cache read performance improvements

pkg/fs/file.go

@@ -15,6 +15,7 @@ import (
 type File struct {
 	log     logr.Logger
 	f       provider.File
+	cache   provider.File
 	md      *Metadata
 	offset  int64
 	offline bool
@@ -83,7 +84,7 @@ func (f *File) Preload(ctx context.Context, unlock func()) {
 func (f *File) Read(p []byte) (n int, err error) {
 	log := f.log
 	if f.hasChunk(len(p)) {
-		n, err = f.md.ReadAt(p, f.offset)
+		n, err = f.cache.ReadAt(p, f.offset)
 		if err == io.EOF {
 			return
 		}
@@ -172,8 +173,8 @@ func (f *File) Stat() (os.FileInfo, error) {
 }
 
 func (f *File) Close() error {
-	if f.offline {
-		return nil
+	if !f.offline && f.cache != nil {
+		f.cache.Close()
 	}
 	return f.f.Close()
 }

pkg/fs/fs.go

@@ -135,6 +135,7 @@ func (fs *FS) OpenDst(name string) (f http.File, err error) {
 	f = &File{
 		log:     log.WithName("file"),
 		f:       file,
+		cache:   file,
 		md:      md,
 		offline: true,
 	}
@@ -198,13 +199,25 @@ func (fs *FS) Open(name string) (f http.File, err error) {
 		f = &Dir{log: log.WithName("dir"), f: file, dc: fs.dc}
 		return
 	}
+	md := fs.mh.Metadata(name, fi.Size())
+
+	var cache provider.File
 	if offline {
 		log.V(2).Info("file offline mode")
+		cache = file
+	} else {
+		cache, err = fs.dst.Open(name)
+		if err != nil {
+			if !skipLog(name) {
+				log.Error(err, "error opening cache file")
+			}
+			return
+		}
 	}
-	md := fs.mh.Metadata(name, fi.Size())
 	f = &File{
 		log:     log.WithName("file"),
 		f:       file,
+		cache:   cache,
 		md:      md,
 		offline: offline,
 	}
@@ -231,7 +244,7 @@ func (fs *FS) openCacheFile(name string, size int64) (df provider.File, err erro
 		log.Error(err, "error opening cache file")
 		return
 	}
-	if truncate {
+	if truncate && size > 0 {
 		err = df.Truncate(size)
 		if err != nil {
 			log.Error(err, "error truncating cache file")

pkg/fs/metadata.go

@@ -389,16 +389,16 @@ func (md *Metadata) AddChunk(off int64, n int) {
 	md.Chunks.Add(off, n)
 }
 
-func (md *Metadata) ReadAt(p []byte, pos int64) (int, error) {
-	if md.f == nil {
-		err := md.openCacheFile()
-		if err != nil {
-			return 0, err
-		}
-	}
-	atomic.StoreInt64(&md.Atime, now())
-	return md.f.ReadAt(p, pos)
-}
+//func (md *Metadata) ReadAt(p []byte, pos int64) (int, error) {
+//	if md.f == nil {
+//		err := md.openCacheFile()
+//		if err != nil {
+//			return 0, err
+//		}
+//	}
+//	atomic.StoreInt64(&md.Atime, now())
+//	return md.f.ReadAt(p, pos)
+//}
 
 func (md *Metadata) WriteAt(data []byte, pos int64) (int, error) {
 	if md.f == nil {

pkg/fs/preload.go

@@ -22,6 +22,9 @@ func (q *queue) Add(ph *PreloadHandler, name string, prio int) {
 	for _, p := range *q {
 		if p.Name == name {
 			p.Prio += prio
+			if p.Prio < 0 {
+				p.Prio = 0
+			}
 			q.Sort()
 			return
 		}