cephfs: use RemoveNetworkFence directly for unfencing

[Rakshith-R]

CephFS unfencing was failing with EINVAL because
RemoveClientEviction tried to remove per-client nonce blocklist entries via go-ceph's OSDBlocklistRemove, which rejects Ceph entity address format (IP:port/nonce).

Per-client blocklist entries from MDS client eviction auto-expire and reconnecting clients get new nonces, so explicit removal is unnecessary. Call RemoveNetworkFence directly to remove only the CIDR range entry, matching the RBD unfence behavior.

Assisted-by: Claude noreply@anthropic.com

[Rakshith-R]

@Mergifyio rebase

[mergify]

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rebase

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[iPraveenParihar]

@Mergifyio rebase

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rebase

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[iPraveenParihar]

@Rakshith-R
Skipping e2e as the code change is not covered in e2e suite.

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Merge Queue Status

• ✅ Entered queue — 2026-05-19 05:46 UTC · Rule: default
• ✅ Checks skipped · PR is already up-to-date
• ✅ Merged — 2026-05-19 05:46 UTC · at ec728f2645f9fbe1a5b28ceb3e34cbc33ec1c4eb · rebase

This pull request spent 13 seconds in the queue, including 2 seconds running CI.

Required conditions to merge

• #approved-reviews-by >= 2 [🛡 GitHub branch protection]
  • cephfs: use RemoveNetworkFence directly for unfencing #6278
• #changes-requested-reviews-by = 0 [🛡 GitHub branch protection]
  • cephfs: use RemoveNetworkFence directly for unfencing #6278