Tracing ext3 file system operations in the QEMU emulator

Abstract

The paper proposes an approach to monitoring file operations through capturing virtual disk accesses in the emulator. This method allows obtaining information about file operations in the OS-agnostic manner but requires a separate implementation for each file system. An important problem for implementing this approach is the correct handling of changes in the file system. Operating systems that cache write requests can perform operations in any order. The authors have created a method for detecting read, write, create, delete and rename operations, and a module for QEMU, which monitors operations in the ext3 file system. The advantage of this method over others is that it does not interfere with the operation of the OS and does not depend on it. It is assumed that the QEMU module for file systems other than ext2/3 can be implemented using the methods described in this article.

Keywords

• виртуальные машины
• файловые системы
• мониторинг
• qemu
• интроспекция