osd: fix deadlock in map handler
osd: fix deadlock in map handler

To avoid deadlock,
- we need to drop osd_lock while we flush.
- we need to take map_lock _after_ we flush.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@newdream.net>

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph