----- Original Message ----- > From: "Denis V. Lunev" <d...@virtuozzo.com> > To: "Paolo Bonzini" <pbonz...@redhat.com> > Cc: "Vladimir Sementsov-Ogievskiy" <vsement...@virtuozzo.com>, > qemu-devel@nongnu.org, qemu-bl...@nongnu.org, > nbd-gene...@lists.sourceforge.net, a...@alex.org.uk, ebl...@redhat.com, > kw...@redhat.com, stefa...@redhat.com, > w...@uter.be > Sent: Tuesday, September 27, 2016 12:25:54 PM > Subject: Re: [PATCH] proto: add 'shift' extension. > > On 09/27/2016 01:15 PM, Paolo Bonzini wrote: > >> We could go in a different direction and export flag > >> 'has_zero_init' which will report that the storage is > >> initialized with all zeroes at the moment. In this > >> case mirroring code will not fall into this > >> branch. > > Why don't you add the zero_init flag to QEMU's NBD driver instead? > > for all cases without knowing real backend on the server side? > I think this would be wrong.
Add it to the command line, and leave it to libvirt or the user to pass "-drive file.driver=nbd,...,file.zero-init=on". Paolo
