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Bug
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Resolution: Unresolved
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Undefined
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None
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rhel-9.5
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Yes
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None
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Regression
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sst_virtualization_storage
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ssg_virtualization
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3
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False
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None
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None
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None
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None
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None
What were you trying to do that didn't work?
Pass a RW fd to vm, but set the disk to RO in vm xml, qemu reports "permission denied" when starts vm or hotplug disk.
Please provide the package NVR for which bug is seen:
libvirt-10.3.0-1.el9.x86_64
qemu-kvm-9.0.0-1.el9.x86_64
How reproducible:
100%
Steps to reproduce
- Start a vm
- Create a disk image, and open a RW fd
[root@dell-per740-78 ~]# qemu-img create -f raw /var/lib/libvirt/images/cdrom1.raw 100M Formatting '/var/lib/libvirt/images/cdrom1.raw', fmt=raw size=104857600 [root@dell-per740-78 ~]# ll -Z /var/lib/libvirt/images/cdrom1.raw -rw-r--r--. 1 root root unconfined_u:object_r:virt_image_t:s0 104857600 May 20 23:02 /var/lib/libvirt/images/cdrom1.raw [root@dell-per740-78 ~]# exec 10<>/var/lib/libvirt/images/cdrom1.raw
- Associate the fd with vm, and try to attach the image to vm as readonly disk
[root@dell-per740-78 ~]# cat fd.xml <disk type="file" device="disk"> <driver name="qemu" type="raw"/> <source file="/var/lib/libvirt/images/cdrom1.raw" fdgroup="fg1"/> <backingStore/> <readonly/> <target dev="vde" bus="virtio"/> </disk> [root@dell-per740-78 ~]# virsh Welcome to virsh, the virtualization interactive terminal. Type: 'help' for help with commands 'quit' to quit virsh # dom-fd-associate rhel9.5 fg1 10 --seclabel-writable virsh # attach-device rhel9.5 fd.xml error: Failed to attach device from fd.xml error: internal error: unable to execute QEMU command 'blockdev-add': Could not dup FD for /dev/fdset/60 flags 0: Permission denied [root@dell-per740-78 ~]# ll -Z /var/lib/libvirt/images/cdrom1.raw -rw-r--r--. 1 root root unconfined_u:object_r:virt_image_t:s0 104857600 May 20 23:03 /var/lib/libvirt/images/cdrom1.raw
Expected results
No "permission denied" error, disk can be attached to vm
Actual results
"permission denied" error when trying to start vm or hotplug the disk.
Additional info
- If I pass a RO fd to vm, the disk can be attached to vm successfully.
# exec 11</var/lib/libvirt/images/cdrom1.raw # virsh virsh # dom-fd-associate rhel9.5 fg1 11 virsh # attach-device rhel9.5 fd.xml Device attached successfully # ll -Z /var/lib/libvirt/images/cdrom1.raw -rw-r--r--. 1 root root system_u:object_r:virt_content_t:s0 104857600 May 20 23:03 /var/lib/libvirt/images/cdrom1.raw
- This issue can not be reproduced on RHEL9.4
libvirt-10.0.0-6.3.el9_4.x86_64
qemu-kvm-8.2.0-11.el9_4.2.x86_64
- relates to
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RHEL-7343 [RFE] [libvirt] Eliminate raw format blockdev to improve disk I/O performance
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- Closed
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