On 12/15/2017 02:04 AM, Fam Zheng wrote:
> Shared write lock is not strictly necessary for creating the overlay image, if
> all what we want is to probe the size.
Theoretically, the size could be changing due to a resize operation.
But realistically, even if that happens, we will (hopefully) see either
the old size or the new size atomically (that is, I seriously doubt the
size information is split across multiple sectors of the in-use image to
the point that we could shard the read).
Series:
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org