Re: [Libguestfs] [libnbd PATCH v2 4/5] api: Add STRICT_FLAGS to set_strict_mode
On 9/17/20 8:32 AM, Richard W.M. Jones wrote:
On Fri, Sep 11, 2020 at 04:49:55PM -0500, Eric Blake wrote:
> The next strict knob: allow the user to pass unknown flags across the
> wire (this is different than passing a known flag at the wrong time).
>
> It is interesting to note that NBD only permits 16 bits of flags, but
> we have a signature that takes uint32_t; if we wanted, we could pack
> libnbd-specific flags in the upper bits that the NBD protocol would
> never see.
This is fine ACK.
About the "guard" change: I probably would have put that change in a
separate commit. Also you could consider having a default_flags
parameter to avoid having to set guard = None everywhere, although you
would still have to make a one-off change to every *_flags. It would
look like this:
let default_flags = { flag_prefix = ""; guard = None; flags = [] }
...
let handshake_flags = {
default_flags with
flag_prefix = "HANDSHAKE_FLAG";
flags = [ ... ]
}
(We already do this with "default_call"). Neither of these is a big deal
though.
Splitting the patch makes sense. Also, I _did_ consider the
'default_flags with' solution before your reply, but only after I had
written the email. In the short term, it is no difference in the amount
of churn (adding one line to every flags definition); but in the long
term, it is nicer if we ever add more items. So from that perspective,
I'll go with that change.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org