[libvirt] [PATCH 1/6] Add virDomainGetBlockInfo API to query disk sizing

[Daniel P. Berrange]

On Wed, Apr 28, 2010 at 04:19:11PM +0200, Daniel Veillard wrote:
> On Wed, Apr 28, 2010 at 01:54:45PM +0100, Daniel P. Berrange wrote:
> > Some applications need to be able to query a guest's disk info,
> > even for paths not managed by the storage pool APIs. This adds
> > a very simple API to get this information, modelled on the
> > virStorageVolGetInfo API, but with an extra field 'physical'.
> > Normally 'physical' and 'allocation' will be identical, but
> > in the case of a qcow2-like file stored inside a block device
> > 'physical' will give the block device size, while 'allocation'
> > will give the qcow2 image size
> [....]
> > +
> > +/** virDomainBlockInfo:
> > + *
> > + * This struct provides information about the size of a block device backing store
> > + *
> > + * Examples:
> > + *
> > + *  - Fully allocated raw file in filesystem:
> > + *       * capacity, allocation, physical: All the same
> > + *
> > + *  - Sparse raw file in filesystem:
> > + *       * capacity: logical size of the file
> > + *       * allocation, physical: number of blocks allocated to file
> > + *
> > + *  - qcow2 file in filesystem
> > + *       * capacity: logical size from qcow2 header
> > + *       * allocation, physical: logical size of the file / highest qcow extent (identical)
> > + *
> > + *  - qcow2 file in a block device
> > + *       * capacity: logical size from qcow2 header
> > + *       * allocation: highest qcow extent written
> > + *       * physical: size of the block device container
> > + */
> 
>   Argh, forgot that in my previous review, we need to explicitely tell
>   the size units, I expect bytes but we're unsing kB in some places
>   so...
> 
> > +typedef struct _virDomainBlockInfo virDomainBlockInfo;
> > +typedef virDomainBlockInfo *virDomainBlockInfoPtr;
> > +struct _virDomainBlockInfo {
> > +    unsigned long long capacity;   /* logical size of the block device backing image */
> > +    unsigned long long allocation; /* allocated extent of the block device backing image */
> > +    unsigned long long physical;   /* physical size of the container of the backing image */
> > +};
> 
>   s/size/size in bytes/g

Yes, they're all bytes.


Daniel
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