Ceph » Linux kernel client

It's possible for semantic changes to occur in one of the
ceph modules (fs/ceph, net/libceph, or block/rbd) that is
not detectable by the kernel's interface versioning mechanism.

A specific example is represented here:
http://tracker.newdream.net/issues/3799

In that case, the proposed change would change responsibility
for taking and dropping references to an object between the
two interacting modules. That is a significant semantic
difference that, once made, makes both affected modules
incompatible with previous versions.

A fairly simple version check could be implemented ensure we
never hit problems due to this sort of incompatibility.