Re: [libvirt] [PATCH 1/2] resize: add virStorageVolResize() API
On 01/30/2012 07:28 AM, Daniel P. Berrange wrote:
>>> 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.
In fact since our existing virDomainBlockResize API is already
using unsigned long long, I'd say we should do shrinkage solely
based off the SHRINK flag, and *not* require a negative size
as well
Here's what I was envisioning:
set my size to an absolute of 10M, regardless of whether it was
previously 5M or 15M:
virStorageVolResize(vol, 10*1024*1024, SHRINK)
set my size to an absolute of 10M, but only if it does not shrink:
virStorageVolResize(vol, 10*1024*1024, 0)
set my size to a relative of 10M larger
virStorageVolResize(vol, 10*1024*1024, DELTA)
set my size to a relative of 10M smaller, provided it was at least 10M
to begin with:
virStorageVolResize(vol, -10*1024*1024, DELTA|SHRINK)
You are proposing that the negative sign should be implied by the
combination of DELTA|SHRINK; I guess I can live with that, since the
other three use cases still work as-is, and DELTA|SHRINK is the only
point where a negative value makes sense (and therefore where implying
the negative is okay).
Shall I go ahead and write the patch?
--
Eric Blake eblake(a)redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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