fix(fs): fix fd leaking issue

src/fs/fs_interface.go

@@ -23,6 +23,7 @@ type ISimpleFS interface {
 	Close() error
 	Sync() error
 	GetFileReader(path string) (ReadCloseSeeker, error)
+	CloseReader(path string) error
 	Root() string
 	ListDir(path string) ([]os.FileInfo, error)
 }

src/fs/local/fs.go

@@ -47,7 +47,7 @@ func NewLocalFS(root string, defaultPerm uint32, opensLimit, openTTL int) *Local
 		opensLimit:     opensLimit,
 		openTTL:        time.Duration(openTTL) * time.Second,
 		opensMtx:       &sync.RWMutex{},
-		opensCleanSize: 10,
+		opensCleanSize: 3,
 		readersMtx:     &sync.RWMutex{},
 		readers:        map[string]*fileInfo{}, // TODO: track readers and close idles
 	}
@@ -57,11 +57,17 @@ func (fs *LocalFS) Root() string {
 	return fs.root
 }
 
+// should be protected by opensMtx
+func (fs *LocalFS) isTooManyOpens() bool {
+	return len(fs.opens)+len(fs.readers) > fs.opensLimit
+}
+
 // closeOpens assumes that it is called after opensMtx.Lock()
-func (fs *LocalFS) closeOpens(closeAll bool, exclude map[string]bool) error {
+func (fs *LocalFS) closeOpens(closeAll, forced bool, exclude map[string]bool) (int, error) {
 	batch := fs.opensCleanSize
 
 	var err error
+	closed := 0
 	for key, info := range fs.opens {
 		if exclude[key] {
 			continue
@@ -72,24 +78,26 @@ func (fs *LocalFS) closeOpens(closeAll bool, exclude map[string]bool) error {
 		}
 		batch--
 
-		if info.lastAccess.Add(fs.openTTL).Before(time.Now()) {
-			delete(fs.opens, key)
+		if forced || info.lastAccess.Add(fs.openTTL).Before(time.Now()) {
 			if err = info.fd.Sync(); err != nil {
-				return err
+				return 0, err
 			}
 			if err := info.fd.Close(); err != nil {
-				return err
+				return 0, err
 			}
+			delete(fs.opens, key)
+			closed++
 		}
 	}
 
-	return nil
+	return closed, nil
 }
 
 func (fs *LocalFS) Sync() error {
 	fs.opensMtx.Lock()
 	defer fs.opensMtx.Unlock()
-	return fs.closeOpens(true, map[string]bool{})
+	_, err := fs.closeOpens(true, true, map[string]bool{})
+	return err
 }
 
 // check refers implementation of Dir.Open() in http package
@@ -103,12 +111,12 @@ func (fs *LocalFS) translate(name string) (string, error) {
 func (fs *LocalFS) Create(path string) error {
 	fs.opensMtx.Lock()
 	defer fs.opensMtx.Unlock()
-	if len(fs.opens) > fs.opensLimit {
-		err := fs.closeOpens(true, map[string]bool{})
+
+	if fs.isTooManyOpens() {
+		_, err := fs.closeOpens(false, true, map[string]bool{})
 		if err != nil {
 			return fmt.Errorf("too many opens and fail to clean: %w", err)
 		}
-		return ErrTooManyOpens
 	}
 
 	fullpath, err := fs.translate(path)
@@ -149,12 +157,19 @@ func (fs *LocalFS) Rename(oldpath, newpath string) error {
 	if err != nil {
 		return err
 	}
-	_, err = os.Stat(fullOldPath)
+	fullNewPath, err := fs.translate(newpath)
 	if err != nil {
 		return err
 	}
 
-	fullNewPath, err := fs.translate(newpath)
+	if fs.isTooManyOpens() {
+		_, err := fs.closeOpens(false, true, map[string]bool{})
+		if err != nil {
+			return fmt.Errorf("too many opens and fail to clean: %w", err)
+		}
+	}
+
+	_, err = os.Stat(fullOldPath)
 	if err != nil {
 		return err
 	}
@@ -182,8 +197,11 @@ func (fs *LocalFS) ReadAt(path string, b []byte, off int64) (int, error) {
 
 		info, ok := fs.opens[fullpath]
 		if !ok {
-			if len(fs.opens) > fs.opensLimit {
-				return nil, ErrTooManyOpens
+			if fs.isTooManyOpens() {
+				_, err := fs.closeOpens(false, true, map[string]bool{})
+				if err != nil {
+					return nil, fmt.Errorf("too many opens and fail to clean: %w", err)
+				}
 			}
 
 			// because the fd may be for other usage, its flag is not set as os.O_RDONLY
@@ -196,7 +214,7 @@ func (fs *LocalFS) ReadAt(path string, b []byte, off int64) (int, error) {
 				lastAccess: time.Now(),
 			}
 			fs.opens[fullpath] = info
-			fs.closeOpens(false, map[string]bool{fullpath: true})
+			// fs.closeOpens(false, true, map[string]bool{fullpath: true})
 		}
 
 		return info, nil
@@ -228,8 +246,11 @@ func (fs *LocalFS) WriteAt(path string, b []byte, off int64) (int, error) {
 
 		info, ok := fs.opens[fullpath]
 		if !ok {
-			if len(fs.opens) > fs.opensLimit {
-				return nil, ErrTooManyOpens
+			if fs.isTooManyOpens() {
+				_, err := fs.closeOpens(false, true, map[string]bool{})
+				if err != nil {
+					return nil, fmt.Errorf("too many opens and fail to clean: %w", err)
+				}
 			}
 
 			// it does NOT create file for writing
@@ -242,7 +263,6 @@ func (fs *LocalFS) WriteAt(path string, b []byte, off int64) (int, error) {
 				lastAccess: time.Now(),
 			}
 			fs.opens[fullpath] = info
-			fs.closeOpens(false, map[string]bool{fullpath: true})
 		}
 
 		return info, nil
@@ -304,6 +324,10 @@ func (fs *LocalFS) GetFileReader(path string) (fs.ReadCloseSeeker, error) {
 		return nil, err
 	}
 
+	if fs.isTooManyOpens() {
+		return nil, ErrTooManyOpens
+	}
+
 	fd, err := os.OpenFile(fullpath, os.O_RDONLY, fs.defaultPerm)
 	if err != nil {
 		return nil, err
@@ -319,6 +343,28 @@ func (fs *LocalFS) GetFileReader(path string) (fs.ReadCloseSeeker, error) {
 	return fd, nil
 }
 
+func (fs *LocalFS) CloseReader(path string) error {
+	fullpath, err := fs.translate(path)
+	if err != nil {
+		return err
+	}
+
+	fs.readersMtx.Lock()
+	defer fs.readersMtx.Unlock()
+	info, ok := fs.readers[fullpath]
+	if !ok {
+		return fmt.Errorf("reader not found: %s", path)
+	}
+
+	err = info.fd.Close()
+	if err != nil {
+		return fmt.Errorf("close reader failed: %w", err)
+	}
+
+	delete(fs.readers, fullpath)
+	return nil
+}
+
 func (fs *LocalFS) ListDir(path string) ([]os.FileInfo, error) {
 	fullpath, err := fs.translate(path)
 	if err != nil {