Opportunistic Lock Operations

If a Win32 application requests opportunistic locks, all files for which it requests locks must be opened for overlapped (asynchronous) input and output using the CreateFile function with the FILE_FLAG_OVERLAPPED flag. After the files are opened for overlapped operation, you can use the DeviceIoControl function with one of the operations listed following to work with those files' opportunistic locks.

FSCTL_OPBATCH_ACK_CLOSE_PENDING
FSCTL_OPLOCK_BREAK_ACK_NO_2
FSCTL_OPLOCK_BREAK_ACKNOWLEDGE
FSCTL_OPLOCK_BREAK_NOTIFY
FSCTL_REQUEST_BATCH_OPLOCK
FSCTL_REQUEST_FILTER_OPLOCK
FSCTL_REQUEST_OPLOCK_LEVEL_1
FSCTL_REQUEST_OPLOCK_LEVEL_2