md: notify the 'degraded' sysfs attribute on failure.

We currently only 'notify' changes to the 'degraded' attribute
when it decreases, not when it increases.

Notifying on failure is a little awkward as it happen in
interrupt context.
So instead, notify when we remove the failed device from the array,
which is very soon afterwards.

Reported-and-tested-by: Mikhail Balabin <mbalabin@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 1c1c562f63dc..33aa06f12b87 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7383,6 +7383,7 @@ static int remove_and_add_spares(struct mddev *mddev)
 {
         struct md_rdev *rdev;
         int spares = 0;
+        int removed = 0;
 
         mddev->curr_resync_completed = 0;
 
@@ -7396,8 +7397,13 @@ static int remove_and_add_spares(struct mddev *mddev)
                                     mddev, rdev) == 0) {
                                 sysfs_unlink_rdev(mddev, rdev);
                                 rdev->raid_disk = -1;
+                                removed++;
                         }
                 }
+        if (removed)
+                sysfs_notify(&mddev->kobj, NULL,
+                             "degraded");
+
 
         list_for_each_entry(rdev, &mddev->disks, same_set) {
                 if (rdev->raid_disk >= 0 &&