kvm: use preallocation option for fat disk resize

[shwstppr]

Description

Fixes #10589

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?

Preallocation flag added after changes,

2025-11-05 11:47:33,315 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Executing command [qemu-img create -o preallocation=full -f qcow2 /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 8589934592 ].
2025-11-05 11:49:07,780 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Successfully executed process [476300] for command [qemu-img create -o preallocation=full -f qcow2 /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 8589934592 ].
2025-11-05 11:49:07,781 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Executing command [qemu-img info -U /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 ].
2025-11-05 11:49:07,805 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Successfully executed process [476358] for command [qemu-img info -U /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 ].
2025-11-05 11:49:07,822 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Executing command [qemu-img convert -O qcow2 -o preallocation=full -U --image-opts driver=qcow2,file.filename=/mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/0abce4b6-b562-11f0-9bc2-1e008f00039b /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 ].
2025-11-05 11:50:49,386 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Successfully executed process [476361] for command [qemu-img convert -O qcow2 -o preallocation=full -U --image-opts driver=qcow2,file.filename=/mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/0abce4b6-b562-11f0-9bc2-1e008f00039b /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 ].
2025-11-05 11:50:49,387 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Executing command [qemu-img resize -o preallocation=full /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 10737418240 ].
2025-11-05 11:50:49,395 WARN  [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Execution of process [476480] for command [qemu-img resize -o preallocation=full /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 10737418240 ] failed.
2025-11-05 11:50:49,395 DEBUG [utils.script.Script] (AgentRequest-Handler-4:[]) (logid:729511e8) Exit value of process [476480] for command [qemu-img resize -o preallocation=full /mnt/ea3a10a7-49cb-3d72-bcc3-dec41ebecb7a/6e320e64-0621-43f5-ac4c-9a0f60201f03 10737418240 ] is [1].

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 3.58%. Comparing base (8c86f24) to head (ece83a8).

❗ There is a different number of reports uploaded between BASE (8c86f24) and HEAD (ece83a8). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (8c86f24)	HEAD (ece83a8)
unittests	1	0

Additional details and impacted files

@@              Coverage Diff              @@
##               main   #11986       +/-   ##
=============================================
- Coverage     17.55%    3.58%   -13.98%     
=============================================
  Files          5910      445     -5465     
  Lines        529334    37534   -491800     
  Branches      64654     6901    -57753     
=============================================
- Hits          92944     1346    -91598     
+ Misses       425933    36024   -389909     
+ Partials      10457      164    -10293     

Flag	Coverage Δ
uitests	3.58% <ø> (ø)
unittests	?

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[shwstppr]

@blueorangutan package

[blueorangutan]

@shwstppr a [SL] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

[weizhouapache]

code lgtm

not tested

[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 15650

[weizhouapache]

@blueorangutan test

[blueorangutan]

@weizhouapache a [SL] Trillian-Jenkins test job (ol8 mgmt + kvm-ol8) has been kicked to run smoke tests

[DaanHoogland]

clgtm