external_snapshot_prepare() tries to move the overlay to the AioContext
of the backing file (the snapshotted node). However, it's possible that
this doesn't work, but the backing file can instead be moved to the
overlay's AioContext (e.g. opening the backing chain for a mirror
target).
bdrv_append
On Tue, Mar 10, 2020 at 12:38:29 +0100, Kevin Wolf wrote:
> external_snapshot_prepare() tries to move the overlay to the AioContext
> of the backing file (the snapshotted node). However, it's possible that
> this doesn't work, but the backing file can instead be moved to the
> overlay's AioContext
