Re: [libvirt] [PATCH RFC] storage: perform btrfs clone if possible

-----Original Message----- From: Eric Blake [mailto:eblake@redhat.com] Sent: Tuesday, November 25, 2014 12:25 AM To: Martin Kletzander; Chen, Hanxiao/陈 晗霄 Cc: libvir-list(a)redhat.com Subject: Re: [libvirt] [PATCH RFC] storage: perform btrfs clone if possible On 11/24/2014 12:09 AM, Martin Kletzander wrote: > On Mon, Nov 24, 2014 at 02:11:47PM +0800, Chen Hanxiao wrote: >> We already had nocow flags in virStorageSource. >> But when creating RAW file, we don't take advantage >> of clone of btrfs. >> This file introduce btrfs_clone_file function, >> and try to use it when !nocow. >> > > I'm not sure we want to do this, but I have nothing against that > either. So I'll just review the code without any other comments. > > > As I said, I'm not commenting on whether we want this in or not, so > for that you should wait for someone's response. I bet there's a > (good) reason behind libvirt not using some lvm/zfs/btrfs features, > but I am too lazy to search for it since it'd be inaccurate anyway. I think it makes sense to expose this functionality; although I suspect it is better if we do so by having the user pass an explicit new flag value to existing API instead of doing it automatically.