[34-longterm 196/209] md: fix regression with re-adding devices to arrays with no metadata

[Paul Gortmaker]

From: NeilBrown <neilb@xxxxxxx>

  =====================================================================
  | This is a commit scheduled for the next v2.6.34 longterm release. |
  | If you see a problem with using this for longterm, please comment.|
  =====================================================================

commit bf572541ab44240163eaa2d486b06f306a31d45a upstream.

Commit 1a855a0606 (2.6.37-rc4) fixed a problem where devices were
re-added when they shouldn't be but caused a regression in a less
common case that means sometimes devices cannot be re-added when they
should be.

In particular, when re-adding a device to an array without metadata
we should always access the device, but after the above commit we
didn't.

This patch sets the In_sync flag in that case so that the re-add
succeeds.

This patch is suitable for any -stable kernel to which 1a855a0606 was
applied.

Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/md/md.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index e56e35e..7db9ceb 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5008,9 +5008,10 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
 		/* set saved_raid_disk if appropriate */
 		if (!mddev->persistent) {
 			if (info->state & (1<<MD_DISK_SYNC)  &&
-			    info->raid_disk < mddev->raid_disks)
+			    info->raid_disk < mddev->raid_disks) {
 				rdev->raid_disk = info->raid_disk;
-			else
+				set_bit(In_sync, &rdev->flags);
+			} else
 				rdev->raid_disk = -1;
 		} else
 			super_types[mddev->major_version].
-- 
1.7.4.4

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