[libvirt] [PATCH 1/2] resize: add virStorageVolResize() API

[Daniel P. Berrange]

On Mon, Jan 30, 2012 at 07:18:06AM -0700, Eric Blake wrote:
> On 01/30/2012 04:08 AM, Daniel P. Berrange wrote:
> > On Fri, Jan 27, 2012 at 05:28:15PM -0700, Eric Blake wrote:
> >> From: "Zeeshan Ali (Khattak)" <zeeshanak at gnome.org>
> >>
> >> Add a new function to allow changing of capacity of storage volumes.
> >> Plan out several flags, even if not all of them will be implemented
> >> up front.
> >>
> 
> >> +typedef enum {
> >> +  VIR_STORAGE_VOL_RESIZE_ALLOCATE = 1 << 0, /* force allocation of new size */
> >> +  VIR_STORAGE_VOL_RESIZE_DELTA    = 1 << 1, /* size is relative to current */
> >> +  VIR_STORAGE_VOL_RESIZE_SHRINK   = 1 << 2, /* allow decrease in capacity */
> >> +} virStorageVolResizeFlags;
> >> +
> >> +int                     virStorageVolResize             (virStorageVolPtr vol,
> >> +                                                         long long capacity,
> >> +                                                         unsigned int flags);
> > 
> > 
> > Why has this changed from 'unsigned long long' to just 'long long'.
> 
> Because of VIR_STORAGE_VOL_RESIZE_DELTA and
> VIR_STORAGE_VOL_RESIZE_SHRINK.  That is,
> 
> virStorageVolResize(vol, -10 * 1024 * 1024, DELTA|SHRINK)
> 
> is a valid call to shave off 10 MiB of data.

Isn't that rather redundant. Either you need a negative size, or you
need a SHRINK flag. If you have a shrink flag, then we don't need a
signed int.

Daniel
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