On Mon 04 Apr 2016 05:26:02 PM CEST, Kevin Wolf wrote: > As the patches to move I/O throttling to BlockBackend didn't make it in > time for the 2.6 release, but the release adds new ways of configuring > VMs whose behaviour would change once the move is done, we need to > outlaw such configurations temporarily. > > The problem exists whenever a BDS has more users than just its BB, for > example it is used as a backing file for another node. (This wasn't > possible in 2.5 yet as we introduced node references to specify a > backing file only recently.) In these cases, the throttling would > apply to these other users now, but after moving throttling to the > BlockBackend the other users wouldn't be throttled any more. > > This patch both prevents making new references to a throttled node as > well as using monitor commands to throttle a node with multiple parents. > > Compared to 2.5 this changes behaviour in some corner cases where > references were allowed before, like bs->file or Quorum children. It > seems reasonable to assume that users didn't use I/O throttling on such > low level nodes. With the upcoming move of throttling into BlockBackend, > such configurations won't be possible anyway. > > Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Alberto Garcia <be...@igalia.com> Berto
