Ceph » CephFS

Let's say there is a hardlink created as below.

touch file1
ln file1 hl_file1

In this case file1 holds the primary inode and hl_file holds the remote inode (small struct, holds info about primary).
Now, if file1 is deleted first, a stray reintegration (the deleted primary straydn is merged with secondary inode) could happen
which links the primary inode to the hl_file1 which is called linkmerge. So in the linkmerge case, the srcdnl is primary straydn
and the destdnl is the remote.