FAST '08 – Abstract
Pp. 207–222 of the Proceedings
EIO: Error Handling is Occasionally Correct
Haryadi S. Gunawi, Cindy Rubio-González, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau, and Ben Liblit, University of Wisconsin, Madison
Abstract
The reliability of file systems depends in part on how well they propagate errors. We develop a static analysis technique, EDP, that analyzes how file systems and storage device drivers propagate error codes. Running our EDP analysis on all file systems and 3 major storage device drivers in Linux 2.6, we find that errors are often incorrectly propagated; 1153 calls (13%) drop an error code without handling it.
We perform a set of analyses to rank the robustness of each subsystem based on the completeness of its error propagation; we find that many popular file systems are less robust than other available choices. We confirm that write errors are neglected more often than read errors. We also find that many violations are not corner-case mistakes, but perhaps intentional choices. Finally, we show that inter-module calls play a part in incorrect error propagation, but that chained propagations do not. In conclusion, error propagation appears complex and hard to perform correctly in modern systems.
- View the full text of this paper in HTML and PDF. Listen to the presentation in
MP3 format.
The Proceedings are published as a collective work, © 2008 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.
|
