ceph: discard incoming messages with bad seq #

We can get old message seq #'s after a tcp reconnect for stateful sessions
(i.e., the MDS).  If we get a higher seq #, that is an error, and we
shouldn't see any bad seq #'s for stateless (mon, osd) connections.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/fs/ceph/messenger.c b/fs/ceph/messenger.c
index e7b91e093f54..509f57d9ccb3 100644
--- a/fs/ceph/messenger.c
+++ b/fs/ceph/messenger.c
@@ -1334,6 +1334,7 @@ static int read_partial_message(struct ceph_connection *con)
         unsigned front_len, middle_len, data_len, data_off;
         int datacrc = con->msgr->nocrc;
         int skip;
+        u64 seq;
 
         dout("read_partial_message con %p msg %p\n", con, m);
 
@@ -1368,6 +1369,25 @@ static int read_partial_message(struct ceph_connection *con)
                 return -EIO;
         data_off = le16_to_cpu(con->in_hdr.data_off);
 
+        /* verify seq# */
+        seq = le64_to_cpu(con->in_hdr.seq);
+        if ((s64)seq - (s64)con->in_seq < 1) {
+                pr_info("skipping %s%lld %s seq %lld, expected %lld\n",
+                        ENTITY_NAME(con->peer_name),
+                        pr_addr(&con->peer_addr.in_addr),
+                        seq, con->in_seq + 1);
+                con->in_base_pos = -front_len - middle_len - data_len -
+                        sizeof(m->footer);
+                con->in_tag = CEPH_MSGR_TAG_READY;
+                con->in_seq++;
+                return 0;
+        } else if ((s64)seq - (s64)con->in_seq > 1) {
+                pr_err("read_partial_message bad seq %lld expected %lld\n",
+                       seq, con->in_seq + 1);
+                con->error_msg = "bad message sequence # for incoming message";
+                return -EBADMSG;
+        }
+
         /* allocate message? */
         if (!con->in_msg) {
                 dout("got hdr type %d front %d data %d\n", con->in_hdr.type,