> Yes, "unknown" process can read data back into pagecache while your ioctl > is running thus undoing your work. But if the writes are already visible on the > *device* at the moment you run the ioctl, then "unknown" process will just > fetch new data and everything is fine... If you need to evict page cache > *before* new data is visible on the device, then you need to suspend the > device first so that it doesn't serve any IO, then evict page cache, then make > new data visible on the device, and finally resume the device. > Suspend/resume of the device can be handled by device mapper (it does > these tricks when you are changing topology of the device on the fly). The writes will be visible to the device *before* the ioctl runs so I have one thing less to worry about! Regarding extending the ioctl to invalidate the page cache, do you have any suggestions where I could start looking? Would such a new ioctl have any chance to be accepted upstream? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
