Libguestfs - Aug 2018 - [PATCH] v2v: parse_libvirt_xml: number disks from 0 (RHBZ#1615885)

When parsing the libvirt XML, make sure to assign the IDs for disks
(s_disk_id) from 0 instead of 1, just like all the other input modes not
based on libvirt XML.
---
 v2v/parse_libvirt_xml.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/v2v/parse_libvirt_xml.ml b/v2v/parse_libvirt_xml.ml
index 78a6e71c0..dac99511c 100644
--- a/v2v/parse_libvirt_xml.ml
+++ b/v2v/parse_libvirt_xml.ml
@@ -246,7 +246,7 @@ let parse_libvirt_xml ?conn xml    (* Non-removable disk
devices. *)
   let disks      let get_disks, add_disk -      let disks = ref [] and i = ref
0 in
+      let disks = ref [] and i = ref (-1) in
       let get_disks () = List.rev !disks in
       let add_disk qemu_uri format controller p_source          incr i;
-- 
2.17.1

On Tue, Aug 14, 2018 at 04:04:10PM +0200, Pino Toscano
wrote:
> When parsing the libvirt XML, make sure to assign the IDs for disks
> (s_disk_id) from 0 instead of 1, just like all the other input modes not
> based on libvirt XML.
> ---
>  v2v/parse_libvirt_xml.ml | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/v2v/parse_libvirt_xml.ml b/v2v/parse_libvirt_xml.ml
> index 78a6e71c0..dac99511c 100644
> --- a/v2v/parse_libvirt_xml.ml
> +++ b/v2v/parse_libvirt_xml.ml
> @@ -246,7 +246,7 @@ let parse_libvirt_xml ?conn xml >    (*
Non-removable disk devices. *)
>    let disks >      let get_disks, add_disk > -      let disks = ref
[] and i = ref 0 in
> +      let disks = ref [] and i = ref (-1) in
>        let get_disks () = List.rev !disks in
>        let add_disk qemu_uri format controller p_source >          incr
i;
NACK.  The s_disk_id field is supposed to just be a unique ID and
-i libvirt is giving it a unique value here so it's not wrong.

The problem with this bug is that the output driver used the s_disk_id
field assuming it was a unique, monotonically increasing number
counting from 0.  (See my other patch to fix that)

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

On Tuesday, 14 August 2018 16:53:02 CEST Richard W.M. Jones
wrote:
> On Tue, Aug 14, 2018 at 04:04:10PM +0200, Pino Toscano wrote:
> > When parsing the libvirt XML, make sure to assign the IDs for disks
> > (s_disk_id) from 0 instead of 1, just like all the other input modes
not
> > based on libvirt XML.
> > ---
> >  v2v/parse_libvirt_xml.ml | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/v2v/parse_libvirt_xml.ml b/v2v/parse_libvirt_xml.ml
> > index 78a6e71c0..dac99511c 100644
> > --- a/v2v/parse_libvirt_xml.ml
> > +++ b/v2v/parse_libvirt_xml.ml
> > @@ -246,7 +246,7 @@ let parse_libvirt_xml ?conn xml > >    (*
Non-removable disk devices. *)
> >    let disks > >      let get_disks, add_disk > > -     
let disks = ref [] and i = ref 0 in
> > +      let disks = ref [] and i = ref (-1) in
> >        let get_disks () = List.rev !disks in
> >        let add_disk qemu_uri format controller p_source > >     
incr i;
> 
> NACK.  The s_disk_id field is supposed to just be a unique ID and
> -i libvirt is giving it a unique value here so it's not wrong.
I did not say it is wrong, just that the way IDs are allocated here
is different than in other input modes.
> The problem with this bug is that the output driver used the s_disk_id
> field assuming it was a unique, monotonically increasing number
> counting from 0.  (See my other patch to fix that)
OK, this I can agree with.  Would it be possible to add this paragraph
to the commit message of the patch?

-- 
Pino Toscano