Re: [Qemu-devel] [Qemu-block] [PATCH] nbd/server: fix NBD_CMD_CACHE

[Kevin Wolf <kwolf@redhat.com>]

Am 03.10.2018 um 17:10 hat Vladimir Sementsov-Ogievskiy geschrieben:
> 03.10.2018 17:57, Eric Blake wrote:
> > On 10/3/18 9:47 AM, Vladimir Sementsov-Ogievskiy wrote:
> >> We should not go to structured-read branch on CACHE command, fix that.
> >>
> >> Bug intoroduced in bc37b06a5cde24 "nbd/server: introduce NBD_CMD_CACHE"
> >
> > s/intoroduced/introduced/
> >
> >> with the whole feature and affects 3.0.0 release.
> >
> > Ouch. It's because I don't have an NBD client that can issue the 
> > command, so the server side got released without sufficient testing. 
> > Is there some way we could enhance qemu-io as NBD client to issue such 
> > a command?
> 
> may be, just add qemu-io command, like x-debug-nbd-cmd, which will just 
> send any nbd command? and prints all server replies? Then we'll be able 
> to write any unit tests on nbd-server. It's not the first time the 
> problem arise..

Shouldn't it be easy to write a simple NBD client in Python and then use
that for test cases? I don't see why this needs to be in qemu-io, and
testing illegal requests is certainly easier with a custom client.

Kevin