Bugfix: Writing to storage when write-back method is chosen

[MMuzzammil1]

Modifications

Closes #14688. Initially I had thought it was purposeful not to offload to storage when write_back policy is in action.
However, tweaking with just this minor change enables offloading to storage. Tested this on AMD MI300x with Mooncake and it seems to be offloading data to the store and fetching as well.

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[gemini-code-assist]

Summary of Changes

Hello @MMuzzammil1, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a bug where the system failed to offload data to backup storage when the write_back caching policy was in effect. The change ensures that after a write operation is acknowledged, the corresponding cache node is properly written to storage if storage offloading is enabled, improving memory management and data persistence for the hiradix_cache.

Highlights

• Storage Offloading: Enabled writing to backup storage for cache nodes when the write_back caching policy is active, addressing a previous misunderstanding that prevented this behavior.
• Bug Fix: Corrected an issue where cache nodes were not being offloaded to storage even when the write_back method was chosen, leading to inefficient memory management.

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[gemini-code-assist]

Code Review

This pull request fixes a bug where data was not offloaded to storage when using the write_back cache policy. The change correctly adds the logic to write to backup storage. However, it also introduces a potential bug by decrementing a lock reference count that was never incremented, which could lead to a negative reference count. I've suggested a fix to remove the incorrect decrement.