ceph: reserve caps for file layout/lock MDS requests

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
index d94ba0d..1913988 100644
--- a/fs/ceph/locks.c
+++ b/fs/ceph/locks.c
@@ -45,6 +45,7 @@
 		return PTR_ERR(req);
 	req->r_inode = inode;
 	ihold(inode);
+	req->r_num_caps = 1;
 
 	/* mds requires start and length rather than start and end */
 	if (LLONG_MAX == fl->fl_end)