On 10/01/2015 02:03 PM, Paolo Bonzini wrote: > > > On 01/10/2015 18:34, John Snow wrote: >> Unless we can prove this to be safe for specific cases, >> the default should be to prohibit migration during BlockJobs. > > Block jobs do not affect the current block, only other block device, > hence they *are* safe for migration. >
Can you elaborate for me here? > What you want, I think, is the target not to be garbage when migration > ends. Based on this you can block specific cases, namely mirror which > you already do allow (patch 2) and backup except for sync='none'. > > Paolo > It would be nice if the target wasn't garbage, yes :) I allow mirror in specific circumstances -- you can't start a mirror, but if an existing mirror has hit the sync phase, that's OK. I can try to do a more exhaustive audit of what should and should not work, but my thought was "guilty before proven innocent." >> In conjunction with >> "migration: disallow_migrate_add_blocker during migration", >> this should be sufficient to disallow the blockjob from starting >> in the event of an in-progress migration. >