On Thu, 03/02 15:23, Kevin Wolf wrote: > Am 02.03.2017 um 12:21 hat Fam Zheng geschrieben: > > On Wed, 03/01 17:22, Kevin Wolf wrote: > > > Am 01.03.2017 um 17:10 hat Fam Zheng geschrieben: > > > > On Wed, 03/01 16:16, Kevin Wolf wrote: > > > > > > I'm not sure about this because: 1) this is intrusive from a user > > > > > > PoV, many > > > > > > scripts and upper layer tools will stop working; > > > > > > > > > > Are you sure? I don't expect user scripts or even proper management > > > > > tools to use qemu-io on running VMs. I do expect that some users are > > > > > using 'convert -s' with running VMs despite our recommendation against > > > > > it. > > > > > > > > > > If they are aware that they're doing something that works only in the > > > > > right circumstances, then breaking it isn't nice. But my gut feeling > > > > > is > > > > > that most of them don't know about the implications of accessing a > > > > > live > > > > > image. In this case breaking their use case and making them think > > > > > about > > > > > whether they want to add something like a --force option sounds like a > > > > > good thing because they aren't caught by surprise when things go wrong > > > > > eventually. > > > > > > > > Yes, the use case is poor for qcow2, and your points stand there. But > > > > image > > > > locking will be at the posix level, which has a wider range of users. I > > > > cannot > > > > draw the same conclusion on raw images as easily. > > > > > > Well, with raw, I'm even less concerned about breaking the commands > > > related to internal snapshots. :-) > > > > Yes, I'm agree with a --force there. For qemu-img map and qemu-io, > > personally I > > think it's better to keep the default working. qemu-io is a expert mode > > tool, > > whoever using it at all should already know what he's doing, --force > > doesn't add > > much protection for the innocent. > > Being an expert doesn't protect you from stupid mistakes like forgetting > that a VM is still running. --force doesn't prevent you from performing > your evil action, but it prevents accidents where you didn't even intend > to be evil for a change. > > I think qemu-io and qemu-img map are tools that only human users should > be using while a VM is running, so breaking command line syntax > compatibility by requiring a --force option wouldn't hurt too much.
OK, that sounds fair. I don't know how to implement the option, though, would you like to take care of it? :) Fam
