[libvirt] [PATCH] fix vol-create when target allocation=0

[Chun Yan Liu]

>>> On 8/24/2015 at 05:47 PM, in message <20150824094707.GD22373 at wheatley>, Martin
Kletzander <mkletzan at redhat.com> wrote: 
> On Mon, Aug 24, 2015 at 01:50:41PM +0800, Chunyan Liu wrote: 
> >Regression is introduced by commit e30297b0. After that, it will 
> >report "Cannot fill file" error with following xml file: 
> ><volume> 
> >  <name>virtinst-vmlinuz-xen.tP1NHh</name> 
> >  <capacity>4343792</capacity> 
> >  <allocation>0</allocation> 
> >  <target> 
> >    <format type="raw"/> 
> >    <nocow/> 
> >  </target> 
> ></volume> 
> >Because of this, installing xen pv guest with virt-manager fails. 
> > 
> >Reason is: posix_fallocate(int fd, off_t offset, off_t len) will 
> >return EINVAL when len is equal to 0. So, this patch adds a check 
> >before calling safezero(). 
> > 
>  
> Oh, god that you've found out the root cause, although the same patch 
> is already on the list: 
>  
> https://www.redhat.com/archives/libvir-list/2015-August/msg00808.html 

Oh yes, it's the same patch. Sorry for not reading the message in time. Really
coincidental sending same patch from different person one after another :)

Chunyan

>  
> Although it would be nice if it had the root cause (or at least the 
> causing commit) in its commit message as well.  Cc'ing the author of 
> the previous patch in case he hasn't pushed yet. 
>  
> Martin 
>