md: md_stop_writes() should always freeze recovery.

__md_stop_writes() will currently sometimes freeze recovery.
So any caller must be ready for that to happen, and indeed they are.

However if __md_stop_writes() doesn't freeze_recovery, then
a recovery could start before mddev_suspend() is called, which
could be awkward.  This can particularly cause problems or dm-raid.

So change __md_stop_writes() to always freeze recovery.  This is safe
and more predicatable.

Reported-by: Brassow Jonathan <jbrassow@redhat.com>
Tested-by: Brassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4c74424..3e2acfa 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5277,8 +5277,8 @@ static void md_clean(struct mddev *mddev)
 
 static void __md_stop_writes(struct mddev *mddev)
 {
+       set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
        if (mddev->sync_thread) {
-               set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
                set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                md_reap_sync_thread(mddev);
        }