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Description of problem: I create a volume with xml <volume> <name>vol-raw</name> <capacity unit="G">1</capacity> <allocation unit='G'>1</allocation> <target> <path>/var/lib/libvirt/images/vol-raw</path> <format type="raw"/> </target> </volume> on dir/fs pool and get the vol-info # virsh vol-info --pool dir_pool vol-raw Name: vol-raw Type: file Capacity: 1.00 GB Allocation: 1.00 GB after I wipe the volume and see the vol-info, the allocation still 1G. If I allocation with 1023M, then after volume wiping, the allocation will change to 0. Version-Release number of selected component (if applicable): qemu-kvm-0.12.1.2-2.159.el6.x86_64 libvirt-0.8.7-18.el6.x86_64 kernel-2.6.32-130.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. define and start a dir/fs pool with <pool type='dir'> <name>dir_pool</name> <uuid>70a7eb15-6c34-ee9c-bf57-69e8e5ff3fb2</uuid> <capacity>0</capacity> <allocation>0</allocation> <available>0</available> <source> </source> <target> <path>/var/lib/libvirt/images</path> <permissions> <mode>0700</mode> <owner>0</owner> <group>0</group> <label>some_label_t</label> </permissions> </target> </pool> # virsh pool-define /tmp/dir_pool.xml # virsh pool-start dir_pool 2. create raw type volume with xml <volume> <name>vol-raw</name> <capacity unit="G">1</capacity> <allocation unit='G'>1</allocation> <target> <path>/var/lib/libvirt/images/vol-raw</path> <format type="raw"/> </target> </volume> # virsh vol-info --pool dir_pool vol-raw Name: vol-raw Type: file Capacity: 1.00 GB Allocation: 1.00 GB 3. wipe volume # virsh vol-wipe --pool dir_pool vol-raw 4. see vol-info # virsh vol-info --pool dir_pool vol-raw Name: vol-raw Type: file Capacity: 1.00 GB Allocation: 1.00 GB Actual results: allocation still 1G Expected results: allocation should be 0G Additional info:
> Actual results: > allocation still 1G > > Expected results: > allocation should be 0G This is a mis-understanding of what wipe will do. The 'wipe' operation is defined to clear all data in the file, such that future reads return all zeros. The effect of 'wipe' on the allocation is left undefined, though the ideal goal is to preserve the existing allocation as closely as possible. Currently if the file is fully allocated, it will remain fully allocated. If it is at all sparse, it will be made completely sparse.