Creating a sparse file, because on file create an inotify will produce an event and dir size will be recalculated, so it can get an actual size.

internal/handlers/handlers.go

@@ -136,6 +136,14 @@ func (h *UploadHandlers) Upload(w http.ResponseWriter, r *http.Request) {
 		}
 		defer fDst.Close()
 
+		// We initialy set a dst file size to occupy space equal to uploaded's size.
+		// This is called a sparse file, if you need to know.
+		// It allows us to have a relatively small buffer size for inotify watcher.
+		// And it really affects that. I tested it.
+		fDst.Seek(fHandler.Size-1, io.SeekStart)
+		fDst.Write([]byte{0})
+		fDst.Seek(0, io.SeekStart)
+
 		_, err = io.Copy(fDst, f)
 		if err != nil {
 			h.logErr.Println("failed to copy uploaded file to destination:", err)