Merge tag 'md-3.4-fixes' of git://neil.brown.name/md

Pull a few more md bug fixes from NeilBrown:
 "2 are tagged for -stable, one being for a fairly serious bug that can
  corrupt metadata and make it hard to recovery an array.  The other is
  for a more recent regression since 3.3"

* tag 'md-3.4-fixes' of git://neil.brown.name/md:
  md: fix possible corruption of array metadata on shutdown.
  md: don't call ->add_disk unless there is good reason.
  DM RAID: Use safe version of rdev_for_each

2 files changed, 6 insertions, 5 deletions

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index b0ba52459ed..68965e66324 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -859,7 +859,7 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
         int ret;
         unsigned redundancy = 0;
         struct raid_dev *dev;
-        struct md_rdev *rdev, *freshest;
+        struct md_rdev *rdev, *tmp, *freshest;
         struct mddev *mddev = &rs->md;
 
         switch (rs->raid_type->level) {
@@ -877,7 +877,7 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
         }
 
         freshest = NULL;
-        rdev_for_each(rdev, mddev) {
+        rdev_for_each_safe(rdev, tmp, mddev) {
                 if (!rdev->meta_bdev)
                         continue;
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index b572e1e386c..477eb2e180c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7560,14 +7560,14 @@ void md_check_recovery(struct mddev *mddev)
                  * any transients in the value of "sync_action".
                  */
                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
-                clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                 /* Clear some bits that don't mean anything, but
                  * might be left set
                  */
                 clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
                 clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
 
-                if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
+                if (!test_and_clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
+                    test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
                         goto unlock;
                 /* no recovery is running.
                  * remove any failed drives, then
@@ -8140,7 +8140,8 @@ static int md_notify_reboot(struct notifier_block *this,
 
         for_each_mddev(mddev, tmp) {
                 if (mddev_trylock(mddev)) {
-                        __md_stop_writes(mddev);
+                        if (mddev->pers)
+                                __md_stop_writes(mddev);
                         mddev->safemode = 2;
                         mddev_unlock(mddev);
                 }