This is a tracker bug to merge following general improvements to ceph_rgw vfs module. 1. Module report ENOENT error from librgw extended attribute APIs as ENOATTR. 2. Make use of existing method to identify open operation for write and use appropriate librgw APIs for the same. 3. Enable use of rename method which was disabled due to limitation of rgw_open/clsoe() semantics 4. Add new module parameters to control number of internal threads used by per librgw instance. 5. Documentation changes