Fix NAS backup filename for legacy LINSTOR path

[WanzenBug]

Description

When backing up a running VM, nasbackup.sh derives the backup filename from the disk source path reported by libvirt. VMs started before the switch to /dev/drbd/by-res/ paths still carry the raw DRBD device node (e.g. /dev/drbd1098) in their live domain XML, which fell into the basename fallback and produced root.drbd1098.qcow2 instead of root..qcow2. Restore always expects the UUID-based name, so these backups could not be restored until the VM was stopped and started.

Resolve raw /dev/drbdNNNN device nodes back to the volume UUID by asking udev for the device's /dev/drbd/by-res/cs- symlink. Apply the same handling in all three backup loops (running-VM XML build, sparsify, and stopped-VM convert).

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

How did you try to break this feature and the system with this change?

[boring-cyborg]

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[Copilot]

Pull request overview

Fixes CloudStack KVM NAS backup filename generation for legacy LINSTOR VMs whose live libvirt XML still references raw /dev/drbdNNNN device nodes, ensuring backups use the expected UUID-based naming so restores can locate the correct qcow2 files.

Changes:

• Add get_linstor_uuid_from_device() to map raw DRBD device nodes back to a LINSTOR volume UUID via udev symlinks.
• Apply the raw-DRBD handling consistently in the running-VM XML generation loop, the post-backup sparsify loop, and the stopped-VM convert loop.

---

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 17.67%. Comparing base (a951ac6) to head (5c5ac0a).
⚠️ Report is 27 commits behind head on 4.22.

Additional details and impacted files

@@             Coverage Diff              @@
##               4.22   #13538      +/-   ##
============================================
- Coverage     17.67%   17.67%   -0.01%     
+ Complexity    15797    15793       -4     
============================================
  Files          5923     5923              
  Lines        533349   533349              
  Branches      65248    65248              
============================================
- Hits          94253    94252       -1     
  Misses       428437   428437              
- Partials      10659    10660       +1     

Flag	Coverage Δ
uitests	3.69% <ø> (ø)
unittests	18.74% <ø> (-0.01%)	⬇️

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[rp-]

yes, I agree to the copilot suggestions, they make sense

[abh1sar]

Code LGTM

[DaanHoogland]

@rp- @abh1sar what kind of testing do you suggest?

[rp-]

@rp- @abh1sar what kind of testing do you suggest?

Maybe @sbrueseke can help with testing, as they have been the initial starter for this change.

[sbrueseke]

It is not possible for me to test this at the moment, because we do not have any stage system which has instances/backups in this state.

[boring-cyborg]

Awesome work, congrats on your first merged pull request!

[weizhouapache]

although this PR has been merged, I am curious why line 209 is added.

      name="datadisk"

@WanzenBug
could you explain ?

@rp- @abh1sar
could you please review this line of code ?

[rp-]

This fixes a pre-existing filename mismatch, if the first disk would be a non Linstor disk, it would keep root for the next Linstor disk instead of datadisk.

Anyway, a prepared PR, will change this again and the qemu-img convert will not be necessary anymore, but I have to wait until #13877 is merged.

[weizhouapache]

@rp-

I am merging 4.22 branch to main branch, and will create 4.23.0.0-RC3

I would suggest to revert this PR. otherwise, 4.23.0.0 will have incomplete changes

[rp-]

It isn't incomplete and fixes the transition from old volumes to new naming.

But if it helps with the 4.23.0.0 release, go ahead, I wasn't aware my merge would intervene with that...

[weizhouapache]

thanks @rp-

since you think it is not incomplete, let's leave as it is