[PATCH -next] dm btree: shadow_child leaves unchecked in split_two_into_three

[Tong Tiangen]

Function shadow_child() leaves variable 'r' unchecked in
split_two_into_three when parent_index not equals to 0.
It's also not coordinate with above relative codes.

Fixes: dee29bf9192b ("dm btree: improve btree residency")
Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
---
 drivers/md/persistent-data/dm-btree.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index 3e5a90580427..0703ca7a7d9a 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -743,8 +743,10 @@ static int split_two_into_three(struct shadow_spine *s, unsigned parent_index,
 			return r;
 	} else {
 		middle_index = parent_index;
-		r = shadow_child(s->info, vt, pn, parent_index - 1, &left);
 		right = shadow_current(s);
+		r = shadow_child(s->info, vt, pn, parent_index - 1, &left);
+		if (r)
+			return r;
 	}
 
 	r = new_block(s->info, &middle);
-- 
2.18.0.huawei.25