When attempting to repair a read error, don't read from
devices with a known bad block.
As we are only reading PAGE_SIZE blocks, we don't try to
narrow down to smaller regions in the hope that only part of this
page is bad - it isn't worth the effort.
Signed-off-by: NeilBrown <neilb@suse.de>
 
                rcu_read_lock();
                do {
+                       sector_t first_bad;
+                       int bad_sectors;
+
                        d = r10_bio->devs[sl].devnum;
                        rdev = rcu_dereference(conf->mirrors[d].rdev);
                        if (rdev &&
-                           test_bit(In_sync, &rdev->flags)) {
+                           test_bit(In_sync, &rdev->flags) &&
+                           is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
+                                       &first_bad, &bad_sectors) == 0) {
                                atomic_inc(&rdev->nr_pending);
                                rcu_read_unlock();
                                success = sync_page_io(rdev,