Ejemplo n.º 1
0
// expandSparse grows the file with zero blocks of 4096
// A small blocksize is chosen to aid in deduplication
func (dm *DagModifier) expandSparse(size int64) error {
	r := io.LimitReader(zeroReader{}, size)
	spl := chunk.NewSizeSplitter(r, 4096)
	blks, errs := chunk.Chan(spl)
	nnode, err := dm.appendData(dm.curNode, blks, errs)
	if err != nil {
		return err
	}
	_, err = dm.dagserv.Add(nnode)
	if err != nil {
		return err
	}
	dm.curNode = nnode
	return nil
}
Ejemplo n.º 2
0
// Sync writes changes to this dag to disk
func (dm *DagModifier) Sync() error {
	// No buffer? Nothing to do
	if dm.wrBuf == nil {
		return nil
	}

	// If we have an active reader, kill it
	if dm.read != nil {
		dm.read = nil
		dm.readCancel()
	}

	// Number of bytes we're going to write
	buflen := dm.wrBuf.Len()

	// Grab key for unpinning after mod operation
	curk, err := dm.curNode.Key()
	if err != nil {
		return err
	}

	// overwrite existing dag nodes
	thisk, done, err := dm.modifyDag(dm.curNode, dm.writeStart, dm.wrBuf)
	if err != nil {
		return err
	}

	nd, err := dm.dagserv.Get(dm.ctx, thisk)
	if err != nil {
		return err
	}

	dm.curNode = nd

	// need to write past end of current dag
	if !done {
		blks, errs := chunk.Chan(dm.splitter(dm.wrBuf))
		nd, err = dm.appendData(dm.curNode, blks, errs)
		if err != nil {
			return err
		}

		thisk, err = dm.dagserv.Add(nd)
		if err != nil {
			return err
		}

		dm.curNode = nd
	}

	// Finalize correct pinning, and flush pinner
	dm.mp.PinWithMode(thisk, pin.Recursive)
	dm.mp.RemovePinWithMode(curk, pin.Recursive)
	err = dm.mp.Flush()
	if err != nil {
		return err
	}

	dm.writeStart += uint64(buflen)

	dm.wrBuf = nil
	return nil
}