bcache: wait for buckets when allocating new btree root

Tested:
- sometimes bcache_tier test would hang on startup with a failure
  to allocate the btree root -- no longer seeing this

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 7347b6100961..9dd9f1c4d0d9 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1060,15 +1060,15 @@ static void btree_node_free(struct btree *b)
 	mutex_unlock(&b->c->bucket_lock);
 }
 
-struct btree *bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
-				   int level)
+struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
+				     int level, bool wait)
 {
 	BKEY_PADDED(key) k;
 	struct btree *b = ERR_PTR(-EAGAIN);
 
 	mutex_lock(&c->bucket_lock);
 retry:
-	if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, op != NULL))
+	if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
 		goto err;
 
 	bkey_put(c, &k.key);
@@ -1100,6 +1100,12 @@ err:
 	return b;
 }
 
+static struct btree *bch_btree_node_alloc(struct cache_set *c,
+					  struct btree_op *op, int level)
+{
+	return __bch_btree_node_alloc(c, op, level, op != NULL);
+}
+
 static struct btree *btree_node_alloc_replacement(struct btree *b,
 						  struct btree_op *op)
 {