We want to be able to reconnect dead connections to existing block
devices, so add a reconfigure netlink command. We will also allow users
to change their timeout on the fly, but everything else will require a
disconnect and reconnect. You won't be able to add more connections
either, simply replace dead connections with new more lively
connections.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The existing ioctl interface for configuring NBD devices is a bit
cumbersome and hard to extend. The other problem is we leave a
userspace app sitting in it's syscall until the device disconnects,
which is less than ideal.
This patch introduces a netlink interface for adding and disconnecting
nbd devices. This has the benefits of being easily extendable without
breaking older userspace applications, and allows us to configure a nbd
device without leaving a userspace app sitting waiting for the device to
disconnect.
With this interface we also gain the ability to configure more devices
than are preallocated at insmod time. We also have gained the ability
to not specify a particular device and be provided one for us so that
userspace doesn't need to find a free device to configure.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
