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

[Avi Kivity <avi@qumranet.com>]

Laurent Vivier wrote:

  

>> It is udev that creates the devices, based on events it receives from 
>> the kernel.  Calling udevsettle after the kernel instructs udev to 
>> create the device files will wait until they are actually created.
>>     
>
> Yes, I agree but the kernel events are generated by the open(), so I
> think I can't use this to know if I can use open(). 
>
> I've used udevmonitor to see what happen:
> - without open() -> no events
> - whith open() whithout sleep() -> no events
> -> open() + sleep() -> events generated by the partition creation.
>
> So, what do I miss ?
>   

For this, it seems like sleep() generates the events, which is a little 
unlikely.  I suggest re-checking this.

There is also some ioctl which can be used to force re-reading the 
partition table, perhaps invoking that and then udevsettle will suffice.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.