ceph: preserve seq # on requeued messages after transient transport errors
If the tcp connection drops and we reconnect to reestablish a stateful
session (with the mds), we need to resend previously sent (and possibly
received) messages with the _same_ seq # so that they can be dropped on
the other end if needed. Only assign a new seq once after the message is
queued.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/messenger.c b/fs/ceph/messenger.c
index a3a8f36..cd4fadb 100644
--- a/fs/ceph/messenger.c
+++ b/fs/ceph/messenger.c
@@ -492,7 +492,14 @@
list_move_tail(&m->list_head, &con->out_sent);
}
- m->hdr.seq = cpu_to_le64(++con->out_seq);
+ /*
+ * only assign outgoing seq # if we haven't sent this message
+ * yet. if it is requeued, resend with it's original seq.
+ */
+ if (m->needs_out_seq) {
+ m->hdr.seq = cpu_to_le64(++con->out_seq);
+ m->needs_out_seq = false;
+ }
dout("prepare_write_message %p seq %lld type %d len %d+%d+%d %d pgs\n",
m, con->out_seq, le16_to_cpu(m->hdr.type),
@@ -1986,6 +1993,8 @@
BUG_ON(msg->front.iov_len != le32_to_cpu(msg->hdr.front_len));
+ msg->needs_out_seq = true;
+
/* queue */
mutex_lock(&con->mutex);
BUG_ON(!list_empty(&msg->list_head));