[PATCH] ioctl: implement NBD_* ioctl decoding

[Dmitry V. Levin]

On Sat, Sep 22, 2018 at 11:52:29AM +0200, Elvira Khabirova wrote:
> On Fri, 21 Sep 2018 22:39:29 +0200, Eugene Syromiatnikov <esyr at redhat.com> wrote:
> > On Fri, Sep 21, 2018 at 04:42:50PM +0200, Elvira Khabirova wrote:
> > > +	ioctl(-1, NBD_SET_FLAGS, 0);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, 0) = -1 EBADF (%m)\n");
> > > +	ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_HAS_FLAGS);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_HAS_FLAGS) = -1 EBADF (%m)\n");
> > > +	ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_READ_ONLY);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_READ_ONLY) = -1 EBADF (%m)\n");
> > > +	ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_SEND_FLUSH);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_SEND_FLUSH) = -1 EBADF (%m)\n");
> > > +	ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_SEND_FUA);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_SEND_FUA) = -1 EBADF (%m)\n");
> > > +	ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_SEND_TRIM);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_SEND_TRIM) = -1 EBADF (%m)\n");
> > > +	ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_CAN_MULTI_CONN);
> > > +	printf("ioctl(-1, NBD_SET_FLAGS, NBD_FLAG_CAN_MULTI_CONN) = -1 EBADF (%m)\n");  
> > 
> > It is probably worth checking various flag combinations, including bits
> > for which there are no constants defined, in order to avoid situation like
> > v4.21~159.
> 
> Could you elaborate?

I suppose Eugene means that one has to specify at least two flags,
e.g. NBD_FLAG_HAS_FLAGS|NBD_FLAG_READ_ONLY
to distinguish printflags() from printxval() in the parser.


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