Re: [libvirt] [PATCH v6 0/7] storage:dir: ploop volumes support

This series of patches introduces the support of ploop volumes in storage pools (dir, fs, etc). Ploop volume is a disk loopback block device consists of root.hds (it is the image file) and DiskDescriptor.xml: https://openvz.org/Ploop/format. Due to this fact it can't be treated as file or any other volume type, moreover, in order to successfully manipulate with such volume, ploop tools should be installed. All callbacks except the wipeVol are supported. First patch introduces ploop volume type. This is a directory with two files inside. The name of the directory is the name of the volume. Patch 2 deals with creating an empty volume and cloning the existing one. Clone is done via simle cp operation. If any of this operation fails - directory will be deleted. Patch 3 deletes recursively ploop directory. Patch 4 uses ploop tool to resize volume. Patch 6 adapts all refreshing functions to work with ploop. To get information the directory is checked. The volume is treated as the ploops one only if it contains ploop files. Every time the pool is refreshed DiskDescriptor.xml is restored. This is necessary, because the content of the volume may have changed. Upload and download (patch 7) can't be done if the volume contains snapshots.