We present Coerced Cache Eviction (CCE), a new method to force writes to disk in the presence of a disk cache that does not properly obey write-cache configuration or flush requests. We demonstrate the utility of CCE by building a new journaling mode within the Linux ext3 file system. When mounted in this discreet mode, ext3 uses CCEs to ensure that writes are properly ordered and thus maintains file system integrity despite the presence of an improperly behaving disk. We show that discreet mode journaling operates with acceptable overheads for most workloads.

We introduce Membrane, a set of changes to the operating system to support restartable file systems. Membrane allows an operating system to tolerate a broad class of file system failures, and does so while remaining transparent to running applications; upon failure, the file system restarts, its state is restored, and pending application requests are serviced as if no failure had occurred. Membrane provides transparent recovery through a lightweight logging and checkpoint infrastructure, and includes novel techniques to improve performance and correctness of its fault-anticipation and recovery machinery. We tested Membrane with ext2, ext3, and VFAT. Through experimentation, we show that Membrane induces little performance overhead and can tolerate a wide range of file system crashes. More critically, Membrane does so with little or no change to existing file systems, thus improving robustness to crashes without mandating intrusive changes to existing file-system code.