fix: prevent silent volume migration in ControllerPublishVolume#143
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fix: prevent silent volume migration in ControllerPublishVolume#143
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ControllerPublishVolume previously overwrote ServerUUIDs unconditionally, silently moving an attached volume to a new node. When the subsequent ControllerUnpublishVolume for the old node found the volume no longer there, it returned success without detaching, leaving a stale VolumeAttachment that caused Multi-Attach deadlocks in production. Fix: fetch the volume before attaching. If it is attached to a different node return FailedPrecondition so the external-attacher waits for the old detach to complete first. If already attached to the requested node return idempotent success. Also add volume locks (TryAcquire/Release, already used on the node side) to DeleteVolume, ControllerPublishVolume, ControllerUnpublishVolume, CreateSnapshot, and ControllerExpandVolume to prevent TOCTOU races between concurrent mutating operations on the same volume.
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ControllerPublishVolume previously overwrote ServerUUIDs unconditionally, silently moving an attached volume to a new node. When the subsequent ControllerUnpublishVolume for the old node found the volume no longer there, it returned success without detaching, leaving a stale VolumeAttachment that caused Multi-Attach deadlocks in production.
Fix: fetch the volume before attaching. If it is attached to a different node return FailedPrecondition so the external-attacher waits for the old detach to complete first. If already attached to the requested node return idempotent success.
Also add volume locks (TryAcquire/Release, already used on the node side) to DeleteVolume, ControllerPublishVolume, ControllerUnpublishVolume, CreateSnapshot, and ControllerExpandVolume to prevent TOCTOU races between concurrent mutating operations on the same volume.
Script to reproduce this case (only worked with
forcedmode). Generated by Claude Code.reproduce-multiattach.sh