On 17.05.2010, at 18:26, Anthony Liguori wrote: > On 05/17/2010 11:23 AM, Paul Brook wrote: >>>> I don't see a difference between the results. Apparently the barrier >>>> option doesn't change a thing. >>>> >>> Ok. I don't like it, but I can see how it's compelling. I'd like to >>> see the documentation improved though. I also think a warning printed >>> on stdio about the safety of the option would be appropriate. >>> >> I disagree with this last bit. >> >> Errors should be issued if the user did something wrong. >> Warnings should be issued if qemu did (or will soon do) something other than >> what the user requested, or otherwise made questionable decisions on the >> user's behalf. >> >> In this case we're doing exactly what the user requested. The only plausible >> failure case is where a user is blindly trying options that they clearly >> don't >> understand or read the documentation for. I have zero sympathy for complaints >> like "Someone on the Internet told me to use --breakme, and broke thinks". >> > > I see it as the equivalent to the Taint bit in Linux. I want to make it > clear to users up front that if you use this option, and you have data loss > issues, don't complain. > > Just putting something in qemu-doc.texi is not enough IMHO. Few people > actually read it.
But that's why it's no default and also called "volatile". If you prefer, we can call it cache=destroys_your_image. Alex
