MD: when RAID journal is missing/faulty, block RESTART_ARRAY_RW

When RAID-4/5/6 array suffers from missing journal device, we put
the array in read only state. We should not allow trasition to
read-write states (clean and active) before replacing journal device.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>

1 files changed, 25 insertions, 2 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index b5057596b630..08a4034351de 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3970,7 +3970,9 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
                 break;
         case clean:
                 if (mddev->pers) {
-                        restart_array(mddev);
+                        err = restart_array(mddev);
+                        if (err)
+                                break;
                         spin_lock(&mddev->lock);
                         if (atomic_read(&mddev->writes_pending) == 0) {
                                 if (mddev->in_sync == 0) {
@@ -3988,7 +3990,9 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
                 break;
         case active:
                 if (mddev->pers) {
-                        restart_array(mddev);
+                        err = restart_array(mddev);
+                        if (err)
+                                break;
                         clear_bit(MD_CHANGE_PENDING, &mddev->flags);
                         wake_up(&mddev->sb_wait);
                         err = 0;
@@ -5351,6 +5355,25 @@ static int restart_array(struct mddev *mddev)
                 return -EINVAL;
         if (!mddev->ro)
                 return -EBUSY;
+        if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
+                struct md_rdev *rdev;
+                bool has_journal = false;
+
+                rcu_read_lock();
+                rdev_for_each_rcu(rdev, mddev) {
+                        if (test_bit(Journal, &rdev->flags) &&
+                            !test_bit(Faulty, &rdev->flags)) {
+                                has_journal = true;
+                                break;
+                        }
+                }
+                rcu_read_unlock();
+
+                /* Don't restart rw with journal missing/faulty */
+                if (!has_journal)
+                        return -EINVAL;
+        }
+
         mddev->safemode = 0;
         mddev->ro = 0;
         set_disk_ro(disk, 0);