fix(juicefs): correct stale PV fuse label key after Dataset recreation

[jakharmonika364]

Ⅰ. Describe what this PR does

When namespace+name exceeds ~52 characters, GetFuseLabelName falls back to a UID-based label key (fluid.io/f-<ownerDatasetUID>). If the Dataset gets deleted and recreated, the ownerDatasetUID changes. SyncRuntime picks up the new UID and updates the fuse daemonset's nodeSelector, but CreatePersistentVolumeForRuntime only creates PVs and never updates them, so the PV's mount_pod_node_selector_key keeps pointing to the old key. The CSI node plugin reads this stale key from the PV to label nodes, the fuse daemonset nodeSelector no longer matches, fuse pods don't get scheduled, and mounts fail.

This PR adds syncPVFuseLabelKey() which is called unconditionally in syncFuseSpec() on every reconcile. It reads the PV's current mount_pod_node_selector_key and patches it if it doesn't match runtimeInfo.GetFuseLabelName(). Running it unconditionally covers the case where the daemonset was already updated in a prior reconcile but the PV patch hadn't happened yet.

Ⅱ. Does this pull request fix one issue?

fixes #6089

Ⅲ. List the added test cases (unit test/integration test) if any, please explain if no tests are needed.

Added TestSyncPVFuseLabelKey in pkg/ddc/juicefs/fuse_label_consistency_test.go:

• Creates a PV with a stale label key (based on ownerDatasetUID_A)
• Initializes the engine with a new ownerDatasetUID_B (simulating Dataset recreation)
• Calls syncPVFuseLabelKey() and asserts the PV's mount_pod_node_selector_key is updated to the UID_B based key

Ⅳ. Describe how to verify it

Run the unit test:

go test ./pkg/ddc/juicefs/ -run TestSyncPVFuseLabelKey -v

Expected output:

Ⅴ. Special notes for reviews

The fix runs a PV GET on every syncFuseSpec call. If the key already matches (common case), no update is made. The slight extra cost per reconcile is acceptable given mounts would otherwise fail silently.

[gemini-code-assist]

Code Review

This pull request introduces a fix for issue #6089 by adding syncPVFuseLabelKey to keep the PV's mount_pod_node_selector_key CSI attribute in sync with the current fuse label key, preventing mount failures when the owner dataset UID changes. It also includes a unit test to verify this behavior. The review feedback points out a critical issue where assigning a value to pv.Spec.CSI.VolumeAttributes could cause a runtime panic if the map is nil, and provides a code suggestion to safely initialize it.

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[fluid-e2e-bot]

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[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 48.48485% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.76%. Comparing base (ccd52dc) to head (e26857d).

Files with missing lines	Patch %	Lines
pkg/ddc/juicefs/sync_runtime.go	48.48%	12 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6090      +/-   ##
==========================================
- Coverage   64.77%   64.76%   -0.02%     
==========================================
  Files         484      484              
  Lines       33892    33925      +33     
==========================================
+ Hits        21954    21970      +16     
- Misses      10215    10227      +12     
- Partials     1723     1728       +5     

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[TrafalgarZZZ]

@jakharmonika364 Thanks for your PR that tries to fix the issue! But I think the changes won't fix the issue because PV is immutable after creation. So syncing PV fuse label key is not possible. We had some internal discussion with JuiceFSRuntime's maintainer @zwwhdls , and we decide to fix that issue by disable syncing fuse nodeSelector (I've opened a PR #6092 ). So I'll close this PR.