md: don't retry recovery of raid1 that fails due to error on source drive.

If a raid1 has only one working drive and it has a sector which
gives an error on read, then an attempt to recover onto a spare will
fail, but as the single remaining drive is not removed from the
array, the recovery will be immediately re-attempted, resulting
in an infinite recovery loop.

So detect this situation and don't retry recovery once an error
on the lone remaining drive is detected.

Allow recovery to be retried once every time a spare is added
in case the problem wasn't actually a media error.

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

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index f5cbb9d2371a..41e2509bf896 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1500,6 +1500,9 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 
         list_add_rcu(&rdev->same_set, &mddev->disks);
         bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);
+
+        /* May as well allow recovery to be retried once */
+        mddev->recovery_disabled = 0;
         return 0;
 
  fail:
@@ -6175,7 +6178,7 @@ static int remove_and_add_spares(mddev_t *mddev)
                         }
                 }
 
-        if (mddev->degraded && ! mddev->ro) {
+        if (mddev->degraded && ! mddev->ro && !mddev->recovery_disabled) {
                 list_for_each_entry(rdev, &mddev->disks, same_set) {
                         if (rdev->raid_disk >= 0 &&
                             !test_bit(In_sync, &rdev->flags) &&