v", err)
// return
} } err := volumeFileScanner.VisitNeedle(n, offset, nh, needleBody) if err == io.EOF { return nil } if err != nil { glog.V(0).Infof("visit needle error: %v", err) return fmt.Errorf("visit needle error: %v", err) } offset += NeedleHeaderSize + rest glog.V(4).Infof("==> new entry offset %d", offset) if n, nh, rest, err = needle.ReadNeedleHeader(datBackend, version, offset); err != nil { if err == io.EOF { return nil } return fmt.Errorf("cannot read needle header at offset %d: %v", offset, err) } glog.V(4).Infof("new entry needle size:%d rest:%d", n.Size, rest) } return nil }
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