possible race condition

[aftersnow]

Now inflightKey is volumeName/mountID, suppose:

(1) Pod A request Model X, inflightKey = "pull-volumeA/mountA"
(2) Pod B request Model X, inflightKey = "pull-volumeB/mountB"

which means same model X can be dowloaded concurrently, causes possible race condition.

[imeoer]

Thanks for identifying this issue, it can indeed occur when concurrently pulling the same model on the same node.

Our initial design uses volumeName/mountID as the inflightKey is to prevent frequent pull requests from same PVC (in controller mode) or pod (in inline/dynamic mode).

If we improve it by using reference as the inflightKey, two cases need consideration:

1. With dragonfly hardlink: upgrade singleinflight to a key-based mutex so puller.Pull runs sequentially, allowing each volumeName/mountID to create its own model directory.

2. Without dragonfly hardlink: hard-link files from the previous model directory to the new one.

This adds a bit of complexity to the logic, but it's still achievable to handle scenario where the same node might concurrently pull the same model.