Re: [Libguestfs] [libnbd PATCH 1/2] api: Tighten rules on completion.callback

On Sun, Jul 16, 2023 at 04:39:18PM +0000, Tage Johansson wrote: > > @@ -194,7 +198,10 @@ calls. The cookie is unique (per libnbd handle) and E<ge> 1. > > > > You may register a function which is called when the command > > completes, see L</Completion callbacks> below. In this case we have > > -specified a null completion callback. > > +specified a null completion callback. If a completion callback is > > +specified, it will only be called if the asynchronous command was > > +sucessfully submitted (if the asynchronous API itself returns an > > > Should probably be "successfully" instead of "sucessfully". > > > > +error, there is nothing further to be completed). > > > > =back > > > > @@ -897,19 +904,25 @@ asynchronous commands are retired. > > > > =head2 Callbacks and locking > > > > -The callbacks are invoked at a point where the libnbd lock is held; as > > -such, it is unsafe for the callback to call any C<nbd_*> APIs on the > > -same nbd object, as it would cause deadlock. > > +The callbacks are invoked at a point where the libnbd lock is held, > > +typically during a call to C<nbd_aio_notify_read>, > > +C<nbd_aio_notify_write>, C<nbd_aio_poll>, or other call that can > > +advance libnbd's state machine. Depending on system load, it is even > > +possible for a callback to reached before completion of the > > > Shouldn't it be "to be reached" instead of "to reached"? Yep on both counts; will fix. Thanks for a careful review.