md: don't update metadata when stopping a read-only array.

read-only arrays should stay that way as much as possible.
Updating the metadata - which could be triggered by a re-add
while assembling the array metadata - should be avoided.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 491afda21fd9..30132280d07b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5293,7 +5293,8 @@ static void __md_stop_writes(struct mddev *mddev)
         bitmap_flush(mddev);
         md_super_wait(mddev);
 
-        if (!mddev->in_sync || mddev->flags) {
+        if (mddev->ro == 0 &&
+            (!mddev->in_sync || mddev->flags)) {
                 /* mark array as shutdown cleanly */
                 mddev->in_sync = 1;
                 md_update_sb(mddev, 1);