libceph: bump CEPH_OSD_MAX_OP to 3

Our longest osd request now contains 3 ops: copyup+hint+write.

Also, CEPH_OSD_MAX_OP value in a BUG_ON in rbd_osd_req_callback() was
hard-coded to 2.  Fix it, and switch to rbd_assert while at it.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

drivers/block/rbd.c

@@ -1654,7 +1654,7 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
 	if (osd_req->r_result < 0)
 		obj_request->result = osd_req->r_result;
 
-	BUG_ON(osd_req->r_num_ops > 2);
+	rbd_assert(osd_req->r_num_ops <= CEPH_OSD_MAX_OP);
 
 	/*
 	 * We support a 64-bit length, but ultimately it has to be

include/linux/ceph/osd_client.h

@@ -43,7 +43,7 @@ struct ceph_osd {
 };
 
 
-#define CEPH_OSD_MAX_OP	2
+#define CEPH_OSD_MAX_OP	3
 
 enum ceph_osd_data_type {
 	CEPH_OSD_DATA_TYPE_NONE = 0,