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
Daniel
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Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
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http://veillard.com/ | virtualization library http://libvirt.org/
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