md-cluster: fix safemode_delay value when converting to clustered bitmap

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
```

Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9d740e4..79a6b2f 100644 (file)
--- 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.
@@ -6034,7 +6036,7 @@ 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);
@@ -7413,6 +7415,7 @@ 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;
                        }
                        mddev_suspend(mddev);
                        md_bitmap_destroy(mddev);
@@ -8408,6 +8411,7 @@ EXPORT_SYMBOL(unregister_md_cluster_operations);
 
 int md_setup_cluster(struct mddev *mddev, int nodes)
 {
+       int ret;
        if (!md_cluster_ops)
                request_module("md-cluster");
        spin_lock(&pers_lock);
@@ -8419,7 +8423,10 @@ int md_setup_cluster(struct mddev *mddev, int nodes)
        }
        spin_unlock(&pers_lock);
 
-       return md_cluster_ops->join(mddev, nodes);
+       ret = md_cluster_ops->join(mddev, nodes);
+       if (!ret)
+               mddev->safemode_delay = 0;
+       return ret;
 }
 
 void md_cluster_stop(struct mddev *mddev)