Added mutex to guard file handle

Author: smkniazi

File.go

@@ -25,9 +25,10 @@ type FileINode struct {
 	Attrs      Attrs       // Cache of file attributes // TODO: implement TTL
 	Parent     *DirINode   // Pointer to the parent directory (allows computing fully-qualified paths on demand)
 
-	activeHandles []*FileHandle // list of opened file handles
-	fileMutex     sync.Mutex    // mutex for activeHandles
-	handle        FileProxy     // handle to the temp file in staging dir
+	activeHandles   []*FileHandle // list of opened file handles
+	fileMutex       sync.Mutex    // mutex for file operation such as open, delete
+	handle          FileProxy     // handle to the temp file in staging dir
+	fileHandleMutex sync.Mutex    // mutex for file handle
 }
 
 // Verify that *File implements necesary FUSE interfaces
@@ -225,7 +226,7 @@ func (file *FileINode) createStagingFile(operation string, existsInDFS bool) err
 			return err
 		}
 	}
-	file.handle = &LocalFileProxy{localFile: stagingFile}
+	file.handle = &LocalFileProxy{localFile: stagingFile, file: file}
 	return nil
 }
 
@@ -252,6 +253,9 @@ func (file *FileINode) downloadToStaging(stagingFile *os.File, operation string)
 
 // Creates new file handle
 func (file *FileINode) NewFileHandle(existsInDFS bool, flags fuse.OpenFlags) (*FileHandle, error) {
+	file.lockFileHandle()
+	defer file.unLockFileHandle()
+
 	operation := Create
 	if existsInDFS {
 		operation = Open
@@ -293,3 +297,11 @@ func (file *FileINode) logInfo(fields Fields) Fields {
 	}
 	return f
 }
+
+func (file *FileINode) lockFileHandle() {
+	file.fileHandleMutex.Lock()
+}
+
+func (file *FileINode) unLockFileHandle() {
+	file.fileHandleMutex.Unlock()
+}

LocalFileProxy.go

@@ -4,34 +4,49 @@ import "os"
 
 type LocalFileProxy struct {
 	localFile *os.File // handle to the temp file in staging dir
+	file      *FileINode
 }
 
 var _ FileProxy = (*LocalFileProxy)(nil)
 
 func (p *LocalFileProxy) Truncate(size int64) error {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.Truncate(size)
 }
 
 func (p *LocalFileProxy) WriteAt(b []byte, off int64) (n int, err error) {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.WriteAt(b, off)
 }
 
 func (p *LocalFileProxy) ReadAt(b []byte, off int64) (n int, err error) {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.ReadAt(b, off)
 }
 
 func (p *LocalFileProxy) Seek(offset int64, whence int) (ret int64, err error) {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.Seek(offset, whence)
 }
 
 func (p *LocalFileProxy) Read(b []byte) (n int, err error) {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.Read(b)
 }
 
 func (p *LocalFileProxy) Close() error {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.Close()
 }
 
 func (p *LocalFileProxy) Sync() error {
+	p.file.lockFileHandle()
+	defer p.file.unLockFileHandle()
 	return p.localFile.Sync()
 }