[PATCH 3.5 16/78] md: Fix skipping recovery for read-only arrays.

[Luis Henriques]

3.5.7.26 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lukasz Dorau <lukasz.dorau at intel.com>

commit 61e4947c99c4494336254ec540c50186d186150b upstream.

Since:
        commit 7ceb17e87bde79d285a8b988cfed9eaeebe60b86
        md: Allow devices to be re-added to a read-only array.

spares are activated on a read-only array. In case of raid1 and raid10
personalities it causes that not-in-sync devices are marked in-sync
without checking if recovery has been finished.

If a read-only array is degraded and one of its devices is not in-sync
(because the array has been only partially recovered) recovery will be skipped.

This patch adds checking if recovery has been finished before marking a device
in-sync for raid1 and raid10 personalities. In case of raid5 personality
such condition is already present (at raid5.c:6029).

Bug was introduced in 3.10 and causes data corruption.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak at intel.com>
Signed-off-by: Lukasz Dorau <lukasz.dorau at intel.com>
Signed-off-by: NeilBrown <neilb at suse.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/md/raid1.c  | 1 +
 drivers/md/raid10.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index aa58c02..0d15abe 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1354,6 +1354,7 @@ static int raid1_spare_active(struct mddev *mddev)
 			}
 		}
 		if (rdev
+		    && rdev->recovery_offset == MaxSector
 		    && !test_bit(Faulty, &rdev->flags)
 		    && !test_and_set_bit(In_sync, &rdev->flags)) {
 			count++;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 5ad042c..2070e9c 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1630,6 +1630,7 @@ static int raid10_spare_active(struct mddev *mddev)
 			}
 			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
 		} else if (tmp->rdev
+			   && tmp->rdev->recovery_offset == MaxSector
 			   && !test_bit(Faulty, &tmp->rdev->flags)
 			   && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
 			count++;
-- 
1.8.3.2