Re: [Qemu-devel] [PATCH] Merge NBD client/server int qemu-nbd

[Laurent Vivier]

Le vendredi 13 juin 2008 à 12:49 -0500, Anthony Liguori a écrit :
> Laurent Vivier wrote:
[...]
> > +static void show_parts(const char *device)
> > +{
> > +    if (fork() == 0) {
> > +        int nbd;
> > +
> > +   /* wait device */
> > +        sleep(1);
> >   
> 
> This looks like a big red-herring.  What is this sleep waiting for any 
> can it be possibly made into something less racy?

Yes, I know, it's BAD (and it can failed sometime...)

But show_parts() must wait its parent has entered in nbd_trip() loop.

Because the open() calls /dev/nbd0 which calls through the socket its
parent and IMHO there is no easy way to know if the server is ready to
process the request.

Perhaps something like:

int timeout = 5;
while ((fd = open(device, O_RDWR)) == -1 && timeout--)
    sleep(1);

Any suggestion ???

Regards,
Laurent
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