Pull Ceph fixes from Ilya Dryomov:
"An rbd exclusive-lock edge case fix and several filesystem fixups.
Nikolay's error path patch is tagged for stable, everything else but
readdir vs frags race was introduced in this merge window"
* tag 'ceph-for-4.9-rc2' of git://github.com/ceph/ceph-client:
ceph: fix non static symbol warning
ceph: fix uninitialized dentry pointer in ceph_real_mount()
ceph: fix readdir vs fragmentation race
ceph: fix error handling in ceph_read_iter
rbd: don't retry watch reregistration if header object is gone
rbd: don't wait for the lock forever if blacklisted