RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Description of problem:
When floppy/cdrom image is missing, snapshot-revert will report error even if with startupPolicy='requisite' 

Also the error message is ambiguous "Unknown error 512" and need to be improved

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.232.el6.x86_64
kernel-2.6.32-225.el6.x86_64
libvirt-0.9.10-3.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1.Start a guest with qcow2 type disk image and a floppy disk like
    <disk type='file' device='floppy'>
      <driver name='qemu' type='raw' cache='none'/>
      <source file='/var/lib/libvirt/images/floppy.img' startupPolicy='requisite'/>
      <target dev='fda' bus='fdc'/>
    </disk>

2.Create snapshot of running guest 
# virsh snapshot-create guest

3.Destroy the guest and remove image /var/lib/libvirt/images/floppy.img

4.Revert to running snapshot
# virsh snapshot-revert [snapshot name]
  
Actual results:
report error:
error: cannot access file '/var/lib/libvirt/images/floppy.img': Unknown error 512

Expected results:
should revert successfully

Additional info:

Patch proposed upstream:

https://www.redhat.com/archives/libvir-list/2012-March/msg00301.html

Another patch proposed upstream (for that weird error message):

https://www.redhat.com/archives/libvir-list/2012-March/msg00324.html

Moving to POST:

http://post-office.corp.redhat.com/archives/rhvirt-patches/2012-March/msg01024.html

Test failed on
kernel-2.6.32-250.el6.x86_64
libvirt-0.9.10-5.el6.x86_64
qemu-kvm-0.12.1.2-2.246.el6.x86_64

After revert, it will report error
virsh snapshot-revert qcow2 1331711016
error: cannot access file '/var/lib/libvirt/images/floppy.img': No such file or directory

So reassign it

Created attachment 569916 [details]
domain xml

Created attachment 569918 [details]
libvirtd.log

Moving to POST:

http://post-office.corp.redhat.com/archives/rhvirt-patches/2012-March/msg01281.html

verify pass on
kernel-2.6.32-250.el6.x86_64
qemu-kvm-0.12.1.2-2.246.el6.x86_64
libvirt-0.9.10-6.el6.x86_64

The snapshot-revert succeeds without error after remove floppy/cdrom image with startupPolicy='requisite'

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2012-0748.html