[Libguestfs] [PATCH 1/3] New API: mdadm-create for creating MD devices.

[Richard W.M. Jones]

On Mon, Nov 14, 2011 at 03:29:45PM +0800, Wanlong Gao wrote:
> On 11/11/2011 08:58 PM, Richard W.M. Jones wrote:
> 
> > From: "Richard W.M. Jones" <rjones at redhat.com>
> 
> 
> Reviewed-by: Wanlong Gao <gaowanlong at cn.fujitsu.com>

Thanks for looking at these patches.  If you (or Fujitsu) have any
other needs for libguestfs, I'd be more than happy to discuss them.

[...]
> > +    if ((chunk & 1023) != 0) {
> > +      reply_with_error ("chunk size must be a multiple of 1024 bytes");
> 
> I'd like to make the 1024 to a macro, what do you thinks so?

I wasn't sure if you meant (a) remove the use of the constant here and
replace it with a macro, or (b) allow users to specify other chunk
sizes (eg. less than 1024 bytes, or not a multiple of 1024 bytes).

As background: The reason we do this check is because the 'mdadm
--chunk' option only allows the size to be specified in K.  We like to
use bytes in the libguestfs API [1].  We can only let users specify
multiples of 1024 here.  It may be in future that mdadm would allow
chunk sizes which are not a multiple of 1024 bytes, but it doesn't
right now.

(a) is possible, but (b) is not possible right now.

Rich.

[1] That is, we like to use bytes in new APIs, but we weren't very
consistent on this point in the early days.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://et.redhat.com/~rjones/virt-df/