Re: [PATCH] nbd: Zero from and len fields in NBD_CMD_DISCONNECT.

[Hani Benhabiles <kroosec@gmail.com>]

On Sun, May 25, 2014 at 02:11:13PM -0400, Paul Clements wrote:
> On Sun, May 25, 2014 at 6:18 AM, Hani Benhabiles <kroosec@gmail.com> wrote:
> > On Sun, May 18, 2014 at 10:11:13AM +0100, Hani Benhabiles wrote:
> >> On Fri, May 16, 2014 at 10:56:33PM -0400, Paul Clements wrote:
> >> > Agreed. But better yet, the request structure should just be zeroed when
> >> > it's allocated.
> >> >
> >>
> >> It is already initialized  in __nbd_ioctl() with the blk_rq_init() call which
> >> sets the __sector value to -1 (which is 0xfffffffffffffe00 after the left shifts.)
> >>
> >> This is the only (non-ugly / non-intrusive) way to do it afaict.
> >>
> >
> > Ping!
> >
> > Anything blocking this patch ?
> 
> It's cleaner to just zero the struct and get rid of the conditional
> zeroing of specific fields. I'll prepare a patch in the next few days.
> 

Sorry, I misunderstood which struct you were talking about!

Will send a v2 shortly.

> Thanks,
> Paul
> 
> >> > On Fri, May 16, 2014 at 7:43 PM, Hani Benhabiles <kroosec@gmail.com> wrote:
> >> >
> >> > > Len field is already set to zero, but not the from field which is sent as
> >> > > 0xfffffffffffffe00. This makes no sense, and may cause confuse server
> >> > > implementations doing sanity checks (qemu-nbd is an example.)
> >> > >
> >> > > Signed-off-by: Hani Benhabiles <hani@linux.com>
> >> > > ---
> >> > >  drivers/block/nbd.c | 2 +-
> >> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> >> > >
> >> > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> >> > > index 3a70ea2..657bdac 100644
> >> > > --- a/drivers/block/nbd.c
> >> > > +++ b/drivers/block/nbd.c
> >> > > @@ -246,7 +246,7 @@ static int nbd_send_req(struct nbd_device *nbd, struct
> >> > > request *req)
> >> > >         request.magic = htonl(NBD_REQUEST_MAGIC);
> >> > >         request.type = htonl(nbd_cmd(req));
> >> > >
> >> > > -       if (nbd_cmd(req) == NBD_CMD_FLUSH) {
> >> > > +       if (nbd_cmd(req) == NBD_CMD_FLUSH || nbd_cmd(req) == NBD_CMD_DISC)
> >> > > {
> >> > >                 /* Other values are reserved for FLUSH requests.  */
> >> > >                 request.from = 0;
> >> > >                 request.len = 0;
> >> > > --
> >> > > 1.8.3.2
> >> > >
> >> > >