cache read performance improvements

pkg/provider/crypto/file.go

@@ -139,7 +139,8 @@ func (f *file) Seek(offset int64, whence int) (n int64, err error) {
 		return
 	}
 	f.nonce = [NonceSize]byte{}
-	inc(&f.nonce, cn)
+	//inc(&f.nonce, cn)
+	put(&f.nonce, cn)
 	f.r.nonce = f.nonce
 	f.w.nonce = f.nonce
 	f.r.off = roff
@@ -187,7 +188,8 @@ func (f *file) WriteAt(data []byte, pos int64) (n int, err error) {
 	c, ok := f.w.cm[cn]
 	if !ok {
 		c = &chunkWriter{offset: off + KDFNonceSize, w: f.w, cn: cn}
-		inc(&c.nonce, cn)
+		//inc(&c.nonce, cn)
+		put(&c.nonce, cn)
 		f.w.cm[cn] = c
 		if f.w.last == nil {
 			f.w.last = c
@@ -199,7 +201,6 @@ func (f *file) WriteAt(data []byte, pos int64) (n int, err error) {
 	if c.full() {
 		// async flush
 		go func() {
-			//_, err = c.flush(notLastChunk)
 			c.flush(notLastChunk)
 		}()
 		delete(f.w.cm, cn)

pkg/provider/crypto/helper.go

@@ -3,6 +3,7 @@ package crypto
 import (
 	"cachefs/pkg/provider"
 	"crypto/rand"
+	"encoding/binary"
 	"io"
 	"math"
 )
@@ -29,7 +30,6 @@ func initNonce(f provider.File) (nonce []byte, err error) {
 			return
 		}
 		_, err = f.Write(nonce)
-		return
 	}
 	return
 }
@@ -76,3 +76,7 @@ func inc(nonce *[NonceSize]byte, n int64) {
 		incNonce(nonce)
 	}
 }
+
+func put(nonce *[NonceSize]byte, n int64) {
+	binary.BigEndian.PutUint64((*nonce)[3:11], uint64(n))
+}

pkg/provider/crypto/helper_test.go

@@ -0,0 +1,15 @@
+package crypto
+
+import (
+	"testing"
+)
+
+func BenchmarkInc(b *testing.B) {
+	var n [NonceSize]byte
+	inc(&n, int64(b.N))
+}
+
+func BenchmarkPut(b *testing.B) {
+	var n [NonceSize]byte
+	put(&n, int64(b.N))
+}

pkg/provider/crypto/reader.go

@@ -10,7 +10,11 @@ import (
 
 type cryptoReader interface {
 	io.Reader
-	io.ReaderAt
+}
+
+type nonce struct {
+	N [NonceSize]byte
+	C int
 }
 
 type reader struct {
@@ -21,9 +25,10 @@ type reader struct {
 	buf    [FullSize]byte
 	off    int64
 
-	err   error
-	nonce [NonceSize]byte
-	cn    int64
+	err    error
+	nonce  [NonceSize]byte
+	cn     int64
+	outBuf []byte
 }
 
 func newReader(key []byte, src cryptoReader) (*reader, error) {
@@ -32,9 +37,10 @@ func newReader(key []byte, src cryptoReader) (*reader, error) {
 		return nil, err
 	}
 	return &reader{
-		a:   aead,
-		src: src,
-		cn:  -1,
+		a:      aead,
+		src:    src,
+		cn:     -1,
+		outBuf: make([]byte, 0, FullSize),
 	}, nil
 }
 
@@ -91,19 +97,24 @@ func (r *reader) readChunk() (last bool, err error) {
 		return false, err
 	}
 
-	outBuf := make([]byte, 0, ChunkSize)
-	out, err := r.a.Open(outBuf, r.nonce[:], in, nil)
+	//outBuf := make([]byte, 0, ChunkSize)
+	out, err := r.a.Open(r.outBuf, r.nonce[:], in, nil)
 	if err != nil && !last {
 		// Check if this was a full-length final chunk.
 		last = true
 		setLastChunkFlag(&r.nonce)
-		out, err = r.a.Open(outBuf, r.nonce[:], in, nil)
+		out, err = r.a.Open(r.outBuf, r.nonce[:], in, nil)
 	}
 	if err != nil {
 		return false, errors.New("failed to decrypt and authenticate payload chunk")
 	}
 
 	incNonce(&r.nonce)
-	r.unread = r.buf[:copy(r.buf[:], out)]
+	//r.unread = r.buf[:copy(r.buf[:], out)]
+	size := FullSize
+	if len(out) < FullSize {
+		size = len(out)
+	}
+	r.unread = out[:size]
 	return last, nil
 }