ocfs2: warn the user on a dead timeout mismatch

Print a warning to the user when a node with a different dead count joins
the region.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 1d26cfcd9f84..504595d6cf65 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -517,6 +517,7 @@ static inline void o2hb_prepare_block(struct o2hb_region *reg,
         hb_block->hb_seq = cpu_to_le64(cputime);
         hb_block->hb_node = node_num;
         hb_block->hb_generation = cpu_to_le64(generation);
+        hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 
         /* This step must always happen last! */
         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
@@ -645,6 +646,8 @@ static int o2hb_check_slot(struct o2hb_region *reg,
         struct o2nm_node *node;
         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
         u64 cputime;
+        unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
+        unsigned int slot_dead_ms;
 
         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 
@@ -733,6 +736,23 @@ fire_callbacks:
                               &o2hb_live_slots[slot->ds_node_num]);
 
                 slot->ds_equal_samples = 0;
+
+                /* We want to be sure that all nodes agree on the
+                 * number of milliseconds before a node will be
+                 * considered dead. The self-fencing timeout is
+                 * computed from this value, and a discrepancy might
+                 * result in heartbeat calling a node dead when it
+                 * hasn't self-fenced yet. */
+                slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
+                if (slot_dead_ms && slot_dead_ms != dead_ms) {
+                        /* TODO: Perhaps we can fail the region here. */
+                        mlog(ML_ERROR, "Node %d on device %s has a dead count "
+                             "of %u ms, but our count is %u ms.\n"
+                             "Please double check your configuration values "
+                             "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
+                             slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
+                             dead_ms);
+                }
                 goto out;
         }
 
diff --git a/fs/ocfs2/cluster/ocfs2_heartbeat.h b/fs/ocfs2/cluster/ocfs2_heartbeat.h
index 94096069cb43..3f4151da9709 100644
--- a/fs/ocfs2/cluster/ocfs2_heartbeat.h
+++ b/fs/ocfs2/cluster/ocfs2_heartbeat.h
@@ -32,6 +32,7 @@ struct o2hb_disk_heartbeat_block {
         __u8  hb_pad1[3];
         __le32 hb_cksum;
         __le64 hb_generation;
+        __le32 hb_dead_ms;
 };
 
 #endif /* _OCFS2_HEARTBEAT_H */