Ceph » CephFS

This is the basic principle that allows scrubs across multiple MDSs: everyone takes responsibility for their own subtrees, and stops at subtree boundaries.

Modify scrub initiating commands such that instead of the input path causing us to acting on the named dentry, they act on any subtrees within the path specified. So if I had a subtree situation like this:
MDS A: /foo /foo/bar/baz
MDS B: /foo/bar

Then a scrub initiated on MDS A for path "/foo" would find both subtrees and start scrubs from the root of both, rather than just from the /foo subtree.