fix: Allow small size differences to match the device min size

[vojtechtrefny]

Cause: We are currently allowing up to 2 % size difference from requested size when creating or resizing volumes to fit them into pool free space (see #199). This applies the same logic for device minimum size limits when resizing.

Consequence: The sizes do not match when running the role again, causing the role to think something has changed.

Fix: Ensure that a small size difference does not cause the role to think the size has changed.

Result: The role is idempotent.

Resolves: https://issues.redhat.com/browse/RHEL-82825

Summary by Sourcery

Allow minor size variations around device minimum limits when resizing volumes to prevent idempotency issues and mirror existing max size tolerance

Bug Fixes:

• Prevent the role from detecting false changes by tolerating small discrepancies (up to ~2%) at device minimum size limits

Enhancements:

• Extend blivet resizing logic to adjust sizes slightly below the device's min_size when within the MAX_TRIM_PERCENT tolerance, mirroring the max_size adjustment

Tests:

• Add test cases for acceptable size differences (+1.5% and –1.5%) for both LVM and XFS volumes to verify correct resizing behavior and idempotency

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 16 lines in your changes missing coverage. Please review.

Project coverage is 10.67%. Comparing base (59fd1c6) to head (8efa482).
Report is 58 commits behind head on main.

Files with missing lines	Patch %	Lines
library/blivet.py	0.00%	16 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (59fd1c6) and HEAD (8efa482). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (59fd1c6)	HEAD (8efa482)
sanity	1	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #526      +/-   ##
==========================================
- Coverage   16.54%   10.67%   -5.88%     
==========================================
  Files           2        8       +6     
  Lines         284     1958    +1674     
  Branches       79        0      -79     
==========================================
+ Hits           47      209     +162     
- Misses        237     1749    +1512     

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[vojtechtrefny]

This version is not yet available, keeping the PR as draft for now.

[vojtechtrefny]

python-blivet-3.12.1-3 is now available in rawhide and should be available in F42 repos soon.

[sourcery-ai]

Reviewer's Guide

This PR updates the resize implementation to tolerate small deviations from device size limits by snapping targets within a 2% threshold to min_size as well as max_size, and adds new tests for both Ext4 and XFS scenarios to verify idempotency when resizing slightly above max and below min limits.

File-Level Changes

Change	Details	Files
Enhance blivet resize logic to adjust for small undersize differences	Add branch for size < current to compute trim_percent against min_size Adjust target size up to device.min_size when within MAX_TRIM_PERCENT Retain early return if adjusted size equals current	library/blivet.py
Introduce tests for acceptable small over/undersize resizing	Define acc_large_size and acc_small_size variables Add Ext4 test block for +1.5% resize tolerance and idempotency Add XFS test block including -1.5% shrink tolerance and cleanup	tests/tests_resize.yml

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[sourcery-ai]

Hey @vojtechtrefny - I've reviewed your changes - here's some feedback:

• The new resize logic for up‐ and down‐sizing in blivet.py is almost identical—consider extracting the common trim_percent calculation and adjustment into a helper to reduce duplication.
• The resize tests in tests/tests_resize.yml repeat the same blocks for ext4 and XFS—factor out the common steps into a reusable include or loop to DRY up the file and make it easier to maintain.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Review instructions: all looks good
• 🟢 Testing: all looks good
• 🟢 Documentation: all looks good

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[richm]

[citest]

[richm]

[citest_bad]

[richm]

@vojtechtrefny ready to merge?

[vojtechtrefny]

@vojtechtrefny ready to merge?

Yes, sorry, I forgot about this. The fixed version of blivet is now available in both rawhide and f42 so this can be merged.