diff --git a/writer.go b/writer.go
index 5939109..5fd70ce 100644
--- a/writer.go
+++ b/writer.go
@@ -33,6 +33,7 @@ type Writer struct {
 
 	//variables used when actually writing.
 	superblock superblock
+	frags      []fragment
 }
 
 //NewWriter creates a new with the default options (Gzip compression and allow errors)
@@ -68,10 +69,11 @@ type fileHolder struct {
 	path        string
 	name        string
 	symLocation string
-	UID         int
+	blockSizes  []uint32
 	GUID        int
 	perm        int
-	size        uint32
+	size        uint64
+	UID         int
 	folder      bool
 	symlink     bool
 }
@@ -164,7 +166,7 @@ func (w *Writer) AddFileTo(filepath string, file *os.File) error {
 //AddReaderTo adds the data from the given reader to the archive as a file located at the given filepath.
 //Data from the reader is not read until the squashfs archive is writen.
 //If the given reader implements io.Closer, it will be closed after it is fully read.
-func (w *Writer) AddReaderTo(filepath string, reader io.Reader) error {
+func (w *Writer) AddReaderTo(filepath string, reader io.Reader, size uint64) error {
 	filepath = path.Clean(filepath)
 	if !strings.HasPrefix(filepath, "/") {
 		filepath = "/" + filepath
@@ -175,6 +177,7 @@ func (w *Writer) AddReaderTo(filepath string, reader io.Reader) error {
 	var holder fileHolder
 	holder.path = path.Dir(filepath)
 	holder.name = path.Base(filepath)
+	holder.size = size
 	holder.reader = reader
 	w.structure[holder.path] = append(w.structure[holder.path], &holder)
 	return nil
diff --git a/compress.go b/writer_compress.go
similarity index 100%
rename from compress.go
rename to writer_compress.go
diff --git a/writer_fragment.go b/writer_fragment.go
new file mode 100644
index 0000000..165be64
--- /dev/null
+++ b/writer_fragment.go
@@ -0,0 +1,21 @@
+package squashfs
+
+type fragment struct {
+	w     *Writer
+	files []*fileHolder
+	sizes []uint32
+}
+
+func (f *fragment) SizeLeft() uint32 {
+	totalSize := uint32(0)
+	for _, siz := range f.sizes {
+		totalSize += siz
+	}
+	return f.w.BlockSize - uint32(totalSize)
+}
+
+func (f *fragment) AddFragment(fil *fileHolder) {
+	//SizeLeft should already be checked
+	f.files = append(f.files, fil)
+	f.sizes = append(f.sizes, fil.blockSizes[len(fil.blockSizes)-1])
+}
diff --git a/writer_inodes.go b/writer_inodes.go
new file mode 100644
index 0000000..685efbe
--- /dev/null
+++ b/writer_inodes.go
@@ -0,0 +1,23 @@
+package squashfs
+
+func (w *Writer) countInodes() (out uint32) {
+	for _, files := range w.structure {
+		out++
+		out += uint32(len(files))
+	}
+	return
+}
+
+//intilialize the block sizes. These values will be overwritten with their compressed sizes later.
+func (w *Writer) calculateBlockSizes(fil *fileHolder) {
+	tmp := fil.size
+	for {
+		if tmp < uint64(w.BlockSize) {
+			fil.blockSizes = append(fil.blockSizes, uint32(tmp))
+			break
+		}
+		tmp -= uint64(w.BlockSize)
+		fil.blockSizes = append(fil.blockSizes, w.BlockSize)
+	}
+	return
+}
diff --git a/writer_write.go b/writer_write.go
index 5f3de19..db1a4e9 100644
--- a/writer_write.go
+++ b/writer_write.go
@@ -3,21 +3,32 @@ package squashfs
 import (
 	"errors"
 	"io"
+	"io/fs"
 	"math"
-	"path"
+	"time"
 )
 
 func (w *Writer) fixFolders() error {
 	for folder := range w.structure {
-		if folder == "/" {
+		if folder == "/" || w.Contains(folder) {
 			continue
 		}
-		dir, name := path.Dir(folder), path.Base(folder)
+		err := w.AddFolderTo(folder, fs.ModePerm)
+		if err != nil {
+			return err
+		}
 	}
+	return nil
 }
 
 //WriteTo attempts to write the archive to the given io.Writer.
+//Folder that aren't present (such as if you add a file at /folder/file, but not the folder /folder)
+//are added with full permission (777).
 func (w *Writer) WriteTo(write io.Writer) (int64, error) {
+	err := w.fixFolders()
+	if err != nil {
+		return 0, err
+	}
 	if w.BlockSize > 1048576 {
 		w.BlockSize = 1048576
 	} else if w.BlockSize < 4096 {
@@ -28,6 +39,8 @@ func (w *Writer) WriteTo(write io.Writer) (int64, error) {
 	w.Flags.NoXattr = true
 	w.superblock = superblock{
 		Magic:           magic,
+		InodeCount:      w.countInodes(),
+		CreationTime:    uint32(time.Now().Unix()),
 		BlockSize:       w.BlockSize,
 		BlockLog:        uint16(math.Log2(float64(w.BlockSize))),
 		CompressionType: uint16(w.compressionType),