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Abstract Specification of the UBIFS File System for Flash Memory

  • Andreas Schierl
  • Gerhard Schellhorn
  • Dominik Haneberg
  • Wolfgang Reif
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5850)

Abstract

Today we see an increasing demand for flash memory because it has certain advantages like resistance against kinetic shock. However, reliable data storage also requires a specialized file system knowing and handling the limitations of flash memory. This paper develops a formal, abstract model for the UBIFS flash file system, which has recently been included in the Linux kernel. We develop formal specifications for the core components of the file system: the inode-based file store, the flash index, its cached copy in the RAM and the journal to save the differences. Based on these data structures we give an abstract specification of the interface operations of UBIFS and prove some of the most important properties using the interactive verification system KIV.

Keywords

Smart Card File System Flash Memory Garbage Collection Symbolic Execution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Balser, M., Bäumler, S., Reif, W., Schellhorn, G.: Interactive verification of concurrent systems using symbolic execution. In: Proceedings of 7th International Workshop of Implementation of Logics, IWIL 2008 (2008)Google Scholar
  2. 2.
    Bäumler, S., Nafz, F., Balser, M., Reif, W.: Compositional proofs with symbolic execution. In: Beckert, B., Klein, G. (eds.) Proceedings of the 5th International Verification Workshop. Ceur Workshop Proceedings, vol. 372 (2008)Google Scholar
  3. 3.
    Börger, E., Stärk, R.F.: Abstract State Machines—A Method for High-Level System Design and Analysis. Springer, Heidelberg (2003)zbMATHGoogle Scholar
  4. 4.
    Butterfield, A., Woodcock, J.: Formalising flash memory: First steps. In: Proc. of the 12th IEEE Int. Conf. on Engineering Complex Computer Systems (ICECCS), Washington DC, USA, pp. 251–260. IEEE Comp. Soc., Los Alamitos (2007)CrossRefGoogle Scholar
  5. 5.
    Damchoom, K., Butler, M., Abrial, J.-R.: Modelling and proof of a tree-structured file system in Event-B and Rodin. In: Liu, S., Maibaum, T., Araki, K. (eds.) ICFEM 2008. LNCS, vol. 5256, pp. 25–44. Springer, Heidelberg (2008)CrossRefGoogle Scholar
  6. 6.
    Dunets, A., Schellhorn, G., Reif, W.: Automating Algebraic Specifications of Non-freely Generated Data Types. In: Cha, S(S.), Choi, J.-Y., Kim, M., Lee, I., Viswanathan, M. (eds.) ATVA 2008. LNCS, vol. 5311, pp. 141–155. Springer, Heidelberg (2008)CrossRefGoogle Scholar
  7. 7.
    Ferreira, M.A., Silva, S.S., Oliveira, J.N.: Verifying Intel flash file system core specification. In: Modelling and Analysis in VDM: Proceedings of the Fourth VDM/Overture Workshop. School of Computing Science, Newcastle University (2008) Technical Report CS-TR-1099Google Scholar
  8. 8.
    Freitas, L., Woodcock, J., Butterfield, A.: Posix and the verification grand challenge: A roadmap. In: ICECCS 2008: Proc. of the 13th IEEE Int. Conf. on Eng. of Complex Computer Systems, Washington, DC, USA, pp. 153–162 (2008)Google Scholar
  9. 9.
    Gal, E., Toledo, S.: Algorithms and data structures for flash memory. ACM computing surveys, 138–163 (2005)Google Scholar
  10. 10.
    Grandy, H., Bischof, M., Schellhorn, G., Reif, W., Stenzel, K.: Verification of Mondex Electronic Purses with KIV: From a Security Protocol to Verified Code. In: Cuellar, J., Maibaum, T., Sere, K. (eds.) FM 2008. LNCS, vol. 5014, pp. 165–180. Springer, Heidelberg (2008)CrossRefGoogle Scholar
  11. 11.
    Gurevich, Y.: Evolving algebras 1993: Lipari guide. In: Börger, E. (ed.) Specification and Validation Methods, pp. 9–36. Oxford Univ. Press, Oxford (1995)Google Scholar
  12. 12.
    Haneberg, D., Schellhorn, G., Grandy, H., Reif, W.: Verification of Mondex Electronic Purses with KIV: From Transactions to a Security Protocol. Formal Aspects of Computing 20(1) (January 2008)Google Scholar
  13. 13.
    Hoare, C.A.R.: The verifying compiler: A grand challenge for computing research. J. ACM 50(1), 63–69 (2003)CrossRefGoogle Scholar
  14. 14.
    Hunter, A.: A brief introduction to the design of UBIFS (2008), http://www.linux-mtd.infradead.org/doc/ubifs_whitepaper.pdf
  15. 15.
    The Open Group Base Specifications Issue 6, IEEE Std 1003.1, 2004 Edition (2004), http://www.unix.org/version3/online.html (login required)
  16. 16.
    Joshi, R., Holzmann, G.J.: A mini challenge: build a verifiable filesystem. Formal Aspects of Computing 19(2) (June 2007)Google Scholar
  17. 17.
    Kang, E., Jackson, D.: Formal modelling and analysis of a flash filesystem in Alloy. In: Börger, E., Butler, M., Bowen, J.P., Boca, P. (eds.) ABZ 2008. LNCS, vol. 5238, pp. 294–308. Springer, Heidelberg (2008)CrossRefGoogle Scholar
  18. 18.
    Web presentation of the Flash File System Case Study in KIV (2009), http://www.informatik.uni-augsburg.de/swt/projects/flash.html
  19. 19.
    LXR - the Linux cross reference, http://lxr.linux.no/
  20. 20.
    Morgan, C., Sufrin, B.: Specification of the UNIX filing system. In: Specification case studies, pp. 91–140. Prentice Hall (UK) Ltd., Hertfordshire (1987)Google Scholar
  21. 21.
    Oliveira, J.N.: Extended Static Checking by Calculation Using the Pointfree Transform. In: Bove, A., et al. (eds.) LerNet ALFA Summer School 2008. LNCS, vol. 5520, pp. 195–251. Springer, Heidelberg (2009)Google Scholar
  22. 22.
    Reeves, G., Neilson, T.: The Mars Rover Spirit FLASH anomaly. In: Aerospace Conference, pp. 4186–4199. IEEE, Los Alamitos (2005)Google Scholar
  23. 23.
    Reif, W., Schellhorn, G., Stenzel, K., Balser, M.: Structured specifications and interactive proofs with KIV. In: Bibel, W., Schmitt, P. (eds.) Automated Deduction—A Basis for Applications, ch. 1, vol. II, pp. 13–39. Kluwer Academic Publishers, Dordrecht (1998)Google Scholar
  24. 24.
    Schellhorn, G., Banach, R.: A concept-driven construction of the mondex protocol using three refinements. In: Börger, E., Butler, M., Bowen, J.P., Boca, P. (eds.) ABZ 2008. LNCS, vol. 5238, pp. 39–41. Springer, Heidelberg (2008)CrossRefGoogle Scholar
  25. 25.
    Schellhorn, G., Grandy, H., Haneberg, D., Moebius, N., Reif, W.: A Systematic Verification Approach for Mondex Electronic Purses using ASMs. In: Glässer, U., Abrial, J.-R. (eds.) Dagstuhl Seminar on Rigorous Methods for Software Construction and Analysis. LNCS, vol. 5115. Springer, Heidelberg (2008)Google Scholar
  26. 26.
    Schellhorn, G., Reif, W., Schairer, A., Karger, P., Austel, V., Toll, D.: Verified Formal Security Models for Multiapplicative Smart Cards. Special issue of the Journal of Computer Security 10(4), 339–367 (2002)Google Scholar
  27. 27.
    Spivey, J.M.: The Z Notation: A Reference Manual. Prentice Hall, Englewood Cliffs (1992)Google Scholar
  28. 28.
    STMicroelectronics. SPC56xB/C/D Automotive 32-bit Flash microcontrollers for car body applications (February 2009), http://www.st.com/stonline/products/promlit/a_automotive.htm
  29. 29.
    Woodhouse, D.: JFFS: The Journalling Flash File System (2001), http://sources.redhat.com/jffs2/jffs2.pdf

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Andreas Schierl
    • 1
  • Gerhard Schellhorn
    • 1
  • Dominik Haneberg
    • 1
  • Wolfgang Reif
    • 1
  1. 1.Lehrstuhl für Softwaretechnik und ProgrammiersprachenUniversität AugsburgAugsburgGermany

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