libceph: ceph_connection_operations::reencode_message() method

Give upper layers a chance to reencode the message after the connection
is negotiated and ->peer_features is set.  OSD client will use this to
support both luminous and pre-luminous OSDs (in a single cluster): the
former need MOSDOp v8; the latter will continue to be sent MOSDOp v4.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index c5c4c71..fbd94d9 100644 (file)
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -44,6 +44,8 @@ struct ceph_connection_operations {
                                        struct ceph_msg_header *hdr,
                                        int *skip);
 
+       void (*reencode_message) (struct ceph_msg *msg);
+
        int (*sign_message) (struct ceph_msg *msg);
        int (*check_message_signature) (struct ceph_msg *msg);
 };

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 9daed25..0c31035 100644 (file)
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1288,13 +1288,16 @@ static void prepare_write_message(struct ceph_connection *con)
                m->hdr.seq = cpu_to_le64(++con->out_seq);
                m->needs_out_seq = false;
        }
-       WARN_ON(m->data_length != le32_to_cpu(m->hdr.data_len));
+
+       if (con->ops->reencode_message)
+               con->ops->reencode_message(m);
 
        dout("prepare_write_message %p seq %lld type %d len %d+%d+%zd\n",
             m, con->out_seq, le16_to_cpu(m->hdr.type),
             le32_to_cpu(m->hdr.front_len), le32_to_cpu(m->hdr.middle_len),
             m->data_length);
-       BUG_ON(le32_to_cpu(m->hdr.front_len) != m->front.iov_len);
+       WARN_ON(m->front.iov_len != le32_to_cpu(m->hdr.front_len));
+       WARN_ON(m->data_length != le32_to_cpu(m->hdr.data_len));
 
        /* tag + hdr + front + middle */
        con_out_kvec_add(con, sizeof (tag_msg), &tag_msg);