Paul Brook wrote:
Finally, it would perhaps be best if the block device emulators wrote
to the qemu console to complain if they give write errors. Otherwise
the errno value and other important information will be lost, which
makes debugging hard.
If by 'qemu console' you mean stderr, then fine, but please don't
spew log messages to the monitor console, because that'll make it
very hard to interact with reliably from management tools.
Actually I think a better default would be for qemu to die right there and
then. If the host is getting IO errors then something is badly wrong, and
you're probably screwed anyway.
If you're passing through a real disk or volume, this denies the guest
the possibility of recover y (for example, if it is running a RAID setup
over multiple volumes, or if you are testing the guest's ability to
recover from errors).
For non-raw formats, you can pass through errors on data, but it is
impossible to recover on metadata errors, so dying on I/O error should
be fine.
--
Any sufficiently difficult bug is indistinguishable from a feature.