[md PATCH 09/17] md/raid10: recognise replacements when assembling array.

[NeilBrown <neilb@suse.de>]

If a Replacement is seen, file it as such.

If we see two replacements (or two normal devices) for the one slot,
abort.

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

 drivers/md/raid10.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index fd28f03..15e3f73 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3195,6 +3195,16 @@ static int run(struct mddev *mddev)
 			continue;
 		disk = conf->mirrors + disk_idx;
 
+		if (test_bit(Replacement, &rdev->flags)) {
+			if (disk->replacement)
+				goto out_free_conf;
+			disk->replacement = rdev;
+		} else {
+			if (disk->rdev)
+				goto out_free_conf;
+			disk->rdev = rdev;
+		}
+
 		disk->rdev = rdev;
 		disk_stack_limits(mddev->gendisk, rdev->bdev,
 				  rdev->data_offset << 9);
@@ -3222,6 +3232,13 @@ static int run(struct mddev *mddev)
 
 		disk = conf->mirrors + i;
 
+		if (!disk->rdev && disk->replacement) {
+			/* The replacement is all we have - use it */
+			disk->rdev = disk->replacement;
+			disk->replacement = NULL;
+			clear_bit(Replacement, &disk->rdev->flags);
+		}
+
 		if (!disk->rdev ||
 		    !test_bit(In_sync, &disk->rdev->flags)) {
 			disk->head_position = 0;