ceph: use rbtree for snap_realms

Switch from radix tree to rbtree for snap realms.  This is much more
appropriate given that realm keys are few and far between.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b2adfccbab98..1f3928785e12 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -656,6 +656,8 @@ static inline void ceph_put_snap_context(struct ceph_snap_context *sc)
 struct ceph_snap_realm {
         u64 ino;
         atomic_t nref;
+        struct rb_node node;
+
         u64 created, seq;
         u64 parent_ino;
         u64 parent_since;   /* snapid when our current parent became so */