On Mon, Aug 03, 2020 at 09:31:17AM -0500, Eric Blake wrote: > On 7/31/20 5:22 PM, Eric Blake wrote: > >From: "Richard W.M. Jones" <[email protected]> > > > >See also: > >https://www.redhat.com/archives/libguestfs/2020-July/msg00090.html > >Message-Id: <[email protected]> > > > >For now, this implementation is only for plugins; adding filter > >support will come later (and probably requires further edits, for the > >ability for any filter to open up an independent connection to the > >plugin without being handed next_ops on entry). > >--- > > >@@ -652,6 +661,46 @@ Returning C<0> will allow the connection to continue. > >If there is an > > error or you want to deny the connection, call C<nbdkit_error> with an > > error message and return C<-1>. > > > >+=head2 C<.list_exports> > >+ > >+ int list_exports (int readonly, int default_only, > >+ struct nbdkit_exports *exports); > > I'm trying to figure out a situation where knowing whether we are > running under 'nbdkit -r' (and thus all exports will be read-only) > will affect the list advertised by the plugin. But then again, we > _do_ pass the readonly flag to both .preconnect and .open, which are > bookends around this call. That said, now's the time to decide > whether to keep it or to simplify the interface by dropping it, > before we bake in a stable release with the API.
A local file which is not writable might be an example of an export that should only be listed when readonly == 1. But ... Unfortunately we only have the -r flag. What would be actually useful information is whether the client wants to connect readonly (ie. it will be sending NBD_FLAG_READ_ONLY) but as that is per-export information we don't know that yet. But I'd say we should probably stick with keeping this flag, along with a stronger disclaimer in the documentation that it might not be as useful as it appears. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW _______________________________________________ Libguestfs mailing list [email protected] https://www.redhat.com/mailman/listinfo/libguestfs
