WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Re: blktap race against xenstore startup

To: "Stephen C. Tweedie" <sct@xxxxxxxxxx>
Subject: Re: [Xen-devel] Re: blktap race against xenstore startup
From: Anthony Liguori <aliguori@xxxxxxxxxx>
Date: Thu, 28 Sep 2006 20:15:46 -0500
Cc: Andrew Warfield <andrew.warfield@xxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Steven Rostedt <rostedt@xxxxxxxxxxx>, Julian Chesterfield <jac90@xxxxxxxxx>
Delivery-date: Thu, 28 Sep 2006 18:16:14 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <1159485838.8884.38.camel@xxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <1159481874.8884.30.camel@xxxxxxxxxxxxxxxxxxxxx> <451C508D.1070103@xxxxxxxxxx> <1159485838.8884.38.camel@xxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 1.5.0.7 (X11/20060922)
Stephen C. Tweedie wrote:
Hi,

On Thu, 2006-09-28 at 17:45 -0500, Anthony Liguori wrote:

Ugh.  There has got to be a better way to synchronise with the initial
population of the dom0 information into xenstore, surely?  Has no other
component of the Xen stack ever seen this before?
I don't know how blktap is launched right now, but the same problem has occurred in the past for other daemons (like xenconsoled).

xenstored won't close standard output until it's ready to receive connections. xend start will wait to start the other daemons until xenstored is ready. How does blktap get spawned?

It (the blktapctrl userland daemon) gets execve'd by xend:

    elif sys.argv[1] == 'start':
        start_xenstored()
        start_consoled()
        start_blktapctrl()
        return daemon.start()

The problem is not that xenstored is dead: it's alive and running, it
just hasn't had the /local/domain tree filled in, so it returns ENOENT.
xenstored *is* ready, but that's not enough.

Ah, I see. So it sounds like blktapctrl ought to be setting a watch for /local/domain.

Regards,

Anthony Liguori

--Stephen




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>