Hi, Currently the source's export is mounted and unmounted on every inter-server copy operation. This causes unnecessary overhead for each copy. This patch series is an enhancement to allow the export to remain mounted for a configurable period (default to 15 minutes). If the export is not being used for the configured time it will be unmounted by a delayed task. If it's used again then its expiration time is extended for another period. Since mount and unmount are no longer done on each copy request, this overhead is no longer used to decide whether the copy should be done with inter-server copy or generic copy. The threshold used to determine sync or async copy is now used for this decision. -Dai v2: fix compiler warning of missing prototype.
