When array convert to clustered bitmap, the safe_mode_delay doesn't
clean and vice versa. the /sys/block/mdX/md/safe_mode_delay keep original
value after changing bitmap type. In safe_delay_store(), the code forbids
setting mddev->safemode_delay when array is clustered. So in cluster-md
env, the expected safemode_delay value should be 0.

Reproducible steps:

node1 # mdadm --zero-superblock /dev/sd{b,c,d}
node1 # mdadm -C /dev/md0 -b internal -e 1.2 -n 2 -l mirror /dev/sdb /dev/sdc
node1 # cat /sys/block/md0/md/safe_mode_delay
0.204
node1 # mdadm -G /dev/md0 -b none
node1 # mdadm --grow /dev/md0 --bitmap=clustered
node1 # cat /sys/block/md0/md/safe_mode_delay
0.204  <== doesn't change, should ZERO for cluster-md

node1 # mdadm --zero-superblock /dev/sd{b,c,d}
node1 # mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sdb /dev/sdc
node1 # cat /sys/block/md0/md/safe_mode_delay
0.000
node1 # mdadm -G /dev/md0 -b none
node1 # cat /sys/block/md0/md/safe_mode_delay
0.000  <== doesn't change, should default value

Signed-off-by: Zhao Heming <redacted>
---
  drivers/md/md.c | 11 +++++++++--
  1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index f567f536b529..1bde3df3fa18 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c

@@ -101,6 +101,8 @@ static void mddev_detach(struct mddev *mddev);
   * count by 2 for every hour elapsed between read errors.
   */
  #define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
+/* Default safemode delay: 200 msec */
+#define DEFAULT_SAFEMODE_DELAY ((200 * HZ)/1000 +1)
  /*
   * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
   * is 1000 KB/sec, so the extra system load does not show up that much.

@@ -5982,7 +5984,7 @@ int md_run(struct mddev *mddev)
  	if (mddev_is_clustered(mddev))
  		mddev->safemode_delay = 0;
  	else
-		mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
+		mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY;
  	mddev->in_sync = 1;
  	smp_wmb();
  	spin_lock(&mddev->lock);

@@ -7361,6 +7363,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
  
  				mddev->bitmap_info.nodes = 0;
  				md_cluster_ops->leave(mddev);
+				mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY;
  			}