Re: [Libguestfs] [libnbd PATCH 1/2] api: Tighter checking of structured read replies

> > But we can have this case: > > > > 1. ask for 32m > > 2. server sends 16m (data_seen increase to 16m) > > 3. server sends 16m (data_seen increase to 32m) > > 4. server sends 1m (data_seen does not increase) > > Yes it does. 32m <= cmd->count is true, so we bump data_seen to 33m. Right! I missed this. > Then, later on when retiring the command, we note that 33m != 32m and > fail the read with EIO (if it has not already failed for other > reasons). > > > 5. entire request succeeds > > > > Shouldn't we fail if server sends unexpected data? > > > > If we detected that all data was received, and we get > > unexpected data, why not fail immediately? > > > > cmd->data_seen += length > > if (cmd->data_seen > cmd->count) > > switch to dead state? > > Switching immediately to a dead state is also possible, but it's nice > to try and keep the connection alive as long as we can with a nice > diagnosis of a failed CMD_READ but still allow further commands, > rather than an abrupt disconnect that takes out all other use of the > server. I agree, this is better. Reviewed-by: Nir Soffer <nsoffer(a)redhat.com&gt;