Allow faulty devices to be removed from a readonly array.

Removing faulty devices from an array is a two stage process.
First the device is moved from being a part of the active array
to being similar to a spare device.  Then it can be removed
by a request from user space.

The first step is currently not performed for read-only arrays,
so the second step can never succeed.

So allow readonly arrays to remove failed devices (which aren't
blocked).

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

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6eb95451f161..25b893ec562e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6003,7 +6003,7 @@ static int remove_and_add_spares(mddev_t *mddev)
                         }
                 }
 
-        if (mddev->degraded) {
+        if (mddev->degraded && ! mddev->ro) {
                 rdev_for_each(rdev, rtmp, mddev) {
                         if (rdev->raid_disk >= 0 &&
                             !test_bit(In_sync, &rdev->flags) &&
@@ -6077,6 +6077,8 @@ void md_check_recovery(mddev_t *mddev)
                 flush_signals(current);
         }
 
+        if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+                return;
         if ( ! (
                 (mddev->flags && !mddev->external) ||
                 test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
@@ -6090,6 +6092,15 @@ void md_check_recovery(mddev_t *mddev)
         if (mddev_trylock(mddev)) {
                 int spares = 0;
 
+                if (mddev->ro) {
+                        /* Only thing we do on a ro array is remove
+                         * failed devices.
+                         */
+                        remove_and_add_spares(mddev);
+                        clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+                        goto unlock;
+                }
+
                 if (!mddev->external) {
                         int did_change = 0;
                         spin_lock_irq(&mddev->write_lock);