On 04/06/2012 01:08 AM, Paolo Bonzini wrote:
Il 06/04/2012 06:36, Eric Blake ha scritto:
If only qemu could get 'drive-reopen' inside 'transaction'...
Just a quick answer to this: if qemu could get 'drive-reopen' inside 'transaction', the standalone command could be made safe just as easily. In fact, in QEMU 1.1 the blockdev-snapshot-sync command got a similar treatment: it became transactionable, _and_ the standalone command became a simple wrapper around a 1-command transaction.
Good point. So unless we have a situation where we want to do 'drive-reopen' on multiple disks at once, we don't actually have to use a transaction command to reopen a single disk. Meanwhile, for similarity with blockdev-snapshot-sync, it looks like I will someday be adding a VIR_DOMAIN_BLOCK_JOB_ABORT_ATOMIC flag, which fails if qemu lacks support for reopen within a transaction, and assuming that qemu exposes a way to see which commands are transactionable. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org