Logical Volume Locks

There is a simple hierarchy: Before a request is issued to obtain or release a Logical Volume lock, the appropriate Volume Group lock must be held. I.e. Before querying or manipulating LV state you must hold a VG lock.
There are currently five Logical Volume locking modes:
- LV_ACTIVATE – make the LV available in the kernel
- LV_DEACTIVATE – remove the LV from the kernel
- LV_EXCLUSIVE – activate on only one node and prevent other nodes subsequently activating the same LV concurrently
- LV_SUSPEND – suspend the flow of I/O to this LV
- LV_RESUME – resume the flow of I/O to this LV

There is a simple hierarchy: Before a request is issued to obtain or release a Logical Volume lock, the appropriate Volume Group lock must be held. I.e. Before querying or manipulating LV state you must hold a VG lock.