[DLM] reject replies to old requests

When recoveries are aborted by other recoveries we can get replies to
status or names requests that we've given up on.  This can cause problems
if we're making another request and receive an old reply.  Add a sequence
number to status/names requests and reject replies that don't match.  A
field already exists for the seq number that's used in other message
types.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 5573d8590e5..64ba4929f90 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -108,6 +108,7 @@ int dlm_rcom_status(struct dlm_ls *ls, int nodeid)
 	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS, 0, &rc, &mh);
 	if (error)
 		goto out;
+	rc->rc_id = ++ls->ls_rcom_seq;
 
 	send_rcom(ls, mh, rc);
 
@@ -140,19 +141,30 @@ static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
 			    sizeof(struct rcom_config), &rc, &mh);
 	if (error)
 		return;
+	rc->rc_id = rc_in->rc_id;
 	rc->rc_result = dlm_recover_status(ls);
 	make_config(ls, (struct rcom_config *) rc->rc_buf);
 
 	send_rcom(ls, mh, rc);
 }
 
-static void receive_rcom_status_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+static void receive_sync_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
 {
+	if (rc_in->rc_id != ls->ls_rcom_seq) {
+		log_debug(ls, "reject old reply %d got %llx wanted %llx",
+			  rc_in->rc_type, rc_in->rc_id, ls->ls_rcom_seq);
+		return;
+	}
 	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
 	set_bit(LSFL_RCOM_READY, &ls->ls_flags);
 	wake_up(&ls->ls_wait_general);
 }
 
+static void receive_rcom_status_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	receive_sync_reply(ls, rc_in);
+}
+
 int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
 {
 	struct dlm_rcom *rc;
@@ -173,6 +185,7 @@ int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
 	if (error)
 		goto out;
 	memcpy(rc->rc_buf, last_name, last_len);
+	rc->rc_id = ++ls->ls_rcom_seq;
 
 	send_rcom(ls, mh, rc);
 
@@ -209,6 +222,7 @@ static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
 	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
 	if (error)
 		return;
+	rc->rc_id = rc_in->rc_id;
 
 	dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
 			      nodeid);
@@ -217,9 +231,7 @@ static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
 
 static void receive_rcom_names_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
 {
-	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
-	set_bit(LSFL_RCOM_READY, &ls->ls_flags);
-	wake_up(&ls->ls_wait_general);
+	receive_sync_reply(ls, rc_in);
 }
 
 int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)