Created attachment 1906493 [details]
qmp.log

Description of problem:
Some driver attributes in target disk xml will be lost after blockcopy

Version-Release number of selected component (if applicable):
libvirt-8.5.0-5.el9.x86_64
qemu-kvm-7.0.0-10.el9.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Prepare a running guest.

1. virsh domstate rhel
   running

2. Prepare a target disk xml with different attributes.

1. cat target.xml
   <disk type="file" device="disk">
   <driver name="qemu" type="qcow2" cache="writeback" copy_on_read="on" discard="unmap" detect_zeroes="unmap">
   <metadata_cache>
   <max_size unit="bytes">1024</max_size>
   </metadata_cache>
   </driver>
   <source file="/tmp/test.copy"/>
   <target dev="vda" bus="virtio"/>
   <address type="pci" domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
   </disk>

3. Do blockcopy.

1. virsh blockcopy rhel vda --xml target.xml --transient-job --wait --verbose
   Block Copy: [100 %]
   Now in mirroring phase
2. virsh blockjob rhel vda --pivot

4. Check the dumpxml.

1. virsh dumpxml rhel | xmllint --xpath //disk -
   <disk type="file" device="disk">
   <driver name="qemu" type="qcow2">
   <metadata_cache>
   <max_size unit="bytes">1024</max_size>
   </metadata_cache>
   </driver>
   <source file="/tmp/test.copy" index="2"/>
   <backingStore/>
   <target dev="vda" bus="virtio"/>
   <alias name="virtio-disk0"/>
   <address type="pci" domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
   </disk>

Actual results:
Only metadata_cache in the disk xml after blockcopy, the others will be lost.

Expected results:
The driver attributes will exist after blockcopy.

Additional info: