On Wed, Jan 25, 2017 at 03:36:20PM -0600, Eric Blake wrote: > How do you get an fd to existing nbd block device? Your intent is to > use an ioctl to request creating/opening a new nbd device that no one > else is using; opening an existing device in order to send that ioctl > may have negative ramifications to the actual user of that existing > device, if not permissions issues that prevent the open from even > happening. Having a separate control fd makes it obvious that you are > asking for a new nbd device, and don't want to stomp on any existing > devices. Yes, - this whole concept of needing a device first to then associate it with a backing store is something we had a in a lot of drivers, and it's always been a major problem. Thus we've been slowly moving all the drivers off it. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html