Re: [Qemu-devel] [PATCH 4/4] qemu-nbd: do not start the block layer in the parent

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/28/2011 02:17 PM, Paolo Bonzini wrote:
>> Yes, it would be better if we could have error output on stderr. Now,
>> "simple" errors such as a missing image file (or wrong path to the
>> image) are reported to syslog instead. It could be the source of some
>> headaches...
>>
>> Is there a way we could have the child send the error to the parent
>> over a pipe and have the parent print it on stderr?
>
> A way could be to change the fork() into a separate thread, so that you
> can daemonize as soon as you accept the socket rather than having to do
> it early.

I tried implementing this, but in general daemonization (which forks and 
leave only the children) breaks the threading.

So we could either keep this series (which moves all errors to syslog, 
but doesn't otherwise change behavior), or I can finish and post an 
alternative series that removes all forking from qemu-nbd *but* changes 
behavior in that "qemu-nbd -c" will not daemonize anymore.

Since this is 1.0 after all, I'm slightly more inclined towards the latter.

Opinions?  Kevin, Anthony?

Paolo