Re: [Qemu-devel] [PATCH 04/21] block: Add bdrv_close_all() handlers

[Paolo Bonzini]

On 26/01/2015 20:27, Max Reitz wrote:
> However, this was wrong: With the NBD attached to some BB, it
> should stay attached until the NBD export is removed or the server
> stopped; medium ejection should have nothing to do with this (other than
> the NBD server not being able to read data while the virtual is open, if
> there is one (and there is one if the NBD server is attached to the same
> BB as a guest device with a tray is; which is correct behavior because
> attaching an NBD server to a guest-used BB should result in the NBD
> server behaving exactly the same as the guest device)).

Not entirely; use of close notifiers was on purpose.  We do not want the
NBD client to start reading data from a different medium without noticing.

If the NBD server is attached to the BDS, it should keep serving the BDS.

If the NBD server is attached to the BB, the clients must have a way to
notice the medium change, and so far the solution was to close the
connection.  I'd be wary to change this, though I understand where you
come from.

Paolo