Ceph

recently i build a setup with key-value db back, but after snapshot is created, i overwrite one object, then OSD daemon is corrupt, I track down this issue , in KeyValueStore.cc

if (exist_clone) {
          dout(0) << "BUG: clone failed will lead to paritial transaction applied" << dendl;
        }

It seem that KeyValueStore::_clone do not implement this semantic as filestore does, you can reproduce this error with following commands

1. rbd -p rbd --new-format --size 10240 create test
2. write data to rbd
3. rbd snap create rbd/test@snap
4. overwrite previous object