Re: [libvirt] 'build' on FS pool now unconditionally formats?

On Wed, Feb 24, 2010 at 03:51:45PM -0500, Cole Robinson wrote: > Hi guys, > > Looking at the new FS pool build options and talking with Dave, I see that > calling PoolBuild on an FS pool now unconditionally calls mkfs. This is really > bad when mixed with virt-manager: previously, we assumed the FS build command > was always non destructive (at most it created a directory), so we called it > every time, and didn't even allow users to opt out, since there wasn't a use > case that called for it. > > This new formatting behavior really needs to be opt in, otherwise all > virt-manager versions creating an FS pool can destroy data. > > Just FYI, for disk pools (and certain LVM configurations) where this operation > has always been destructive, we default to build=off, and loudly warn the user > if they choose otherwise. We can do that with this new option as well, but the > previous behavior really needs to be reinstated IMO (and before the new release). > > I fully accept that this could be a bug in virt-manager's assumptions of the > build command, but even consider a virsh user: previously build just created a > directory, now it formats a partition, without any XML change. I was initially reluctant of changing the behaviour, and asked to use a flag to keep the original default semantic. I got convinced that noone could rely on it because the function was basically incomplete. But since virt-manager ships with an expectation on the previous behaviour, I revert my position, we need to add a _FORMAT = 4 flag for this call and only call mkfs if that flag is passed. Fix is trivial we should not push 0.7.7 without it,