Re: [Xen-devel] [PATCH for-4.5] xl: print message to stdout when (!debug && dryrun)

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Sat, 2014-12-13 at 13:46 -0500, Konrad Rzeszutek Wilk wrote:
> On Sat, Dec 13, 2014 at 06:42:09PM +0000, Wei Liu wrote:
> > On Sat, Dec 13, 2014 at 01:37:16PM -0500, Konrad Rzeszutek Wilk wrote:
> > > On Sat, Dec 13, 2014 at 04:54:05PM +0000, Wei Liu wrote:
> > > > In commit d36a3734a ("xl: fix migration failure with xl migrate
> > > > --debug"), message is printed to stderr for both debug mode
> > > > and dryrun mode. That caused rdname() in xendomains fails to parse
> > > > domain name since it's expecting input from xl's stdout.
> > > > 
> > > > So this patch separates those two cases. If xl is running in debug mode,
> > > > then message is printed to stderr; if xl is running in dryrun mode and
> > > > debug is not enabled, message is printed to stdout. This will fix
> > > > xendomains and other scripts that use "xl create --dryrun", as well as
> > > > not re-introducing the old bug fixed in d36a3734a.
> > > > 
> > > > Reported-by: Mark Pryor <tlviewer@xxxxxxxxx>
> > > > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> > > > Cc: M A Young <m.a.young@xxxxxxxxxxxx>
> > > > Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > > > Cc: Konrad Wilk <konrad.wilk@xxxxxxxxxx>
> > > > ---
> > > > This is a regression, and this bug is so subtle that's a bit hard to
> > > > debug from user's point of view. So I think this should go into 4.5.
> > > > 
> > > > Mark posted a workaround in
> > > > <104017455.78913.1418434454763.JavaMail.yahoo@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> > > > but to be honest I don't think it's nice to have everyone patch their
> > > > scripts in order to work around this.
> > > > ---
> > > >  tools/libxl/xl_cmdimpl.c |    4 +++-
> > > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> > > > index 3737c7e..0a5f7c8 100644
> > > > --- a/tools/libxl/xl_cmdimpl.c
> > > > +++ b/tools/libxl/xl_cmdimpl.c
> > > > @@ -2472,8 +2472,10 @@ static uint32_t create_domain(struct 
> > > > domain_create *dom_info)
> > > >          }
> > > >      }
> > > >  
> > > > -    if (debug || dom_info->dryrun)
> > > > +    if (debug)
> > > >          printf_info(default_output_format, -1, &d_config, stderr);
> > > > +    if (!debug && dom_info->dryrun)
> > > 
> > > Could this 'else if (dom_info->dry_run)' ?
> > > 
> > > I know that semantically it is exactly the same as the 'if (!debug ..)' 
> > > but
> > > it just "feels" more proper? Thought since you are the maintainer in that
> > > area - your opinion on how you want to do that is of course authoritive.
> > > 
> > 
> > I don't have strong preference on this. I just happened to type in
> > whatever style that flowed though my mind at that particular point. If
> > Ian and you both feel strongly about this I can certainly resend. :-)
> 
> Lets wait to see what Ian says (or what he ends up checking in).

I really ought to read the thread before replying. I do prefer the else
if style, or the ternary operator one I also proposed.



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel