The DOM lock bit is taken opportunistically at open to improve possible read/write access but it uses PW lock mode and can be combined with other lock bits. The proposed improvements are:
1. when file is closed and there were no read/write, drop DOM bit and downgrade lock mode to less strict lock mode (CR/CW)
2. if there was write then write data on close (LU-11428) and also downgrade lock mode to PR
3. if DOM bit is dropped and there are other bits remains in lock - downgrade lock mode too