From 120464c0a596ba1ea2df613399015e78181c5aac Mon Sep 17 00:00:00 2001
From: ston1th <ston1th@giftfish.de>
Date: Sun, 31 Jul 2022 12:39:14 +0200
Subject: [PATCH] added experimental async cache write

---
 pkg/fs/file.go | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/pkg/fs/file.go b/pkg/fs/file.go
index 7cc99df..8b2c08c 100644
--- a/pkg/fs/file.go
+++ b/pkg/fs/file.go
@@ -127,16 +127,21 @@ func (f *File) readToCache(p []byte) (n int, err error) {
 	log := f.log
 	n, err = f.readSource(p)
 	if n > 0 {
-		if n, err = f.md.WriteAt(p[:n], f.offset); err != nil {
-			log.Error(err, "error writing cache file")
-			return
-		}
+		// async cache write
+		buf := make([]byte, n)
+		copy(buf, p[:n])
+		go func(p []byte, offset int64, n int) {
+			if n, err = f.md.WriteAt(p, offset); err != nil {
+				log.Error(err, "error writing cache file")
+				return
+			}
+			f.md.AddChunk(offset, n)
+		}(buf, f.offset, n)
 	}
 	if err != nil && err != io.EOF {
 		log.Error(err, "error reading source file")
 		return
 	}
-	f.md.AddChunk(f.offset, n)
 	f.offset += int64(n)
 	if n > 0 && n < len(p) {
 		_, err = f.Seek(f.offset, io.SeekStart)