+static void handle_get_version_reply(struct ceph_mon_client *monc,
+ struct ceph_msg *msg)
+{
+ struct ceph_mon_generic_request *req;
+ u64 tid = le64_to_cpu(msg->hdr.tid);
+ void *p = msg->front.iov_base;
+ void *end = p + msg->front_alloc_len;
+ u64 handle;
+
+ dout("%s %p tid %llu\n", __func__, msg, tid);
+
+ ceph_decode_need(&p, end, 2*sizeof(u64), bad);
+ handle = ceph_decode_64(&p);
+ if (tid != 0 && tid != handle)
+ goto bad;
+
+ mutex_lock(&monc->mutex);
+ req = __lookup_generic_req(monc, handle);
+ if (req) {
+ *(u64 *)req->buf = ceph_decode_64(&p);
+ req->result = 0;
+ get_generic_request(req);
+ }
+ mutex_unlock(&monc->mutex);
+ if (req) {
+ complete_all(&req->completion);
+ put_generic_request(req);
+ }
+
+ return;
+bad:
+ pr_err("corrupt mon_get_version reply\n");
+ ceph_msg_dump(msg);
+}
+
+/*
+ * Send MMonGetVersion and wait for the reply.
+ *
+ * @what: one of "mdsmap", "osdmap" or "monmap"
+ */
+int ceph_monc_do_get_version(struct ceph_mon_client *monc, const char *what,
+ u64 *newest)
+{
+ struct ceph_mon_generic_request *req;
+ void *p, *end;
+ u64 tid;
+ int err;
+
+ req = kzalloc(sizeof(*req), GFP_NOFS);
+ if (!req)
+ return -ENOMEM;
+
+ kref_init(&req->kref);
+ req->buf = newest;
+ req->buf_len = sizeof(*newest);
+ init_completion(&req->completion);
+
+ req->request = ceph_msg_new(CEPH_MSG_MON_GET_VERSION,
+ sizeof(u64) + sizeof(u32) + strlen(what),
+ GFP_NOFS, true);
+ if (!req->request) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ req->reply = ceph_msg_new(CEPH_MSG_MON_GET_VERSION_REPLY, 1024,
+ GFP_NOFS, true);
+ if (!req->reply) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ p = req->request->front.iov_base;
+ end = p + req->request->front_alloc_len;
+
+ /* fill out request */
+ mutex_lock(&monc->mutex);
+ tid = ++monc->last_tid;
+ ceph_encode_64(&p, tid); /* handle */
+ ceph_encode_string(&p, end, what, strlen(what));
+
+ err = __do_generic_request(monc, tid, req);
+
+ mutex_unlock(&monc->mutex);
+out:
+ kref_put(&req->kref, release_generic_request);
+ return err;
+}
+EXPORT_SYMBOL(ceph_monc_do_get_version);
+