ocfs2/cluster: Fix output in file elapsed_time_in_ms

The o2hb debugfs file, elapsed_time_in_ms, should return values only after the
timer is armed atleast once.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 4728a746281d..a4e855e3690e 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1198,6 +1198,7 @@ static int o2hb_debug_open(struct inode *inode, struct file *file)
         struct o2hb_debug_buf *db = inode->i_private;
         struct o2hb_region *reg;
         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+        unsigned long lts;
         char *buf = NULL;
         int i = -1;
         int out = 0;
@@ -1234,9 +1235,11 @@ static int o2hb_debug_open(struct inode *inode, struct file *file)
 
         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
                 reg = (struct o2hb_region *)db->db_data;
-                out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
-                                jiffies_to_msecs(jiffies -
-                                                 reg->hr_last_timeout_start));
+                lts = reg->hr_last_timeout_start;
+                /* If 0, it has never been set before */
+                if (lts)
+                        lts = jiffies_to_msecs(jiffies - lts);
+                out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
                 goto done;
 
         case O2HB_DB_TYPE_REGION_PINNED: