[DLM] add version check

Check if we receive a message from another lockspace member running a
version of the dlm with an incompatible inter-node message protocol.

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

1 files changed, 11 insertions, 3 deletions

diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 521ad9bb47b7..54fba9bd6740 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -82,8 +82,17 @@ static void make_config(struct dlm_ls *ls, struct rcom_config *rf)
         rf->rf_lsflags = ls->ls_exflags;
 }
 
-static int check_config(struct dlm_ls *ls, struct rcom_config *rf, int nodeid)
+static int check_config(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
 {
+        struct rcom_config *rf = (struct rcom_config *) rc->rc_buf;
+
+        if ((rc->rc_header.h_version & 0xFFFF0000) != DLM_HEADER_MAJOR) {
+                log_error(ls, "version mismatch: %x nodeid %d: %x",
+                          DLM_HEADER_MAJOR | DLM_HEADER_MINOR, nodeid,
+                          rc->rc_header.h_version);
+                return -EINVAL;
+        }
+
         if (rf->rf_lvblen != ls->ls_lvblen ||
             rf->rf_lsflags != ls->ls_exflags) {
                 log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",
@@ -145,8 +154,7 @@ int dlm_rcom_status(struct dlm_ls *ls, int nodeid)
                 log_debug(ls, "remote node %d not ready", nodeid);
                 rc->rc_result = 0;
         } else
-                error = check_config(ls, (struct rcom_config *) rc->rc_buf,
-                                     nodeid);
+                error = check_config(ls, rc, nodeid);
         /* the caller looks at rc_result for the remote recovery status */
  out:
         return error;