ceph: use ihold when we already have an inode ref

We should use ihold whenever we already have a stable inode ref, even
when we aren't holding i_lock.  This avoids adding new and unnecessary
locking dependencies.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
index 476b329..7f0f72c 100644
--- a/fs/ceph/locks.c
+++ b/fs/ceph/locks.c
@@ -23,7 +23,8 @@
 	req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 
 	/* mds requires start and length rather than start and end */
 	if (LLONG_MAX == fl->fl_end)