text: However, there is a lock for each grain. The lock can be in shared or exclusive mode. For 
  multiple targets, a common lock is shared, and the mappings are derived from a particular 
  source volume. The lock is used in the following modes under the following conditions: 
  
  (cid:2) The lock is held in shared mode during a read from the target volume, which touches a 
  grain that was not copied from the source. 
  
  (cid:2) The lock is held in exclusive mode while a grain is being copied from the source to the 
  target. 
  
  If the lock is held in shared mode and another process wants to use the lock in shared mode, 
  this request is granted unless a process is already waiting to use the lock in exclusive mode. 
  
  If the lock is held in shared mode and it is requested to be exclusive, the requesting process 
  must wait until all holders of the shared lock free it. 
  
  Similarly, if the lock is held in exclusive mode, a process wanting to use the lock in shared or 
  exclusive mode must wait for it to be freed. 
  
  **11.1.17 Event handling**
  
  When a FlashCopy mapping is not copying or stopping, the FlashCopy function does not 
  affect the handling or reporting of events for error conditions that are encountered in the I/O 
  path. Event handling and reporting are affected only by FlashCopy when a FlashCopy 
  mapping is copying or stopping, that is, actively moving data. 