[Libguestfs] [PATCH v2 04/11] resize: add support for logical partitions for calculate_surplus

[Chen, Hanxiao]

> -----Original Message-----
> From: Richard W.M. Jones [mailto:rjones at redhat.com]
> Sent: Thursday, May 28, 2015 7:16 PM
> To: Chen, Hanxiao/陈 晗霄
> Cc: libguestfs at redhat.com
> Subject: Re: [Libguestfs] [PATCH v2 04/11] resize: add support for logical partitions
> for calculate_surplus
> 
> On Thu, May 28, 2015 at 12:11:17PM +0100, Richard W.M. Jones wrote:
> > On Wed, May 20, 2015 at 06:51:30AM -0400, Chen Hanxiao wrote:
> > > Add support for logical partitions.
> > >  - count number of logical_partition (we've split partitions list)
> > >  - don't count size of extended partition
> > >    For it'll duplicate with logical partition, we'll count it later
> > >  - we need at leat 1 gap between logical partitions.
> > >    so --aligment=1 will be increased by 1
> > >
> > > Signed-off-by: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>
> > > ---
> > >  resize/resize.ml | 17 +++++++++++++++--
> > >  1 file changed, 15 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/resize/resize.ml b/resize/resize.ml
> > > index 92f7304..a0ed713 100644
> > > --- a/resize/resize.ml
> > > +++ b/resize/resize.ml
> > > @@ -741,8 +741,10 @@ read the man page virt-resize(1).
> > >      (* We need some overhead for partitioning. *)
> > >      let overhead =
> > >        let maxl64 = List.fold_left max 0L in
> > > +      (* We need at least 1 sector gap between logical partitions *)
> > > +      let alignment = if alignment = 1L then 2L else alignment in
> > >
> > > -      let nr_partitions = List.length partitions in
> > > +      let nr_partitions = List.length partitions + List.length
> logical_partitions in
> >
> > I don't understand this at all.  Why do logical partitions count
> > towards the surplus?  I don't think they do.
> 
> OK I guess the answer is because logical partitions now need their
> own alignment (within the extended partition), and that contributes
> to the required surplus for the disk.
> 
> Do we resize the extended partition sufficiently (eg. if the extended
> partition has 100 aligned logical partitions)?
> 

My fault, we don't need the surplus of logical partitions.

For resizing extended partition, is in:
[10/11] resize: add support resize extended partition
https://www.redhat.com/archives/libguestfs/2015-May/msg00103.html

For dealing with alignment of logical partitions, is in:
[06/11] resize: add support for logical partitions of calculate_target_partitions
https://www.redhat.com/archives/libguestfs/2015-May/msg00098.html

Regards,
- Chen