Re: [Xen-devel] [PATCH 2/2] scripts: Use stat to check lock claim

[Wei Liu <wl@xxxxxxx>]

On Mon, Mar 30, 2020 at 02:28:30PM +0100, Ian Jackson wrote:
> Wei Liu writes ("Re: [PATCH 2/2] scripts: Use stat to check lock claim"):
> > On Thu, Mar 12, 2020 at 10:54:17AM -0400, Jason Andryuk wrote:
> > > Replace the perl locking check with stat(1).  Stat is able to fstat
> > > stdin (file descriptor 0) when passed '-' as an argument.  This is now
> > > used to check $_lockfd.  stat(1) support for '-' was introduced to
> > > coreutils in 2009.
> > > 
> > > After A releases its lock, script B will return from flock and execute
> > > stat.  Since the lockfile has been removed by A, stat prints an error to
> > > stderr and exits non-zero.  Redirect stderr to /dev/null to avoid
> > > filling /var/log/xen/xen-hotplug.log with "No such file or directory"
> > > messages.
> > > 
> > > Placing the stat call inside the "if" condition ensures we only check
> > > the stat output when the command completed successfully.
> > > 
> > > This change removes the only runtime dependency of the xen toolstack on
> > > perl.
> > > 
> > > Suggested-by: Ian Jackson <ian.jackson@xxxxxxxxxx>
> > > Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
> > 
> > Ian, ping?
> > 
> > I already applied patch 1. This patch looks to be good as well.
> 
> Sorry.  Yes.
> 
> Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>

Thanks, I will apply this patch shortly.

Wei.