lotus/extern/sector-storage/piece_provider.go
2021-06-07 15:03:09 +05:30

154 lines
5.8 KiB
Go

package sectorstorage
import (
"bufio"
"context"
"io"
"github.com/ipfs/go-cid"
"golang.org/x/xerrors"
"github.com/filecoin-project/go-state-types/abi"
"github.com/filecoin-project/specs-storage/storage"
"github.com/filecoin-project/lotus/extern/sector-storage/fr32"
"github.com/filecoin-project/lotus/extern/sector-storage/stores"
"github.com/filecoin-project/lotus/extern/sector-storage/storiface"
)
type Unsealer interface {
// SectorsUnsealPiece will Unseal a Sealed sector file for the given sector.
SectorsUnsealPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize, randomness abi.SealRandomness, commd *cid.Cid) error
}
type PieceProvider interface {
// ReadPiece is used to read an Unsealed piece at the given offset and of the given size from a Sector
ReadPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize, ticket abi.SealRandomness, unsealed cid.Cid) (io.ReadCloser, bool, error)
}
type pieceProvider struct {
storage *stores.Remote
index stores.SectorIndex
uns Unsealer
}
func NewPieceProvider(storage *stores.Remote, index stores.SectorIndex, uns Unsealer) PieceProvider {
return &pieceProvider{
storage: storage,
index: index,
uns: uns,
}
}
// tryReadUnsealedPiece will try to read the unsealed piece from an existing unsealed sector file for the given sector from any worker that has it.
// It will NOT try to schedule an Unseal of a sealed sector file for the read.
//
// Returns a nil reader if the piece does NOT exist in any unsealed file or there is no unsealed file for the given sector on any of the workers.
func (p *pieceProvider) tryReadUnsealedPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize) (io.ReadCloser, context.CancelFunc, error) {
// acquire a lock purely for reading unsealed sectors
ctx, cancel := context.WithCancel(ctx)
if err := p.index.StorageLock(ctx, sector.ID, storiface.FTUnsealed, storiface.FTNone); err != nil {
cancel()
return nil, nil, xerrors.Errorf("acquiring read sector lock: %w", err)
}
// Reader returns a reader for an unsealed piece at the given offset in the given sector.
// The returned reader will be nil if none of the workers has an unsealed sector file containing
// the unsealed piece.
r, err := p.storage.Reader(ctx, sector, abi.PaddedPieceSize(offset.Padded()), size.Padded())
if err != nil {
log.Debugf("did not get storage reader;sector=%+v, err:%s", sector.ID, err)
cancel()
return nil, nil, err
}
if r == nil {
cancel()
}
return r, cancel, nil
}
// ReadPiece is used to read an Unsealed piece at the given offset and of the given size from a Sector
// If an Unsealed sector file exists with the Piece Unsealed in it, we'll use that for the read.
// Otherwise, we will Unseal a Sealed sector file for the given sector and read the Unsealed piece from it.
// If we do NOT have an existing unsealed file containing the given piece thus causing us to schedule an Unseal,
// the returned boolean parameter will be set to true.
// If we have an existing unsealed file containing the given piece, the returned boolean will be set to false.
func (p *pieceProvider) ReadPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize, ticket abi.SealRandomness, unsealed cid.Cid) (io.ReadCloser, bool, error) {
if err := offset.Valid(); err != nil {
return nil, false, xerrors.Errorf("offset is not valid: %w", err)
}
if err := size.Validate(); err != nil {
return nil, false, xerrors.Errorf("size is not a valid piece size: %w", err)
}
r, unlock, err := p.tryReadUnsealedPiece(ctx, sector, offset, size)
log.Debugf("result of first tryReadUnsealedPiece: r=%+v, err=%s", r, err)
if xerrors.Is(err, storiface.ErrSectorNotFound) {
log.Debugf("no unsealed sector file with unsealed piece, sector=%+v, offset=%d, size=%d", sector, offset, size)
err = nil
}
if err != nil {
log.Errorf("returning error from ReadPiece:%s", err)
return nil, false, err
}
var uns bool
if r == nil {
// a nil reader means that none of the workers has an unsealed sector file
// containing the unsealed piece.
// we now need to unseal a sealed sector file for the given sector to read the unsealed piece from it.
uns = true
commd := &unsealed
if unsealed == cid.Undef {
commd = nil
}
if err := p.uns.SectorsUnsealPiece(ctx, sector, offset, size, ticket, commd); err != nil {
log.Errorf("failed to SectorsUnsealPiece: %s", err)
return nil, false, xerrors.Errorf("unsealing piece: %w", err)
}
log.Debugf("unsealed a sector file to read the piece, sector=%+v, offset=%d, size=%d", sector, offset, size)
r, unlock, err = p.tryReadUnsealedPiece(ctx, sector, offset, size)
if err != nil {
log.Errorf("failed to tryReadUnsealedPiece after SectorsUnsealPiece: %s", err)
return nil, true, xerrors.Errorf("read after unsealing: %w", err)
}
if r == nil {
log.Errorf("got no reader after unsealing piece")
return nil, true, xerrors.Errorf("got no reader after unsealing piece")
}
log.Debugf("got a reader to read unsealed piece, sector=%+v, offset=%d, size=%d", sector, offset, size)
} else {
log.Debugf("unsealed piece already exists, no need to unseal, sector=%+v, offset=%d, size=%d", sector, offset, size)
}
upr, err := fr32.NewUnpadReader(r, size.Padded())
if err != nil {
unlock()
return nil, uns, xerrors.Errorf("creating unpadded reader: %w", err)
}
log.Debugf("returning reader to read unsealed piece, sector=%+v, offset=%d, size=%d", sector, offset, size)
return &funcCloser{
Reader: bufio.NewReaderSize(upr, 127),
close: func() error {
err = r.Close()
unlock()
return err
},
}, uns, nil
}
type funcCloser struct {
io.Reader
close func() error
}
func (fc *funcCloser) Close() error { return fc.close() }