nfs-reexport null deref in ceph_init_dentry
3 - minor
Al Viro observes:
* ceph: nfs export code is fucked and AFAICT untested - the first call of ceph_init_dentry() from ceph_fh_to_parent() that actually tries to do anything (i.e. gets called on fh of directory outside of current dentry tree) will blow up on attempt to dereference ->d_parent->d_inode.
Probably the d_op initialization should be moved to a different helper. We can do the d_op initialization in NFS reexport explicitly since it's always the live namespace (no snapshot reexport). And test!